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| author | Catalin Marinas <catalin.marinas@arm.com> | 2010-05-07 17:26:24 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-05-08 11:44:30 +0200 |
| commit | f4d6477f7f073b99220386d62f5bf54bec3482cc (patch) | |
| tree | 4c6a13a762f54bfd30550a70226268edcb9d38a7 /arch/arm | |
| parent | ARM: 6106/1: Implement copy_to_user_page() for noMMU (diff) | |
| download | linux-f4d6477f7f073b99220386d62f5bf54bec3482cc.tar.xz linux-f4d6477f7f073b99220386d62f5bf54bec3482cc.zip | |
ARM: 6111/1: Implement read/write for ownership in the ARMv6 DMA cache ops
The Snoop Control Unit on the ARM11MPCore hardware does not detect the
cache operations and the dma_cache_maint*() functions may leave stale
cache entries on other CPUs. The solution implemented in this patch
performs a Read or Write For Ownership in the ARMv6 DMA cache
maintenance functions. These LDR/STR instructions change the cache line
state to shared or exclusive so that the cache maintenance operation has
the desired effect.
Tested-by: George G. Davis <gdavis@mvista.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mm/cache-v6.S | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S index 9d89c67a1cc3..e46ecd847138 100644 --- a/arch/arm/mm/cache-v6.S +++ b/arch/arm/mm/cache-v6.S @@ -211,6 +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 +#endif #ifdef HARVARD_CACHE mcr p15, 0, r0, c7, c6, 1 @ invalidate D line #else @@ -231,6 +234,9 @@ v6_dma_inv_range: v6_dma_clean_range: bic r0, r0, #D_CACHE_LINE_SIZE - 1 1: +#ifdef CONFIG_SMP + ldr r2, [r0] @ read for ownership +#endif #ifdef HARVARD_CACHE mcr p15, 0, r0, c7, c10, 1 @ clean D line #else @@ -251,6 +257,10 @@ v6_dma_clean_range: ENTRY(v6_dma_flush_range) bic r0, r0, #D_CACHE_LINE_SIZE - 1 1: +#ifdef CONFIG_SMP + ldr r2, [r0] @ read for ownership + str r2, [r0] @ write for ownership +#endif #ifdef HARVARD_CACHE mcr p15, 0, r0, c7, c14, 1 @ clean & invalidate D line #else @@ -273,7 +283,9 @@ ENTRY(v6_dma_map_area) add r1, r1, r0 teq r2, #DMA_FROM_DEVICE beq v6_dma_inv_range - b v6_dma_clean_range + teq r2, #DMA_TO_DEVICE + beq v6_dma_clean_range + b v6_dma_flush_range ENDPROC(v6_dma_map_area) /* @@ -283,9 +295,6 @@ ENDPROC(v6_dma_map_area) * - dir - DMA direction */ ENTRY(v6_dma_unmap_area) - add r1, r1, r0 - teq r2, #DMA_TO_DEVICE - bne v6_dma_inv_range mov pc, lr ENDPROC(v6_dma_unmap_area) |