[PATCHv8 00/10] ARM: DMA-mapping framework redesign

[PATCHv8 00/10] ARM: DMA-mapping framework redesign

[Marek Szyprowski]

Hello,

Linux v3.4-rc2, which include dma-mapping preparation patches, has been
released two days ago, now it's time for the next spin of ARM
dma-mapping redesign patches. This version includes various fixes posted
separately to v7, mainly related to incorrect io address space bitmap
setup and a major issue with broken mmap for memory which comes from
dma_declare_coherent(). The patches have been also rebased onto Linux
v3.4-rc2 which comes with dma_map_ops related changes.

The code has been tested on Samsung Exynos4 'UniversalC210' and NURI
boards with IOMMU driver posted by KyongHo Cho, I will put separate
branch which shows how to integrate this driver with this patchset.

The patches are also available on my git repository at:
git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git 3.4-rc2-arm-dma-v8


History of the development:

v1: (initial version of the DMA-mapping redesign patches):
http://www.spinics.net/lists/linux-mm/msg21241.html

v2:
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000571.html
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000577.html

v3:
http://www.spinics.net/lists/linux-mm/msg25490.html

v4 and v5:
http://www.spinics.net/lists/arm-kernel/msg151147.html
http://www.spinics.net/lists/arm-kernel/msg154889.html

v6:
http://www.spinics.net/lists/linux-mm/msg29903.html

v7:
http://www.spinics.net/lists/arm-kernel/msg162149.html

Best regards
Marek Szyprowski
Samsung Poland R&D Center


Patch summary:

Marek Szyprowski (10):
  common: add dma_mmap_from_coherent() function
  ARM: dma-mapping: use pr_* instread of printk
  ARM: dma-mapping: introduce ARM_DMA_ERROR constant
  ARM: dma-mapping: remove offset parameter to prepare for generic
    dma_ops
  ARM: dma-mapping: use asm-generic/dma-mapping-common.h
  ARM: dma-mapping: implement dma sg methods on top of any generic dma
    ops
  ARM: dma-mapping: move all dma bounce code to separate dma ops
    structure
  ARM: dma-mapping: remove redundant code and cleanup
  ARM: dma-mapping: use alloc, mmap, free from dma_ops
  ARM: dma-mapping: add support for IOMMU mapper

 arch/arm/Kconfig                   |    9 +
 arch/arm/common/dmabounce.c        |   84 +++-
 arch/arm/include/asm/device.h      |    4 +
 arch/arm/include/asm/dma-iommu.h   |   34 ++
 arch/arm/include/asm/dma-mapping.h |  407 ++++-----------
 arch/arm/mm/dma-mapping.c          | 1019 ++++++++++++++++++++++++++++++------
 arch/arm/mm/vmregion.h             |    2 +-
 drivers/base/dma-coherent.c        |   42 ++
 include/asm-generic/dma-coherent.h |    4 +-
 9 files changed, 1138 insertions(+), 467 deletions(-)
 create mode 100644 arch/arm/include/asm/dma-iommu.h

-- 
1.7.1.569.g6f426

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[PATCHv8 00/10] ARM: DMA-mapping framework redesign

[Marek Szyprowski]

Hello,

Linux v3.4-rc2, which include dma-mapping preparation patches, has been
released two days ago, now it's time for the next spin of ARM
dma-mapping redesign patches. This version includes various fixes posted
separately to v7, mainly related to incorrect io address space bitmap
setup and a major issue with broken mmap for memory which comes from
dma_declare_coherent(). The patches have been also rebased onto Linux
v3.4-rc2 which comes with dma_map_ops related changes.

The code has been tested on Samsung Exynos4 'UniversalC210' and NURI
boards with IOMMU driver posted by KyongHo Cho, I will put separate
branch which shows how to integrate this driver with this patchset.

The patches are also available on my git repository at:
git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git 3.4-rc2-arm-dma-v8


History of the development:

v1: (initial version of the DMA-mapping redesign patches):
http://www.spinics.net/lists/linux-mm/msg21241.html

v2:
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000571.html
http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000577.html

v3:
http://www.spinics.net/lists/linux-mm/msg25490.html

v4 and v5:
http://www.spinics.net/lists/arm-kernel/msg151147.html
http://www.spinics.net/lists/arm-kernel/msg154889.html

v6:
http://www.spinics.net/lists/linux-mm/msg29903.html

v7:
http://www.spinics.net/lists/arm-kernel/msg162149.html

Best regards
Marek Szyprowski
Samsung Poland R&D Center


Patch summary:

Marek Szyprowski (10):
  common: add dma_mmap_from_coherent() function
  ARM: dma-mapping: use pr_* instread of printk
  ARM: dma-mapping: introduce ARM_DMA_ERROR constant
  ARM: dma-mapping: remove offset parameter to prepare for generic
    dma_ops
  ARM: dma-mapping: use asm-generic/dma-mapping-common.h
  ARM: dma-mapping: implement dma sg methods on top of any generic dma
    ops
  ARM: dma-mapping: move all dma bounce code to separate dma ops
    structure
  ARM: dma-mapping: remove redundant code and cleanup
  ARM: dma-mapping: use alloc, mmap, free from dma_ops
  ARM: dma-mapping: add support for IOMMU mapper

 arch/arm/Kconfig                   |    9 +
 arch/arm/common/dmabounce.c        |   84 +++-
 arch/arm/include/asm/device.h      |    4 +
 arch/arm/include/asm/dma-iommu.h   |   34 ++
 arch/arm/include/asm/dma-mapping.h |  407 ++++-----------
 arch/arm/mm/dma-mapping.c          | 1019 ++++++++++++++++++++++++++++++------
 arch/arm/mm/vmregion.h             |    2 +-
 drivers/base/dma-coherent.c        |   42 ++
 include/asm-generic/dma-coherent.h |    4 +-
 9 files changed, 1138 insertions(+), 467 deletions(-)
 create mode 100644 arch/arm/include/asm/dma-iommu.h

-- 
1.7.1.569.g6f426

[PATCHv8 01/10] common: add dma_mmap_from_coherent() function

[Marek Szyprowski]

Add a common helper for dma-mapping core for mapping a coherent buffer
to userspace.

Reported-by: Subash Patel <subashrp@gmail.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/base/dma-coherent.c        |   42 ++++++++++++++++++++++++++++++++++++
 include/asm-generic/dma-coherent.h |    4 ++-
 2 files changed, 45 insertions(+), 1 deletions(-)

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index bb0025c..1b85949 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -10,6 +10,7 @@
 struct dma_coherent_mem {
 	void		*virt_base;
 	dma_addr_t	device_base;
+	phys_addr_t	pfn_base;
 	int		size;
 	int		flags;
 	unsigned long	*bitmap;
@@ -44,6 +45,7 @@ int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
 
 	dev->dma_mem->virt_base = mem_base;
 	dev->dma_mem->device_base = device_addr;
+	dev->dma_mem->pfn_base = PFN_DOWN(bus_addr);
 	dev->dma_mem->size = pages;
 	dev->dma_mem->flags = flags;
 
@@ -176,3 +178,43 @@ int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
 	return 0;
 }
 EXPORT_SYMBOL(dma_release_from_coherent);
+
+/**
+ * dma_mmap_from_coherent() - try to mmap the memory allocated from
+ * per-device coherent memory pool to userspace
+ * @dev:	device from which the memory was allocated
+ * @vma:	vm_area for the userspace memory
+ * @vaddr:	cpu address returned by dma_alloc_from_coherent
+ * @size:	size of the memory buffer allocated by dma_alloc_from_coherent
+ *
+ * This checks whether the memory was allocated from the per-device
+ * coherent memory pool and if so, maps that memory to the provided vma.
+ *
+ * Returns 1 if we correctly mapped the memory, or 0 if
+ * dma_release_coherent() should proceed with mapping memory from
+ * generic pools.
+ */
+int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
+			   void *vaddr, size_t size, int *ret)
+{
+	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+
+	if (mem && vaddr >= mem->virt_base && vaddr + size <=
+		   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
+		unsigned long off = vma->vm_pgoff;
+		int start = (vaddr - mem->virt_base) >> PAGE_SHIFT;
+		int user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+		int count = size >> PAGE_SHIFT;
+
+		*ret = -ENXIO;
+		if (off < count && user_count <= count - off) {
+			unsigned pfn = mem->pfn_base + start + off;
+			*ret = remap_pfn_range(vma, vma->vm_start, pfn,
+					       user_count << PAGE_SHIFT,
+					       vma->vm_page_prot);
+		}
+		return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(dma_mmap_from_coherent);
diff --git a/include/asm-generic/dma-coherent.h b/include/asm-generic/dma-coherent.h
index 85a3ffa..abfb268 100644
--- a/include/asm-generic/dma-coherent.h
+++ b/include/asm-generic/dma-coherent.h
@@ -3,13 +3,15 @@
 
 #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT
 /*
- * These two functions are only for dma allocator.
+ * These three functions are only for dma allocator.
  * Don't use them in device drivers.
  */
 int dma_alloc_from_coherent(struct device *dev, ssize_t size,
 				       dma_addr_t *dma_handle, void **ret);
 int dma_release_from_coherent(struct device *dev, int order, void *vaddr);
 
+int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,
+			    void *cpu_addr, size_t size, int *ret);
 /*
  * Standard interface
  */
-- 
1.7.1.569.g6f426

[PATCHv8 02/10] ARM: dma-mapping: use pr_* instread of printk

[Marek Szyprowski]

Replace all calls to printk with pr_* functions family.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/mm/dma-mapping.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index db23ae4..366f3a2 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -184,14 +184,14 @@ static int __init consistent_init(void)
 
 		pud = pud_alloc(&init_mm, pgd, base);
 		if (!pud) {
-			printk(KERN_ERR "%s: no pud tables\n", __func__);
+			pr_err("%s: no pud tables\n", __func__);
 			ret = -ENOMEM;
 			break;
 		}
 
 		pmd = pmd_alloc(&init_mm, pud, base);
 		if (!pmd) {
-			printk(KERN_ERR "%s: no pmd tables\n", __func__);
+			pr_err("%s: no pmd tables\n", __func__);
 			ret = -ENOMEM;
 			break;
 		}
@@ -199,7 +199,7 @@ static int __init consistent_init(void)
 
 		pte = pte_alloc_kernel(pmd, base);
 		if (!pte) {
-			printk(KERN_ERR "%s: no pte tables\n", __func__);
+			pr_err("%s: no pte tables\n", __func__);
 			ret = -ENOMEM;
 			break;
 		}
@@ -222,7 +222,7 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
 	int bit;
 
 	if (!consistent_pte) {
-		printk(KERN_ERR "%s: not initialised\n", __func__);
+		pr_err("%s: not initialised\n", __func__);
 		dump_stack();
 		return NULL;
 	}
@@ -281,14 +281,14 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 
 	c = arm_vmregion_find_remove(&consistent_head, (unsigned long)cpu_addr);
 	if (!c) {
-		printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
+		pr_err("%s: trying to free invalid coherent area: %p\n",
 		       __func__, cpu_addr);
 		dump_stack();
 		return;
 	}
 
 	if ((c->vm_end - c->vm_start) != size) {
-		printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
+		pr_err("%s: freeing wrong coherent size (%ld != %d)\n",
 		       __func__, c->vm_end - c->vm_start, size);
 		dump_stack();
 		size = c->vm_end - c->vm_start;
@@ -310,8 +310,8 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 		}
 
 		if (pte_none(pte) || !pte_present(pte))
-			printk(KERN_CRIT "%s: bad page in kernel page table\n",
-			       __func__);
+			pr_crit("%s: bad page in kernel page table\n",
+				__func__);
 	} while (size -= PAGE_SIZE);
 
 	flush_tlb_kernel_range(c->vm_start, c->vm_end);
-- 
1.7.1.569.g6f426

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[PATCHv8 02/10] ARM: dma-mapping: use pr_* instread of printk

[Marek Szyprowski]

Replace all calls to printk with pr_* functions family.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/mm/dma-mapping.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index db23ae4..366f3a2 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -184,14 +184,14 @@ static int __init consistent_init(void)
 
 		pud = pud_alloc(&init_mm, pgd, base);
 		if (!pud) {
-			printk(KERN_ERR "%s: no pud tables\n", __func__);
+			pr_err("%s: no pud tables\n", __func__);
 			ret = -ENOMEM;
 			break;
 		}
 
 		pmd = pmd_alloc(&init_mm, pud, base);
 		if (!pmd) {
-			printk(KERN_ERR "%s: no pmd tables\n", __func__);
+			pr_err("%s: no pmd tables\n", __func__);
 			ret = -ENOMEM;
 			break;
 		}
@@ -199,7 +199,7 @@ static int __init consistent_init(void)
 
 		pte = pte_alloc_kernel(pmd, base);
 		if (!pte) {
-			printk(KERN_ERR "%s: no pte tables\n", __func__);
+			pr_err("%s: no pte tables\n", __func__);
 			ret = -ENOMEM;
 			break;
 		}
@@ -222,7 +222,7 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
 	int bit;
 
 	if (!consistent_pte) {
-		printk(KERN_ERR "%s: not initialised\n", __func__);
+		pr_err("%s: not initialised\n", __func__);
 		dump_stack();
 		return NULL;
 	}
@@ -281,14 +281,14 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 
 	c = arm_vmregion_find_remove(&consistent_head, (unsigned long)cpu_addr);
 	if (!c) {
-		printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
+		pr_err("%s: trying to free invalid coherent area: %p\n",
 		       __func__, cpu_addr);
 		dump_stack();
 		return;
 	}
 
 	if ((c->vm_end - c->vm_start) != size) {
-		printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
+		pr_err("%s: freeing wrong coherent size (%ld != %d)\n",
 		       __func__, c->vm_end - c->vm_start, size);
 		dump_stack();
 		size = c->vm_end - c->vm_start;
@@ -310,8 +310,8 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 		}
 
 		if (pte_none(pte) || !pte_present(pte))
-			printk(KERN_CRIT "%s: bad page in kernel page table\n",
-			       __func__);
+			pr_crit("%s: bad page in kernel page table\n",
+				__func__);
 	} while (size -= PAGE_SIZE);
 
 	flush_tlb_kernel_range(c->vm_start, c->vm_end);
-- 
1.7.1.569.g6f426

Re: [PATCHv8 02/10] ARM: dma-mapping: use pr_* instread of printk

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> 
> Replace all calls to printk with pr_* functions family.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Arnd Bergmann <arnd@arndb.de>

[PATCHv8 03/10] ARM: dma-mapping: introduce ARM_DMA_ERROR constant

[Marek Szyprowski]

Replace all uses of ~0 with ARM_DMA_ERROR, what should make the code
easier to read.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/common/dmabounce.c        |    6 +++---
 arch/arm/include/asm/dma-mapping.h |    4 +++-
 arch/arm/mm/dma-mapping.c          |    2 +-
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 595ecd29..a1abdc9 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -254,7 +254,7 @@ static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
 	if (buf == NULL) {
 		dev_err(dev, "%s: unable to map unsafe buffer %p!\n",
 		       __func__, ptr);
-		return ~0;
+		return ARM_DMA_ERROR;
 	}
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
@@ -320,7 +320,7 @@ dma_addr_t __dma_map_page(struct device *dev, struct page *page,
 
 	ret = needs_bounce(dev, dma_addr, size);
 	if (ret < 0)
-		return ~0;
+		return ARM_DMA_ERROR;
 
 	if (ret == 0) {
 		__dma_page_cpu_to_dev(page, offset, size, dir);
@@ -329,7 +329,7 @@ dma_addr_t __dma_map_page(struct device *dev, struct page *page,
 
 	if (PageHighMem(page)) {
 		dev_err(dev, "DMA buffer bouncing of HIGHMEM pages is not supported\n");
-		return ~0;
+		return ARM_DMA_ERROR;
 	}
 
 	return map_single(dev, page_address(page) + offset, size, dir);
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index cb3b7c9..3dbec1d 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -10,6 +10,8 @@
 #include <asm-generic/dma-coherent.h>
 #include <asm/memory.h>
 
+#define ARM_DMA_ERROR	(~0)
+
 #ifdef __arch_page_to_dma
 #error Please update to __arch_pfn_to_dma
 #endif
@@ -123,7 +125,7 @@ extern int dma_set_mask(struct device *, u64);
  */
 static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
-	return dma_addr == ~0;
+	return dma_addr == ARM_DMA_ERROR;
 }
 
 /*
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 366f3a2..8762d5a 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -342,7 +342,7 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	 */
 	gfp &= ~(__GFP_COMP);
 
-	*handle = ~0;
+	*handle = ARM_DMA_ERROR;
 	size = PAGE_ALIGN(size);
 
 	page = __dma_alloc_buffer(dev, size, gfp);
-- 
1.7.1.569.g6f426

Re: [PATCHv8 03/10] ARM: dma-mapping: introduce ARM_DMA_ERROR constant

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> Replace all uses of ~0 with ARM_DMA_ERROR, what should make the code
> easier to read.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

I like the idea, but why not name this DMA_ERROR_CODE like the other
architectures do? I think in the long run we should put the definition
into a global header file.

	Arnd

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Re: [PATCHv8 03/10] ARM: dma-mapping: introduce ARM_DMA_ERROR constant

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> Replace all uses of ~0 with ARM_DMA_ERROR, what should make the code
> easier to read.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

I like the idea, but why not name this DMA_ERROR_CODE like the other
architectures do? I think in the long run we should put the definition
into a global header file.

	Arnd

RE: [PATCHv8 03/10] ARM: dma-mapping: introduce ARM_DMA_ERROR constant

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 1:32 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > Replace all uses of ~0 with ARM_DMA_ERROR, what should make the code
> > easier to read.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> 
> I like the idea, but why not name this DMA_ERROR_CODE like the other
> architectures do? I think in the long run we should put the definition
> into a global header file.

