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 --- include/asm-arm/arch-ixp23xx/memory.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/asm-arm/arch-ixp23xx') diff --git a/include/asm-arm/arch-ixp23xx/memory.h b/include/asm-arm/arch-ixp23xx/memory.h index bebcf0aa0d7..6e19f46d54d 100644 --- a/include/asm-arm/arch-ixp23xx/memory.h +++ b/include/asm-arm/arch-ixp23xx/memory.h @@ -28,6 +28,7 @@ * to an address that the kernel can use. */ #ifndef __ASSEMBLY__ +#include #define __virt_to_bus(v) \ ({ unsigned int ret; \ @@ -40,6 +41,22 @@ data = *((volatile int *)IXP23XX_PCI_SDRAM_BAR); \ __phys_to_virt((((b - (data & 0xfffffff0)) + 0x00000000))); }) +/* + * Coherency support. Only supported on A2 CPUs or on A1 + * systems that have the cache coherency workaround. + */ +static inline int __ixp23xx_arch_is_coherent(void) +{ + extern unsigned int processor_id; + + if (((processor_id & 15) >= 2) || machine_is_roadrunner()) + return 1; + + return 0; +} + +#define arch_is_coherent() __ixp23xx_arch_is_coherent() + #endif -- cgit v1.2.3