[PATCH 14/17] dma-mapping: add a new dma_alloc_pages API

Christoph Hellwig
2020-09-14T15:19:44Z

This API is the equivalent of alloc_pages, except that the returned memory
is guaranteed to be DMA addressable by the passed in device. The
implementation will also be used to provide a more sensible replacement
for DMA_ATTR_NON_CONSISTENT flag.

Additionally dma_alloc_noncoherent is switched over to use dma_alloc_pages
as its backend.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
Documentation/core-api/dma-attributes.rst | 8 ---
arch/alpha/kernel/pci_iommu.c | 2 +
arch/arm/mm/dma-mapping-nommu.c | 2 +
arch/arm/mm/dma-mapping.c | 4 ++
arch/ia64/hp/common/sba_iommu.c | 2 +
arch/mips/jazz/jazzdma.c | 7 +--
arch/powerpc/kernel/dma-iommu.c | 2 +
arch/powerpc/platforms/ps3/system-bus.c | 4 ++
arch/powerpc/platforms/pseries/vio.c | 2 +
arch/s390/pci/pci_dma.c | 2 +
arch/x86/kernel/amd_gart_64.c | 2 +
drivers/iommu/dma-iommu.c | 2 +
drivers/iommu/intel/iommu.c | 4 ++
drivers/parisc/ccio-dma.c | 2 +
drivers/parisc/sba_iommu.c | 2 +
drivers/xen/swiotlb-xen.c | 2 +
include/linux/dma-direct.h | 5 ++
include/linux/dma-mapping.h | 34 ++++++------
include/linux/dma-noncoherent.h | 3 --
kernel/dma/direct.c | 52 ++++++++++++++++++-
kernel/dma/mapping.c | 63 +++++++++++++++++++++--
kernel/dma/ops_helpers.c | 35 +++++++++++++
kernel/dma/virt.c | 2 +
23 files changed, 206 insertions(+), 37 deletions(-)

diff --git a/Documentation/core-api/dma-attributes.rst b/Documentation/core-api/dma-attributes.rst
index 29dcbe8826e85e..1887d92e8e9269 100644
--- a/Documentation/core-api/dma-attributes.rst
+++ b/Documentation/core-api/dma-attributes.rst
@@ -25,14 +25,6 @@ Since it is optional for platforms to implement DMA_ATTR_WRITE_COMBINE,
those that do not will simply ignore the attribute and exhibit default
behavior.

-DMA_ATTR_NON_CONSISTENT
------------------------
-
-DMA_ATTR_NON_CONSISTENT lets the platform to choose to return either
-consistent or non-consistent memory as it sees fit. By using this API,
-you are guaranteeing to the platform that you have all the correct and
-necessary sync points for this memory in the driver.
-
DMA_ATTR_NO_KERNEL_MAPPING
--------------------------

diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
index 6f7de4f4e191e7..447e0fd0ed3895 100644
--- a/arch/alpha/kernel/pci_iommu.c
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -952,5 +952,7 @@ const struct dma_map_ops alpha_pci_ops = {
.dma_supported = alpha_pci_supported,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};
EXPORT_SYMBOL(alpha_pci_ops);
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index 287ef898a55e11..43c6d66b6e733a 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -176,6 +176,8 @@ static void arm_nommu_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist
const struct dma_map_ops arm_nommu_dma_ops = {
.alloc = arm_nommu_dma_alloc,
.free = arm_nommu_dma_free,
+ .alloc_pages = dma_direct_alloc_pages,
+ .free_pages = dma_direct_free_pages,
.mmap = arm_nommu_dma_mmap,
.map_page = arm_nommu_dma_map_page,
.unmap_page = arm_nommu_dma_unmap_page,
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8a8949174b1c06..7738b4d23f692f 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -199,6 +199,8 @@ static int arm_dma_supported(struct device *dev, u64 mask)
const struct dma_map_ops arm_dma_ops = {
.alloc = arm_dma_alloc,
.free = arm_dma_free,
+ .alloc_pages = dma_direct_alloc_pages,
+ .free_pages = dma_direct_free_pages,
.mmap = arm_dma_mmap,
.get_sgtable = arm_dma_get_sgtable,
.map_page = arm_dma_map_page,
@@ -226,6 +228,8 @@ static int arm_coherent_dma_mmap(struct device *dev, struct vm_area_struct *vma,
const struct dma_map_ops arm_coherent_dma_ops = {
.alloc = arm_coherent_dma_alloc,
.free = arm_coherent_dma_free,
+ .alloc_pages = dma_direct_alloc_pages,
+ .free_pages = dma_direct_free_pages,
.mmap = arm_coherent_dma_mmap,
.get_sgtable = arm_dma_get_sgtable,
.map_page = arm_coherent_dma_map_page,
diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
index b49b73a95067d2..cafbb848a34e4d 100644
--- a/arch/ia64/hp/common/sba_iommu.c
+++ b/arch/ia64/hp/common/sba_iommu.c
@@ -2070,6 +2070,8 @@ static const struct dma_map_ops sba_dma_ops = {
.dma_supported = sba_dma_supported,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};