Ok, no problem, I will unify it with other architectures.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

[PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Marek Szyprowski]

This patch removes the need for offset parameter in dma bounce
functions. This is required to let dma-mapping framework on ARM
architecture use common, generic dma-mapping helpers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/common/dmabounce.c        |   13 +++++--
 arch/arm/include/asm/dma-mapping.h |   67 +++++++++++++++++------------------
 arch/arm/mm/dma-mapping.c          |    4 +-
 3 files changed, 45 insertions(+), 39 deletions(-)

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index a1abdc9..c9f54b6 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -173,7 +173,8 @@ find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_
 	read_lock_irqsave(&device_info->lock, flags);
 
 	list_for_each_entry(b, &device_info->safe_buffers, node)
-		if (b->safe_dma_addr == safe_dma_addr) {
+		if (b->safe_dma_addr <= safe_dma_addr &&
+		    b->safe_dma_addr + b->size > safe_dma_addr) {
 			rb = b;
 			break;
 		}
@@ -362,9 +363,10 @@ void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
 EXPORT_SYMBOL(__dma_unmap_page);
 
 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
-		unsigned long off, size_t sz, enum dma_data_direction dir)
+		size_t sz, enum dma_data_direction dir)
 {
 	struct safe_buffer *buf;
+	unsigned long off;
 
 	dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
 		__func__, addr, off, sz, dir);
@@ -373,6 +375,8 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 	if (!buf)
 		return 1;
 
+	off = addr - buf->safe_dma_addr;
+
 	BUG_ON(buf->direction != dir);
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
@@ -391,9 +395,10 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
 
 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
-		unsigned long off, size_t sz, enum dma_data_direction dir)
+		size_t sz, enum dma_data_direction dir)
 {
 	struct safe_buffer *buf;
+	unsigned long off;
 
 	dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
 		__func__, addr, off, sz, dir);
@@ -402,6 +407,8 @@ int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
 	if (!buf)
 		return 1;
 
+	off = addr - buf->safe_dma_addr;
+
 	BUG_ON(buf->direction != dir);
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 3dbec1d..02d651f 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -266,19 +266,17 @@ extern void __dma_unmap_page(struct device *, dma_addr_t, size_t,
 /*
  * Private functions
  */
-int dmabounce_sync_for_cpu(struct device *, dma_addr_t, unsigned long,
-		size_t, enum dma_data_direction);
-int dmabounce_sync_for_device(struct device *, dma_addr_t, unsigned long,
-		size_t, enum dma_data_direction);
+int dmabounce_sync_for_cpu(struct device *, dma_addr_t, size_t, enum dma_data_direction);
+int dmabounce_sync_for_device(struct device *, dma_addr_t, size_t, enum dma_data_direction);
 #else
 static inline int dmabounce_sync_for_cpu(struct device *d, dma_addr_t addr,
-	unsigned long offset, size_t size, enum dma_data_direction dir)
+	size_t size, enum dma_data_direction dir)
 {
 	return 1;
 }
 
 static inline int dmabounce_sync_for_device(struct device *d, dma_addr_t addr,
-	unsigned long offset, size_t size, enum dma_data_direction dir)
+	size_t size, enum dma_data_direction dir)
 {
 	return 1;
 }
@@ -401,6 +399,33 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t handle,
 	__dma_unmap_page(dev, handle, size, dir);
 }
 
+
+static inline void dma_sync_single_for_cpu(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	BUG_ON(!valid_dma_direction(dir));
+
+	debug_dma_sync_single_for_cpu(dev, handle, size, dir);
+
+	if (!dmabounce_sync_for_cpu(dev, handle, size, dir))
+		return;
+
+	__dma_single_dev_to_cpu(dma_to_virt(dev, handle), size, dir);
+}
+
+static inline void dma_sync_single_for_device(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	BUG_ON(!valid_dma_direction(dir));
+
+	debug_dma_sync_single_for_device(dev, handle, size, dir);
+
+	if (!dmabounce_sync_for_device(dev, handle, size, dir))
+		return;
+
+	__dma_single_cpu_to_dev(dma_to_virt(dev, handle), size, dir);
+}
+
 /**
  * dma_sync_single_range_for_cpu
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -423,40 +448,14 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev,
 		dma_addr_t handle, unsigned long offset, size_t size,
 		enum dma_data_direction dir)
 {
-	BUG_ON(!valid_dma_direction(dir));
-
-	debug_dma_sync_single_for_cpu(dev, handle + offset, size, dir);
-
-	if (!dmabounce_sync_for_cpu(dev, handle, offset, size, dir))
-		return;
-
-	__dma_single_dev_to_cpu(dma_to_virt(dev, handle) + offset, size, dir);
+	dma_sync_single_for_cpu(dev, handle + offset, size, dir);
 }
 
 static inline void dma_sync_single_range_for_device(struct device *dev,
 		dma_addr_t handle, unsigned long offset, size_t size,
 		enum dma_data_direction dir)
 {
-	BUG_ON(!valid_dma_direction(dir));
-
-	debug_dma_sync_single_for_device(dev, handle + offset, size, dir);
-
-	if (!dmabounce_sync_for_device(dev, handle, offset, size, dir))
-		return;
-
-	__dma_single_cpu_to_dev(dma_to_virt(dev, handle) + offset, size, dir);
-}
-
-static inline void dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	dma_sync_single_range_for_cpu(dev, handle, 0, size, dir);
-}
-
-static inline void dma_sync_single_for_device(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	dma_sync_single_range_for_device(dev, handle, 0, size, dir);
+	dma_sync_single_for_device(dev, handle + offset, size, dir);
 }
 
 /*
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8762d5a..ed16a7b 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -657,7 +657,7 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s), 0,
+		if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s),
 					    sg_dma_len(s), dir))
 			continue;
 
@@ -683,7 +683,7 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		if (!dmabounce_sync_for_device(dev, sg_dma_address(s), 0,
+		if (!dmabounce_sync_for_device(dev, sg_dma_address(s),
 					sg_dma_len(s), dir))
 			continue;
 
-- 
1.7.1.569.g6f426

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[PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Marek Szyprowski]

This patch removes the need for offset parameter in dma bounce
functions. This is required to let dma-mapping framework on ARM
architecture use common, generic dma-mapping helpers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/common/dmabounce.c        |   13 +++++--
 arch/arm/include/asm/dma-mapping.h |   67 +++++++++++++++++------------------
 arch/arm/mm/dma-mapping.c          |    4 +-
 3 files changed, 45 insertions(+), 39 deletions(-)

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index a1abdc9..c9f54b6 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -173,7 +173,8 @@ find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_
 	read_lock_irqsave(&device_info->lock, flags);
 
 	list_for_each_entry(b, &device_info->safe_buffers, node)
-		if (b->safe_dma_addr == safe_dma_addr) {
+		if (b->safe_dma_addr <= safe_dma_addr &&
+		    b->safe_dma_addr + b->size > safe_dma_addr) {
 			rb = b;
 			break;
 		}
@@ -362,9 +363,10 @@ void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
 EXPORT_SYMBOL(__dma_unmap_page);
 
 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
-		unsigned long off, size_t sz, enum dma_data_direction dir)
+		size_t sz, enum dma_data_direction dir)
 {
 	struct safe_buffer *buf;
+	unsigned long off;
 
 	dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
 		__func__, addr, off, sz, dir);
@@ -373,6 +375,8 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 	if (!buf)
 		return 1;
 
+	off = addr - buf->safe_dma_addr;
+
 	BUG_ON(buf->direction != dir);
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
@@ -391,9 +395,10 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
 
 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
-		unsigned long off, size_t sz, enum dma_data_direction dir)
+		size_t sz, enum dma_data_direction dir)
 {
 	struct safe_buffer *buf;
+	unsigned long off;
 
 	dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
 		__func__, addr, off, sz, dir);
@@ -402,6 +407,8 @@ int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
 	if (!buf)
 		return 1;
 
+	off = addr - buf->safe_dma_addr;
+
 	BUG_ON(buf->direction != dir);
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 3dbec1d..02d651f 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -266,19 +266,17 @@ extern void __dma_unmap_page(struct device *, dma_addr_t, size_t,
 /*
  * Private functions
  */
-int dmabounce_sync_for_cpu(struct device *, dma_addr_t, unsigned long,
-		size_t, enum dma_data_direction);
-int dmabounce_sync_for_device(struct device *, dma_addr_t, unsigned long,
-		size_t, enum dma_data_direction);
+int dmabounce_sync_for_cpu(struct device *, dma_addr_t, size_t, enum dma_data_direction);
+int dmabounce_sync_for_device(struct device *, dma_addr_t, size_t, enum dma_data_direction);
 #else
 static inline int dmabounce_sync_for_cpu(struct device *d, dma_addr_t addr,
-	unsigned long offset, size_t size, enum dma_data_direction dir)
+	size_t size, enum dma_data_direction dir)
 {
 	return 1;
 }
 
 static inline int dmabounce_sync_for_device(struct device *d, dma_addr_t addr,
-	unsigned long offset, size_t size, enum dma_data_direction dir)
+	size_t size, enum dma_data_direction dir)
 {
 	return 1;
 }
@@ -401,6 +399,33 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t handle,
 	__dma_unmap_page(dev, handle, size, dir);
 }
 
+
+static inline void dma_sync_single_for_cpu(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	BUG_ON(!valid_dma_direction(dir));
+
+	debug_dma_sync_single_for_cpu(dev, handle, size, dir);
+
+	if (!dmabounce_sync_for_cpu(dev, handle, size, dir))
+		return;
+
+	__dma_single_dev_to_cpu(dma_to_virt(dev, handle), size, dir);
+}
+
+static inline void dma_sync_single_for_device(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	BUG_ON(!valid_dma_direction(dir));
+
+	debug_dma_sync_single_for_device(dev, handle, size, dir);
+
+	if (!dmabounce_sync_for_device(dev, handle, size, dir))
+		return;
+
+	__dma_single_cpu_to_dev(dma_to_virt(dev, handle), size, dir);
+}
+
 /**
  * dma_sync_single_range_for_cpu
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -423,40 +448,14 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev,
 		dma_addr_t handle, unsigned long offset, size_t size,
 		enum dma_data_direction dir)
 {
-	BUG_ON(!valid_dma_direction(dir));
-
-	debug_dma_sync_single_for_cpu(dev, handle + offset, size, dir);
-
-	if (!dmabounce_sync_for_cpu(dev, handle, offset, size, dir))
-		return;
-
-	__dma_single_dev_to_cpu(dma_to_virt(dev, handle) + offset, size, dir);
+	dma_sync_single_for_cpu(dev, handle + offset, size, dir);
 }
 
 static inline void dma_sync_single_range_for_device(struct device *dev,
 		dma_addr_t handle, unsigned long offset, size_t size,
 		enum dma_data_direction dir)
 {
-	BUG_ON(!valid_dma_direction(dir));
-
-	debug_dma_sync_single_for_device(dev, handle + offset, size, dir);
-
-	if (!dmabounce_sync_for_device(dev, handle, offset, size, dir))
-		return;
-
-	__dma_single_cpu_to_dev(dma_to_virt(dev, handle) + offset, size, dir);
-}
-
-static inline void dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	dma_sync_single_range_for_cpu(dev, handle, 0, size, dir);
-}
-
-static inline void dma_sync_single_for_device(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	dma_sync_single_range_for_device(dev, handle, 0, size, dir);
+	dma_sync_single_for_device(dev, handle + offset, size, dir);
 }
 
 /*
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8762d5a..ed16a7b 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -657,7 +657,7 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s), 0,
+		if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s),
 					    sg_dma_len(s), dir))
 			continue;
 
@@ -683,7 +683,7 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		if (!dmabounce_sync_for_device(dev, sg_dma_address(s), 0,
+		if (!dmabounce_sync_for_device(dev, sg_dma_address(s),
 					sg_dma_len(s), dir))
 			continue;
 
-- 
1.7.1.569.g6f426

Re: [PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch removes the need for offset parameter in dma bounce
> functions. This is required to let dma-mapping framework on ARM
> architecture use common, generic dma-mapping helpers.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

This one worries me a little. I always thought that the range sync 
functions were specifically needed for the dmabounce code. At the
very least, I would expect the changeset comment to have an explanation
of why this was initially done this way and why it's now safe to do
do it otherwise.

	Arnd

Re: [PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch removes the need for offset parameter in dma bounce
> functions. This is required to let dma-mapping framework on ARM
> architecture use common, generic dma-mapping helpers.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

This one worries me a little. I always thought that the range sync 
functions were specifically needed for the dmabounce code. At the
very least, I would expect the changeset comment to have an explanation
of why this was initially done this way and why it's now safe to do
do it otherwise.

	Arnd

RE: [PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 1:43 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > This patch removes the need for offset parameter in dma bounce
> > functions. This is required to let dma-mapping framework on ARM
> > architecture use common, generic dma-mapping helpers.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> 
> This one worries me a little. I always thought that the range sync
> functions were specifically needed for the dmabounce code. At the
> very least, I would expect the changeset comment to have an explanation
> of why this was initially done this way and why it's now safe to do
> do it otherwise.

Well, range sync functions are available from the early days of the dma 
mapping api (at least that's what I've found reading the change log and
old patches). They are the correct way of doing a partial syncs on the 
buffer (usually used by the network device drivers). This patch changes
only the internal implementation of the dma bounce functions to let 
them tunnel through dma_map_ops structure. The driver api stays
unchanged, so driver are obliged to call dma_*_range_* functions to
keep code clean and easy to understand. 

The only drawback I can see from this patch is reduced detection of
the dma api abuse. Let us consider the following code:

dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE);
dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE);

Without the patch such code fails, because dma bounce code is unable
to find the bounce buffer for the given dma_address. After the patch
the sync call will be equivalent to: 

	dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE);

which succeeds.

I don't consider this as a real problem. DMA API abuse should be caught
by debug_dma_* function family, so we can simplify the internal low-level
implementation without losing anything.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

Re: [PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Arnd Bergmann]

On Wednesday 11 April 2012, Marek Szyprowski wrote:
> Well, range sync functions are available from the early days of the dma 
> mapping api (at least that's what I've found reading the change log and
> old patches). They are the correct way of doing a partial syncs on the 
> buffer (usually used by the network device drivers). This patch changes
> only the internal implementation of the dma bounce functions to let 
> them tunnel through dma_map_ops structure. The driver api stays
> unchanged, so driver are obliged to call dma_*_range_* functions to
> keep code clean and easy to understand. 
> 
> The only drawback I can see from this patch is reduced detection of
> the dma api abuse. Let us consider the following code:
> 
> dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE);
> dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE);
> 
> Without the patch such code fails, because dma bounce code is unable
> to find the bounce buffer for the given dma_address. After the patch
> the sync call will be equivalent to: 
> 
>         dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE);
> 
> which succeeds.
> 
> I don't consider this as a real problem. DMA API abuse should be caught
> by debug_dma_* function family, so we can simplify the internal low-level
> implementation without losing anything.
> 

Ok, fair enough. Can you put the above text into the changelog?

	Arnd

RE: [PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Marek Szyprowski]

Hi Arnd,

On Wednesday, April 11, 2012 2:19 PM Arnd Bergmann wrote:

> On Wednesday 11 April 2012, Marek Szyprowski wrote:
> > Well, range sync functions are available from the early days of the dma
> > mapping api (at least that's what I've found reading the change log and
> > old patches). They are the correct way of doing a partial syncs on the
> > buffer (usually used by the network device drivers). This patch changes
> > only the internal implementation of the dma bounce functions to let
> > them tunnel through dma_map_ops structure. The driver api stays
> > unchanged, so driver are obliged to call dma_*_range_* functions to
> > keep code clean and easy to understand.
> >
> > The only drawback I can see from this patch is reduced detection of
> > the dma api abuse. Let us consider the following code:
> >
> > dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE);
> > dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE);
> >
> > Without the patch such code fails, because dma bounce code is unable
> > to find the bounce buffer for the given dma_address. After the patch
> > the sync call will be equivalent to:
> >
> >         dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE);
> >
> > which succeeds.
> >
> > I don't consider this as a real problem. DMA API abuse should be caught
> > by debug_dma_* function family, so we can simplify the internal low-level
> > implementation without losing anything.
> >
> 
> Ok, fair enough. Can you put the above text into the changelog?

Yes, I will update it in the next release.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center


--
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RE: [PATCHv8 04/10] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

[Marek Szyprowski]

Hi Arnd,

On Wednesday, April 11, 2012 2:19 PM Arnd Bergmann wrote:

> On Wednesday 11 April 2012, Marek Szyprowski wrote:
> > Well, range sync functions are available from the early days of the dma
> > mapping api (at least that's what I've found reading the change log and
> > old patches). They are the correct way of doing a partial syncs on the
> > buffer (usually used by the network device drivers). This patch changes
> > only the internal implementation of the dma bounce functions to let
> > them tunnel through dma_map_ops structure. The driver api stays
> > unchanged, so driver are obliged to call dma_*_range_* functions to
> > keep code clean and easy to understand.
> >
> > The only drawback I can see from this patch is reduced detection of
> > the dma api abuse. Let us consider the following code:
> >
> > dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE);
> > dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE);
> >
> > Without the patch such code fails, because dma bounce code is unable
> > to find the bounce buffer for the given dma_address. After the patch
> > the sync call will be equivalent to:
> >
> >         dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE);
> >
> > which succeeds.
> >
> > I don't consider this as a real problem. DMA API abuse should be caught
> > by debug_dma_* function family, so we can simplify the internal low-level
> > implementation without losing anything.
> >
> 
> Ok, fair enough. Can you put the above text into the changelog?

