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authorLennert Buytenhek <buytenh@wantstofly.org>2006-04-02 03:07:39 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-04-02 03:07:39 +0400
commit23759dc6430428897a36c4d493f611eca55c9481 (patch)
treec62050927599b36ed223753c35fd737e3c0c6762 /arch/arm/mm/consistent.c
parentd3f4c571b6e596f9d39c596426269006a309d3b8 (diff)
downloadlinux-23759dc6430428897a36c4d493f611eca55c9481.tar.xz
[ARM] 3439/2: xsc3: add I/O coherency support
Patch from Lennert Buytenhek This patch adds support for the I/O coherent cache available on the xsc3. The approach is to provide a simple API to determine whether the chipset supports coherency by calling arch_is_coherent() and then setting the appropriate system memory PTE and PMD bits. In addition, we call this API on dma_alloc_coherent() and dma_map_single() calls. A generic version exists that will compile out all the coherency-related code that is not needed on the majority of ARM systems. Note that we do not check for coherency in the dma_alloc_writecombine() function as that still requires a special PTE setting. We also don't touch dma_mmap_coherent() as that is a special ARM-only API that is by definition only used on non-coherent system. Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm/consistent.c')
-rw-r--r--arch/arm/mm/consistent.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/arm/mm/consistent.c b/arch/arm/mm/consistent.c
index 8a1bfcd50087..50e6b6bfb2e2 100644
--- a/arch/arm/mm/consistent.c
+++ b/arch/arm/mm/consistent.c
@@ -18,6 +18,7 @@
#include <linux/device.h>
#include <linux/dma-mapping.h>
+#include <asm/memory.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/sizes.h>
@@ -272,6 +273,17 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
void *
dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
{
+ if (arch_is_coherent()) {
+ void *virt;
+
+ virt = kmalloc(size, gfp);
+ if (!virt)
+ return NULL;
+ *handle = virt_to_dma(dev, virt);
+
+ return virt;
+ }
+
return __dma_alloc(dev, size, handle, gfp,
pgprot_noncached(pgprot_kernel));
}
@@ -350,6 +362,11 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr
WARN_ON(irqs_disabled());
+ if (arch_is_coherent()) {
+ kfree(cpu_addr);
+ return;
+ }
+
size = PAGE_ALIGN(size);
spin_lock_irqsave(&consistent_lock, flags);