ARM: 6187/1: The v6_dma_inv_range() function must preserve data on SMP
A recent patch for DMA cache maintenance on ARM11MPCore added a write
for ownership trick to the v6_dma_inv_range() function. Such operation
destroys data already present in the buffer. However, this function is
used with with dma_sync_single_for_device() which is supposed to
preserve the existing data transfered into the buffer. This patch adds a
combination of read/write for ownership to preserve the original data.
Reported-by: Ronen Shitrit <rshitrit@marvell.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/cache-v6.S b/arch/arm/mm/cache-v6.S
index e46ecd8..332b48c 100644
--- a/arch/arm/mm/cache-v6.S
+++ b/arch/arm/mm/cache-v6.S
@@ -212,7 +212,8 @@
#endif
1:
#ifdef CONFIG_SMP
- str r0, [r0] @ write for ownership
+ ldr r2, [r0] @ read for ownership
+ str r2, [r0] @ write for ownership
#endif
#ifdef HARVARD_CACHE
mcr p15, 0, r0, c7, c6, 1 @ invalidate D line