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>

drivers/usb/dwc2/hcd.c

@@ -697,29 +697,45 @@ static void *dwc2_hc_init_xfer(struct dwc2_hsotg *hsotg,
 }
 
 static int dwc2_hc_setup_align_buf(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
-				   struct dwc2_host_chan *chan, void *bufptr)
+				   struct dwc2_host_chan *chan,
+				   struct dwc2_hcd_urb *urb, void *bufptr)
 {
 	u32 buf_size;
-
-	if (chan->ep_type != USB_ENDPOINT_XFER_ISOC)
-		buf_size = hsotg->core_params->max_transfer_size;
-	else
-		buf_size = 4096;
+	struct urb *usb_urb;
+	struct usb_hcd *hcd;
 
 	if (!qh->dw_align_buf) {
+		if (chan->ep_type != USB_ENDPOINT_XFER_ISOC)
+			buf_size = hsotg->core_params->max_transfer_size;
+		else
+			/* 3072 = 3 max-size Isoc packets */
+			buf_size = 3072;
+
 		qh->dw_align_buf = dma_alloc_coherent(hsotg->dev, buf_size,
 						      &qh->dw_align_buf_dma,
 						      GFP_ATOMIC);
 		if (!qh->dw_align_buf)
 			return -ENOMEM;
+		qh->dw_align_buf_size = buf_size;
 	}
 
-	if (!chan->ep_is_in && chan->xfer_len) {
-		dma_sync_single_for_cpu(hsotg->dev, chan->xfer_dma, buf_size,
-					DMA_TO_DEVICE);
-		memcpy(qh->dw_align_buf, bufptr, chan->xfer_len);
-		dma_sync_single_for_device(hsotg->dev, chan->xfer_dma, buf_size,
-					   DMA_TO_DEVICE);
+	if (chan->xfer_len) {
+		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
+		usb_urb = urb->priv;
+
+		if (usb_urb) {
+			if (usb_urb->transfer_flags &
+			    (URB_SETUP_MAP_SINGLE | URB_DMA_MAP_SG |
+			     URB_DMA_MAP_PAGE | URB_DMA_MAP_SINGLE)) {
+				hcd = dwc2_hsotg_to_hcd(hsotg);
+				usb_hcd_unmap_urb_for_dma(hcd, usb_urb);
+			}
+			if (!chan->ep_is_in)
+				memcpy(qh->dw_align_buf, bufptr,
+				       chan->xfer_len);
+		} else {
+			dev_warn(hsotg->dev, "no URB in dwc2_urb\n");
+		}
 	}
 
 	chan->align_buf = qh->dw_align_buf_dma;
@@ -828,7 +844,7 @@ static int dwc2_assign_and_init_hc(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
 	/* Non DWORD-aligned buffer case */
 	if (bufptr) {
 		dev_vdbg(hsotg->dev, "Non-aligned buffer\n");
-		if (dwc2_hc_setup_align_buf(hsotg, qh, chan, bufptr)) {
+		if (dwc2_hc_setup_align_buf(hsotg, qh, chan, urb, bufptr)) {
 			dev_err(hsotg->dev,
 				"%s: Failed to allocate memory to handle non-dword aligned buffer\n",
 				__func__);

drivers/usb/dwc2/hcd.h

@@ -243,7 +243,8 @@ enum dwc2_transaction_type {
  * @ntd:                Actual number of transfer descriptors in a list
  * @dw_align_buf:       Used instead of original buffer if its physical address
  *                      is not dword-aligned
- * @dw_align_buf_dma:   DMA address for align_buf
+ * @dw_align_buf_size:  Size of dw_align_buf
+ * @dw_align_buf_dma:   DMA address for dw_align_buf
  * @qtd_list:           List of QTDs for this QH
  * @channel:            Host channel currently processing transfers for this QH
  * @qh_list_entry:      Entry for QH in either the periodic or non-periodic
@@ -276,6 +277,7 @@ struct dwc2_qh {
 	u16 start_split_frame;
 	u16 ntd;
 	u8 *dw_align_buf;
+	int dw_align_buf_size;
 	dma_addr_t dw_align_buf_dma;
 	struct list_head qtd_list;
 	struct dwc2_host_chan *channel;

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;

drivers/usb/dwc2/hcd_queue.c

@@ -229,19 +229,11 @@ static struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
  */
 void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
 {
-	u32 buf_size;
-
-	if (hsotg->core_params->dma_desc_enable > 0) {
+	if (hsotg->core_params->dma_desc_enable > 0)
 		dwc2_hcd_qh_free_ddma(hsotg, qh);
-	} else if (qh->dw_align_buf) {
-		if (qh->ep_type == USB_ENDPOINT_XFER_ISOC)
-			buf_size = 4096;
-		else
-			buf_size = hsotg->core_params->max_transfer_size;
-		dma_free_coherent(hsotg->dev, buf_size, qh->dw_align_buf,
-				  qh->dw_align_buf_dma);
-	}
-
+	else if (qh->dw_align_buf)
+		dma_free_coherent(hsotg->dev, qh->dw_align_buf_size,
+				  qh->dw_align_buf, qh->dw_align_buf_dma);
 	kfree(qh);
 }