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/mm-armv.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/arm/mm/mm-armv.c') diff --git a/arch/arm/mm/mm-armv.c b/arch/arm/mm/mm-armv.c index 5e5d05bcad5..f14b2d0f369 100644 --- a/arch/arm/mm/mm-armv.c +++ b/arch/arm/mm/mm-armv.c @@ -388,6 +388,17 @@ void __init build_mem_type_table(void) cp = &cache_policies[cachepolicy]; kern_pgprot = user_pgprot = cp->pte; + /* + * Enable CPU-specific coherency if supported. + * (Only available on XSC3 at the moment.) + */ + if (arch_is_coherent()) { + if (cpu_is_xsc3()) { + mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S; + mem_types[MT_MEMORY].prot_pte |= L_PTE_COHERENT; + } + } + /* * ARMv6 and above have extended page tables. */ -- cgit v1.2.3