[PATCH 3/3] MIPS: dma-default: do not flush caches in dma_sync_single_* excessively

[Denis Orlov]

Change the logic to be different depending on whether we are doing
synchronization for a cpu or a device. This gets rid of unnecessary
cache flushing in some cases. While at it, also simplify code a bit,
collapsing two cases with the same code in a switch statement in
dma_sync_single_for_device().

The functional change itself is taken from Linux commit
'MIPS: make dma_sync_*_for_cpu a little less overzealous'
(hash: cbf1449ba5aec9cf4c68b69f899391a8d42e9b8f).

Signed-off-by: Denis Orlov <denorl2009 at gmail.com>
---
 arch/mips/lib/dma-default.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/arch/mips/lib/dma-default.c b/arch/mips/lib/dma-default.c
index f6c750b8ac..0347d7a7db 100644
--- a/arch/mips/lib/dma-default.c
+++ b/arch/mips/lib/dma-default.c
@@ -6,39 +6,37 @@
 #include <dma.h>
 #include <asm/io.h>
 
-static inline void __dma_sync_mips(unsigned long addr, size_t size,
-				   enum dma_data_direction direction)
+void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
+			     enum dma_data_direction dir)
 {
-	switch (direction) {
+	unsigned long virt = (unsigned long)phys_to_virt(address);
+
+	switch (dir) {
 	case DMA_TO_DEVICE:
-		dma_flush_range(addr, addr + size);
 		break;
-
 	case DMA_FROM_DEVICE:
-		dma_inv_range(addr, addr + size);
-		break;
-
 	case DMA_BIDIRECTIONAL:
-		dma_flush_range(addr, addr + size);
+		dma_inv_range(virt, virt + size);
 		break;
-
 	default:
 		BUG();
 	}
 }
 
-void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
-			     enum dma_data_direction dir)
-{
-	unsigned long virt = (unsigned long)phys_to_virt(address);
-
-	__dma_sync_mips(virt, size, dir);
-}
-
 void dma_sync_single_for_device(dma_addr_t address, size_t size,
 				enum dma_data_direction dir)
 {
 	unsigned long virt = (unsigned long)phys_to_virt(address);
 
-	__dma_sync_mips(virt, size, dir);
+	switch (dir) {
+	case DMA_FROM_DEVICE:
+		dma_inv_range(virt, virt + size);
+		break;
+	case DMA_TO_DEVICE:
+	case DMA_BIDIRECTIONAL:
+		dma_flush_range(virt, virt + size);
+		break;
+	default:
+		BUG();
+	}
 }
-- 
2.30.2