From 23759dc6430428897a36c4d493f611eca55c9481 Mon Sep 17 00:00:00 2001 From: Lennert Buytenhek Date: Sun, 2 Apr 2006 00:07:39 +0100 Subject: [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 Signed-off-by: Lennert Buytenhek Signed-off-by: Russell King --- arch/arm/mm/consistent.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'arch/arm/mm/consistent.c') diff --git a/arch/arm/mm/consistent.c b/arch/arm/mm/consistent.c index 8a1bfcd5008..50e6b6bfb2e 100644 --- a/arch/arm/mm/consistent.c +++ b/arch/arm/mm/consistent.c @@ -18,6 +18,7 @@ #include #include +#include #include #include #include @@ -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); -- cgit