This reverts commit d13d870986eeecc58d8652268557e4a159b9d4c4.
While the patch itself is correct, it at least breaks USB on the
Raspberry Pi 3b.
With this patch dma_sync_single_for_device() is passed the DMA address.
This is correct as even the prototype suggests that it should get a
dma_addr_t. Unfortunately this is not what the function implements and
also not what the users expect. Most if not all users simply pass a CPU
pointer casted to unsigned long. dma_sync_single_for_device() on ARM
then takes the DMA address as a CPU pointer and does cache maintenance
on it.
Before we can merge this patch again dma_sync_single_for_device() must
get a struct device * argument and (on ARM) the cpu_to_dma() conversion
must be reverted before doing cache maintenance.
---
drivers/dma/map.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/dma/map.c b/drivers/dma/map.c
index fea04c38a3..114c0f7db3 100644
--- a/drivers/dma/map.c
+++ b/drivers/dma/map.c
@@ -23,15 +23,17 @@ static inline void *dma_to_cpu(struct device *dev, dma_addr_t addr)
dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
enum dma_data_direction dir)
{
- dma_addr_t ret = cpu_to_dma(dev, ptr);
+ unsigned long addr = (unsigned long)ptr;
- dma_sync_single_for_device(ret, size, dir);
+ dma_sync_single_for_device(addr, size, dir);
- return ret;
+ return cpu_to_dma(dev, ptr);
}
void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
enum dma_data_direction dir)
{
- dma_sync_single_for_cpu(dma_addr, size, dir);
+ unsigned long addr = (unsigned long)dma_to_cpu(dev, dma_addr);
+
+ dma_sync_single_for_cpu(addr, size, dir);
}
--
2.39.2
