usb: dwc3: gadget: Correct ISOC DATA PIDs for short packets

[karo-tx-linux.git] / drivers / usb / dwc3 / gadget.c

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 9e41605a276ba8bc8718340272f2cf21d27cfed7..f064f1549333dcd7dab10fd491e43cf31bac887e 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -191,14 +191,16 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 
        req->started = false;
        list_del(&req->list);
-       req->trb = NULL;
        req->remaining = 0;
 
        if (req->request.status == -EINPROGRESS)
                req->request.status = status;
 
-       usb_gadget_unmap_request_by_dev(dwc->sysdev,
-                                       &req->request, req->direction);
+       if (req->trb)
+               usb_gadget_unmap_request_by_dev(dwc->sysdev,
+                                               &req->request, req->direction);
+
+       req->trb = NULL;
 
        trace_dwc3_gadget_giveback(req);
 
@@ -894,9 +896,40 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb,
                if (!node) {
                        trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS_FIRST;
 
+                       /*
+                        * USB Specification 2.0 Section 5.9.2 states that: "If
+                        * there is only a single transaction in the microframe,
+                        * only a DATA0 data packet PID is used.  If there are
+                        * two transactions per microframe, DATA1 is used for
+                        * the first transaction data packet and DATA0 is used
+                        * for the second transaction data packet.  If there are
+                        * three transactions per microframe, DATA2 is used for
+                        * the first transaction data packet, DATA1 is used for
+                        * the second, and DATA0 is used for the third."
+                        *
+                        * IOW, we should satisfy the following cases:
+                        *
+                        * 1) length <= maxpacket
+                        *      - DATA0
+                        *
+                        * 2) maxpacket < length <= (2 * maxpacket)
+                        *      - DATA1, DATA0
+                        *
+                        * 3) (2 * maxpacket) < length <= (3 * maxpacket)
+                        *      - DATA2, DATA1, DATA0
+                        */
                        if (speed == USB_SPEED_HIGH) {
                                struct usb_ep *ep = &dep->endpoint;
-                               trb->size |= DWC3_TRB_SIZE_PCM1(ep->mult - 1);
+                               unsigned int mult = ep->mult - 1;
+                               unsigned int maxp = usb_endpoint_maxp(ep->desc);
+
+                               if (length <= (2 * maxp))
+                                       mult--;
+
+                               if (length <= maxp)
+                                       mult--;
+
+                               trb->size |= DWC3_TRB_SIZE_PCM1(mult);
                        }
                } else {
                        trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS;