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-rw-r--r--arch/arm/mm/Kconfig21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 346ae14824a..101105e5261 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