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authorRussell King <rmk+kernel@arm.linux.org.uk>2009-11-24 16:27:17 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-02-15 15:22:11 +0000
commit4ea0d7371e808628d11154b0d44140b70f05b998 (patch)
tree7673b2fc850475a587144a02c9f568a2831f0c2f /arch
parent18eabe2347ae7a11b3db768695913724166dfb0e (diff)
ARM: dma-mapping: push buffer ownership down into dma-mapping.c
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Tested-By: Santosh Shilimkar <santosh.shilimkar@ti.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/dma-mapping.h39
-rw-r--r--arch/arm/mm/dma-mapping.c34
2 files changed, 55 insertions, 18 deletions
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index e850f5c1607..256ee1c9f51 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -57,46 +57,57 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr)
#endif
/*
- * Private support functions: these are not part of the API and are
- * liable to change. Drivers must not use these.
- */
-extern void dma_cache_maint(const void *kaddr, size_t size, int rw);
-extern void dma_cache_maint_page(struct page *page, unsigned long offset,
- size_t size, int rw);
-
-/*
* 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.
*
- * As above, these are private support functions and not part of the API.
- * Drivers must not use these.
+ * 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_cache_maint(kaddr, size, dir);
+ ___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)
{
- /* nothing to do */
+ 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_cache_maint_page(page, off, size, dir);
+ ___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)
{
- /* nothing to do */
+ 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);
}
/*
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index a316c945952..bbf87880b91 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -404,7 +404,7 @@ EXPORT_SYMBOL(dma_free_coherent);
* platforms with CONFIG_DMABOUNCE.
* Use the driver DMA support - see dma-mapping.h (dma_sync_*)
*/
-void dma_cache_maint(const void *start, size_t size, int direction)
+static void dma_cache_maint(const void *start, size_t size, int direction)
{
void (*inner_op)(const void *, const void *);
void (*outer_op)(unsigned long, unsigned long);
@@ -431,7 +431,20 @@ void dma_cache_maint(const void *start, size_t size, int direction)
inner_op(start, start + size);
outer_op(__pa(start), __pa(start) + size);
}
-EXPORT_SYMBOL(dma_cache_maint);
+
+void ___dma_single_cpu_to_dev(const void *kaddr, size_t size,
+ enum dma_data_direction dir)
+{
+ dma_cache_maint(kaddr, size, dir);
+}
+EXPORT_SYMBOL(___dma_single_cpu_to_dev);
+
+void ___dma_single_dev_to_cpu(const void *kaddr, size_t size,
+ enum dma_data_direction dir)
+{
+ /* nothing to do */
+}
+EXPORT_SYMBOL(___dma_single_dev_to_cpu);
static void dma_cache_maint_contiguous(struct page *page, unsigned long offset,
size_t size, int direction)
@@ -474,7 +487,7 @@ static void dma_cache_maint_contiguous(struct page *page, unsigned long offset,
outer_op(paddr, paddr + size);
}
-void dma_cache_maint_page(struct page *page, unsigned long offset,
+static void dma_cache_maint_page(struct page *page, unsigned long offset,
size_t size, int dir)
{
/*
@@ -499,7 +512,20 @@ void dma_cache_maint_page(struct page *page, unsigned long offset,
left -= len;
} while (left);
}
-EXPORT_SYMBOL(dma_cache_maint_page);
+
+void ___dma_page_cpu_to_dev(struct page *page, unsigned long off,
+ size_t size, enum dma_data_direction dir)
+{
+ dma_cache_maint_page(page, off, size, dir);
+}
+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)
+{
+ /* nothing to do */
+}
+EXPORT_SYMBOL(___dma_page_dev_to_cpu);
/**
* dma_map_sg - map a set of SG buffers for streaming mode DMA