Yes, I will update it in the next release.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

[PATCHv8 05/10] ARM: dma-mapping: use asm-generic/dma-mapping-common.h

[Marek Szyprowski]

This patch modifies dma-mapping implementation on ARM architecture to
use common dma_map_ops structure and asm-generic/dma-mapping-common.h
helpers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/Kconfig                   |    1 +
 arch/arm/include/asm/device.h      |    1 +
 arch/arm/include/asm/dma-mapping.h |  196 +++++-------------------------------
 arch/arm/mm/dma-mapping.c          |  148 ++++++++++++++++-----------
 4 files changed, 115 insertions(+), 231 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cf006d4..0fd27d4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -4,6 +4,7 @@ config ARM
 	select HAVE_AOUT
 	select HAVE_DMA_API_DEBUG
 	select HAVE_IDE if PCI || ISA || PCMCIA
+	select HAVE_DMA_ATTRS
 	select HAVE_MEMBLOCK
 	select RTC_LIB
 	select SYS_SUPPORTS_APM_EMULATION
diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index 7aa3680..6e2cb0e 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -7,6 +7,7 @@
 #define ASMARM_DEVICE_H
 
 struct dev_archdata {
+	struct dma_map_ops	*dma_ops;
 #ifdef CONFIG_DMABOUNCE
 	struct dmabounce_device_info *dmabounce;
 #endif
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 02d651f..424b67a 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -11,6 +11,27 @@
 #include <asm/memory.h>
 
 #define ARM_DMA_ERROR	(~0)
+extern struct dma_map_ops arm_dma_ops;
+
+static inline struct dma_map_ops *get_dma_ops(struct device *dev)
+{
+	if (dev && dev->archdata.dma_ops)
+		return dev->archdata.dma_ops;
+	return &arm_dma_ops;
+}
+
+static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
+{
+	BUG_ON(!dev);
+	dev->archdata.dma_ops = ops;
+}
+
+#include <asm-generic/dma-mapping-common.h>
+
+static inline int dma_set_mask(struct device *dev, u64 mask)
+{
+	return get_dma_ops(dev)->set_dma_mask(dev, mask);
+}
 
 #ifdef __arch_page_to_dma
 #error Please update to __arch_pfn_to_dma
@@ -119,7 +140,6 @@ static inline void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
 
 extern int dma_supported(struct device *, u64);
 extern int dma_set_mask(struct device *, u64);
-
 /*
  * DMA errors are defined by all-bits-set in the DMA address.
  */
@@ -297,179 +317,17 @@ static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
 }
 #endif /* CONFIG_DMABOUNCE */
 
-/**
- * dma_map_single - map a single buffer for streaming DMA
- * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
- * @cpu_addr: CPU direct mapped address of buffer
- * @size: size of buffer to map
- * @dir: DMA transfer direction
- *
- * Ensure that any data held in the cache is appropriately discarded
- * or written back.
- *
- * The device owns this memory once this call has completed.  The CPU
- * can regain ownership by calling dma_unmap_single() or
- * dma_sync_single_for_cpu().
- */
-static inline dma_addr_t dma_map_single(struct device *dev, void *cpu_addr,
-		size_t size, enum dma_data_direction dir)
-{
-	unsigned long offset;
-	struct page *page;
-	dma_addr_t addr;
-
-	BUG_ON(!virt_addr_valid(cpu_addr));
-	BUG_ON(!virt_addr_valid(cpu_addr + size - 1));
-	BUG_ON(!valid_dma_direction(dir));
-
-	page = virt_to_page(cpu_addr);
-	offset = (unsigned long)cpu_addr & ~PAGE_MASK;
-	addr = __dma_map_page(dev, page, offset, size, dir);
-	debug_dma_map_page(dev, page, offset, size, dir, addr, true);
-
-	return addr;
-}
-
-/**
- * dma_map_page - map a portion of a page for streaming DMA
- * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
- * @page: page that buffer resides in
- * @offset: offset into page for start of buffer
- * @size: size of buffer to map
- * @dir: DMA transfer direction
- *
- * Ensure that any data held in the cache is appropriately discarded
- * or written back.
- *
- * The device owns this memory once this call has completed.  The CPU
- * can regain ownership by calling dma_unmap_page().
- */
-static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir)
-{
-	dma_addr_t addr;
-
-	BUG_ON(!valid_dma_direction(dir));
-
-	addr = __dma_map_page(dev, page, offset, size, dir);
-	debug_dma_map_page(dev, page, offset, size, dir, addr, false);
-
-	return addr;
-}
-
-/**
- * dma_unmap_single - unmap a single buffer previously mapped
- * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
- * @handle: DMA address of buffer
- * @size: size of buffer (same as passed to dma_map_single)
- * @dir: DMA transfer direction (same as passed to dma_map_single)
- *
- * Unmap a single streaming mode DMA translation.  The handle and size
- * must match what was provided in the previous dma_map_single() call.
- * All other usages are undefined.
- *
- * After this call, reads by the CPU to the buffer are guaranteed to see
- * whatever the device wrote there.
- */
-static inline void dma_unmap_single(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	debug_dma_unmap_page(dev, handle, size, dir, true);
-	__dma_unmap_page(dev, handle, size, dir);
-}
-
-/**
- * dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
- * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
- * @handle: DMA address of buffer
- * @size: size of buffer (same as passed to dma_map_page)
- * @dir: DMA transfer direction (same as passed to dma_map_page)
- *
- * Unmap a page streaming mode DMA translation.  The handle and size
- * must match what was provided in the previous dma_map_page() call.
- * All other usages are undefined.
- *
- * After this call, reads by the CPU to the buffer are guaranteed to see
- * whatever the device wrote there.
- */
-static inline void dma_unmap_page(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	debug_dma_unmap_page(dev, handle, size, dir, false);
-	__dma_unmap_page(dev, handle, size, dir);
-}
-
-
-static inline void dma_sync_single_for_cpu(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	BUG_ON(!valid_dma_direction(dir));
-
-	debug_dma_sync_single_for_cpu(dev, handle, size, dir);
-
-	if (!dmabounce_sync_for_cpu(dev, handle, size, dir))
-		return;
-
-	__dma_single_dev_to_cpu(dma_to_virt(dev, handle), size, dir);
-}
-
-static inline void dma_sync_single_for_device(struct device *dev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	BUG_ON(!valid_dma_direction(dir));
-
-	debug_dma_sync_single_for_device(dev, handle, size, dir);
-
-	if (!dmabounce_sync_for_device(dev, handle, size, dir))
-		return;
-
-	__dma_single_cpu_to_dev(dma_to_virt(dev, handle), size, dir);
-}
-
-/**
- * dma_sync_single_range_for_cpu
- * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
- * @handle: DMA address of buffer
- * @offset: offset of region to start sync
- * @size: size of region to sync
- * @dir: DMA transfer direction (same as passed to dma_map_single)
- *
- * Make physical memory consistent for a single streaming mode DMA
- * translation after a transfer.
- *
- * If you perform a dma_map_single() but wish to interrogate the
- * buffer using the cpu, yet do not wish to teardown the PCI dma
- * mapping, you must call this function before doing so.  At the
- * next point you give the PCI dma address back to the card, you
- * must first the perform a dma_sync_for_device, and then the
- * device again owns the buffer.
- */
-static inline void dma_sync_single_range_for_cpu(struct device *dev,
-		dma_addr_t handle, unsigned long offset, size_t size,
-		enum dma_data_direction dir)
-{
-	dma_sync_single_for_cpu(dev, handle + offset, size, dir);
-}
-
-static inline void dma_sync_single_range_for_device(struct device *dev,
-		dma_addr_t handle, unsigned long offset, size_t size,
-		enum dma_data_direction dir)
-{
-	dma_sync_single_for_device(dev, handle + offset, size, dir);
-}
-
 /*
  * The scatter list versions of the above methods.
  */
-extern int dma_map_sg(struct device *, struct scatterlist *, int,
-		enum dma_data_direction);
-extern void dma_unmap_sg(struct device *, struct scatterlist *, int,
+extern int arm_dma_map_sg(struct device *, struct scatterlist *, int,
+		enum dma_data_direction, struct dma_attrs *attrs);
+extern void arm_dma_unmap_sg(struct device *, struct scatterlist *, int,
+		enum dma_data_direction, struct dma_attrs *attrs);
+extern void arm_dma_sync_sg_for_cpu(struct device *, struct scatterlist *, int,
 		enum dma_data_direction);
-extern void dma_sync_sg_for_cpu(struct device *, struct scatterlist *, int,
+extern void arm_dma_sync_sg_for_device(struct device *, struct scatterlist *, int,
 		enum dma_data_direction);
-extern void dma_sync_sg_for_device(struct device *, struct scatterlist *, int,
-		enum dma_data_direction);
-
 
 #endif /* __KERNEL__ */
 #endif
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index ed16a7b..4841fec 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -29,6 +29,85 @@
 
 #include "mm.h"
 
+/**
+ * arm_dma_map_page - map a portion of a page for streaming DMA
+ * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
+ * @page: page that buffer resides in
+ * @offset: offset into page for start of buffer
+ * @size: size of buffer to map
+ * @dir: DMA transfer direction
+ *
+ * Ensure that any data held in the cache is appropriately discarded
+ * or written back.
+ *
+ * The device owns this memory once this call has completed.  The CPU
+ * can regain ownership by calling dma_unmap_page().
+ */
+static inline dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
+	     unsigned long offset, size_t size, enum dma_data_direction dir,
+	     struct dma_attrs *attrs)
+{
+	return __dma_map_page(dev, page, offset, size, dir);
+}
+
+/**
+ * arm_dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
+ * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
+ * @handle: DMA address of buffer
+ * @size: size of buffer (same as passed to dma_map_page)
+ * @dir: DMA transfer direction (same as passed to dma_map_page)
+ *
+ * Unmap a page streaming mode DMA translation.  The handle and size
+ * must match what was provided in the previous dma_map_page() call.
+ * All other usages are undefined.
+ *
+ * After this call, reads by the CPU to the buffer are guaranteed to see
+ * whatever the device wrote there.
+ */
+static inline void arm_dma_unmap_page(struct device *dev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir,
+		struct dma_attrs *attrs)
+{
+	__dma_unmap_page(dev, handle, size, dir);
+}
+
+static inline void arm_dma_sync_single_for_cpu(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	unsigned int offset = handle & (PAGE_SIZE - 1);
+	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
+	if (!dmabounce_sync_for_cpu(dev, handle, size, dir))
+		return;
+
+	__dma_page_dev_to_cpu(page, offset, size, dir);
+}
+
+static inline void arm_dma_sync_single_for_device(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	unsigned int offset = handle & (PAGE_SIZE - 1);
+	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
+	if (!dmabounce_sync_for_device(dev, handle, size, dir))
+		return;
+
+	__dma_page_cpu_to_dev(page, offset, size, dir);
+}
+
+static int arm_dma_set_mask(struct device *dev, u64 dma_mask);
+
+struct dma_map_ops arm_dma_ops = {
+	.map_page		= arm_dma_map_page,
+	.unmap_page		= arm_dma_unmap_page,
+	.map_sg			= arm_dma_map_sg,
+	.unmap_sg		= arm_dma_unmap_sg,
+	.sync_single_for_cpu	= arm_dma_sync_single_for_cpu,
+	.sync_single_for_device	= arm_dma_sync_single_for_device,
+	.sync_sg_for_cpu	= arm_dma_sync_sg_for_cpu,
+	.sync_sg_for_device	= arm_dma_sync_sg_for_device,
+	.set_dma_mask		= arm_dma_set_mask,
+};
+EXPORT_SYMBOL(arm_dma_ops);
+
 static u64 get_coherent_dma_mask(struct device *dev)
 {
 	u64 mask = (u64)arm_dma_limit;
@@ -458,47 +537,6 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
 }
 EXPORT_SYMBOL(dma_free_coherent);
 
-/*
- * Make an area consistent for devices.
- * Note: Drivers should NOT use this function directly, as it will break
- * platforms with CONFIG_DMABOUNCE.
- * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
- */
-void ___dma_single_cpu_to_dev(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	unsigned long paddr;
-
-	BUG_ON(!virt_addr_valid(kaddr) || !virt_addr_valid(kaddr + size - 1));
-
-	dmac_map_area(kaddr, size, dir);
-
-	paddr = __pa(kaddr);
-	if (dir == DMA_FROM_DEVICE) {
-		outer_inv_range(paddr, paddr + size);
-	} else {
-		outer_clean_range(paddr, paddr + size);
-	}
-	/* FIXME: non-speculating: flush on bidirectional mappings? */
-}
-EXPORT_SYMBOL(___dma_single_cpu_to_dev);
-
-void ___dma_single_dev_to_cpu(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	BUG_ON(!virt_addr_valid(kaddr) || !virt_addr_valid(kaddr + size - 1));
-
-	/* FIXME: non-speculating: not required */
-	/* don't bother invalidating if DMA to device */
-	if (dir != DMA_TO_DEVICE) {
-		unsigned long paddr = __pa(kaddr);
-		outer_inv_range(paddr, paddr + size);
-	}
-
-	dmac_unmap_area(kaddr, size, dir);
-}
-EXPORT_SYMBOL(___dma_single_dev_to_cpu);
-
 static void dma_cache_maint_page(struct page *page, unsigned long offset,
 	size_t size, enum dma_data_direction dir,
 	void (*op)(const void *, size_t, int))
@@ -596,21 +634,18 @@ EXPORT_SYMBOL(___dma_page_dev_to_cpu);
  * Device ownership issues as mentioned for dma_map_single are the same
  * here.
  */
-int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
-		enum dma_data_direction dir)
+int arm_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+		enum dma_data_direction dir, struct dma_attrs *attrs)
 {
 	struct scatterlist *s;
 	int i, j;
 
-	BUG_ON(!valid_dma_direction(dir));
-
 	for_each_sg(sg, s, nents, i) {
 		s->dma_address = __dma_map_page(dev, sg_page(s), s->offset,
 						s->length, dir);
 		if (dma_mapping_error(dev, s->dma_address))
 			goto bad_mapping;
 	}
-	debug_dma_map_sg(dev, sg, nents, nents, dir);
 	return nents;
 
  bad_mapping:
@@ -618,7 +653,6 @@ int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 		__dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir);
 	return 0;
 }
-EXPORT_SYMBOL(dma_map_sg);
 
 /**
  * dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
@@ -630,18 +664,15 @@ EXPORT_SYMBOL(dma_map_sg);
  * Unmap a set of streaming mode DMA translations.  Again, CPU access
  * rules concerning calls here are the same as for dma_unmap_single().
  */
-void dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-		enum dma_data_direction dir)
+void arm_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
+		enum dma_data_direction dir, struct dma_attrs *attrs)
 {
 	struct scatterlist *s;
 	int i;
 
-	debug_dma_unmap_sg(dev, sg, nents, dir);
-
 	for_each_sg(sg, s, nents, i)
 		__dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir);
 }
-EXPORT_SYMBOL(dma_unmap_sg);
 
 /**
  * dma_sync_sg_for_cpu
@@ -650,7 +681,7 @@ EXPORT_SYMBOL(dma_unmap_sg);
  * @nents: number of buffers to map (returned from dma_map_sg)
  * @dir: DMA transfer direction (same as was passed to dma_map_sg)
  */
-void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+void arm_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 			int nents, enum dma_data_direction dir)
 {
 	struct scatterlist *s;
@@ -664,10 +695,7 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 		__dma_page_dev_to_cpu(sg_page(s), s->offset,
 				      s->length, dir);
 	}
-
-	debug_dma_sync_sg_for_cpu(dev, sg, nents, dir);
 }
-EXPORT_SYMBOL(dma_sync_sg_for_cpu);
 
 /**
  * dma_sync_sg_for_device
@@ -676,7 +704,7 @@ EXPORT_SYMBOL(dma_sync_sg_for_cpu);
  * @nents: number of buffers to map (returned from dma_map_sg)
  * @dir: DMA transfer direction (same as was passed to dma_map_sg)
  */
-void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 			int nents, enum dma_data_direction dir)
 {
 	struct scatterlist *s;
@@ -690,10 +718,7 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 		__dma_page_cpu_to_dev(sg_page(s), s->offset,
 				      s->length, dir);
 	}
-
-	debug_dma_sync_sg_for_device(dev, sg, nents, dir);
 }
-EXPORT_SYMBOL(dma_sync_sg_for_device);
 
 /*
  * Return whether the given device DMA address mask can be supported
@@ -709,7 +734,7 @@ int dma_supported(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(dma_supported);
 
-int dma_set_mask(struct device *dev, u64 dma_mask)
+static int arm_dma_set_mask(struct device *dev, u64 dma_mask)
 {
 	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 		return -EIO;
@@ -720,7 +745,6 @@ int dma_set_mask(struct device *dev, u64 dma_mask)
 
 	return 0;
 }
-EXPORT_SYMBOL(dma_set_mask);
 
 #define PREALLOC_DMA_DEBUG_ENTRIES	4096
 
-- 
1.7.1.569.g6f426

Re: [PATCHv8 05/10] ARM: dma-mapping: use asm-generic/dma-mapping-common.h

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch modifies dma-mapping implementation on ARM architecture to
> use common dma_map_ops structure and asm-generic/dma-mapping-common.h
> helpers.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  arch/arm/Kconfig                   |    1 +
>  arch/arm/include/asm/device.h      |    1 +
>  arch/arm/include/asm/dma-mapping.h |  196 +++++-------------------------------
>  arch/arm/mm/dma-mapping.c          |  148 ++++++++++++++++-----------
>  4 files changed, 115 insertions(+), 231 deletions(-)

Looks good in principle. One question: Now that many of the functions are only
used in the dma_map_ops, can you make them 'static' instead?

	Arnd

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Re: [PATCHv8 05/10] ARM: dma-mapping: use asm-generic/dma-mapping-common.h

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch modifies dma-mapping implementation on ARM architecture to
> use common dma_map_ops structure and asm-generic/dma-mapping-common.h
> helpers.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  arch/arm/Kconfig                   |    1 +
>  arch/arm/include/asm/device.h      |    1 +
>  arch/arm/include/asm/dma-mapping.h |  196 +++++-------------------------------
>  arch/arm/mm/dma-mapping.c          |  148 ++++++++++++++++-----------
>  4 files changed, 115 insertions(+), 231 deletions(-)

Looks good in principle. One question: Now that many of the functions are only
used in the dma_map_ops, can you make them 'static' instead?

	Arnd

RE: [PATCHv8 05/10] ARM: dma-mapping: use asm-generic/dma-mapping-common.h

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 1:47 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > This patch modifies dma-mapping implementation on ARM architecture to
> > use common dma_map_ops structure and asm-generic/dma-mapping-common.h
> > helpers.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> > ---
> >  arch/arm/Kconfig                   |    1 +
> >  arch/arm/include/asm/device.h      |    1 +
> >  arch/arm/include/asm/dma-mapping.h |  196 +++++-------------------------------
> >  arch/arm/mm/dma-mapping.c          |  148 ++++++++++++++++-----------
> >  4 files changed, 115 insertions(+), 231 deletions(-)
> 
> Looks good in principle. One question: Now that many of the functions are only
> used in the dma_map_ops, can you make them 'static' instead?