static int __init
diff --git a/arch/mips/jazz/jazzdma.c b/arch/mips/jazz/jazzdma.c
index 2bf849caf507b1..f53bc043334c01 100644
--- a/arch/mips/jazz/jazzdma.c
+++ b/arch/mips/jazz/jazzdma.c
@@ -506,9 +506,6 @@ static void *jazz_dma_alloc(struct device *dev, size_t size,
*dma_handle = vdma_alloc(virt_to_phys(ret), size);
if (*dma_handle == DMA_MAPPING_ERROR)
goto out_free_pages;
-
- if (attrs & DMA_ATTR_NON_CONSISTENT)
- return ret;
arch_dma_prep_coherent(page, size);
return (void *)(UNCAC_BASE + __pa(ret));

@@ -521,8 +518,6 @@ static void jazz_dma_free(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle, unsigned long attrs)
{
vdma_free(dma_handle);
- if (!(attrs & DMA_ATTR_NON_CONSISTENT))
- vaddr = __va(vaddr - UNCAC_BASE);
__free_pages(virt_to_page(vaddr), get_order(size));
}

@@ -622,5 +617,7 @@ const struct dma_map_ops jazz_dma_ops = {
.sync_sg_for_device = jazz_dma_sync_sg_for_device,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};
EXPORT_SYMBOL(jazz_dma_ops);
diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
index 569fecd7b5b234..d4e702d74b3393 100644
--- a/arch/powerpc/kernel/dma-iommu.c
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -137,4 +137,6 @@ const struct dma_map_ops dma_iommu_ops = {
.get_required_mask = dma_iommu_get_required_mask,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};
diff --git a/arch/powerpc/platforms/ps3/system-bus.c b/arch/powerpc/platforms/ps3/system-bus.c
index 3542b7bd6a4689..7bc5f9be3e12d8 100644
--- a/arch/powerpc/platforms/ps3/system-bus.c
+++ b/arch/powerpc/platforms/ps3/system-bus.c
@@ -696,6 +696,8 @@ static const struct dma_map_ops ps3_sb_dma_ops = {
.unmap_page = ps3_unmap_page,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};

static const struct dma_map_ops ps3_ioc0_dma_ops = {
@@ -708,6 +710,8 @@ static const struct dma_map_ops ps3_ioc0_dma_ops = {
.unmap_page = ps3_unmap_page,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};

/**
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 0487b26f6f1af3..98ed7b09b3fe50 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -608,6 +608,8 @@ static const struct dma_map_ops vio_dma_mapping_ops = {
.get_required_mask = dma_iommu_get_required_mask,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};

