[U-Boot] [RFC PATCH 1/2] armv8: Fix dcache disable function

[York Sun]

Current code turns off d-cache first, then flush all levels of cache.
This results data loss. As soon as d-cache is off, the dirty cache
is discarded according to the test on LS2080A. This issue was not
seen as long as external L3 cache was flushed to push the data to
main memory. However, external L3 cache is not guaranteed to have
the data. To fix this, flush the d-cache by way/set first to make
sure cache is clean before turning it off.

Signed-off-by: York Sun <york.sun at nxp.com>
CC: David Feng <fenghua at phytium.com.cn>
---

 arch/arm/cpu/armv8/cache_v8.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/cpu/armv8/cache_v8.c b/arch/arm/cpu/armv8/cache_v8.c
index cd3f6c1..92d6277 100644
--- a/arch/arm/cpu/armv8/cache_v8.c
+++ b/arch/arm/cpu/armv8/cache_v8.c
@@ -478,9 +478,9 @@ void dcache_disable(void)
 	if (!(sctlr & CR_C))
 		return;
 
+	flush_dcache_all();
 	set_sctlr(sctlr & ~(CR_C|CR_M));
 
-	flush_dcache_all();
 	__asm_invalidate_tlb_all();
 }
 
-- 
2.7.4