Some of these non static functions (mainly arm_dma_*_sg_* family) are also used by dma bounce
code introduced in the next patch, that's why I left them without static attribute.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

[PATCHv8 06/10] ARM: dma-mapping: implement dma sg methods on top of any generic dma ops

[Marek Szyprowski]

This patch converts all dma_sg methods to be generic (independent of the
current DMA mapping implementation for ARM architecture). All dma sg
operations are now implemented on top of respective
dma_map_page/dma_sync_single_for* operations from dma_map_ops structure.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/mm/dma-mapping.c |   43 +++++++++++++++++++------------------------
 1 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4841fec..d7137bd 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -619,7 +619,7 @@ void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
 EXPORT_SYMBOL(___dma_page_dev_to_cpu);
 
 /**
- * dma_map_sg - map a set of SG buffers for streaming mode DMA
+ * arm_dma_map_sg - map a set of SG buffers for streaming mode DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @sg: list of buffers
  * @nents: number of buffers to map
@@ -637,12 +637,13 @@ EXPORT_SYMBOL(___dma_page_dev_to_cpu);
 int arm_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 		enum dma_data_direction dir, struct dma_attrs *attrs)
 {
+	struct dma_map_ops *ops = get_dma_ops(dev);
 	struct scatterlist *s;
 	int i, j;
 
 	for_each_sg(sg, s, nents, i) {
-		s->dma_address = __dma_map_page(dev, sg_page(s), s->offset,
-						s->length, dir);
+		s->dma_address = ops->map_page(dev, sg_page(s), s->offset,
+						s->length, dir, attrs);
 		if (dma_mapping_error(dev, s->dma_address))
 			goto bad_mapping;
 	}
@@ -650,12 +651,12 @@ int arm_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 
  bad_mapping:
 	for_each_sg(sg, s, i, j)
-		__dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir);
+		ops->unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, attrs);
 	return 0;
 }
 
 /**
- * dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
+ * arm_dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @sg: list of buffers
  * @nents: number of buffers to unmap (same as was passed to dma_map_sg)
@@ -667,15 +668,17 @@ int arm_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 void arm_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 		enum dma_data_direction dir, struct dma_attrs *attrs)
 {
+	struct dma_map_ops *ops = get_dma_ops(dev);
 	struct scatterlist *s;
+
 	int i;
 
 	for_each_sg(sg, s, nents, i)
-		__dma_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir);
+		ops->unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, attrs);
 }
 
 /**
- * dma_sync_sg_for_cpu
+ * arm_dma_sync_sg_for_cpu
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @sg: list of buffers
  * @nents: number of buffers to map (returned from dma_map_sg)
@@ -684,21 +687,17 @@ void arm_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 void arm_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 			int nents, enum dma_data_direction dir)
 {
+	struct dma_map_ops *ops = get_dma_ops(dev);
 	struct scatterlist *s;
 	int i;
 
-	for_each_sg(sg, s, nents, i) {
-		if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s),
-					    sg_dma_len(s), dir))
-			continue;
-
-		__dma_page_dev_to_cpu(sg_page(s), s->offset,
-				      s->length, dir);
-	}
+	for_each_sg(sg, s, nents, i)
+		ops->sync_single_for_cpu(dev, sg_dma_address(s), s->length,
+					 dir);
 }
 
 /**
- * dma_sync_sg_for_device
+ * arm_dma_sync_sg_for_device
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @sg: list of buffers
  * @nents: number of buffers to map (returned from dma_map_sg)
@@ -707,17 +706,13 @@ void arm_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 			int nents, enum dma_data_direction dir)
 {
+	struct dma_map_ops *ops = get_dma_ops(dev);
 	struct scatterlist *s;
 	int i;
 
-	for_each_sg(sg, s, nents, i) {
-		if (!dmabounce_sync_for_device(dev, sg_dma_address(s),
-					sg_dma_len(s), dir))
-			continue;
-
-		__dma_page_cpu_to_dev(sg_page(s), s->offset,
-				      s->length, dir);
-	}
+	for_each_sg(sg, s, nents, i)
+		ops->sync_single_for_device(dev, sg_dma_address(s), s->length,
+					    dir);
 }
 
 /*
-- 
1.7.1.569.g6f426

[PATCHv8 07/10] ARM: dma-mapping: move all dma bounce code to separate dma ops structure

[Marek Szyprowski]

This patch removes dma bounce hooks from the common dma mapping
implementation on ARM architecture and creates a separate set of
dma_map_ops for dma bounce devices.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/common/dmabounce.c        |   62 ++++++++++++++++++-----
 arch/arm/include/asm/dma-mapping.h |   99 +-----------------------------------
 arch/arm/mm/dma-mapping.c          |   79 +++++++++++++++++++++++++----
 3 files changed, 120 insertions(+), 120 deletions(-)

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index c9f54b6..119f487 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -308,8 +308,9 @@ static inline void unmap_single(struct device *dev, struct safe_buffer *buf,
  * substitute the safe buffer for the unsafe one.
  * (basically move the buffer from an unsafe area to a safe one)
  */
-dma_addr_t __dma_map_page(struct device *dev, struct page *page,
-		unsigned long offset, size_t size, enum dma_data_direction dir)
+static dma_addr_t dmabounce_map_page(struct device *dev, struct page *page,
+		unsigned long offset, size_t size, enum dma_data_direction dir,
+		struct dma_attrs *attrs)
 {
 	dma_addr_t dma_addr;
 	int ret;
@@ -324,7 +325,7 @@ dma_addr_t __dma_map_page(struct device *dev, struct page *page,
 		return ARM_DMA_ERROR;
 
 	if (ret == 0) {
-		__dma_page_cpu_to_dev(page, offset, size, dir);
+		arm_dma_ops.sync_single_for_device(dev, dma_addr, size, dir);
 		return dma_addr;
 	}
 
@@ -335,7 +336,6 @@ dma_addr_t __dma_map_page(struct device *dev, struct page *page,
 
 	return map_single(dev, page_address(page) + offset, size, dir);
 }
-EXPORT_SYMBOL(__dma_map_page);
 
 /*
  * see if a mapped address was really a "safe" buffer and if so, copy
@@ -343,8 +343,8 @@ EXPORT_SYMBOL(__dma_map_page);
  * the safe buffer.  (basically return things back to the way they
  * should be)
  */
-void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
-		enum dma_data_direction dir)
+static void dmabounce_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
+		enum dma_data_direction dir, struct dma_attrs *attrs)
 {
 	struct safe_buffer *buf;
 
@@ -353,16 +353,14 @@ void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
 
 	buf = find_safe_buffer_dev(dev, dma_addr, __func__);
 	if (!buf) {
-		__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, dma_addr)),
-			dma_addr & ~PAGE_MASK, size, dir);
+		arm_dma_ops.sync_single_for_cpu(dev, dma_addr, size, dir);
 		return;
 	}
 
 	unmap_single(dev, buf, size, dir);
 }
-EXPORT_SYMBOL(__dma_unmap_page);
 
-int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
+static int __dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 		size_t sz, enum dma_data_direction dir)
 {
 	struct safe_buffer *buf;
@@ -392,9 +390,17 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 	}
 	return 0;
 }
-EXPORT_SYMBOL(dmabounce_sync_for_cpu);
 
-int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
+static void dmabounce_sync_for_cpu(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	if (!__dmabounce_sync_for_cpu(dev, handle, size, dir))
+		return;
+
+	arm_dma_ops.sync_single_for_cpu(dev, handle, size, dir);
+}
+
+static int __dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
 		size_t sz, enum dma_data_direction dir)
 {
 	struct safe_buffer *buf;
@@ -424,7 +430,35 @@ int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
 	}
 	return 0;
 }
-EXPORT_SYMBOL(dmabounce_sync_for_device);
+
+static void dmabounce_sync_for_device(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	if (!__dmabounce_sync_for_device(dev, handle, size, dir))
+		return;
+
+	arm_dma_ops.sync_single_for_device(dev, handle, size, dir);
+}
+
+static int dmabounce_set_mask(struct device *dev, u64 dma_mask)
+{
+	if (dev->archdata.dmabounce)
+		return 0;
+
+	return arm_dma_ops.set_dma_mask(dev, dma_mask);
+}
+
+static struct dma_map_ops dmabounce_ops = {
+	.map_page		= dmabounce_map_page,
+	.unmap_page		= dmabounce_unmap_page,
+	.sync_single_for_cpu	= dmabounce_sync_for_cpu,
+	.sync_single_for_device	= dmabounce_sync_for_device,
+	.map_sg			= generic_dma_map_sg,
+	.unmap_sg		= generic_dma_unmap_sg,
+	.sync_sg_for_cpu	= generic_dma_sync_sg_for_cpu,
+	.sync_sg_for_device	= generic_dma_sync_sg_for_device,
+	.set_dma_mask		= dmabounce_set_mask,
+};
 
 static int dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev,
 		const char *name, unsigned long size)
@@ -486,6 +520,7 @@ int dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size,
 #endif
 
 	dev->archdata.dmabounce = device_info;
+	set_dma_ops(dev, &dmabounce_ops);
 
 	dev_info(dev, "dmabounce: registered device\n");
 
@@ -504,6 +539,7 @@ void dmabounce_unregister_dev(struct device *dev)
 	struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
 
 	dev->archdata.dmabounce = NULL;
+	set_dma_ops(dev, NULL);
 
 	if (!device_info) {
 		dev_warn(dev,
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 424b67a..5f35f22 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -85,62 +85,6 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
 #endif
 
 /*
- * The DMA API is built upon the notion of "buffer ownership".  A buffer
- * is either exclusively owned by the CPU (and therefore may be accessed
- * by it) or exclusively owned by the DMA device.  These helper functions
- * represent the transitions between these two ownership states.
- *
- * Note, however, that on later ARMs, this notion does not work due to
- * speculative prefetches.  We model our approach on the assumption that
- * the CPU does do speculative prefetches, which means we clean caches
- * before transfers and delay cache invalidation until transfer completion.
- *
- * Private support functions: these are not part of the API and are
- * liable to change.  Drivers must not use these.
- */
-static inline void __dma_single_cpu_to_dev(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	extern void ___dma_single_cpu_to_dev(const void *, size_t,
-		enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_single_cpu_to_dev(kaddr, size, dir);
-}
-
-static inline void __dma_single_dev_to_cpu(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	extern void ___dma_single_dev_to_cpu(const void *, size_t,
-		enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_single_dev_to_cpu(kaddr, size, dir);
-}
-
-static inline void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
-	size_t size, enum dma_data_direction dir)
-{
-	extern void ___dma_page_cpu_to_dev(struct page *, unsigned long,
-		size_t, enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_page_cpu_to_dev(page, off, size, dir);
-}
-
-static inline void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
-	size_t size, enum dma_data_direction dir)
-{
-	extern void ___dma_page_dev_to_cpu(struct page *, unsigned long,
-		size_t, enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_page_dev_to_cpu(page, off, size, dir);
-}
-
-extern int dma_supported(struct device *, u64);
-extern int dma_set_mask(struct device *, u64);
-/*
  * DMA errors are defined by all-bits-set in the DMA address.
  */
 static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
@@ -163,6 +107,8 @@ static inline void dma_free_noncoherent(struct device *dev, size_t size,
 {
 }
 
+extern int dma_supported(struct device *dev, u64 mask);
+
 /**
  * dma_alloc_coherent - allocate consistent memory for DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -235,7 +181,6 @@ int dma_mmap_writecombine(struct device *, struct vm_area_struct *,
 extern void __init init_consistent_dma_size(unsigned long size);
 
 
-#ifdef CONFIG_DMABOUNCE
 /*
  * For SA-1111, IXP425, and ADI systems  the dma-mapping functions are "magic"
  * and utilize bounce buffers as needed to work around limited DMA windows.
@@ -275,47 +220,7 @@ extern int dmabounce_register_dev(struct device *, unsigned long,
  */
 extern void dmabounce_unregister_dev(struct device *);
 
-/*
- * The DMA API, implemented by dmabounce.c.  See below for descriptions.
- */
-extern dma_addr_t __dma_map_page(struct device *, struct page *,
-		unsigned long, size_t, enum dma_data_direction);
-extern void __dma_unmap_page(struct device *, dma_addr_t, size_t,
-		enum dma_data_direction);
-
-/*
- * Private functions
- */
-int dmabounce_sync_for_cpu(struct device *, dma_addr_t, size_t, enum dma_data_direction);
-int dmabounce_sync_for_device(struct device *, dma_addr_t, size_t, enum dma_data_direction);
-#else
-static inline int dmabounce_sync_for_cpu(struct device *d, dma_addr_t addr,
-	size_t size, enum dma_data_direction dir)
-{
-	return 1;
-}
-
-static inline int dmabounce_sync_for_device(struct device *d, dma_addr_t addr,
-	size_t size, enum dma_data_direction dir)
-{
-	return 1;
-}
-
 
-static inline dma_addr_t __dma_map_page(struct device *dev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir)
-{
-	__dma_page_cpu_to_dev(page, offset, size, dir);
-	return pfn_to_dma(dev, page_to_pfn(page)) + offset;
-}
-
-static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
-		handle & ~PAGE_MASK, size, dir);
-}
-#endif /* CONFIG_DMABOUNCE */
 
 /*
  * The scatter list versions of the above methods.
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index d7137bd..695c219 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -29,6 +29,75 @@
 
 #include "mm.h"
 
+/*
+ * The DMA API is built upon the notion of "buffer ownership".  A buffer
+ * is either exclusively owned by the CPU (and therefore may be accessed
+ * by it) or exclusively owned by the DMA device.  These helper functions
+ * represent the transitions between these two ownership states.
+ *
+ * Note, however, that on later ARMs, this notion does not work due to
+ * speculative prefetches.  We model our approach on the assumption that
+ * the CPU does do speculative prefetches, which means we clean caches
+ * before transfers and delay cache invalidation until transfer completion.
+ *
+ * Private support functions: these are not part of the API and are
+ * liable to change.  Drivers must not use these.
+ */
+static inline void __dma_single_cpu_to_dev(const void *kaddr, size_t size,
+	enum dma_data_direction dir)
+{
+	extern void ___dma_single_cpu_to_dev(const void *, size_t,
+		enum dma_data_direction);
+
+	if (!arch_is_coherent())
+		___dma_single_cpu_to_dev(kaddr, size, dir);
+}
+
+static inline void __dma_single_dev_to_cpu(const void *kaddr, size_t size,
+	enum dma_data_direction dir)
+{
+	extern void ___dma_single_dev_to_cpu(const void *, size_t,
+		enum dma_data_direction);
+
+	if (!arch_is_coherent())
+		___dma_single_dev_to_cpu(kaddr, size, dir);
+}
+
+static inline void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
+	size_t size, enum dma_data_direction dir)
+{
+	extern void ___dma_page_cpu_to_dev(struct page *, unsigned long,
+		size_t, enum dma_data_direction);
+
+	if (!arch_is_coherent())
+		___dma_page_cpu_to_dev(page, off, size, dir);
+}
+
+static inline void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
+	size_t size, enum dma_data_direction dir)
+{
+	extern void ___dma_page_dev_to_cpu(struct page *, unsigned long,
+		size_t, enum dma_data_direction);
+
+	if (!arch_is_coherent())
+		___dma_page_dev_to_cpu(page, off, size, dir);
+}
+
+
+static inline dma_addr_t __dma_map_page(struct device *dev, struct page *page,
+	     unsigned long offset, size_t size, enum dma_data_direction dir)
+{
+	__dma_page_cpu_to_dev(page, offset, size, dir);
+	return pfn_to_dma(dev, page_to_pfn(page)) + offset;
+}
+
+static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir)
+{
+	__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
+		handle & ~PAGE_MASK, size, dir);
+}
+
 /**
  * arm_dma_map_page - map a portion of a page for streaming DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -76,9 +145,6 @@ static inline void arm_dma_sync_single_for_cpu(struct device *dev,
 {
 	unsigned int offset = handle & (PAGE_SIZE - 1);
 	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
-	if (!dmabounce_sync_for_cpu(dev, handle, size, dir))
-		return;
-
 	__dma_page_dev_to_cpu(page, offset, size, dir);
 }
 
@@ -87,9 +153,6 @@ static inline void arm_dma_sync_single_for_device(struct device *dev,
 {
 	unsigned int offset = handle & (PAGE_SIZE - 1);
 	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
-	if (!dmabounce_sync_for_device(dev, handle, size, dir))
-		return;
-
 	__dma_page_cpu_to_dev(page, offset, size, dir);
 }
 
@@ -596,7 +659,6 @@ void ___dma_page_cpu_to_dev(struct page *page, unsigned long off,
 	}
 	/* FIXME: non-speculating: flush on bidirectional mappings? */
 }
-EXPORT_SYMBOL(___dma_page_cpu_to_dev);
 
 void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
@@ -616,7 +678,6 @@ void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
 	if (dir != DMA_TO_DEVICE && off == 0 && size >= PAGE_SIZE)
 		set_bit(PG_dcache_clean, &page->flags);
 }
-EXPORT_SYMBOL(___dma_page_dev_to_cpu);
 
 /**
  * arm_dma_map_sg - map a set of SG buffers for streaming mode DMA
@@ -734,9 +795,7 @@ static int arm_dma_set_mask(struct device *dev, u64 dma_mask)
 	if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 		return -EIO;
 
-#ifndef CONFIG_DMABOUNCE
 	*dev->dma_mask = dma_mask;
-#endif
 
 	return 0;
 }
-- 
1.7.1.569.g6f426

Re: [PATCHv8 07/10] ARM: dma-mapping: move all dma bounce code to separate dma ops structure

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch removes dma bounce hooks from the common dma mapping
> implementation on ARM architecture and creates a separate set of
> dma_map_ops for dma bounce devices.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> Acked-by: Kyungmin Park <kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>

I could be misunderstanding something, but it looks like this
one should come before patch 6, where you remove
some of the dmabounce functions. Can you clarify?

	Arnd

Re: [PATCHv8 07/10] ARM: dma-mapping: move all dma bounce code to separate dma ops structure

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch removes dma bounce hooks from the common dma mapping
> implementation on ARM architecture and creates a separate set of
> dma_map_ops for dma bounce devices.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

I could be misunderstanding something, but it looks like this
one should come before patch 6, where you remove
some of the dmabounce functions. Can you clarify?

	Arnd

RE: [PATCHv8 07/10] ARM: dma-mapping: move all dma bounce code to separate dma ops structure

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 2:24 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > This patch removes dma bounce hooks from the common dma mapping
> > implementation on ARM architecture and creates a separate set of
> > dma_map_ops for dma bounce devices.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > Acked-by: Kyungmin Park <kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> 
> I could be misunderstanding something, but it looks like this
> one should come before patch 6, where you remove
> some of the dmabounce functions. Can you clarify?

