So far, dwc3 has always missed request->zero
handling for every endpoint. Let's implement
that so we can handle cases where transfer must
be finished with a ZLP.
Note that dwc3 is a little special. Even though
we're dealing with a ZLP, we still need a buffer
of wMaxPacketSize bytes; to hide that detail from
every gadget driver, we have a preallocated buffer
of 1024 bytes (biggest bulk size) to use (and
share) among all endpoints.
Reported-by: Ravi B <ravib...@ti.com>
Signed-off-by: Felipe Balbi <ba...@ti.com>
---
since v1:
- remove unnecessary 'free_on_complete' flag
drivers/usb/dwc3/core.h | 3 +++
drivers/usb/dwc3/gadget.c | 51 +++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 36f1cb74588c..29130682e547 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -37,6 +37,7 @@
#define DWC3_MSG_MAX 500
/* Global constants */
+#define DWC3_ZLP_BUF_SIZE 1024 /* size of a superspeed bulk */
#define DWC3_EP0_BOUNCE_SIZE 512
#define DWC3_ENDPOINTS_NUM 32
#define DWC3_XHCI_RESOURCES_NUM 2
@@ -647,6 +648,7 @@ struct dwc3_scratchpad_array {
* @ctrl_req: usb control request which is used for ep0
* @ep0_trb: trb which is used for the ctrl_req
* @ep0_bounce: bounce buffer for ep0
+ * @zlp_buf: used when request->zero is set
* @setup_buf: used while precessing STD USB requests
* @ctrl_req_addr: dma address of ctrl_req
* @ep0_trb: dma address of ep0_trb
@@ -734,6 +736,7 @@ struct dwc3 {
struct usb_ctrlrequest *ctrl_req;
struct dwc3_trb *ep0_trb;
void *ep0_bounce;
+ void *zlp_buf;
void *scratchbuf;
u8 *setup_buf;
dma_addr_t ctrl_req_addr;
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index e341f034296f..5a77e9925939 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1158,6 +1158,32 @@ out:
return ret;
}
+static void __dwc3_gadget_ep_zlp_complete(struct usb_ep *ep,
+ struct usb_request *request)
+{
+ dwc3_gadget_ep_free_request(ep, request);
+}
+
+static int __dwc3_gadget_ep_queue_zlp(struct dwc3 *dwc, struct dwc3_ep *dep)
+{
+ struct dwc3_request *req;
+ struct usb_request *request;
+ struct usb_ep *ep = &dep->endpoint;
+
+ dwc3_trace(trace_dwc3_gadget, "queueing ZLP\n");
+ request = dwc3_gadget_ep_alloc_request(ep, GFP_ATOMIC);
+ if (!request)
+ return -ENOMEM;
+
+ request->length = 0;
+ request->buf = dwc->zlp_buf;
+ request->complete = __dwc3_gadget_ep_zlp_complete;
+
+ req = to_dwc3_request(request);
+
+ return __dwc3_gadget_ep_queue(dep, req);
+}
+
static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
gfp_t gfp_flags)
{
@@ -1171,6 +1197,17 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep,
struct usb_request *request,
spin_lock_irqsave(&dwc->lock, flags);
ret = __dwc3_gadget_ep_queue(dep, req);
+
+ /*
+ * Okay, here's the thing, if gadget driver has requested for a ZLP by
+ * setting request->zero, instead of doing magic, we will just queue an
+ * extra usb_request ourselves so that it gets handled the same way as
+ * any other request.
+ */
+ if (ret == 0 && request->zero && (request->length % ep->maxpacket == 0))
+ ret = __dwc3_gadget_ep_queue_zlp(dwc, dep);
+
+out:
spin_unlock_irqrestore(&dwc->lock, flags);
return ret;
@@ -2743,6 +2780,12 @@ int dwc3_gadget_init(struct dwc3 *dwc)
goto err3;
}
+ dwc->zlp_buf = kzalloc(DWC3_ZLP_BUF_SIZE, GFP_KERNEL);
+ if (!dwc->zlp_buf) {
+ ret = -ENOMEM;
+ goto err4;
+ }
+
dwc->gadget.ops = &dwc3_gadget_ops;
dwc->gadget.max_speed = USB_SPEED_SUPER;
dwc->gadget.speed = USB_SPEED_UNKNOWN;
@@ -2762,16 +2805,19 @@ int dwc3_gadget_init(struct dwc3 *dwc)
ret = dwc3_gadget_init_endpoints(dwc);
if (ret)
- goto err4;
+ goto err5;
ret = usb_add_gadget_udc(dwc->dev, &dwc->gadget);
if (ret) {
dev_err(dwc->dev, "failed to register udc\n");
- goto err4;
+ goto err5;
}
return 0;
+err5:
+ kfree(dwc->zlp_buf);
+
err4:
dwc3_gadget_free_endpoints(dwc);
dma_free_coherent(dwc->dev, DWC3_EP0_BOUNCE_SIZE,
@@ -2804,6 +2850,7 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
dwc->ep0_bounce, dwc->ep0_bounce_addr);
kfree(dwc->setup_buf);
+ kfree(dwc->zlp_buf);
dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb),
dwc->ep0_trb, dwc->ep0_trb_addr);
--
2.6.3
--
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