Hi Eddie,
We should only need to do only one time cache operation for a buffer
ready to do DMA transfer, so you need to remove another cache invalidate
operation for the same buffer in the same function.
Thanks,
- Kever
On 04/01/2017 02:51 PM, Eddie Cai wrote:
We should invalidate the dcache before starting the DMA. In case there are
any dirty lines from the DMA buffer in the cache, subsequent cache-line
replacements may corrupt the buffer in memory while the DMA is still going on.
Cache-line replacement can happen if the CPU tries to bring some other memory
locations into the cache while the DMA is going on.
Signed-off-by: Eddie Cai <[email protected]>
---
drivers/usb/host/dwc2.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index 5ac602e..a151ba6 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -811,12 +811,17 @@ static int transfer_chunk(struct dwc2_hc_regs *hc_regs,
void *aligned_buffer,
(*pid << DWC2_HCTSIZ_PID_OFFSET),
&hc_regs->hctsiz);
- if (!in && xfer_len) {
- memcpy(aligned_buffer, buffer, xfer_len);
-
- flush_dcache_range((unsigned long)aligned_buffer,
- (unsigned long)aligned_buffer +
- roundup(xfer_len, ARCH_DMA_MINALIGN));
+ if (xfer_len) {
+ if(in){
+ invalidate_dcache_range((unsigned long)aligned_buffer,
+ (unsigned long)aligned_buffer +
+ roundup(xfer_len,
ARCH_DMA_MINALIGN));
+ }else{
+ memcpy(aligned_buffer, buffer, xfer_len);
+ flush_dcache_range((unsigned long)aligned_buffer,
+ (unsigned long)aligned_buffer +
+ roundup(xfer_len,
ARCH_DMA_MINALIGN));
+ }
}
writel(phys_to_bus((unsigned long)aligned_buffer), &hc_regs->hcdma);
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