From: Felipe Balbi <balbi@xxxxxx>
In case we have transfers which aren't aligned
to wMaxPacketSize, we need to be careful with
how we start the transfer with the HW. OUT
transfers _must_ be aligned with wMaxPacketSize
and in order to guarantee that, we use a bounce
buffer.
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/usb/dwc3/ep0.c | 37 ++++++++++++++++++++++++++++++++-----
1 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index a6fc5c3..f1e0a5e 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -185,10 +185,29 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep,
req->epnum = dep->number;
list_add_tail(&req->list, &dep->request_list);
- dwc3_map_buffer_to_dma(req);
+ if (req->request.length == 0) {
+ ret = dwc3_ep0_start_trans(dwc, dep->number,
+ dwc->ctrl_req_addr, 0);
+ } else if ((req->request.length % dep->endpoint.maxpacket)
+ && (dep->number == 0)) {
+ dwc->ep0_bounced = true;
+
+ WARN_ON(req->request.length > dep->endpoint.maxpacket);
+
+ /*
+ * REVISIT in case request length is bigger than EP0
+ * wMaxPacketSize, we will need two chained TRBs to handle
+ * the transfer.
+ */
+ ret = dwc3_ep0_start_trans(dwc, dep->number,
+ dwc->ep0_bounce_addr, dep->endpoint.maxpacket);
+ } else {
+ dwc3_map_buffer_to_dma(req);
+
+ ret = dwc3_ep0_start_trans(dwc, dep->number,
+ req->request.dma, req->request.length);
+ }
- ret = dwc3_ep0_start_trans(dwc, dep->number, req->request.dma,
- req->request.length);
if (ret < 0) {
list_del(&req->list);
dwc3_unmap_buffer_from_dma(req);
@@ -655,8 +674,16 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
dwc3_trb_to_nat(dwc->ep0_trb, &trb);
- transferred = ur->length - trb.length;
- ur->actual += transferred;
+ if (dwc->ep0_bounced) {
+ struct dwc3_ep *ep0 = dwc->eps[0];
+
+ transferred = min(ur->length, dep->endpoint.maxpacket - trb.length);
+ memcpy(ur->buf, dwc->ep0_bounce, transferred);
+ dwc->ep0_bounced = false;
+ } else {
+ transferred = ur->length - trb.length;
+ ur->actual += transferred;
+ }
if ((epnum & 1) && ur->actual < ur->length) {
/* for some reason we did not get everything out */
--
1.7.7
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