[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>
diff --git a/include/asm-arm/dma-mapping.h b/include/asm-arm/dma-mapping.h
index e3e8541..63ca741 100644
--- a/include/asm-arm/dma-mapping.h
+++ b/include/asm-arm/dma-mapping.h
@@ -47,7 +47,7 @@
static inline int dma_is_consistent(dma_addr_t handle)
{
- return 0;
+ return !!arch_is_coherent();
}
/*
@@ -145,7 +145,9 @@
dma_map_single(struct device *dev, void *cpu_addr, size_t size,
enum dma_data_direction dir)
{
- consistent_sync(cpu_addr, size, dir);
+ if (!arch_is_coherent())
+ consistent_sync(cpu_addr, size, dir);
+
return virt_to_dma(dev, (unsigned long)cpu_addr);
}
#else
@@ -255,7 +257,9 @@
sg->dma_address = page_to_dma(dev, sg->page) + sg->offset;
virt = page_address(sg->page) + sg->offset;
- consistent_sync(virt, sg->length, dir);
+
+ if (!arch_is_coherent())
+ consistent_sync(virt, sg->length, dir);
}
return nents;
@@ -310,14 +314,16 @@
dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle, size_t size,
enum dma_data_direction dir)
{
- consistent_sync((void *)dma_to_virt(dev, handle), size, dir);
+ if (!arch_is_coherent())
+ consistent_sync((void *)dma_to_virt(dev, handle), size, dir);
}
static inline void
dma_sync_single_for_device(struct device *dev, dma_addr_t handle, size_t size,
enum dma_data_direction dir)
{
- consistent_sync((void *)dma_to_virt(dev, handle), size, dir);
+ if (!arch_is_coherent())
+ consistent_sync((void *)dma_to_virt(dev, handle), size, dir);
}
#else
extern void dma_sync_single_for_cpu(struct device*, dma_addr_t, size_t, enum dma_data_direction);
@@ -347,7 +353,8 @@
for (i = 0; i < nents; i++, sg++) {
char *virt = page_address(sg->page) + sg->offset;
- consistent_sync(virt, sg->length, dir);
+ if (!arch_is_coherent())
+ consistent_sync(virt, sg->length, dir);
}
}
@@ -359,7 +366,8 @@
for (i = 0; i < nents; i++, sg++) {
char *virt = page_address(sg->page) + sg->offset;
- consistent_sync(virt, sg->length, dir);
+ if (!arch_is_coherent())
+ consistent_sync(virt, sg->length, dir);
}
}
#else