/**
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 4a37d8f4de9d9d..9291023e9469c2 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -668,6 +668,8 @@ const struct dma_map_ops s390_pci_dma_ops = {
.unmap_page = s390_dma_unmap_pages,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
/* dma_supported is unconditionally true without a callback */
};
EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 153374b996a279..c96dcaa572ebd3 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -677,6 +677,8 @@ static const struct dma_map_ops gart_dma_ops = {
.get_sgtable = dma_common_get_sgtable,
.dma_supported = dma_direct_supported,
.get_required_mask = dma_direct_get_required_mask,
+ .alloc_pages = dma_direct_alloc_pages,
+ .free_pages = dma_direct_free_pages,
};

static void gart_iommu_shutdown(void)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 5141d49a046baa..00a5b49248e334 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1120,6 +1120,8 @@ static unsigned long iommu_dma_get_merge_boundary(struct device *dev)
static const struct dma_map_ops iommu_dma_ops = {
.alloc = iommu_dma_alloc,
.free = iommu_dma_free,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
.mmap = iommu_dma_mmap,
.get_sgtable = iommu_dma_get_sgtable,
.map_page = iommu_dma_map_page,
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 7983c13b9eef7d..26eb7aafa0bda6 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3669,6 +3669,8 @@ static const struct dma_map_ops intel_dma_ops = {
.dma_supported = dma_direct_supported,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
.get_required_mask = intel_get_required_mask,
};

@@ -3922,6 +3924,8 @@ static const struct dma_map_ops bounce_dma_ops = {
.sync_sg_for_device = bounce_sync_sg_for_device,
.map_resource = bounce_map_resource,
.unmap_resource = bounce_unmap_resource,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
.dma_supported = dma_direct_supported,
};

diff --git a/drivers/parisc/ccio-dma.c b/drivers/parisc/ccio-dma.c
index ba16b7f8f80612..8cf0b9c8bdf795 100644
--- a/drivers/parisc/ccio-dma.c
+++ b/drivers/parisc/ccio-dma.c
@@ -1024,6 +1024,8 @@ static const struct dma_map_ops ccio_ops = {
.map_sg = ccio_map_sg,
.unmap_sg = ccio_unmap_sg,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};

#ifdef CONFIG_PROC_FS
diff --git a/drivers/parisc/sba_iommu.c b/drivers/parisc/sba_iommu.c
index 959bda193b9603..6fcde7980358ae 100644
--- a/drivers/parisc/sba_iommu.c
+++ b/drivers/parisc/sba_iommu.c
@@ -1076,6 +1076,8 @@ static const struct dma_map_ops sba_ops = {
.map_sg = sba_map_sg,
.unmap_sg = sba_unmap_sg,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 39a0f2e0847c95..030a225624b060 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -578,4 +578,6 @@ const struct dma_map_ops xen_swiotlb_dma_ops = {
.dma_supported = xen_swiotlb_dma_supported,
.mmap = dma_common_mmap,
.get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 805010ea5346f9..c11bb935fc7fe3 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -77,6 +77,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t gfp, unsigned long attrs);
void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs);
+struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
+void dma_direct_free_pages(struct device *dev, size_t size,
+ struct page *page, dma_addr_t dma_addr,
+ enum dma_data_direction dir);
int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs);
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 5b4e97b0846fd3..bf592cf0db4acb 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -27,11 +27,6 @@
* buffered to improve performance.
*/
#define DMA_ATTR_WRITE_COMBINE (1UL << 2)
-/*
- * DMA_ATTR_NON_CONSISTENT: Lets the platform to choose to return either
- * consistent or non-consistent memory as it sees fit.
- */
-#define DMA_ATTR_NON_CONSISTENT (1UL << 3)
/*
* DMA_ATTR_NO_KERNEL_MAPPING: Lets the platform to avoid creating a kernel
* virtual mapping for the allocated buffer.
@@ -80,6 +75,11 @@ struct dma_map_ops {
void (*free)(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
unsigned long attrs);
+ struct page *(*alloc_pages)(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir,
+ gfp_t gfp);
+ void (*free_pages)(struct device *dev, size_t size, struct page *vaddr,
+ dma_addr_t dma_handle, enum dma_data_direction dir);
int (*mmap)(struct device *, struct vm_area_struct *,
void *, dma_addr_t, size_t,
unsigned long attrs);
@@ -381,17 +381,14 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev)
}
#endif /* CONFIG_HAS_DMA */

