From dbee0c6fb4c1269b2dfc8b0b7a29907ea7fed560 Mon Sep 17 00:00:00 2001 From: Lorenzo Pieralisi Date: Fri, 7 Sep 2012 11:06:57 +0530 Subject: [PATCH] ARM: kernel: update cpu_suspend code to use cache LoUIS operations In processors like A15/A7 L2 cache is unified and integrated within the processor cache hierarchy, so that it is not considered an outer cache anymore. For processors like A15/A7 flush_cache_all() ends up cleaning all cache levels up to Level of Coherency (LoC) that includes the L2 unified cache. When a single CPU is suspended (CPU idle) a complete L2 clean is not required, so generic cpu_suspend code must clean the data cache using the newly introduced cache LoUIS function. The context and stack pointer (context pointer) are cleaned to main memory using cache area functions that operate on MVA and guarantee that the data is written back to main memory (perform cache cleaning up to the Point of Coherency - PoC) so that the processor can fetch the context when the MMU is off in the cpu_resume code path. outer_cache management remains unchanged. Reviewed-by: Santosh Shilimkar Reviewed-by: Nicolas Pitre Signed-off-by: Lorenzo Pieralisi Tested-by: Shawn Guo --- arch/arm/kernel/suspend.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c index 1794cc3b0f18..358bca3a995e 100644 --- a/arch/arm/kernel/suspend.c +++ b/arch/arm/kernel/suspend.c @@ -17,6 +17,8 @@ extern void cpu_resume_mmu(void); */ void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr) { + u32 *ctx = ptr; + *save_ptr = virt_to_phys(ptr); /* This must correspond to the LDM in cpu_resume() assembly */ @@ -26,7 +28,20 @@ void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr) cpu_do_suspend(ptr); - flush_cache_all(); + flush_cache_louis(); + + /* + * flush_cache_louis does not guarantee that + * save_ptr and ptr are cleaned to main memory, + * just up to the Level of Unification Inner Shareable. + * Since the context pointer and context itself + * are to be retrieved with the MMU off that + * data must be cleaned from all cache levels + * to main memory using "area" cache primitives. + */ + __cpuc_flush_dcache_area(ctx, ptrsz); + __cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr)); + outer_clean_range(*save_ptr, *save_ptr + ptrsz); outer_clean_range(virt_to_phys(save_ptr), virt_to_phys(save_ptr) + sizeof(*save_ptr));