usb: dwc2: handle DMA buffer unmapping sanely

The driver's handling of DMA buffers for non-aligned transfers
was kind of nuts. For IN transfers, it left the URB DMA buffer
mapped until the transfer completed, then synced it, copied the
data from the bounce buffer, then synced it again.

Instead of that, just call usb_hcd_unmap_urb_for_dma() to unmap
the buffer before starting the transfer. Then no syncing is
required when doing the copy. This should also allow handling of
other types of mappings besides just dma_map_single() ones.

Also reduce the size of the bounce buffer allocation for Isoc
endpoints to 3K, since that's the largest possible transfer size.

Tested on Raspberry Pi and Altera SOCFPGA.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 0 insertions, 22 deletions

diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c
index f06249c1b918..551ba878b003 100644
--- a/drivers/usb/dwc2/hcd_intr.c
+++ b/drivers/usb/dwc2/hcd_intr.c
@@ -465,12 +465,8 @@ static int dwc2_update_urb_state(struct dwc2_hsotg *hsotg,
 	/* Non DWORD-aligned buffer case handling */
 	if (chan->align_buf && xfer_length && chan->ep_is_in) {
 		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
-		dma_sync_single_for_cpu(hsotg->dev, urb->dma, urb->length,
-					DMA_FROM_DEVICE);
 		memcpy(urb->buf + urb->actual_length, chan->qh->dw_align_buf,
 		       xfer_length);
-		dma_sync_single_for_device(hsotg->dev, urb->dma, urb->length,
-					   DMA_FROM_DEVICE);
 	}
 
 	dev_vdbg(hsotg->dev, "urb->actual_length=%d xfer_length=%d\n",
@@ -560,14 +556,9 @@ static enum dwc2_halt_status dwc2_update_isoc_urb_state(
 		    chan->ep_is_in) {
 			dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n",
 				 __func__);
-			dma_sync_single_for_cpu(hsotg->dev, urb->dma,
-						urb->length, DMA_FROM_DEVICE);
 			memcpy(urb->buf + frame_desc->offset +
 			       qtd->isoc_split_offset, chan->qh->dw_align_buf,
 			       frame_desc->actual_length);
-			dma_sync_single_for_device(hsotg->dev, urb->dma,
-						   urb->length,
-						   DMA_FROM_DEVICE);
 		}
 		break;
 	case DWC2_HC_XFER_FRAME_OVERRUN:
@@ -594,14 +585,9 @@ static enum dwc2_halt_status dwc2_update_isoc_urb_state(
 		    chan->ep_is_in) {
 			dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n",
 				 __func__);
-			dma_sync_single_for_cpu(hsotg->dev, urb->dma,
-						urb->length, DMA_FROM_DEVICE);
 			memcpy(urb->buf + frame_desc->offset +
 			       qtd->isoc_split_offset, chan->qh->dw_align_buf,
 			       frame_desc->actual_length);
-			dma_sync_single_for_device(hsotg->dev, urb->dma,
-						   urb->length,
-						   DMA_FROM_DEVICE);
 		}
 
 		/* Skip whole frame */
@@ -937,12 +923,8 @@ static int dwc2_xfercomp_isoc_split_in(struct dwc2_hsotg *hsotg,
 
 	if (chan->align_buf) {
 		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
-		dma_sync_single_for_cpu(hsotg->dev, qtd->urb->dma,
-					qtd->urb->length, DMA_FROM_DEVICE);
 		memcpy(qtd->urb->buf + frame_desc->offset +
 		       qtd->isoc_split_offset, chan->qh->dw_align_buf, len);
-		dma_sync_single_for_device(hsotg->dev, qtd->urb->dma,
-					   qtd->urb->length, DMA_FROM_DEVICE);
 	}
 
 	qtd->isoc_split_offset += len;
@@ -1170,12 +1152,8 @@ static void dwc2_update_urb_state_abn(struct dwc2_hsotg *hsotg,
 	/* Non DWORD-aligned buffer case handling */
 	if (chan->align_buf && xfer_length && chan->ep_is_in) {
 		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
-		dma_sync_single_for_cpu(hsotg->dev, urb->dma, urb->length,
-					DMA_FROM_DEVICE);
 		memcpy(urb->buf + urb->actual_length, chan->qh->dw_align_buf,
 		       xfer_length);
-		dma_sync_single_for_device(hsotg->dev, urb->dma, urb->length,
-					   DMA_FROM_DEVICE);
 	}
 
 	urb->actual_length += xfer_length;