-static inline void *dma_alloc_noncoherent(struct device *dev, size_t size,
- dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
-{
- return dma_alloc_attrs(dev, size, dma_handle, gfp,
- DMA_ATTR_NON_CONSISTENT);
-}
-static inline void dma_free_noncoherent(struct device *dev, size_t size,
- void *vaddr, dma_addr_t dma_handle, enum dma_data_direction dir)
-{
- dma_free_attrs(dev, size, vaddr, dma_handle, DMA_ATTR_NON_CONSISTENT);
-}
+struct page *dma_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
+void dma_free_pages(struct device *dev, size_t size, struct page *page,
+ dma_addr_t dma_handle, enum dma_data_direction dir);
+void *dma_alloc_noncoherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
+void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, enum dma_data_direction dir);

static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
@@ -517,7 +514,10 @@ static inline void dma_sync_sgtable_for_device(struct device *dev,
extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs);
-
+struct page *dma_common_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
+void dma_common_free_pages(struct device *dev, size_t size, struct page *vaddr,
+ dma_addr_t dma_handle, enum dma_data_direction dir);
struct page **dma_common_find_pages(void *cpu_addr);
void *dma_common_contiguous_remap(struct page *page, size_t size,
pgprot_t prot, const void *caller);
diff --git a/include/linux/dma-noncoherent.h b/include/linux/dma-noncoherent.h
index 0888656369a45b..e61283e06576a8 100644
--- a/include/linux/dma-noncoherent.h
+++ b/include/linux/dma-noncoherent.h
@@ -31,9 +31,6 @@ static __always_inline bool dma_alloc_need_uncached(struct device *dev,
return false;
if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
return false;
- if (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) &&
- (attrs & DMA_ATTR_NON_CONSISTENT))
- return false;
return true;
}

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 54db9cfdaecc6d..9ba320383b0d19 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * Copyright (C) 2018 Christoph Hellwig.
+ * Copyright (C) 2018-2020 Christoph Hellwig.
*
* DMA operations that map physical memory directly without using an IOMMU.
*/
@@ -287,6 +287,56 @@ void dma_direct_free(struct device *dev, size_t size,
dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size);
}

+struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+ struct page *page;
+ void *ret;
+
+ if (dma_should_alloc_from_pool(dev, gfp, 0)) {
+ page = dma_alloc_from_pool(dev, size, &ret, gfp,
+ dma_coherent_ok);
+ if (!page)
+ return NULL;
+ goto done;
+ }
+
+ page = __dma_direct_alloc_pages(dev, size, gfp);
+ if (!page)
+ return NULL;
+ ret = page_address(page);
+ if (force_dma_unencrypted(dev)) {
+ if (set_memory_decrypted((unsigned long)ret,
+ 1 << get_order(size)))
+ goto out_free_pages;
+ }
+ memset(ret, 0, size);
+done:
+ *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+ return page;
+out_free_pages:
+ dma_free_contiguous(dev, page, size);
+ return NULL;
+}
+
+void dma_direct_free_pages(struct device *dev, size_t size,
+ struct page *page, dma_addr_t dma_addr,
+ enum dma_data_direction dir)
+{
+ unsigned int page_order = get_order(size);
+ void *vaddr = page_address(page);
+
+ /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
+ if (dma_should_free_from_pool(dev, 0) &&
+ dma_free_from_pool(dev, vaddr, size))
+ return;
+
+ if (force_dma_unencrypted(dev))
+ set_memory_encrypted((unsigned long)vaddr, 1 << page_order);
+
+ dma_free_contiguous(dev, page, size);
+}
+
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_SWIOTLB)
void dma_direct_sync_sg_for_device(struct device *dev,
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index e71abcec8d3913..6f86c925b8251d 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -330,9 +330,7 @@ pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)
{
if (force_dma_unencrypted(dev))
prot = pgprot_decrypted(prot);
- if (dev_is_dma_coherent(dev) ||
- (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) &&
- (attrs & DMA_ATTR_NON_CONSISTENT)))
+ if (dev_is_dma_coherent(dev))
return prot;
#ifdef CONFIG_ARCH_HAS_DMA_WRITE_COMBINE
if (attrs & DMA_ATTR_WRITE_COMBINE)
@@ -461,6 +459,65 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
}
EXPORT_SYMBOL(dma_free_attrs);

