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 eddie.cai.linux@gmail.com Reviewed-by: Stefan Brüns stefan.bruens@rwth-aachen.de --- drivers/usb/host/dwc2.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c index 5ac602e..f295843 100644 --- a/drivers/usb/host/dwc2.c +++ b/drivers/usb/host/dwc2.c @@ -811,12 +811,19 @@ 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( + (uintptr_t)aligned_buffer, + (uintptr_t)aligned_buffer + + roundup(xfer_len, ARCH_DMA_MINALIGN)); + } else { + memcpy(aligned_buffer, buffer, xfer_len); + flush_dcache_range( + (uintptr_t)aligned_buffer, + (uintptr_t)aligned_buffer + + roundup(xfer_len, ARCH_DMA_MINALIGN)); + } }
writel(phys_to_bus((unsigned long)aligned_buffer), &hc_regs->hcdma);