Before patch no 6, there were custom methods for all scatter/gather
related operations. They iterated over the whole scatter list and called
cache related operations directly (which in turn checked if we use dma
bounce code or not and called respective version). Patch no 6 changed
them not to use such shortcut for direct calling cache related operations.

Instead it provides similar loop over scatter list and calls methods
from the current device's dma_map_ops structure. This way, after patch no 
7 these functions call simple dma_map_page() method for all standard 
devices and dma bounce aware version for devices registered for dma 
bouncing (with use different dma_map_ops).

I can provide a separate set of scatter/gather list related functions for
the linear dma mapping implementation and dma bouncing implementation 
if you think that the current approach is too complicated or 
over-engineered.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

RE: [PATCHv8 07/10] ARM: dma-mapping: move all dma bounce code to separate dma ops structure

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 2:24 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > This patch removes dma bounce hooks from the common dma mapping
> > implementation on ARM architecture and creates a separate set of
> > dma_map_ops for dma bounce devices.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> 
> I could be misunderstanding something, but it looks like this
> one should come before patch 6, where you remove
> some of the dmabounce functions. Can you clarify?

Before patch no 6, there were custom methods for all scatter/gather
related operations. They iterated over the whole scatter list and called
cache related operations directly (which in turn checked if we use dma
bounce code or not and called respective version). Patch no 6 changed
them not to use such shortcut for direct calling cache related operations.

Instead it provides similar loop over scatter list and calls methods
from the current device's dma_map_ops structure. This way, after patch no 
7 these functions call simple dma_map_page() method for all standard 
devices and dma bounce aware version for devices registered for dma 
bouncing (with use different dma_map_ops).

I can provide a separate set of scatter/gather list related functions for
the linear dma mapping implementation and dma bouncing implementation 
if you think that the current approach is too complicated or 
over-engineered.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

Re: [PATCHv8 07/10] ARM: dma-mapping: move all dma bounce code to separate dma ops structure

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> Before patch no 6, there were custom methods for all scatter/gather
> related operations. They iterated over the whole scatter list and called
> cache related operations directly (which in turn checked if we use dma
> bounce code or not and called respective version). Patch no 6 changed
> them not to use such shortcut for direct calling cache related operations.
> 
> Instead it provides similar loop over scatter list and calls methods
> from the current device's dma_map_ops structure. This way, after patch no 
> 7 these functions call simple dma_map_page() method for all standard 
> devices and dma bounce aware version for devices registered for dma 
> bouncing (with use different dma_map_ops).

Ok, thanks for the explanation.

> I can provide a separate set of scatter/gather list related functions for
> the linear dma mapping implementation and dma bouncing implementation 
> if you think that the current approach is too complicated or 
> over-engineered.

It's probably not needed, though I have not looked at the big picture
with all the patches applied. which I should do at some point.

	Arnd

[PATCHv8 08/10] ARM: dma-mapping: remove redundant code and cleanup

[Marek Szyprowski]

This patch just performs a global cleanup in DMA mapping implementation
for ARM architecture. Some of the tiny helper functions have been moved
to the caller code, some have been merged together.

Signed-off-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Acked-by: Kyungmin Park <kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 arch/arm/mm/dma-mapping.c |   88 ++++++++++++--------------------------------
 1 files changed, 24 insertions(+), 64 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 695c219..485c693 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -40,64 +40,12 @@
  * the CPU does do speculative prefetches, which means we clean caches
  * before transfers and delay cache invalidation until transfer completion.
  *
- * Private support functions: these are not part of the API and are
- * liable to change.  Drivers must not use these.
  */
-static inline void __dma_single_cpu_to_dev(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	extern void ___dma_single_cpu_to_dev(const void *, size_t,
-		enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_single_cpu_to_dev(kaddr, size, dir);
-}
-
-static inline void __dma_single_dev_to_cpu(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	extern void ___dma_single_dev_to_cpu(const void *, size_t,
-		enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_single_dev_to_cpu(kaddr, size, dir);
-}
-
-static inline void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
-	size_t size, enum dma_data_direction dir)
-{
-	extern void ___dma_page_cpu_to_dev(struct page *, unsigned long,
+static void __dma_page_cpu_to_dev(struct page *, unsigned long,
 		size_t, enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_page_cpu_to_dev(page, off, size, dir);
-}
-
-static inline void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
-	size_t size, enum dma_data_direction dir)
-{
-	extern void ___dma_page_dev_to_cpu(struct page *, unsigned long,
+static void __dma_page_dev_to_cpu(struct page *, unsigned long,
 		size_t, enum dma_data_direction);
 
-	if (!arch_is_coherent())
-		___dma_page_dev_to_cpu(page, off, size, dir);
-}
-
-
-static inline dma_addr_t __dma_map_page(struct device *dev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir)
-{
-	__dma_page_cpu_to_dev(page, offset, size, dir);
-	return pfn_to_dma(dev, page_to_pfn(page)) + offset;
-}
-
-static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
-		handle & ~PAGE_MASK, size, dir);
-}
-
 /**
  * arm_dma_map_page - map a portion of a page for streaming DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -112,11 +60,13 @@ static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
  * The device owns this memory once this call has completed.  The CPU
  * can regain ownership by calling dma_unmap_page().
  */
-static inline dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
+static dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
 	     unsigned long offset, size_t size, enum dma_data_direction dir,
 	     struct dma_attrs *attrs)
 {
-	return __dma_map_page(dev, page, offset, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_cpu_to_dev(page, offset, size, dir);
+	return pfn_to_dma(dev, page_to_pfn(page)) + offset;
 }
 
 /**
@@ -133,27 +83,31 @@ static inline dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
  * After this call, reads by the CPU to the buffer are guaranteed to see
  * whatever the device wrote there.
  */
-static inline void arm_dma_unmap_page(struct device *dev, dma_addr_t handle,
+static void arm_dma_unmap_page(struct device *dev, dma_addr_t handle,
 		size_t size, enum dma_data_direction dir,
 		struct dma_attrs *attrs)
 {
-	__dma_unmap_page(dev, handle, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
+				      handle & ~PAGE_MASK, size, dir);
 }
 
-static inline void arm_dma_sync_single_for_cpu(struct device *dev,
+static void arm_dma_sync_single_for_cpu(struct device *dev,
 		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 {
 	unsigned int offset = handle & (PAGE_SIZE - 1);
 	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
-	__dma_page_dev_to_cpu(page, offset, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_dev_to_cpu(page, offset, size, dir);
 }
 
-static inline void arm_dma_sync_single_for_device(struct device *dev,
+static void arm_dma_sync_single_for_device(struct device *dev,
 		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 {
 	unsigned int offset = handle & (PAGE_SIZE - 1);
 	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
-	__dma_page_cpu_to_dev(page, offset, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_cpu_to_dev(page, offset, size, dir);
 }
 
 static int arm_dma_set_mask(struct device *dev, u64 dma_mask);
@@ -644,7 +598,13 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset,
 	} while (left);
 }
 
-void ___dma_page_cpu_to_dev(struct page *page, unsigned long off,
+/*
+ * Make an area consistent for devices.
+ * Note: Drivers should NOT use this function directly, as it will break
+ * platforms with CONFIG_DMABOUNCE.
+ * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
+ */
+static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
 {
 	unsigned long paddr;
@@ -660,7 +620,7 @@ void ___dma_page_cpu_to_dev(struct page *page, unsigned long off,
 	/* FIXME: non-speculating: flush on bidirectional mappings? */
 }
 
-void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
+static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
 {
 	unsigned long paddr = page_to_phys(page) + off;
-- 
1.7.1.569.g6f426

[PATCHv8 08/10] ARM: dma-mapping: remove redundant code and cleanup

[Marek Szyprowski]

This patch just performs a global cleanup in DMA mapping implementation
for ARM architecture. Some of the tiny helper functions have been moved
to the caller code, some have been merged together.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/mm/dma-mapping.c |   88 ++++++++++++--------------------------------
 1 files changed, 24 insertions(+), 64 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 695c219..485c693 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -40,64 +40,12 @@
  * the CPU does do speculative prefetches, which means we clean caches
  * before transfers and delay cache invalidation until transfer completion.
  *
- * Private support functions: these are not part of the API and are
- * liable to change.  Drivers must not use these.
  */
-static inline void __dma_single_cpu_to_dev(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	extern void ___dma_single_cpu_to_dev(const void *, size_t,
-		enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_single_cpu_to_dev(kaddr, size, dir);
-}
-
-static inline void __dma_single_dev_to_cpu(const void *kaddr, size_t size,
-	enum dma_data_direction dir)
-{
-	extern void ___dma_single_dev_to_cpu(const void *, size_t,
-		enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_single_dev_to_cpu(kaddr, size, dir);
-}
-
-static inline void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
-	size_t size, enum dma_data_direction dir)
-{
-	extern void ___dma_page_cpu_to_dev(struct page *, unsigned long,
+static void __dma_page_cpu_to_dev(struct page *, unsigned long,
 		size_t, enum dma_data_direction);
-
-	if (!arch_is_coherent())
-		___dma_page_cpu_to_dev(page, off, size, dir);
-}
-
-static inline void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
-	size_t size, enum dma_data_direction dir)
-{
-	extern void ___dma_page_dev_to_cpu(struct page *, unsigned long,
+static void __dma_page_dev_to_cpu(struct page *, unsigned long,
 		size_t, enum dma_data_direction);
 
-	if (!arch_is_coherent())
-		___dma_page_dev_to_cpu(page, off, size, dir);
-}
-
-
-static inline dma_addr_t __dma_map_page(struct device *dev, struct page *page,
-	     unsigned long offset, size_t size, enum dma_data_direction dir)
-{
-	__dma_page_cpu_to_dev(page, offset, size, dir);
-	return pfn_to_dma(dev, page_to_pfn(page)) + offset;
-}
-
-static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
-		handle & ~PAGE_MASK, size, dir);
-}
-
 /**
  * arm_dma_map_page - map a portion of a page for streaming DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -112,11 +60,13 @@ static inline void __dma_unmap_page(struct device *dev, dma_addr_t handle,
  * The device owns this memory once this call has completed.  The CPU
  * can regain ownership by calling dma_unmap_page().
  */
-static inline dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
+static dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
 	     unsigned long offset, size_t size, enum dma_data_direction dir,
 	     struct dma_attrs *attrs)
 {
-	return __dma_map_page(dev, page, offset, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_cpu_to_dev(page, offset, size, dir);
+	return pfn_to_dma(dev, page_to_pfn(page)) + offset;
 }
 
 /**
@@ -133,27 +83,31 @@ static inline dma_addr_t arm_dma_map_page(struct device *dev, struct page *page,
  * After this call, reads by the CPU to the buffer are guaranteed to see
  * whatever the device wrote there.
  */
-static inline void arm_dma_unmap_page(struct device *dev, dma_addr_t handle,
+static void arm_dma_unmap_page(struct device *dev, dma_addr_t handle,
 		size_t size, enum dma_data_direction dir,
 		struct dma_attrs *attrs)
 {
-	__dma_unmap_page(dev, handle, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
+				      handle & ~PAGE_MASK, size, dir);
 }
 
-static inline void arm_dma_sync_single_for_cpu(struct device *dev,
+static void arm_dma_sync_single_for_cpu(struct device *dev,
 		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 {
 	unsigned int offset = handle & (PAGE_SIZE - 1);
 	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
-	__dma_page_dev_to_cpu(page, offset, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_dev_to_cpu(page, offset, size, dir);
 }
 
-static inline void arm_dma_sync_single_for_device(struct device *dev,
+static void arm_dma_sync_single_for_device(struct device *dev,
 		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 {
 	unsigned int offset = handle & (PAGE_SIZE - 1);
 	struct page *page = pfn_to_page(dma_to_pfn(dev, handle-offset));
-	__dma_page_cpu_to_dev(page, offset, size, dir);
+	if (!arch_is_coherent())
+		__dma_page_cpu_to_dev(page, offset, size, dir);
 }
 
 static int arm_dma_set_mask(struct device *dev, u64 dma_mask);
@@ -644,7 +598,13 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset,
 	} while (left);
 }
 
-void ___dma_page_cpu_to_dev(struct page *page, unsigned long off,
+/*
+ * Make an area consistent for devices.
+ * Note: Drivers should NOT use this function directly, as it will break
+ * platforms with CONFIG_DMABOUNCE.
+ * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
+ */
+static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
 {
 	unsigned long paddr;
@@ -660,7 +620,7 @@ void ___dma_page_cpu_to_dev(struct page *page, unsigned long off,
 	/* FIXME: non-speculating: flush on bidirectional mappings? */
 }
 
-void ___dma_page_dev_to_cpu(struct page *page, unsigned long off,
+static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
 	size_t size, enum dma_data_direction dir)
 {
 	unsigned long paddr = page_to_phys(page) + off;
-- 
1.7.1.569.g6f426

Re: [PATCHv8 08/10] ARM: dma-mapping: remove redundant code and cleanup

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> 
> This patch just performs a global cleanup in DMA mapping implementation
> for ARM architecture. Some of the tiny helper functions have been moved
> to the caller code, some have been merged together.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Arnd Bergmann <arnd@arndb.de>

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Re: [PATCHv8 08/10] ARM: dma-mapping: remove redundant code and cleanup

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> 
> This patch just performs a global cleanup in DMA mapping implementation
> for ARM architecture. Some of the tiny helper functions have been moved
> to the caller code, some have been merged together.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCHv8 00/10] ARM: DMA-mapping framework redesign

[Subash Patel]

Hello Marek,

I have tested below patch series for vanilla 3.4-rc2 (without videobuf2 
support for dmabuf patches) with and without IOMMU support on origen 
board. These patches are good now. You can add:

Tested-By: Subash Patel <subash.ramaswamy-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> for whole series.

Regards,
Subash

On 04/10/2012 04:34 PM, Marek Szyprowski wrote:
> Hello,
>
> Linux v3.4-rc2, which include dma-mapping preparation patches, has been
> released two days ago, now it's time for the next spin of ARM
> dma-mapping redesign patches. This version includes various fixes posted
> separately to v7, mainly related to incorrect io address space bitmap
> setup and a major issue with broken mmap for memory which comes from
> dma_declare_coherent(). The patches have been also rebased onto Linux
> v3.4-rc2 which comes with dma_map_ops related changes.
>
> The code has been tested on Samsung Exynos4 'UniversalC210' and NURI
> boards with IOMMU driver posted by KyongHo Cho, I will put separate
> branch which shows how to integrate this driver with this patchset.
>
> The patches are also available on my git repository at:
> git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git 3.4-rc2-arm-dma-v8
>
>
> History of the development:
>
> v1: (initial version of the DMA-mapping redesign patches):
> http://www.spinics.net/lists/linux-mm/msg21241.html
>
> v2:
> http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000571.html
> http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000577.html
>
> v3:
> http://www.spinics.net/lists/linux-mm/msg25490.html
>
> v4 and v5:
> http://www.spinics.net/lists/arm-kernel/msg151147.html
> http://www.spinics.net/lists/arm-kernel/msg154889.html
>
> v6:
> http://www.spinics.net/lists/linux-mm/msg29903.html
>
> v7:
> http://www.spinics.net/lists/arm-kernel/msg162149.html
>
> Best regards
> Marek Szyprowski
> Samsung Poland R&D Center
>
>
> Patch summary:
>
> Marek Szyprowski (10):
>    common: add dma_mmap_from_coherent() function
>    ARM: dma-mapping: use pr_* instread of printk
>    ARM: dma-mapping: introduce ARM_DMA_ERROR constant
>    ARM: dma-mapping: remove offset parameter to prepare for generic
>      dma_ops
>    ARM: dma-mapping: use asm-generic/dma-mapping-common.h
>    ARM: dma-mapping: implement dma sg methods on top of any generic dma
>      ops
>    ARM: dma-mapping: move all dma bounce code to separate dma ops
>      structure
>    ARM: dma-mapping: remove redundant code and cleanup
>    ARM: dma-mapping: use alloc, mmap, free from dma_ops
>    ARM: dma-mapping: add support for IOMMU mapper
>
>   arch/arm/Kconfig                   |    9 +
>   arch/arm/common/dmabounce.c        |   84 +++-
>   arch/arm/include/asm/device.h      |    4 +
>   arch/arm/include/asm/dma-iommu.h   |   34 ++
>   arch/arm/include/asm/dma-mapping.h |  407 ++++-----------
>   arch/arm/mm/dma-mapping.c          | 1019 ++++++++++++++++++++++++++++++------
>   arch/arm/mm/vmregion.h             |    2 +-
>   drivers/base/dma-coherent.c        |   42 ++
>   include/asm-generic/dma-coherent.h |    4 +-
>   9 files changed, 1138 insertions(+), 467 deletions(-)
>   create mode 100644 arch/arm/include/asm/dma-iommu.h
>

Re: [PATCHv8 00/10] ARM: DMA-mapping framework redesign

[Subash Patel]

Hello Marek,

I have tested below patch series for vanilla 3.4-rc2 (without videobuf2 
support for dmabuf patches) with and without IOMMU support on origen 
board. These patches are good now. You can add:

Tested-By: Subash Patel <subash.ramaswamy@linaro.org> for whole series.

