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Old 10-01-2012, 10:00 AM
Ike Panhc
 
Default ARM: add coherent dma ops

From: Rob Herring <rob.herring@calxeda.com>

BugLink: http://launchpad.net/bugs/1059432

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 <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ike Panhc <ike.pan@canonical.com>
---
arch/arm/include/asm/dma-mapping.h | 1 +
arch/arm/mm/dma-mapping.c | 70 +++++++++++++++++++++++++++++-------
2 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index bbef15d..03caee2 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -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)
{
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 68b61bc..9fba055 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -72,11 +72,18 @@ 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
@@ -95,7 +102,7 @@ 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);
}
@@ -105,8 +112,7 @@ 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,
@@ -114,8 +120,7 @@ static 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 (!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);
@@ -136,6 +141,21 @@ 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,
+ .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;
@@ -667,7 +687,7 @@ 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;
@@ -700,7 +720,7 @@ 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 (!IS_ENABLED(CONFIG_CMA))
addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
@@ -728,7 +748,20 @@ 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));
}

@@ -759,8 +792,9 @@ 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));

@@ -769,7 +803,7 @@ 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 (!IS_ENABLED(CONFIG_CMA)) {
__dma_free_remap(cpu_addr, size);
@@ -785,6 +819,18 @@ 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);
+}
+
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))
--
1.7.9.5


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