Revert "usb: dwc3: gadget: always decrement by 1"

[cascardo/linux.git] / drivers / usb / dwc3 / gadget.c

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8f8c215..122e64d 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -829,7 +829,7 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
        if (!req->request.no_interrupt && !chain)
                trb->ctrl |= DWC3_TRB_CTRL_IOC | DWC3_TRB_CTRL_ISP_IMI;
 
-       if (last)
+       if (last && !usb_endpoint_xfer_isoc(dep->endpoint.desc))
                trb->ctrl |= DWC3_TRB_CTRL_LST;
 
        if (chain)
@@ -1433,7 +1433,7 @@ static int dwc3_gadget_get_frame(struct usb_gadget *g)
 
 static int __dwc3_gadget_wakeup(struct dwc3 *dwc)
 {
-       unsigned long           timeout;
+       int                     retries;
 
        int                     ret;
        u32                     reg;
@@ -1484,9 +1484,9 @@ static int __dwc3_gadget_wakeup(struct dwc3 *dwc)
        }
 
        /* poll until Link State changes to ON */
-       timeout = jiffies + msecs_to_jiffies(100);
+       retries = 20000;
 
-       while (!time_after(jiffies, timeout)) {
+       while (retries--) {
                reg = dwc3_readl(dwc->regs, DWC3_DSTS);
 
                /* in HS, means ON */
@@ -1955,7 +1955,8 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
 
 static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
                struct dwc3_request *req, struct dwc3_trb *trb,
-               const struct dwc3_event_depevt *event, int status)
+               const struct dwc3_event_depevt *event, int status,
+               int chain)
 {
        unsigned int            count;
        unsigned int            s_pkt = 0;
@@ -1964,17 +1965,22 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
        dep->queued_requests--;
        trace_dwc3_complete_trb(dep, trb);
 
+       /*
+        * If we're in the middle of series of chained TRBs and we
+        * receive a short transfer along the way, DWC3 will skip
+        * through all TRBs including the last TRB in the chain (the
+        * where CHN bit is zero. DWC3 will also avoid clearing HWO
+        * bit and SW has to do it manually.
+        *
+        * We're going to do that here to avoid problems of HW trying
+        * to use bogus TRBs for transfers.
+        */
+       if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO))
+               trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+
        if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN)
-               /*
-                * We continue despite the error. There is not much we
-                * can do. If we don't clean it up we loop forever. If
-                * we skip the TRB then it gets overwritten after a
-                * while since we use them in a ring buffer. A BUG()
-                * would help. Lets hope that if this occurs, someone
-                * fixes the root cause instead of looking away :)
-                */
-               dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n",
-                               dep->name, trb);
+               return 1;
+
        count = trb->size & DWC3_TRB_SIZE_MASK;
 
        if (dep->direction) {
@@ -2013,15 +2019,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
                        s_pkt = 1;
        }
 
-       /*
-        * We assume here we will always receive the entire data block
-        * which we should receive. Meaning, if we program RX to
-        * receive 4K but we receive only 2K, we assume that's all we
-        * should receive and we simply bounce the request back to the
-        * gadget driver for further processing.
-        */
-       req->request.actual += req->request.length - count;
-       if (s_pkt)
+       if (s_pkt && !chain)
                return 1;
        if ((event->status & DEPEVT_STATUS_LST) &&
                        (trb->ctrl & (DWC3_TRB_CTRL_LST |
@@ -2040,13 +2038,17 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
        struct dwc3_trb         *trb;
        unsigned int            slot;
        unsigned int            i;
+       int                     count = 0;
        int                     ret;
 
        do {
+               int chain;
+
                req = next_request(&dep->started_list);
                if (WARN_ON_ONCE(!req))
                        return 1;
 
+               chain = req->request.num_mapped_sgs > 0;
                i = 0;
                do {
                        slot = req->first_trb_index + i;
@@ -2054,13 +2056,22 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
                                slot++;
                        slot %= DWC3_TRB_NUM;
                        trb = &dep->trb_pool[slot];
+                       count += trb->size & DWC3_TRB_SIZE_MASK;
 
                        ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
-                                       event, status);
+                                       event, status, chain);
                        if (ret)
                                break;
                } while (++i < req->request.num_mapped_sgs);
 
+               /*
+                * We assume here we will always receive the entire data block
+                * which we should receive. Meaning, if we program RX to
+                * receive 4K but we receive only 2K, we assume that's all we
+                * should receive and we simply bounce the request back to the
+                * gadget driver for further processing.
+                */
+               req->request.actual += req->request.length - count;
                dwc3_gadget_giveback(dep, req, status);
 
                if (ret)