diff options
Diffstat (limited to 'arch/arm/mm')
| -rw-r--r-- | arch/arm/mm/Kconfig | 21 | ||||
| -rw-r--r-- | arch/arm/mm/cache-v6.S | 18 | ||||
| -rw-r--r-- | arch/arm/mm/dma-mapping.c | 18 |
3 files changed, 44 insertions, 13 deletions
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index 346ae14824a5..101105e52610 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -735,6 +735,25 @@ config NEEDS_SYSCALL_FOR_CMPXCHG Forget about fast user space cmpxchg support. It is just not possible. +config DMA_CACHE_RWFO + bool "Enable read/write for ownership DMA cache maintenance" + depends on CPU_V6 && SMP + default y + help + The Snoop Control Unit on ARM11MPCore does not detect the + cache maintenance operations and the dma_{map,unmap}_area() + functions may leave stale cache entries on other CPUs. By + enabling this option, Read or Write For Ownership in the ARMv6 + DMA cache maintenance functions is performed. These LDR/STR + instructions change the cache line state to shared or modified + so that the cache operation has the desired effect. + + Note that the workaround is only valid on processors that do + not perform speculative loads into the D-cache. For such + processors, if cache maintenance operations are not broadcast + in hardware, other workarounds are needed (e.g. cache + maintenance broadcasting in software via FIQ). + config OUTER_CACHE bool @@ -794,6 +813,8 @@ config ARM_L1_CACHE_SHIFT config ARM_DMA_MEM_BUFFERABLE bool "Use non-cacheable memory for DMA" if CPU_V6 && !CPU_V7 + depends on !(MACH_REALVIEW_PB1176 || REALVIEW_EB_ARM11MP || \ + MACH_REALVIEW_PB11MP) default y if CPU_V6 || CPU_V7 help Historically, the kernel has used strongly ordered mappings to diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S index e46ecd847138..86aa689ef1aa 100644 --- a/arch/arm/mm/cache-v6.S +++ b/arch/arm/mm/cache-v6.S @@ -211,8 +211,9 @@ v6_dma_inv_range: mcrne p15, 0, r1, c7, c15, 1 @ clean & invalidate unified line #endif 1: -#ifdef CONFIG_SMP - str r0, [r0] @ write for ownership +#ifdef CONFIG_DMA_CACHE_RWFO + ldr r2, [r0] @ read for ownership + str r2, [r0] @ write for ownership #endif #ifdef HARVARD_CACHE mcr p15, 0, r0, c7, c6, 1 @ invalidate D line @@ -234,7 +235,7 @@ v6_dma_inv_range: v6_dma_clean_range: bic r0, r0, #D_CACHE_LINE_SIZE - 1 1: -#ifdef CONFIG_SMP +#ifdef CONFIG_DMA_CACHE_RWFO ldr r2, [r0] @ read for ownership #endif #ifdef HARVARD_CACHE @@ -257,7 +258,7 @@ v6_dma_clean_range: ENTRY(v6_dma_flush_range) bic r0, r0, #D_CACHE_LINE_SIZE - 1 1: -#ifdef CONFIG_SMP +#ifdef CONFIG_DMA_CACHE_RWFO ldr r2, [r0] @ read for ownership str r2, [r0] @ write for ownership #endif @@ -283,9 +284,13 @@ ENTRY(v6_dma_map_area) add r1, r1, r0 teq r2, #DMA_FROM_DEVICE beq v6_dma_inv_range +#ifndef CONFIG_DMA_CACHE_RWFO + b v6_dma_clean_range +#else teq r2, #DMA_TO_DEVICE beq v6_dma_clean_range b v6_dma_flush_range +#endif ENDPROC(v6_dma_map_area) /* @@ -295,6 +300,11 @@ ENDPROC(v6_dma_map_area) * - dir - DMA direction */ ENTRY(v6_dma_unmap_area) +#ifndef CONFIG_DMA_CACHE_RWFO + add r1, r1, r0 + teq r2, #DMA_TO_DEVICE + bne v6_dma_inv_range +#endif mov pc, lr ENDPROC(v6_dma_unmap_area) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 13fa536d82e6..9e7742f0a102 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -24,15 +24,6 @@ #include <asm/tlbflush.h> #include <asm/sizes.h> -/* Sanity check size */ -#if (CONSISTENT_DMA_SIZE % SZ_2M) -#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB" -#endif - -#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) -#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT) -#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT) - static u64 get_coherent_dma_mask(struct device *dev) { u64 mask = ISA_DMA_THRESHOLD; @@ -123,6 +114,15 @@ static void __dma_free_buffer(struct page *page, size_t size) } #ifdef CONFIG_MMU +/* Sanity check size */ +#if (CONSISTENT_DMA_SIZE % SZ_2M) +#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB" +#endif + +#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) +#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT) +#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT) + /* * These are the page tables (2MB each) covering uncached, DMA consistent allocations */ |