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ARM: add coherent dma ops
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arch_is_coherent is problematic as it is a global symbol. This
doesn't work for multi-platform kernels or platforms which can support
per device coherent DMA.

This adds arm_coherent_dma_ops to be used for devices which connected
coherently (i.e. to the ACP port on Cortex-A9 or A15). The arm_dma_ops
are modified at boot when arch_is_coherent is true.

Signed-off-by: Rob Herring <[email protected]>
Cc: Russell King <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Signed-off-by: Marek Szyprowski <[email protected]>
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@mszyprow
Rob Herring authored and mszyprow committed Oct 2, 2012
1 parent a0d271c commit dd37e94
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Showing 2 changed files with 60 additions and 12 deletions.
1 change: 1 addition & 0 deletions arch/arm/include/asm/dma-mapping.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@

#define DMA_ERROR_CODE (~0)
extern struct dma_map_ops arm_dma_ops;
extern struct dma_map_ops arm_coherent_dma_ops;

static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
Expand Down
71 changes: 59 additions & 12 deletions arch/arm/mm/dma-mapping.c
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Original file line number Diff line number Diff line change
Expand Up @@ -73,11 +73,18 @@ 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)
{
if (!arch_is_coherent() && !dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
__dma_page_cpu_to_dev(page, offset, size, dir);
return pfn_to_dma(dev, page_to_pfn(page)) + offset;
}

static dma_addr_t arm_coherent_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 pfn_to_dma(dev, page_to_pfn(page)) + offset;
}

/**
* 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
Expand All @@ -96,7 +103,7 @@ 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)
{
if (!arch_is_coherent() && !dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
if (!dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
__dma_page_dev_to_cpu(pfn_to_page(dma_to_pfn(dev, handle)),
handle & ~PAGE_MASK, size, dir);
}
Expand All @@ -106,17 +113,15 @@ static 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 (!arch_is_coherent())
__dma_page_dev_to_cpu(page, offset, size, dir);
__dma_page_dev_to_cpu(page, offset, size, dir);
}

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));
if (!arch_is_coherent())
__dma_page_cpu_to_dev(page, offset, size, dir);
__dma_page_cpu_to_dev(page, offset, size, dir);
}

static int arm_dma_set_mask(struct device *dev, u64 dma_mask);
Expand All @@ -138,6 +143,22 @@ struct dma_map_ops arm_dma_ops = {
};
EXPORT_SYMBOL(arm_dma_ops);

static void *arm_coherent_dma_alloc(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs);
static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs);

struct dma_map_ops arm_coherent_dma_ops = {
.alloc = arm_coherent_dma_alloc,
.free = arm_coherent_dma_free,
.mmap = arm_dma_mmap,
.get_sgtable = arm_dma_get_sgtable,
.map_page = arm_coherent_dma_map_page,
.map_sg = arm_dma_map_sg,
.set_dma_mask = arm_dma_set_mask,
};
EXPORT_SYMBOL(arm_coherent_dma_ops);

static u64 get_coherent_dma_mask(struct device *dev)
{
u64 mask = (u64)arm_dma_limit;
Expand Down Expand Up @@ -586,7 +607,7 @@ static void *__alloc_simple_buffer(struct device *dev, size_t size, gfp_t gfp,


static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
gfp_t gfp, pgprot_t prot, const void *caller)
gfp_t gfp, pgprot_t prot, bool is_coherent, const void *caller)
{
u64 mask = get_coherent_dma_mask(dev);
struct page *page;
Expand Down Expand Up @@ -619,7 +640,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
*handle = DMA_ERROR_CODE;
size = PAGE_ALIGN(size);

if (arch_is_coherent() || nommu())
if (is_coherent || nommu())
addr = __alloc_simple_buffer(dev, size, gfp, &page);
else if (gfp & GFP_ATOMIC)
addr = __alloc_from_pool(size, &page);
Expand Down Expand Up @@ -647,7 +668,20 @@ void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
if (dma_alloc_from_coherent(dev, size, handle, &memory))
return memory;

return __dma_alloc(dev, size, handle, gfp, prot,
return __dma_alloc(dev, size, handle, gfp, prot, false,
__builtin_return_address(0));
}

static void *arm_coherent_dma_alloc(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);
void *memory;

if (dma_alloc_from_coherent(dev, size, handle, &memory))
return memory;

return __dma_alloc(dev, size, handle, gfp, prot, true,
__builtin_return_address(0));
}

Expand Down Expand Up @@ -684,8 +718,9 @@ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
/*
* Free a buffer as defined by the above mapping.
*/
void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs)
static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs,
bool is_coherent)
{
struct page *page = pfn_to_page(dma_to_pfn(dev, handle));

Expand All @@ -694,7 +729,7 @@ void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,

size = PAGE_ALIGN(size);

if (arch_is_coherent() || nommu()) {
if (is_coherent || nommu()) {
__dma_free_buffer(page, size);
} else if (__free_from_pool(cpu_addr, size)) {
return;
Expand All @@ -710,6 +745,18 @@ void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
}
}

void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs)
{
__arm_dma_free(dev, size, cpu_addr, handle, attrs, false);
}

static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, struct dma_attrs *attrs)
{
__arm_dma_free(dev, size, cpu_addr, handle, attrs, true);
}

int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t handle, size_t size,
struct dma_attrs *attrs)
Expand Down

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