The arch_sync_dma_for_cpu()/arch_sync_dma_for_device() implementation is
broken for some combinations that end up in a BUG() instead of performing
the necessary flushes.
The implementation of arch should follow the following rules:
map for_cpu for_device unmap
TO_DEV writeback none writeback none
TO_CPU invalidate invalidate* invalidate invalidate*
BIDIR writeback invalidate writeback invalidate
Link: https://lore.kernel.org/lkml/20180518215548.GH17671@xxxxxxxxxxxxxxxxxxxxx/
Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
---
arch/csky/mm/dma-mapping.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/csky/mm/dma-mapping.c b/arch/csky/mm/dma-mapping.c
index 16c2087..30a2041 100644
--- a/arch/csky/mm/dma-mapping.c
+++ b/arch/csky/mm/dma-mapping.c
@@ -217,7 +217,8 @@ void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
break;
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
- BUG();
+ dma_wbinv_range(vaddr + offset, vaddr + offset + size);
+ break;
default:
BUG();
}
@@ -240,7 +241,7 @@ void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
switch (dir) {
case DMA_TO_DEVICE:
- BUG();
+ break;
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
dma_wbinv_range(vaddr + offset, vaddr + offset + size);
--
2.7.4
