+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
+ provide DMA coherent memory. With the advent of ARMv7, mapping
+ memory with differing types results in unpredictable behaviour,
+ so on these CPUs, this option is forced on.
+
+ Multiple mappings with differing attributes is also unpredictable
+ on ARMv6 CPUs, but since they do not have aggressive speculative
+ prefetch, no harm appears to occur.
+
+ However, drivers may be missing the necessary barriers for ARMv6,
+ and therefore turning this on may result in unpredictable driver
+ behaviour. Therefore, we offer this as an option.
+
+ You are recommended say 'Y' here and debug any affected drivers.
+