DWC3 requires epout to have buffer size aligned to MaxPacketSize value.
This patch implements necessary quirk for it.

Signed-off-by: David Cohen <david.a.co...@linux.intel.com>
---
 drivers/usb/dwc3/core.h   |  6 ++++++
 drivers/usb/dwc3/gadget.c | 23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index f8af8d44af85..ff42d7ddc546 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -571,6 +571,12 @@ struct dwc3_request {
        struct dwc3_ep          *dep;
        u32                     start_slot;
 
+       /*
+        * If gadget/epout, we need to pad buffer size to align with
+        * maxpacketsize.
+        */
+       size_t                  pad;
+
        u8                      epnum;
        struct dwc3_trb         *trb;
        dma_addr_t              trb_dma;
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 5452c0fce360..7c2d36f6ad4b 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1130,6 +1130,14 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, 
struct usb_request *request,
        dev_vdbg(dwc->dev, "queing request %p to %s length %d\n",
                        request, ep->name, request->length);
 
+       /* If ep out, roundup request->length to epout maxpacketsize */
+       if (!(dep->number & 1)) {
+               unsigned int aligned = roundup(request->length,
+                                              ep->desc->wMaxPacketSize);
+               req->pad = aligned - request->length;
+               request->length = aligned;
+       }
+
        spin_lock_irqsave(&dwc->lock, flags);
        ret = __dwc3_gadget_ep_queue(dep, req);
        spin_unlock_irqrestore(&dwc->lock, flags);
@@ -1173,6 +1181,15 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
        }
 
 out1:
+       if (!(dep->number & 1)) {
+               /*
+                * Sanitize request->length after pad was applied before
+                * queue.
+                */
+               request->length -= req->pad;
+               req->pad = 0;
+       }
+
        /* giveback the request */
        dwc3_gadget_giveback(dep, req, -ECONNRESET);
 
@@ -2600,6 +2617,12 @@ int dwc3_gadget_init(struct dwc3 *dwc)
        dwc->gadget.name                = "dwc3-gadget";
 
        /*
+        * Per databook, DWC3 needs buffer size to be aligned to MaxPacketSize
+        * on ep out.
+        */
+       dwc->gadget.quirk_ep_out_aligned_size = true;
+
+       /*
         * REVISIT: Here we should clear all pending IRQs to be
         * sure we're starting from a well known location.
         */
-- 
1.8.4.2

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