Commit 04c03d10 authored by Felipe Balbi's avatar Felipe Balbi
Browse files

usb: dwc3: gadget: handle request->zero 



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: default avatarRavi B <ravibabu@ti.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 3ff4b573

drivers/usb/dwc3/core.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

drivers/usb/dwc3/gadget.c

+48 −2
Original line number Diff line number Diff line
@@ -1159,6 +1159,32 @@ 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)

{
@@ -1172,6 +1198,16 @@ 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);



	spin_unlock_irqrestore(&dwc->lock, flags);



	return ret;
@@ -2744,6 +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.speed		= USB_SPEED_UNKNOWN;

	dwc->gadget.sg_supported	= true;
@@ -2785,16 +2827,19 @@ 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,
@@ -2827,6 +2872,7 @@ 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);

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