+struct page *dma_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+ struct page *page;
+
+ if (WARN_ON_ONCE(!dev->coherent_dma_mask))
+ return NULL;
+ if (WARN_ON_ONCE(gfp & (__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM)))
+ return NULL;
+
+ size = PAGE_ALIGN(size);
+ if (dma_alloc_direct(dev, ops))
+ page = dma_direct_alloc_pages(dev, size, dma_handle, dir, gfp);
+ else if (ops->alloc_pages)
+ page = ops->alloc_pages(dev, size, dma_handle, dir, gfp);
+ else
+ return NULL;
+
+ debug_dma_map_page(dev, page, 0, size, dir, *dma_handle);
+
+ return page;
+}
+EXPORT_SYMBOL_GPL(dma_alloc_pages);
+
+void dma_free_pages(struct device *dev, size_t size, struct page *page,
+ dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+
+ size = PAGE_ALIGN(size);
+ debug_dma_unmap_page(dev, dma_handle, size, dir);
+
+ if (dma_alloc_direct(dev, ops))
+ dma_direct_free_pages(dev, size, page, dma_handle, dir);
+ else if (ops->free_pages)
+ ops->free_pages(dev, size, page, dma_handle, dir);
+}
+EXPORT_SYMBOL_GPL(dma_free_pages);
+
+void *dma_alloc_noncoherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+ struct page *page;
+
+ page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
+ if (!page)
+ return NULL;
+ return page_address(page);
+}
+EXPORT_SYMBOL_GPL(dma_alloc_noncoherent);
+
+void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+ dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
+}
+EXPORT_SYMBOL_GPL(dma_free_noncoherent);
+
int dma_supported(struct device *dev, u64 mask)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
index e443c69be4299f..5828e5e01b7913 100644
--- a/kernel/dma/ops_helpers.c
+++ b/kernel/dma/ops_helpers.c
@@ -3,6 +3,7 @@
* Helpers for DMA ops implementations. These generally rely on the fact that
* the allocated memory contains normal pages in the direct kernel mapping.
*/
+#include <linux/dma-contiguous.h>
#include <linux/dma-noncoherent.h>

/*
@@ -49,3 +50,37 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
return -ENXIO;
#endif /* CONFIG_MMU */
}
+
+struct page *dma_common_alloc_pages(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+ struct page *page;
+
+ page = dma_alloc_contiguous(dev, size, gfp);
+ if (!page)
+ page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size));
+ if (!page)
+ return NULL;
+
+ *dma_handle = ops->map_page(dev, page, 0, size, dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ if (*dma_handle == DMA_MAPPING_ERROR) {
+ dma_free_contiguous(dev, page, size);
+ return NULL;
+ }
+
+ memset(page_address(page), 0, size);
+ return page;
+}
+
+void dma_common_free_pages(struct device *dev, size_t size, struct page *page,
+ dma_addr_t dma_handle, enum dma_data_direction dir)
+{
+ const struct dma_map_ops *ops = get_dma_ops(dev);
+
+ if (ops->unmap_page)
+ ops->unmap_page(dev, dma_handle, size, dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ dma_free_contiguous(dev, page, size);
+}
diff --git a/kernel/dma/virt.c b/kernel/dma/virt.c
index ebe128833af7b5..6986bf1fd6689c 100644
--- a/kernel/dma/virt.c
+++ b/kernel/dma/virt.c
@@ -55,5 +55,7 @@ const struct dma_map_ops dma_virt_ops = {
.free = dma_virt_free,
.map_page = dma_virt_map_page,
.map_sg = dma_virt_map_sg,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
};
EXPORT_SYMBOL(dma_virt_ops);
--
2.28.0