[PATCH 02/18] ARM/dma-mapping: Consolidate IOMMU ops callbacks

Robin Murphy
2020-08-20T15:13:05Z

Merge the coherent and non-coherent callbacks down to a single
implementation each, relying on the generic dev->dma_coherent
flag at the points where the difference matters.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
arch/arm/Kconfig | 4 +-
arch/arm/mm/dma-mapping.c | 281 +++++++++++---------------------------
2 files changed, 79 insertions(+), 206 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e00d94b16658..b91273f9fd43 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -19,8 +19,8 @@ config ARM
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
select ARCH_HAS_STRICT_MODULE_RWX if MMU
- select ARCH_HAS_SYNC_DMA_FOR_DEVICE if SWIOTLB
- select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB
+ select ARCH_HAS_SYNC_DMA_FOR_DEVICE if SWIOTLB || ARM_DMA_USE_IOMMU
+ select ARCH_HAS_SYNC_DMA_FOR_CPU if SWIOTLB || ARM_DMA_USE_IOMMU
select ARCH_HAS_TEARDOWN_DMA_OPS if MMU
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index ffa387f343dc..1bb7e9608f75 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1418,13 +1418,13 @@ static void __iommu_free_atomic(struct device *dev, void *cpu_addr,
__free_from_pool(cpu_addr, size);
}

-static void *__arm_iommu_alloc_attrs(struct device *dev, size_t size,
- dma_addr_t *handle, gfp_t gfp, unsigned long attrs,
- int coherent_flag)
+static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
+ dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
{
pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
struct page **pages;
void *addr = NULL;
+ int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;

*handle = DMA_MAPPING_ERROR;
size = PAGE_ALIGN(size);
@@ -1467,19 +1467,7 @@ static void *__arm_iommu_alloc_attrs(struct device *dev, size_t size,
return NULL;
}

-static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
- dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
-{
- return __arm_iommu_alloc_attrs(dev, size, handle, gfp, attrs, NORMAL);
-}
-
-static void *arm_coherent_iommu_alloc_attrs(struct device *dev, size_t size,
- dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
-{
- return __arm_iommu_alloc_attrs(dev, size, handle, gfp, attrs, COHERENT);
-}
-
-static int __arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
+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,
unsigned long attrs)
{
@@ -1493,35 +1481,24 @@ static int __arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma
if (vma->vm_pgoff >= nr_pages)
return -ENXIO;

+ if (!dev->dma_coherent)
+ vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
+
err = vm_map_pages(vma, pages, nr_pages);
if (err)
pr_err("Remapping memory failed: %d\n", err);

return err;
}
-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, unsigned long attrs)
-{
- vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);
-
- return __arm_iommu_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, attrs);
-}
-
-static int arm_coherent_iommu_mmap_attrs(struct device *dev,
- struct vm_area_struct *vma, void *cpu_addr,
- dma_addr_t dma_addr, size_t size, unsigned long attrs)
-{
- return __arm_iommu_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, attrs);
-}

/*
* free a page as defined by the above mapping.
* Must not be called with IRQs disabled.
*/
-static void __arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
- dma_addr_t handle, unsigned long attrs, int coherent_flag)
+static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
+ dma_addr_t handle, unsigned long attrs)
{
+ int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
struct page **pages;
size = PAGE_ALIGN(size);

@@ -1543,19 +1520,6 @@ static void __arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_ad
__iommu_free_buffer(dev, pages, size, attrs);
}

-static void arm_iommu_free_attrs(struct device *dev, size_t size,
- void *cpu_addr, dma_addr_t handle,
- unsigned long attrs)
-{
- __arm_iommu_free_attrs(dev, size, cpu_addr, handle, attrs, NORMAL);
-}
-
-static void arm_coherent_iommu_free_attrs(struct device *dev, size_t size,
- void *cpu_addr, dma_addr_t handle, unsigned long attrs)
-{
- __arm_iommu_free_attrs(dev, size, cpu_addr, handle, attrs, COHERENT);
-}
-
static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr,
size_t size, unsigned long attrs)
@@ -1575,8 +1539,7 @@ static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
*/
static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
size_t size, dma_addr_t *handle,
- enum dma_data_direction dir, unsigned long attrs,
- bool is_coherent)
+ enum dma_data_direction dir, unsigned long attrs)
{
struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
dma_addr_t iova, iova_base;
@@ -1596,7 +1559,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
phys_addr_t phys = page_to_phys(sg_page(s));
unsigned int len = PAGE_ALIGN(s->offset + s->length);

- if (!is_coherent && (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
+ if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);

prot = __dma_info_to_prot(dir, attrs);
@@ -1616,70 +1579,6 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
return ret;
}

-static int __iommu_map_sg(struct device *dev, struct scatterlist *sg, int nents,
- enum dma_data_direction dir, unsigned long attrs,
- bool is_coherent)
-{
- 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 = DMA_MAPPING_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, attrs, is_coherent) < 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, attrs,
- is_coherent) < 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_coherent_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 i/o coherent 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}.
- */
-static int arm_coherent_iommu_map_sg(struct device *dev, struct scatterlist *sg,
- int nents, enum dma_data_direction dir, unsigned long attrs)
-{
- return __iommu_map_sg(dev, sg, nents, dir, attrs, true);
-}
-
/**
* arm_iommu_map_sg - map a set of SG buffers for streaming mode DMA
* @dev: valid struct device pointer
@@ -1695,41 +1594,45 @@ static int arm_coherent_iommu_map_sg(struct device *dev, struct scatterlist *sg,
static int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
- return __iommu_map_sg(dev, sg, nents, dir, attrs, false);
-}
+ 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);