Regards,
Subash

On 04/10/2012 04:34 PM, Marek Szyprowski wrote:
> Hello,
>
> Linux v3.4-rc2, which include dma-mapping preparation patches, has been
> released two days ago, now it's time for the next spin of ARM
> dma-mapping redesign patches. This version includes various fixes posted
> separately to v7, mainly related to incorrect io address space bitmap
> setup and a major issue with broken mmap for memory which comes from
> dma_declare_coherent(). The patches have been also rebased onto Linux
> v3.4-rc2 which comes with dma_map_ops related changes.
>
> The code has been tested on Samsung Exynos4 'UniversalC210' and NURI
> boards with IOMMU driver posted by KyongHo Cho, I will put separate
> branch which shows how to integrate this driver with this patchset.
>
> The patches are also available on my git repository at:
> git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git 3.4-rc2-arm-dma-v8
>
>
> History of the development:
>
> v1: (initial version of the DMA-mapping redesign patches):
> http://www.spinics.net/lists/linux-mm/msg21241.html
>
> v2:
> http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000571.html
> http://lists.linaro.org/pipermail/linaro-mm-sig/2011-September/000577.html
>
> v3:
> http://www.spinics.net/lists/linux-mm/msg25490.html
>
> v4 and v5:
> http://www.spinics.net/lists/arm-kernel/msg151147.html
> http://www.spinics.net/lists/arm-kernel/msg154889.html
>
> v6:
> http://www.spinics.net/lists/linux-mm/msg29903.html
>
> v7:
> http://www.spinics.net/lists/arm-kernel/msg162149.html
>
> Best regards
> Marek Szyprowski
> Samsung Poland R&D Center
>
>
> Patch summary:
>
> Marek Szyprowski (10):
>    common: add dma_mmap_from_coherent() function
>    ARM: dma-mapping: use pr_* instread of printk
>    ARM: dma-mapping: introduce ARM_DMA_ERROR constant
>    ARM: dma-mapping: remove offset parameter to prepare for generic
>      dma_ops
>    ARM: dma-mapping: use asm-generic/dma-mapping-common.h
>    ARM: dma-mapping: implement dma sg methods on top of any generic dma
>      ops
>    ARM: dma-mapping: move all dma bounce code to separate dma ops
>      structure
>    ARM: dma-mapping: remove redundant code and cleanup
>    ARM: dma-mapping: use alloc, mmap, free from dma_ops
>    ARM: dma-mapping: add support for IOMMU mapper
>
>   arch/arm/Kconfig                   |    9 +
>   arch/arm/common/dmabounce.c        |   84 +++-
>   arch/arm/include/asm/device.h      |    4 +
>   arch/arm/include/asm/dma-iommu.h   |   34 ++
>   arch/arm/include/asm/dma-mapping.h |  407 ++++-----------
>   arch/arm/mm/dma-mapping.c          | 1019 ++++++++++++++++++++++++++++++------
>   arch/arm/mm/vmregion.h             |    2 +-
>   drivers/base/dma-coherent.c        |   42 ++
>   include/asm-generic/dma-coherent.h |    4 +-
>   9 files changed, 1138 insertions(+), 467 deletions(-)
>   create mode 100644 arch/arm/include/asm/dma-iommu.h
>

[PATCHv8 09/10] ARM: dma-mapping: use alloc, mmap, free from dma_ops

[Marek Szyprowski]

This patch converts dma_alloc/free/mmap_{coherent,writecombine}
functions to use generic alloc/free/mmap methods from dma_map_ops
structure. A new DMA_ATTR_WRITE_COMBINE DMA attribute have been
introduced to implement writecombine methods.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 arch/arm/common/dmabounce.c        |    3 +
 arch/arm/include/asm/dma-mapping.h |  107 ++++++++++++++++++++++++++----------
 arch/arm/mm/dma-mapping.c          |   54 ++++++------------
 3 files changed, 98 insertions(+), 66 deletions(-)

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 119f487..dbae5ad 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -449,6 +449,9 @@ static int dmabounce_set_mask(struct device *dev, u64 dma_mask)
 }
 
 static struct dma_map_ops dmabounce_ops = {
+	.alloc			= arm_dma_alloc,
+	.free			= arm_dma_free,
+	.mmap			= arm_dma_mmap,
 	.map_page		= dmabounce_map_page,
 	.unmap_page		= dmabounce_unmap_page,
 	.sync_single_for_cpu	= dmabounce_sync_for_cpu,
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 5f35f22..d56d6d2 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -5,6 +5,7 @@
 
 #include <linux/mm_types.h>
 #include <linux/scatterlist.h>
+#include <linux/dma-attrs.h>
 #include <linux/dma-debug.h>
 
 #include <asm-generic/dma-coherent.h>
@@ -110,68 +111,115 @@ static inline void dma_free_noncoherent(struct device *dev, size_t size,
 extern int dma_supported(struct device *dev, u64 mask);
 
 /**
- * dma_alloc_coherent - allocate consistent memory for DMA
+ * arm_dma_alloc - allocate consistent memory for DMA
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @size: required memory size
  * @handle: bus-specific DMA address
+ * @attrs: optinal attributes that specific mapping properties
  *
- * Allocate some uncached, unbuffered memory for a device for
- * performing DMA.  This function allocates pages, and will
- * return the CPU-viewed address, and sets @handle to be the
- * device-viewed address.
+ * Allocate some memory for a device for performing DMA.  This function
+ * allocates pages, and will return the CPU-viewed address, and sets @handle
+ * to be the device-viewed address.
  */
-extern void *dma_alloc_coherent(struct device *, size_t, dma_addr_t *, gfp_t);
+extern void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
+			   gfp_t gfp, struct dma_attrs *attrs);
+
+#define dma_alloc_coherent(d, s, h, f) dma_alloc_attrs(d, s, h, f, NULL)
+
+static inline void *dma_alloc_attrs(struct device *dev, size_t size,
+				       dma_addr_t *dma_handle, gfp_t flag,
+				       struct dma_attrs *attrs)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+	void *cpu_addr;
+	BUG_ON(!ops);
+
+	cpu_addr = ops->alloc(dev, size, dma_handle, flag, attrs);
+	debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr);
+	return cpu_addr;
+}
 
 /**
- * dma_free_coherent - free memory allocated by dma_alloc_coherent
+ * arm_dma_free - free memory allocated by arm_dma_alloc
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @size: size of memory originally requested in dma_alloc_coherent
  * @cpu_addr: CPU-view address returned from dma_alloc_coherent
  * @handle: device-view address returned from dma_alloc_coherent
+ * @attrs: optinal attributes that specific mapping properties
  *
  * Free (and unmap) a DMA buffer previously allocated by
- * dma_alloc_coherent().
+ * arm_dma_alloc().
  *
  * References to memory and mappings associated with cpu_addr/handle
  * during and after this call executing are illegal.
  */
-extern void dma_free_coherent(struct device *, size_t, void *, dma_addr_t);
+extern void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
+			 dma_addr_t handle, struct dma_attrs *attrs);
+
+#define dma_free_coherent(d, s, c, h) dma_free_attrs(d, s, c, h, NULL)
+
+static inline void dma_free_attrs(struct device *dev, size_t size,
+				     void *cpu_addr, dma_addr_t dma_handle,
+				     struct dma_attrs *attrs)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+	BUG_ON(!ops);
+
+	debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
+	ops->free(dev, size, cpu_addr, dma_handle, attrs);
+}
 
 /**
- * dma_mmap_coherent - map a coherent DMA allocation into user space
+ * arm_dma_mmap - map a coherent DMA allocation into user space
  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  * @vma: vm_area_struct describing requested user mapping
  * @cpu_addr: kernel CPU-view address returned from dma_alloc_coherent
  * @handle: device-view address returned from dma_alloc_coherent
  * @size: size of memory originally requested in dma_alloc_coherent
+ * @attrs: optinal attributes that specific mapping properties
  *
  * Map a coherent DMA buffer previously allocated by dma_alloc_coherent
  * into user space.  The coherent DMA buffer must not be freed by the
  * driver until the user space mapping has been released.
  */
-int dma_mmap_coherent(struct device *, struct vm_area_struct *,
-		void *, dma_addr_t, size_t);
+extern int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+			void *cpu_addr, dma_addr_t dma_addr, size_t size,
+			struct dma_attrs *attrs);
 
+#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)
 
-/**
- * dma_alloc_writecombine - allocate writecombining memory for DMA
- * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
- * @size: required memory size
- * @handle: bus-specific DMA address
- *
- * Allocate some uncached, buffered memory for a device for
- * performing DMA.  This function allocates pages, and will
- * return the CPU-viewed address, and sets @handle to be the
- * device-viewed address.
- */
-extern void *dma_alloc_writecombine(struct device *, size_t, dma_addr_t *,
-		gfp_t);
+static inline int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
+				  void *cpu_addr, dma_addr_t dma_addr,
+				  size_t size, struct dma_attrs *attrs)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+	BUG_ON(!ops);
+	return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
+}
 
-#define dma_free_writecombine(dev,size,cpu_addr,handle) \
-	dma_free_coherent(dev,size,cpu_addr,handle)
+static inline void *dma_alloc_writecombine(struct device *dev, size_t size,
+				       dma_addr_t *dma_handle, gfp_t flag)
+{
+	DEFINE_DMA_ATTRS(attrs);
+	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	return dma_alloc_attrs(dev, size, dma_handle, flag, &attrs);
+}
 
-int dma_mmap_writecombine(struct device *, struct vm_area_struct *,
-		void *, dma_addr_t, size_t);
+static inline void dma_free_writecombine(struct device *dev, size_t size,
+				     void *cpu_addr, dma_addr_t dma_handle)
+{
+	DEFINE_DMA_ATTRS(attrs);
+	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	return dma_free_attrs(dev, size, cpu_addr, dma_handle, &attrs);
+}
+
+static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
+		      void *cpu_addr, dma_addr_t dma_addr, size_t size)
+{
+	DEFINE_DMA_ATTRS(attrs);
+	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
+}
 
 /*
  * This can be called during boot to increase the size of the consistent
@@ -180,7 +228,6 @@ int dma_mmap_writecombine(struct device *, struct vm_area_struct *,
  */
 extern void __init init_consistent_dma_size(unsigned long size);
 
-
 /*
  * For SA-1111, IXP425, and ADI systems  the dma-mapping functions are "magic"
  * and utilize bounce buffers as needed to work around limited DMA windows.
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 485c693..69f6e8e 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -113,6 +113,9 @@ static void arm_dma_sync_single_for_device(struct device *dev,
 static int arm_dma_set_mask(struct device *dev, u64 dma_mask);
 
 struct dma_map_ops arm_dma_ops = {
+	.alloc			= arm_dma_alloc,
+	.free			= arm_dma_free,
+	.mmap			= arm_dma_mmap,
 	.map_page		= arm_dma_map_page,
 	.unmap_page		= arm_dma_unmap_page,
 	.map_sg			= arm_dma_map_sg,
@@ -462,35 +465,27 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
  * Allocate DMA-coherent memory space and return both the kernel remapped
  * virtual and bus address for that space.
  */
-void *
-dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
+void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
+		    gfp_t gfp, struct dma_attrs *attrs)
 {
+	pgprot_t prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
+			pgprot_writecombine(pgprot_kernel) :
+			pgprot_dmacoherent(pgprot_kernel);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
 		return memory;
 
-	return __dma_alloc(dev, size, handle, gfp,
-			   pgprot_dmacoherent(pgprot_kernel),
+	return __dma_alloc(dev, size, handle, gfp, prot,
 			   __builtin_return_address(0));
 }
-EXPORT_SYMBOL(dma_alloc_coherent);
 
 /*
- * Allocate a writecombining region, in much the same way as
- * dma_alloc_coherent above.
+ * Create userspace mapping for the DMA-coherent memory.
  */
-void *
-dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
-{
-	return __dma_alloc(dev, size, handle, gfp,
-			   pgprot_writecombine(pgprot_kernel),
-			   __builtin_return_address(0));
-}
-EXPORT_SYMBOL(dma_alloc_writecombine);
-
-static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
-		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
+int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+		 void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		 struct dma_attrs *attrs)
 {
 	int ret = -ENXIO;
 #ifdef CONFIG_MMU
@@ -498,6 +493,9 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	struct arm_vmregion *c;
 
 	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+	vma->vm_page_prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
+			    pgprot_writecombine(vma->vm_page_prot) :
+			    pgprot_dmacoherent(vma->vm_page_prot);
 
 	c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
 	if (c) {
@@ -518,27 +516,12 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
 	return ret;
 }
 
-int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
-		      void *cpu_addr, dma_addr_t dma_addr, size_t size)
-{
-	vma->vm_page_prot = pgprot_dmacoherent(vma->vm_page_prot);
-	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
-}
-EXPORT_SYMBOL(dma_mmap_coherent);
-
-int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
-			  void *cpu_addr, dma_addr_t dma_addr, size_t size)
-{
-	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
-	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
-}
-EXPORT_SYMBOL(dma_mmap_writecombine);
-
 /*
  * free a page as defined by the above mapping.
  * Must not be called with IRQs disabled.
  */
-void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
+void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
+		  dma_addr_t handle, struct dma_attrs *attrs)
 {
 	WARN_ON(irqs_disabled());
 
@@ -552,7 +535,6 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
 
 	__dma_free_buffer(pfn_to_page(dma_to_pfn(dev, handle)), size);
 }
-EXPORT_SYMBOL(dma_free_coherent);
 
 static void dma_cache_maint_page(struct page *page, unsigned long offset,
 	size_t size, enum dma_data_direction dir,
-- 
1.7.1.569.g6f426

Re: [PATCHv8 09/10] ARM: dma-mapping: use alloc, mmap, free from dma_ops

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch converts dma_alloc/free/mmap_{coherent,writecombine}
> functions to use generic alloc/free/mmap methods from dma_map_ops
> structure. A new DMA_ATTR_WRITE_COMBINE DMA attribute have been
> introduced to implement writecombine methods.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> Acked-by: Kyungmin Park <kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>

Acked-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>

Re: [PATCHv8 09/10] ARM: dma-mapping: use alloc, mmap, free from dma_ops

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> This patch converts dma_alloc/free/mmap_{coherent,writecombine}
> functions to use generic alloc/free/mmap methods from dma_map_ops
> structure. A new DMA_ATTR_WRITE_COMBINE DMA attribute have been
> introduced to implement writecombine methods.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Arnd Bergmann <arnd@arndb.de>

[PATCHv8 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Marek Szyprowski]

This patch add a complete implementation of DMA-mapping API for
devices which have IOMMU support.

This implementation tries to optimize dma address space usage by remapping
all possible physical memory chunks into a single dma address space chunk.

DMA address space is managed on top of the bitmap stored in the
dma_iommu_mapping structure stored in device->archdata. Platform setup
code has to initialize parameters of the dma address space (base address,
size, allocation precision order) with arm_iommu_create_mapping() function.
To reduce the size of the bitmap, all allocations are aligned to the
specified order of base 4 KiB pages.

dma_alloc_* functions allocate physical memory in chunks, each with
alloc_pages() function to avoid failing if the physical memory gets
fragmented. In worst case the allocated buffer is composed of 4 KiB page
chunks.

dma_map_sg() function minimizes the total number of dma address space
chunks by merging of physical memory chunks into one larger dma address
space chunk. If requested chunk (scatter list entry) boundaries
match physical page boundaries, most calls to dma_map_sg() requests will
result in creating only one chunk in dma address space.

dma_map_page() simply creates a mapping for the given page(s) in the dma
address space.

All dma functions also perform required cache operation like their
counterparts from the arm linear physical memory mapping version.

This patch contains code and fixes kindly provided by:
- Krishna Reddy <vdumpa@nvidia.com>,
- Andrzej Pietrasiewicz <andrzej.p@samsung.com>,
- Hiroshi DOYU <hdoyu@nvidia.com>

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/arm/Kconfig                 |    8 +
 arch/arm/include/asm/device.h    |    3 +
 arch/arm/include/asm/dma-iommu.h |   34 ++
 arch/arm/mm/dma-mapping.c        |  731 +++++++++++++++++++++++++++++++++++++-
 arch/arm/mm/vmregion.h           |    2 +-
 5 files changed, 763 insertions(+), 15 deletions(-)
 create mode 100644 arch/arm/include/asm/dma-iommu.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 0fd27d4..874e519 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -46,6 +46,14 @@ config ARM
 config ARM_HAS_SG_CHAIN
 	bool
 
+config NEED_SG_DMA_LENGTH
+	bool
+
+config ARM_DMA_USE_IOMMU
+	select NEED_SG_DMA_LENGTH
+	select ARM_HAS_SG_CHAIN
+	bool
+
 config HAVE_PWM
 	bool
 
diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index 6e2cb0e..b69c0d3 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -14,6 +14,9 @@ struct dev_archdata {
 #ifdef CONFIG_IOMMU_API
 	void *iommu; /* private IOMMU data */
 #endif
+#ifdef CONFIG_ARM_DMA_USE_IOMMU
+	struct dma_iommu_mapping	*mapping;
+#endif
 };
 
 struct omap_device;
diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h
new file mode 100644
index 0000000..799b094
--- /dev/null
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -0,0 +1,34 @@
+#ifndef ASMARM_DMA_IOMMU_H
+#define ASMARM_DMA_IOMMU_H
+
+#ifdef __KERNEL__
+
+#include <linux/mm_types.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-debug.h>
+#include <linux/kmemcheck.h>
+
+struct dma_iommu_mapping {
+	/* iommu specific data */
+	struct iommu_domain	*domain;
+
+	void			*bitmap;
+	size_t			bits;
+	unsigned int		order;
+	dma_addr_t		base;
+
+	spinlock_t		lock;
+	struct kref		kref;
+};
+
+struct dma_iommu_mapping *
+arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
+			 int order);
+
+void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
+
+int arm_iommu_attach_device(struct device *dev,
+					struct dma_iommu_mapping *mapping);
+
+#endif /* __KERNEL__ */
+#endif
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 69f6e8e..6e88f66 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -19,6 +19,8 @@
 #include <linux/dma-mapping.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
+#include <linux/iommu.h>
+#include <linux/vmalloc.h>
 
 #include <asm/memory.h>
 #include <asm/highmem.h>
@@ -26,6 +28,7 @@
 #include <asm/tlbflush.h>
 #include <asm/sizes.h>
 #include <asm/mach/arch.h>
+#include <asm/dma-iommu.h>
 
 #include "mm.h"
 
@@ -155,6 +158,21 @@ static u64 get_coherent_dma_mask(struct device *dev)
 	return mask;
 }
 
+static void __dma_clear_buffer(struct page *page, size_t size)
+{
+	void *ptr;
+	/*
+	 * Ensure that the allocated pages are zeroed, and that any data
+	 * lurking in the kernel direct-mapped region is invalidated.
+	 */
+	ptr = page_address(page);
+	if (ptr) {
+		memset(ptr, 0, size);
+		dmac_flush_range(ptr, ptr + size);
+		outer_flush_range(__pa(ptr), __pa(ptr) + size);
+	}
+}
+
 /*
  * Allocate a DMA buffer for 'dev' of size 'size' using the
  * specified gfp mask.  Note that 'size' must be page aligned.
@@ -163,7 +181,6 @@ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gf
 {
 	unsigned long order = get_order(size);
 	struct page *page, *p, *e;
-	void *ptr;
 	u64 mask = get_coherent_dma_mask(dev);
 
