commit 2c2196f4c7da112039d7dde9617a5e3c1d06cfca
author Xu Ziyuan <xzy.xu@rock-chips.com> Thu Jul 14 14:52:35 2016 +0800
committer Simon Glass <sjg@chromium.org> Mon Jul 25 20:44:19 2016 -0600
tree 33768026a1ec458f79ba7b19234b71d27bbd7497
parent b729dc0e86940fbfe06e6234fcabbc2a51710124

usb: dwc2 : invalidate dcache before starting DMA

Invalidate dcache before starting the DMA to ensure coherency. 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: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c

diff --git a/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c b/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c
index 12f5c85..0d6d2fb 100644
--- a/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c
+++ b/drivers/usb/gadget/dwc2_udc_otg_xfer_dma.c
@@ -110,6 +110,9 @@
 
 	ctrl =  readl(&reg->out_endp[ep_num].doepctl);
 
+	invalidate_dcache_range((unsigned long) ep->dma_buf,
+				(unsigned long) ep->dma_buf + ep->len);
+
 	writel((unsigned int) ep->dma_buf, &reg->out_endp[ep_num].doepdma);
 	writel(DOEPT_SIZ_PKT_CNT(pktcnt) | DOEPT_SIZ_XFER_SIZE(length),
 	       &reg->out_endp[ep_num].doeptsiz);