-static void __iommu_unmap_sg(struct device *dev, struct scatterlist *sg,
- int nents, enum dma_data_direction dir,
- unsigned long attrs, bool is_coherent)
-{
- struct scatterlist *s;
- int i;
+ for (i = 1; i < nents; i++) {
+ s = sg_next(s);

- 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 (!is_coherent && (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
- __dma_page_dev_to_cpu(sg_page(s), s->offset,
- s->length, dir);
+ s->dma_address = DMA_MAPPING_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, attrs) < 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, attrs) < 0)
+ goto bad_mapping;

-/**
- * arm_coherent_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().
- */
-static void arm_coherent_iommu_unmap_sg(struct device *dev,
- struct scatterlist *sg, int nents, enum dma_data_direction dir,
- unsigned long attrs)
-{
- __iommu_unmap_sg(dev, sg, nents, dir, attrs, true);
+ 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;
}

/**
@@ -1747,7 +1650,17 @@ static void arm_iommu_unmap_sg(struct device *dev,
enum dma_data_direction dir,
unsigned long attrs)
{
- __iommu_unmap_sg(dev, sg, nents, dir, attrs, false);
+ 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 (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ __dma_page_dev_to_cpu(sg_page(s), s->offset,
+ s->length, dir);
+ }
}

/**
@@ -1787,18 +1700,17 @@ static void arm_iommu_sync_sg_for_device(struct device *dev,
__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
}

-
/**
- * arm_coherent_iommu_map_page
+ * 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
*
- * Coherent IOMMU aware version of arm_dma_map_page()
+ * IOMMU aware version of arm_dma_map_page()
*/
-static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *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,
unsigned long attrs)
{
@@ -1806,6 +1718,9 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p
dma_addr_t dma_addr;
int ret, prot, len = PAGE_ALIGN(size + offset);

+ if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ __dma_page_cpu_to_dev(page, offset, size, dir);
+
dma_addr = __alloc_iova(mapping, len);
if (dma_addr == DMA_MAPPING_ERROR)
return dma_addr;
@@ -1822,50 +1737,6 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p
return DMA_MAPPING_ERROR;
}

-/**
- * 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,
- unsigned long attrs)
-{
- if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
- __dma_page_cpu_to_dev(page, offset, size, dir);
-
- return arm_coherent_iommu_map_page(dev, page, offset, size, dir, attrs);
-}
-
-/**
- * arm_coherent_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)
- *
- * Coherent IOMMU aware version of arm_dma_unmap_page()
- */
-static void arm_coherent_iommu_unmap_page(struct device *dev, dma_addr_t handle,
- size_t size, enum dma_data_direction dir, unsigned long attrs)
-{
- struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
- dma_addr_t iova = handle & PAGE_MASK;
- int offset = handle & ~PAGE_MASK;
- int len = PAGE_ALIGN(size + offset);
-
- if (!iova)
- return;
-
- iommu_unmap(mapping->domain, iova, len);
- __free_iova(mapping, iova, len);
-}
-
/**
* arm_iommu_unmap_page
* @dev: valid struct device pointer
@@ -1880,15 +1751,17 @@ static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
{
struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
dma_addr_t iova = handle & PAGE_MASK;
- struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
+ struct page *page;
int offset = handle & ~PAGE_MASK;
int len = PAGE_ALIGN(size + offset);

if (!iova)
return;

- if ((attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
+ if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+ page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
__dma_page_dev_to_cpu(page, offset, size, dir);
+ }

iommu_unmap(mapping->domain, iova, len);
__free_iova(mapping, iova, len);
@@ -2000,16 +1873,16 @@ static const struct dma_map_ops iommu_ops = {
};

static const struct dma_map_ops iommu_coherent_ops = {
- .alloc = arm_coherent_iommu_alloc_attrs,
- .free = arm_coherent_iommu_free_attrs,
- .mmap = arm_coherent_iommu_mmap_attrs,
+ .alloc = arm_iommu_alloc_attrs,
+ .free = arm_iommu_free_attrs,
+ .mmap = arm_iommu_mmap_attrs,
.get_sgtable = arm_iommu_get_sgtable,

- .map_page = arm_coherent_iommu_map_page,
- .unmap_page = arm_coherent_iommu_unmap_page,
+ .map_page = arm_iommu_map_page,
+ .unmap_page = arm_iommu_unmap_page,

- .map_sg = arm_coherent_iommu_map_sg,
- .unmap_sg = arm_coherent_iommu_unmap_sg,
+ .map_sg = arm_iommu_map_sg,
+ .unmap_sg = arm_iommu_unmap_sg,

.map_resource = arm_iommu_map_resource,
.unmap_resource = arm_iommu_unmap_resource,
@@ -2291,7 +2164,7 @@ void arch_teardown_dma_ops(struct device *dev)
set_dma_ops(dev, NULL);
}

-#ifdef CONFIG_SWIOTLB
+#if defined(CONFIG_SWIOTLB) || defined(CONFIG_ARM_DMA_USE_IOMMU)
void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
@@ -2319,4 +2192,4 @@ void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
{
__arm_dma_free(dev, size, cpu_addr, dma_handle, attrs, false);
}
-#endif /* CONFIG_SWIOTLB */
+#endif /* CONFIG_SWIOTLB || CONFIG_ARM_DMA_USE_IOMMU */
--
2.28.0.dirty