 #ifdef CONFIG_DMA_API_DEBUG
@@ -192,14 +209,7 @@ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gf
 	for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
 		__free_page(p);
 
-	/*
-	 * Ensure that the allocated pages are zeroed, and that any data
-	 * lurking in the kernel direct-mapped region is invalidated.
-	 */
-	ptr = page_address(page);
-	memset(ptr, 0, size);
-	dmac_flush_range(ptr, ptr + size);
-	outer_flush_range(__pa(ptr), __pa(ptr) + size);
+	__dma_clear_buffer(page, size);
 
 	return page;
 }
@@ -348,7 +358,7 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
 		u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
 
 		pte = consistent_pte[idx] + off;
-		c->vm_pages = page;
+		c->priv = page;
 
 		do {
 			BUG_ON(!pte_none(*pte));
@@ -461,6 +471,14 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	return addr;
 }
 
+static inline pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot)
+{
+	prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
+			    pgprot_writecombine(prot) :
+			    pgprot_dmacoherent(prot);
+	return prot;
+}
+
 /*
  * Allocate DMA-coherent memory space and return both the kernel remapped
  * virtual and bus address for that space.
@@ -468,9 +486,7 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 		    gfp_t gfp, struct dma_attrs *attrs)
 {
-	pgprot_t prot = dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs) ?
-			pgprot_writecombine(pgprot_kernel) :
-			pgprot_dmacoherent(pgprot_kernel);
+	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
@@ -497,16 +513,20 @@ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 			    pgprot_writecombine(vma->vm_page_prot) :
 			    pgprot_dmacoherent(vma->vm_page_prot);
 
+	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
+		return ret;
+
 	c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
 	if (c) {
 		unsigned long off = vma->vm_pgoff;
+		struct page *pages = c->priv;
 
 		kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
 
 		if (off < kern_size &&
 		    user_size <= (kern_size - off)) {
 			ret = remap_pfn_range(vma, vma->vm_start,
-					      page_to_pfn(c->vm_pages) + off,
+					      page_to_pfn(pages) + off,
 					      user_size << PAGE_SHIFT,
 					      vma->vm_page_prot);
 		}
@@ -645,6 +665,9 @@ int arm_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 	int i, j;
 
 	for_each_sg(sg, s, nents, i) {
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+		s->dma_length = s->length;
+#endif
 		s->dma_address = ops->map_page(dev, sg_page(s), s->offset,
 						s->length, dir, attrs);
 		if (dma_mapping_error(dev, s->dma_address))
@@ -753,3 +776,683 @@ static int __init dma_debug_do_init(void)
 	return 0;
 }
 fs_initcall(dma_debug_do_init);
+
+#ifdef CONFIG_ARM_DMA_USE_IOMMU
+
+/* IOMMU */
+
+static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
+				      size_t size)
+{
+	unsigned int order = get_order(size);
+	unsigned int align = 0;
+	unsigned int count, start;
+	unsigned long flags;
+
+	count = ((PAGE_ALIGN(size) >> PAGE_SHIFT) +
+		 (1 << mapping->order) - 1) >> mapping->order;
+
+	if (order > mapping->order)
+		align = (1 << (order - mapping->order)) - 1;
+
+	spin_lock_irqsave(&mapping->lock, flags);
+	start = bitmap_find_next_zero_area(mapping->bitmap, mapping->bits, 0,
+					   count, align);
+	if (start > mapping->bits) {
+		spin_unlock_irqrestore(&mapping->lock, flags);
+		return ARM_DMA_ERROR;
+	}
+
+	bitmap_set(mapping->bitmap, start, count);
+	spin_unlock_irqrestore(&mapping->lock, flags);
+
+	return mapping->base + (start << (mapping->order + PAGE_SHIFT));
+}
+
+static inline void __free_iova(struct dma_iommu_mapping *mapping,
+			       dma_addr_t addr, size_t size)
+{
+	unsigned int start = (addr - mapping->base) >>
+			     (mapping->order + PAGE_SHIFT);
+	unsigned int count = ((size >> PAGE_SHIFT) +
+			      (1 << mapping->order) - 1) >> mapping->order;
+	unsigned long flags;
+
+	spin_lock_irqsave(&mapping->lock, flags);
+	bitmap_clear(mapping->bitmap, start, count);
+	spin_unlock_irqrestore(&mapping->lock, flags);
+}
+
+static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, gfp_t gfp)
+{
+	struct page **pages;
+	int count = size >> PAGE_SHIFT;
+	int array_size = count * sizeof(struct page *);
+	int i = 0;
+
+	if (array_size <= PAGE_SIZE)
+		pages = kzalloc(array_size, gfp);
+	else
+		pages = vzalloc(array_size);
+	if (!pages)
+		return NULL;
+
+	while (count) {
+		int j, order = __ffs(count);
+
+		pages[i] = alloc_pages(gfp | __GFP_NOWARN, order);
+		while (!pages[i] && order)
+			pages[i] = alloc_pages(gfp | __GFP_NOWARN, --order);
+		if (!pages[i])
+			goto error;
+
+		if (order)
+			split_page(pages[i], order);
+		j = 1 << order;
+		while (--j)
+			pages[i + j] = pages[i] + j;
+
+		__dma_clear_buffer(pages[i], PAGE_SIZE << order);
+		i += 1 << order;
+		count -= 1 << order;
+	}
+
+	return pages;
+error:
+	while (--i)
+		if (pages[i])
+			__free_pages(pages[i], 0);
+	if (array_size < PAGE_SIZE)
+		kfree(pages);
+	else
+		vfree(pages);
+	return NULL;
+}
+
+static int __iommu_free_buffer(struct device *dev, struct page **pages, size_t size)
+{
+	int count = size >> PAGE_SHIFT;
+	int array_size = count * sizeof(struct page *);
+	int i;
+	for (i = 0; i < count; i++)
+		if (pages[i])
+			__free_pages(pages[i], 0);
+	if (array_size < PAGE_SIZE)
+		kfree(pages);
+	else
+		vfree(pages);
+	return 0;
+}
+
+/*
+ * Create a CPU mapping for a specified pages
+ */
+static void *
+__iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot)
+{
+	struct arm_vmregion *c;
+	size_t align;
+	size_t count = size >> PAGE_SHIFT;
+	int bit;
+
+	if (!consistent_pte[0]) {
+		pr_err("%s: not initialised\n", __func__);
+		dump_stack();
+		return NULL;
+	}
+
+	/*
+	 * Align the virtual region allocation - maximum alignment is
+	 * a section size, minimum is a page size.  This helps reduce
+	 * fragmentation of the DMA space, and also prevents allocations
+	 * smaller than a section from crossing a section boundary.
+	 */
+	bit = fls(size - 1);
+	if (bit > SECTION_SHIFT)
+		bit = SECTION_SHIFT;
+	align = 1 << bit;
+
+	/*
+	 * Allocate a virtual address in the consistent mapping region.
+	 */
+	c = arm_vmregion_alloc(&consistent_head, align, size,
+			    gfp & ~(__GFP_DMA | __GFP_HIGHMEM), NULL);
+	if (c) {
+		pte_t *pte;
+		int idx = CONSISTENT_PTE_INDEX(c->vm_start);
+		int i = 0;
+		u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);
+
+		pte = consistent_pte[idx] + off;
+		c->priv = pages;
+
+		do {
+			BUG_ON(!pte_none(*pte));
+
+			set_pte_ext(pte, mk_pte(pages[i], prot), 0);
+			pte++;
+			off++;
+			i++;
+			if (off >= PTRS_PER_PTE) {
+				off = 0;
+				pte = consistent_pte[++idx];
+			}
+		} while (i < count);
+
+		dsb();
+
+		return (void *)c->vm_start;
+	}
+	return NULL;
+}
+
+/*
+ * Create a mapping in device IO address space for specified pages
+ */
+static dma_addr_t
+__iommu_create_mapping(struct device *dev, struct page **pages, size_t size)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	dma_addr_t dma_addr, iova;
+	int i, ret = ARM_DMA_ERROR;
+
+	dma_addr = __alloc_iova(mapping, size);
+	if (dma_addr == ARM_DMA_ERROR)
+		return dma_addr;
+
+	iova = dma_addr;
+	for (i = 0; i < count; ) {
+		unsigned int next_pfn = page_to_pfn(pages[i]) + 1;
+		phys_addr_t phys = page_to_phys(pages[i]);
+		unsigned int len, j;
+
+		for (j = i + 1; j < count; j++, next_pfn++)
+			if (page_to_pfn(pages[j]) != next_pfn)
+				break;
+
+		len = (j - i) << PAGE_SHIFT;
+		ret = iommu_map(mapping->domain, iova, phys, len, 0);
+		if (ret < 0)
+			goto fail;
+		iova += len;
+		i = j;
+	}
+	return dma_addr;
+fail:
+	iommu_unmap(mapping->domain, dma_addr, iova-dma_addr);
+	__free_iova(mapping, dma_addr, size);
+	return ARM_DMA_ERROR;
+}
+
+static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t size)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+
+	/*
+	 * add optional in-page offset from iova to size and align
+	 * result to page size
+	 */
+	size = PAGE_ALIGN((iova & ~PAGE_MASK) + size);
+	iova &= PAGE_MASK;
+
+	iommu_unmap(mapping->domain, iova, size);
+	__free_iova(mapping, iova, size);
+	return 0;
+}
+
+static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
+	    dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
+{
+	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
+	struct page **pages;
+	void *addr = NULL;
+
+	*handle = ARM_DMA_ERROR;
+	size = PAGE_ALIGN(size);
+
+	pages = __iommu_alloc_buffer(dev, size, gfp);
+	if (!pages)
+		return NULL;
+
+	*handle = __iommu_create_mapping(dev, pages, size);
+	if (*handle == ARM_DMA_ERROR)
+		goto err_buffer;
+
+	addr = __iommu_alloc_remap(pages, size, gfp, prot);
+	if (!addr)
+		goto err_mapping;
+
+	return addr;
+
+err_mapping:
+	__iommu_remove_mapping(dev, *handle, size);
+err_buffer:
+	__iommu_free_buffer(dev, pages, size);
+	return NULL;
+}
+
+static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
+		    void *cpu_addr, dma_addr_t dma_addr, size_t size,
+		    struct dma_attrs *attrs)
+{
+	struct arm_vmregion *c;
+
+	vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
+	c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
+
+	if (c) {
+		struct page **pages = c->priv;
+
+		unsigned long uaddr = vma->vm_start;
+		unsigned long usize = vma->vm_end - vma->vm_start;
+		int i = 0;
+
+		do {
+			int ret;
+
+			ret = vm_insert_page(vma, uaddr, pages[i++]);
+			if (ret) {
+				pr_err("Remapping memory, error: %d\n", ret);
+				return ret;
+			}
+
+			uaddr += PAGE_SIZE;
+			usize -= PAGE_SIZE;
+		} while (usize > 0);
+	}
+	return 0;
+}
+
+/*
+ * free a page as defined by the above mapping.
+ * Must not be called with IRQs disabled.
+ */
+void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+			  dma_addr_t handle, struct dma_attrs *attrs)
+{
+	struct arm_vmregion *c;
+	size = PAGE_ALIGN(size);
+
+	c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
+	if (c) {
+		struct page **pages = c->priv;
+		__dma_free_remap(cpu_addr, size);
+		__iommu_remove_mapping(dev, handle, size);
+		__iommu_free_buffer(dev, pages, size);
+	}
+}
+
+/*
+ * Map a part of the scatter-gather list into contiguous io address space
+ */
+static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
+			  size_t size, dma_addr_t *handle,
+			  enum dma_data_direction dir)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+	dma_addr_t iova, iova_base;
+	int ret = 0;
+	unsigned int count;
+	struct scatterlist *s;
+
+	size = PAGE_ALIGN(size);
+	*handle = ARM_DMA_ERROR;
+
+	iova_base = iova = __alloc_iova(mapping, size);
+	if (iova == ARM_DMA_ERROR)
+		return -ENOMEM;
+
+	for (count = 0, s = sg; count < (size >> PAGE_SHIFT); s = sg_next(s)) {
+		phys_addr_t phys = page_to_phys(sg_page(s));
+		unsigned int len = PAGE_ALIGN(s->offset + s->length);
+
+		if (!arch_is_coherent())
+			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
+
+		ret = iommu_map(mapping->domain, iova, phys, len, 0);
+		if (ret < 0)
+			goto fail;
+		count += len >> PAGE_SHIFT;
+		iova += len;
+	}
+	*handle = iova_base;
+
+	return 0;
+fail:
+	iommu_unmap(mapping->domain, iova_base, count * PAGE_SIZE);
+	__free_iova(mapping, iova_base, size);
+	return ret;
+}
+
+/**
+ * arm_iommu_map_sg - map a set of SG buffers for streaming mode DMA
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to map
+ * @dir: DMA transfer direction
+ *
+ * Map a set of buffers described by scatterlist in streaming mode for DMA.
+ * The scatter gather list elements are merged together (if possible) and
+ * tagged with the appropriate dma address and length. They are obtained via
+ * sg_dma_{address,length}.
+ */
+int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+		     enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+	struct scatterlist *s = sg, *dma = sg, *start = sg;
+	int i, count = 0;
+	unsigned int offset = s->offset;
+	unsigned int size = s->offset + s->length;
+	unsigned int max = dma_get_max_seg_size(dev);
+
+	for (i = 1; i < nents; i++) {
+		s = sg_next(s);
+
+		s->dma_address = ARM_DMA_ERROR;
+		s->dma_length = 0;
+
+		if (s->offset || (size & ~PAGE_MASK) || size + s->length > max) {
+			if (__map_sg_chunk(dev, start, size, &dma->dma_address,
+			    dir) < 0)
+				goto bad_mapping;
+
+			dma->dma_address += offset;
+			dma->dma_length = size - offset;
+
+			size = offset = s->offset;
+			start = s;
+			dma = sg_next(dma);
+			count += 1;
+		}
+		size += s->length;
+	}
+	if (__map_sg_chunk(dev, start, size, &dma->dma_address, dir) < 0)
+		goto bad_mapping;
+
+	dma->dma_address += offset;
+	dma->dma_length = size - offset;
+
+	return count+1;
+
+bad_mapping:
+	for_each_sg(sg, s, count, i)
+		__iommu_remove_mapping(dev, sg_dma_address(s), sg_dma_len(s));
+	return 0;
+}
+
+/**
+ * arm_iommu_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to unmap (same as was passed to dma_map_sg)
+ * @dir: DMA transfer direction (same as was passed to dma_map_sg)
+ *
+ * Unmap a set of streaming mode DMA translations.  Again, CPU access
+ * rules concerning calls here are the same as for dma_unmap_single().
+ */
+void arm_iommu_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
+			enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i) {
+		if (sg_dma_len(s))
+			__iommu_remove_mapping(dev, sg_dma_address(s),
+					       sg_dma_len(s));
+		if (!arch_is_coherent())
+			__dma_page_dev_to_cpu(sg_page(s), s->offset,
+					      s->length, dir);
+	}
+}
+
+/**
+ * arm_iommu_sync_sg_for_cpu
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to map (returned from dma_map_sg)
+ * @dir: DMA transfer direction (same as was passed to dma_map_sg)
+ */
+void arm_iommu_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+			int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i)
+		if (!arch_is_coherent())
+			__dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir);
+
+}
+
+/**
+ * arm_iommu_sync_sg_for_device
+ * @dev: valid struct device pointer
+ * @sg: list of buffers
+ * @nents: number of buffers to map (returned from dma_map_sg)
+ * @dir: DMA transfer direction (same as was passed to dma_map_sg)
+ */
+void arm_iommu_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+			int nents, enum dma_data_direction dir)
+{
+	struct scatterlist *s;
+	int i;
+
+	for_each_sg(sg, s, nents, i)
+		if (!arch_is_coherent())
+			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
+}
+
+
+/**
+ * arm_iommu_map_page
+ * @dev: valid struct device pointer
+ * @page: page that buffer resides in
+ * @offset: offset into page for start of buffer
+ * @size: size of buffer to map
+ * @dir: DMA transfer direction
+ *
+ * IOMMU aware version of arm_dma_map_page()
+ */
+static dma_addr_t arm_iommu_map_page(struct device *dev, struct page *page,
+	     unsigned long offset, size_t size, enum dma_data_direction dir,
+	     struct dma_attrs *attrs)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+	dma_addr_t dma_addr;
+	int ret, len = PAGE_ALIGN(size + offset);
+
+	if (!arch_is_coherent())
+		__dma_page_cpu_to_dev(page, offset, size, dir);
+
+	dma_addr = __alloc_iova(mapping, len);
+	if (dma_addr == ARM_DMA_ERROR)
+		return dma_addr;
+
+	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, 0);
+	if (ret < 0)
+		goto fail;
+
+	return dma_addr + offset;
+fail:
+	__free_iova(mapping, dma_addr, len);
+	return ARM_DMA_ERROR;
+}
+
+/**
+ * arm_iommu_unmap_page
+ * @dev: valid struct device pointer
+ * @handle: DMA address of buffer
+ * @size: size of buffer (same as passed to dma_map_page)
+ * @dir: DMA transfer direction (same as passed to dma_map_page)
+ *
+ * IOMMU aware version of arm_dma_unmap_page()
+ */
+static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir,
+		struct dma_attrs *attrs)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+	dma_addr_t iova = handle & PAGE_MASK;
+	struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+	int offset = handle & ~PAGE_MASK;
+	int len = PAGE_ALIGN(size + offset);
+
+	if (!iova)
+		return;
+
+	if (!arch_is_coherent())
+		__dma_page_dev_to_cpu(page, offset, size, dir);
+
+	iommu_unmap(mapping->domain, iova, len);
+	__free_iova(mapping, iova, len);
+}
+
+static void arm_iommu_sync_single_for_cpu(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+	dma_addr_t iova = handle & PAGE_MASK;
+	struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+	unsigned int offset = handle & ~PAGE_MASK;
+
+	if (!iova)
+		return;
+
+	if (!arch_is_coherent())
+		__dma_page_dev_to_cpu(page, offset, size, dir);
+}
+
+static void arm_iommu_sync_single_for_device(struct device *dev,
+		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+	dma_addr_t iova = handle & PAGE_MASK;
+	struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+	unsigned int offset = handle & ~PAGE_MASK;
+
+	if (!iova)
+		return;
+
+	__dma_page_cpu_to_dev(page, offset, size, dir);
+}
+
+const struct dma_map_ops iommu_ops = {
+	.alloc		= arm_iommu_alloc_attrs,
+	.free		= arm_iommu_free_attrs,
+	.mmap		= arm_iommu_mmap_attrs,
+
+	.map_page		= arm_iommu_map_page,
+	.unmap_page		= arm_iommu_unmap_page,
+	.sync_single_for_cpu	= arm_iommu_sync_single_for_cpu,
+	.sync_single_for_device	= arm_iommu_sync_single_for_device,
+
+	.map_sg			= arm_iommu_map_sg,
+	.unmap_sg		= arm_iommu_unmap_sg,
+	.sync_sg_for_cpu	= arm_iommu_sync_sg_for_cpu,
+	.sync_sg_for_device	= arm_iommu_sync_sg_for_device,
+};
+
+/**
+ * arm_iommu_create_mapping
+ * @bus: pointer to the bus holding the client device (for IOMMU calls)
+ * @base: start address of the valid IO address space
+ * @size: size of the valid IO address space
+ * @order: accuracy of the IO addresses allocations
+ *
+ * Creates a mapping structure which holds information about used/unused
+ * IO address ranges, which is required to perform memory allocation and
+ * mapping with IOMMU aware functions.
+ *
+ * The client device need to be attached to the mapping with
+ * arm_iommu_attach_device function.
+ */
+struct dma_iommu_mapping *
+arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
+			 int order)
+{
+	unsigned int count = size >> (PAGE_SHIFT + order);
+	unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
+	struct dma_iommu_mapping *mapping;
+	int err = -ENOMEM;
+
+	if (!count)
+		return ERR_PTR(-EINVAL);
+
+	mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
+	if (!mapping)
+		goto err;
+
+	mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+	if (!mapping->bitmap)
+		goto err2;
+
+	mapping->base = base;
+	mapping->bits = BITS_PER_BYTE * bitmap_size;
+	mapping->order = order;
+	spin_lock_init(&mapping->lock);
+
+	mapping->domain = iommu_domain_alloc(bus);
+	if (!mapping->domain)
+		goto err3;
+
+	kref_init(&mapping->kref);
+	return mapping;
+err3:
+	kfree(mapping->bitmap);
+err2:
+	kfree(mapping);
+err:
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(arm_iommu_create_mapping);
+
+static void release_iommu_mapping(struct kref *kref)
+{
+	struct dma_iommu_mapping *mapping =
+		container_of(kref, struct dma_iommu_mapping, kref);
+
+	iommu_domain_free(mapping->domain);
+	kfree(mapping->bitmap);
+	kfree(mapping);
+}
+
+
+void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping)
+{
+	if (mapping)
+		kref_put(&mapping->kref, release_iommu_mapping);
+}
+EXPORT_SYMBOL(arm_iommu_release_mapping);
+
+/**
+ * arm_iommu_attach_device
+ * @dev: valid struct device pointer
+ * @mapping: io address space mapping structure (returned from
+ *	arm_iommu_create_mapping)
+ *
+ * Attaches specified io address space mapping to the provided device,
+ * this replaces the dma operations (dma_map_ops pointer) with the
+ * IOMMU aware version. More than one client might be attached to
+ * the same io address space mapping.
+ */
+int arm_iommu_attach_device(struct device *dev,
+			    struct dma_iommu_mapping *mapping)
+{
+	int err;
+
+	err = iommu_attach_device(mapping->domain, dev);
+	if (err)
+		return err;
+
+	kref_get(&mapping->kref);
+	dev->archdata.mapping = mapping;
+	set_dma_ops(dev, &iommu_ops);
+
+	pr_info("Attached IOMMU controller to %s device.\n", dev_name(dev));
+	return 0;
+}
+EXPORT_SYMBOL(arm_iommu_attach_device);
+
+#endif
diff --git a/arch/arm/mm/vmregion.h b/arch/arm/mm/vmregion.h
index 162be66..bf312c3 100644
--- a/arch/arm/mm/vmregion.h
+++ b/arch/arm/mm/vmregion.h
@@ -17,7 +17,7 @@ struct arm_vmregion {
 	struct list_head	vm_list;
 	unsigned long		vm_start;
 	unsigned long		vm_end;
-	struct page		*vm_pages;
+	void			*priv;
 	int			vm_active;
 	const void		*caller;
 };
-- 
1.7.1.569.g6f426

