From 319f551a0a167b49b5bbb4a9ff4802046a572bc5 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 24 Mar 2010 16:47:53 +0100 Subject: ARM: 5994/1: ARM: Add outer_cache_fns.sync function pointer (2/4) This patch introduces the outer_cache_fns.sync function pointer together with the OUTER_CACHE_SYNC config option that can be used to drain the write buffer of the outer cache. Signed-off-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/mm/Kconfig | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/arm/mm/Kconfig') diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index c4ed9f9..88a24de 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -736,6 +736,12 @@ config NEEDS_SYSCALL_FOR_CMPXCHG config OUTER_CACHE bool +config OUTER_CACHE_SYNC + bool + help + The outer cache has a outer_cache_fns.sync function pointer + that can be used to drain the write buffer of the outer cache. + config CACHE_FEROCEON_L2 bool "Enable the Feroceon L2 cache controller" depends on ARCH_KIRKWOOD || ARCH_MV78XX0 -- cgit v1.1 From 23107c542068b2b94390aa333f6b330af64961e4 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 24 Mar 2010 16:48:53 +0100 Subject: ARM: 5995/1: ARM: Add L2x0 outer_sync() support (3/4) The L2x0 cache controllers need to explicitly drain their write buffer even for Normal Noncacheable memory accesses. Signed-off-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/mm/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm/mm/Kconfig') diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index 88a24de..55a2a00 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -763,6 +763,7 @@ config CACHE_L2X0 REALVIEW_EB_A9MP || ARCH_MX35 || ARCH_MX31 || MACH_REALVIEW_PBX || ARCH_NOMADIK || ARCH_OMAP4 default y select OUTER_CACHE + select OUTER_CACHE_SYNC help This option enables the L2x0 PrimeCell. -- cgit v1.1 From e7c5650f6067f65f8e961394f376d4862808d0d2 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 24 Mar 2010 16:49:54 +0100 Subject: ARM: 5996/1: ARM: Change the mandatory barriers implementation (4/4) The mandatory barriers (mb, rmb, wmb) are used even on uniprocessor systems for things like ordering Normal Non-cacheable memory accesses with DMA transfer (via Device memory writes). The current implementation uses dmb() for mb() and friends but this is not sufficient. The DMB only ensures the relative ordering of the observability of accesses by other processors or devices acting as masters. In case of DMA transfers started by writes to device memory, the relative ordering is not ensured because accesses to slave ports of a device are not considered observable by the DMB definition. A DSB is required for the data to reach the main memory (even if mapped as Normal Non-cacheable) before the device receives the notification to begin the transfer. Furthermore, some L2 cache controllers (like L2x0 or PL310) buffer stores to Normal Non-cacheable memory and this would need to be drained with the outer_sync() function call. The patch also allows platforms to define their own mandatory barriers implementation by selecting CONFIG_ARCH_HAS_BARRIERS and providing a mach/barriers.h file. Note that the SMP barriers are unchanged (being DMBs as before) since they are only guaranteed to work with Normal Cacheable memory. Signed-off-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/mm/Kconfig | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/arm/mm/Kconfig') diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index 55a2a00..5bd7c89 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -788,3 +788,9 @@ config ARM_L1_CACHE_SHIFT int default 6 if ARM_L1_CACHE_SHIFT_6 default 5 + +config ARCH_HAS_BARRIERS + bool + help + This option allows the use of custom mandatory barriers + included via the mach/barriers.h file. -- cgit v1.1