Re: [PATCHv8 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> +/**
> + * arm_iommu_create_mapping
> + * @bus: pointer to the bus holding the client device (for IOMMU calls)
> + * @base: start address of the valid IO address space
> + * @size: size of the valid IO address space
> + * @order: accuracy of the IO addresses allocations
> + *
> + * Creates a mapping structure which holds information about used/unused
> + * IO address ranges, which is required to perform memory allocation and
> + * mapping with IOMMU aware functions.
> + *
> + * The client device need to be attached to the mapping with
> + * arm_iommu_attach_device function.
> + */
> +struct dma_iommu_mapping *
> +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
> +                        int order)
> +{
> +       unsigned int count = size >> (PAGE_SHIFT + order);
> +       unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
> +       struct dma_iommu_mapping *mapping;
> +       int err = -ENOMEM;
> +
> +       if (!count)
> +               return ERR_PTR(-EINVAL);
> +
> +       mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
> +       if (!mapping)
> +               goto err;
> +
> +       mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +       if (!mapping->bitmap)
> +               goto err2;
> +
> +       mapping->base = base;
> +       mapping->bits = BITS_PER_BYTE * bitmap_size;
> +       mapping->order = order;
> +       spin_lock_init(&mapping->lock);
> +
> +       mapping->domain = iommu_domain_alloc(bus);
> +       if (!mapping->domain)
> +               goto err3;
> +
> +       kref_init(&mapping->kref);
> +       return mapping;
> +err3:
> +       kfree(mapping->bitmap);
> +err2:
> +       kfree(mapping);
> +err:
> +       return ERR_PTR(err);
> +}
> +EXPORT_SYMBOL(arm_iommu_create_mapping);

I don't understand this function, mostly I guess because you have not
provided any users. A few questions here:

* What is ARM specific about it that it is named arm_iommu_create_mapping?
  Isn't this completely generic, at least on the interface side?

* Why is this exported to modules? Which device drivers do you expect
  to call it?

* Why do you pass the bus_type in here? That seems like the completely
  wrong thing to do when all devices are on the same bus type (e.g.
  amba or platform) but are connected to different instances that each
  have their own iommu. I guess this is a question for Jörg, because the
  base iommu interface provides iommu_domain_alloc().

	Arnd

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Re: [PATCHv8 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Arnd Bergmann]

On Tuesday 10 April 2012, Marek Szyprowski wrote:
> +/**
> + * arm_iommu_create_mapping
> + * @bus: pointer to the bus holding the client device (for IOMMU calls)
> + * @base: start address of the valid IO address space
> + * @size: size of the valid IO address space
> + * @order: accuracy of the IO addresses allocations
> + *
> + * Creates a mapping structure which holds information about used/unused
> + * IO address ranges, which is required to perform memory allocation and
> + * mapping with IOMMU aware functions.
> + *
> + * The client device need to be attached to the mapping with
> + * arm_iommu_attach_device function.
> + */
> +struct dma_iommu_mapping *
> +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
> +                        int order)
> +{
> +       unsigned int count = size >> (PAGE_SHIFT + order);
> +       unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
> +       struct dma_iommu_mapping *mapping;
> +       int err = -ENOMEM;
> +
> +       if (!count)
> +               return ERR_PTR(-EINVAL);
> +
> +       mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
> +       if (!mapping)
> +               goto err;
> +
> +       mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +       if (!mapping->bitmap)
> +               goto err2;
> +
> +       mapping->base = base;
> +       mapping->bits = BITS_PER_BYTE * bitmap_size;
> +       mapping->order = order;
> +       spin_lock_init(&mapping->lock);
> +
> +       mapping->domain = iommu_domain_alloc(bus);
> +       if (!mapping->domain)
> +               goto err3;
> +
> +       kref_init(&mapping->kref);
> +       return mapping;
> +err3:
> +       kfree(mapping->bitmap);
> +err2:
> +       kfree(mapping);
> +err:
> +       return ERR_PTR(err);
> +}
> +EXPORT_SYMBOL(arm_iommu_create_mapping);

I don't understand this function, mostly I guess because you have not
provided any users. A few questions here:

* What is ARM specific about it that it is named arm_iommu_create_mapping?
  Isn't this completely generic, at least on the interface side?

* Why is this exported to modules? Which device drivers do you expect
  to call it?

* Why do you pass the bus_type in here? That seems like the completely
  wrong thing to do when all devices are on the same bus type (e.g.
  amba or platform) but are connected to different instances that each
  have their own iommu. I guess this is a question for Jörg, because the
  base iommu interface provides iommu_domain_alloc().

	Arnd

RE: [PATCHv8 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 1:58 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > +/**
> > + * arm_iommu_create_mapping
> > + * @bus: pointer to the bus holding the client device (for IOMMU calls)
> > + * @base: start address of the valid IO address space
> > + * @size: size of the valid IO address space
> > + * @order: accuracy of the IO addresses allocations
> > + *
> > + * Creates a mapping structure which holds information about used/unused
> > + * IO address ranges, which is required to perform memory allocation and
> > + * mapping with IOMMU aware functions.
> > + *
> > + * The client device need to be attached to the mapping with
> > + * arm_iommu_attach_device function.
> > + */
> > +struct dma_iommu_mapping *
> > +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
> > +                        int order)
> > +{
> > +       unsigned int count = size >> (PAGE_SHIFT + order);
> > +       unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
> > +       struct dma_iommu_mapping *mapping;
> > +       int err = -ENOMEM;
> > +
> > +       if (!count)
> > +               return ERR_PTR(-EINVAL);
> > +
> > +       mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
> > +       if (!mapping)
> > +               goto err;
> > +
> > +       mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> > +       if (!mapping->bitmap)
> > +               goto err2;
> > +
> > +       mapping->base = base;
> > +       mapping->bits = BITS_PER_BYTE * bitmap_size;
> > +       mapping->order = order;
> > +       spin_lock_init(&mapping->lock);
> > +
> > +       mapping->domain = iommu_domain_alloc(bus);
> > +       if (!mapping->domain)
> > +               goto err3;
> > +
> > +       kref_init(&mapping->kref);
> > +       return mapping;
> > +err3:
> > +       kfree(mapping->bitmap);
> > +err2:
> > +       kfree(mapping);
> > +err:
> > +       return ERR_PTR(err);
> > +}
> > +EXPORT_SYMBOL(arm_iommu_create_mapping);
> 
> I don't understand this function, mostly I guess because you have not
> provided any users. A few questions here:
> 
> * What is ARM specific about it that it is named arm_iommu_create_mapping?
>   Isn't this completely generic, at least on the interface side?
> 
> * Why is this exported to modules? Which device drivers do you expect
>   to call it?
> 
> * Why do you pass the bus_type in here? That seems like the completely
>   wrong thing to do when all devices are on the same bus type (e.g.
>   amba or platform) but are connected to different instances that each
>   have their own iommu. I guess this is a question for Jörg, because the
>   base iommu interface provides iommu_domain_alloc().

I will soon post a patch which shows how my IOMMU aware dma-mapping 
integrates with Samsung Exynos4 SYSMMU driver, so I will be able to answer
all your questions by pointing to the respective lines in either IOMMU
framework or my integration code.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

RE: [PATCHv8 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 1:58 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > +/**
> > + * arm_iommu_create_mapping
> > + * @bus: pointer to the bus holding the client device (for IOMMU calls)
> > + * @base: start address of the valid IO address space
> > + * @size: size of the valid IO address space
> > + * @order: accuracy of the IO addresses allocations
> > + *
> > + * Creates a mapping structure which holds information about used/unused
> > + * IO address ranges, which is required to perform memory allocation and
> > + * mapping with IOMMU aware functions.
> > + *
> > + * The client device need to be attached to the mapping with
> > + * arm_iommu_attach_device function.
> > + */
> > +struct dma_iommu_mapping *
> > +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
> > +                        int order)
> > +{
> > +       unsigned int count = size >> (PAGE_SHIFT + order);
> > +       unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
> > +       struct dma_iommu_mapping *mapping;
> > +       int err = -ENOMEM;
> > +
> > +       if (!count)
> > +               return ERR_PTR(-EINVAL);
> > +
> > +       mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
> > +       if (!mapping)
> > +               goto err;
> > +
> > +       mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> > +       if (!mapping->bitmap)
> > +               goto err2;
> > +
> > +       mapping->base = base;
> > +       mapping->bits = BITS_PER_BYTE * bitmap_size;
> > +       mapping->order = order;
> > +       spin_lock_init(&mapping->lock);
> > +
> > +       mapping->domain = iommu_domain_alloc(bus);
> > +       if (!mapping->domain)
> > +               goto err3;
> > +
> > +       kref_init(&mapping->kref);
> > +       return mapping;
> > +err3:
> > +       kfree(mapping->bitmap);
> > +err2:
> > +       kfree(mapping);
> > +err:
> > +       return ERR_PTR(err);
> > +}
> > +EXPORT_SYMBOL(arm_iommu_create_mapping);
> 
> I don't understand this function, mostly I guess because you have not
> provided any users. A few questions here:
> 
> * What is ARM specific about it that it is named arm_iommu_create_mapping?
>   Isn't this completely generic, at least on the interface side?
> 
> * Why is this exported to modules? Which device drivers do you expect
>   to call it?
> 
> * Why do you pass the bus_type in here? That seems like the completely
>   wrong thing to do when all devices are on the same bus type (e.g.
>   amba or platform) but are connected to different instances that each
>   have their own iommu. I guess this is a question for Jörg, because the
>   base iommu interface provides iommu_domain_alloc().

I will soon post a patch which shows how my IOMMU aware dma-mapping 
integrates with Samsung Exynos4 SYSMMU driver, so I will be able to answer
all your questions by pointing to the respective lines in either IOMMU
framework or my integration code.

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

RE: [PATCHv8 10/10] ARM: dma-mapping: add support for IOMMU mapper

[Marek Szyprowski]

Hi Arnd,

On Tuesday, April 10, 2012 1:58 PM Arnd Bergmann wrote:

> On Tuesday 10 April 2012, Marek Szyprowski wrote:
> > +/**
> > + * arm_iommu_create_mapping
> > + * @bus: pointer to the bus holding the client device (for IOMMU calls)
> > + * @base: start address of the valid IO address space
> > + * @size: size of the valid IO address space
> > + * @order: accuracy of the IO addresses allocations
> > + *
> > + * Creates a mapping structure which holds information about used/unused
> > + * IO address ranges, which is required to perform memory allocation and
> > + * mapping with IOMMU aware functions.
> > + *
> > + * The client device need to be attached to the mapping with
> > + * arm_iommu_attach_device function.
> > + */
> > +struct dma_iommu_mapping *
> > +arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
> > +                        int order)
> > +{
> > +       unsigned int count = size >> (PAGE_SHIFT + order);
> > +       unsigned int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
> > +       struct dma_iommu_mapping *mapping;
> > +       int err = -ENOMEM;
> > +
> > +       if (!count)
> > +               return ERR_PTR(-EINVAL);
> > +
> > +       mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
> > +       if (!mapping)
> > +               goto err;
> > +
> > +       mapping->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> > +       if (!mapping->bitmap)
> > +               goto err2;
> > +
> > +       mapping->base = base;
> > +       mapping->bits = BITS_PER_BYTE * bitmap_size;
> > +       mapping->order = order;
> > +       spin_lock_init(&mapping->lock);
> > +
> > +       mapping->domain = iommu_domain_alloc(bus);
> > +       if (!mapping->domain)
> > +               goto err3;
> > +
> > +       kref_init(&mapping->kref);
> > +       return mapping;
> > +err3:
> > +       kfree(mapping->bitmap);
> > +err2:
> > +       kfree(mapping);
> > +err:
> > +       return ERR_PTR(err);
> > +}
> > +EXPORT_SYMBOL(arm_iommu_create_mapping);
> 
> I don't understand this function, mostly I guess because you have not
> provided any users. A few questions here:
> 
> * What is ARM specific about it that it is named arm_iommu_create_mapping?
>   Isn't this completely generic, at least on the interface side?

This function is quite generic. It creates 'struct dma_iommu_mapping' object,
which is stored in the client's device arch data. This object mainly stores
information about io/dma address space: base address, allocation bitmap and
respective iommu domain. Please note that more than one device can be assigned
to the given dma_iommu_mapping to match different hardware topologies.

This function is called by the board/(sub-)platform startup code to initialize
iommu based dma-mapping. For the example usage please refer to 
s5p_create_iommu_mapping() function in arch/arm/mach-exynos/dev-sysmmu.c on 
3.4-rc2-arm-dma-v8-samsung branch in 
git://git.linaro.org/people/mszyprowski/linux-dma-mapping.git

GITWeb shortcut: 
http://git.linaro.org/gitweb?p=people/mszyprowski/linux-dma-mapping.git;a=blob;f=arch/arm/mach-exyno
s/dev-sysmmu.c;h=31f2d6caf0e9949def18abd18af3f9d16737ae19;hb=6025093750d41f88406042e6486e331b806dc87
5#l283

> * Why is this exported to modules? Which device drivers do you expect
>   to call it?

I thought it might be useful to use modules for registering devices, but 
now I see that no platform use such approach. I will drop these exports 
unless someone finds a real use case for them.

> * Why do you pass the bus_type in here? That seems like the completely
>   wrong thing to do when all devices are on the same bus type (e.g.
>   amba or platform) but are connected to different instances that each
>   have their own iommu. I guess this is a question for Jörg, because the
>   base iommu interface provides iommu_domain_alloc().

That's only a consequence of the iommu api. I would also prefer to use client 
device pointer here instead of the bus id, but maybe I don't have enough 
knowledge about desktop IOMMUs. I suspect that there is also a need to assign
one IOMMU driver to the whole bus (like pci bus) and it originates from such
systems. In embedded world we usually have only one iommu driver which 
operates on the platform bus devices. On Samsung Exynos4 we have over a dozen
SYSMMU controllers for various multimedia blocks, but they are all exactly 
the same. We use one iommu ops structure and store a pointer to the real 
iommu controller instance inside arch data of the client struct device.
 
Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center