usb: dwc3: ep0: improve handling of unaligned OUT requests

Just like we did for all other endpoint types, let's rely on a chained
TRB pointing to ep0_bounce_addr in order to align transfer size. This
will make the code simpler.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

3 files changed, 29 insertions, 92 deletions

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index bbb7c3f6749e..8dc416daa85c 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -42,7 +42,7 @@
 #define DWC3_PULL_UP_TIMEOUT	500	/* ms */
 #define DWC3_ZLP_BUF_SIZE	1024	/* size of a superspeed bulk */
 #define DWC3_BOUNCE_SIZE	1024	/* size of a superspeed bulk */
-#define DWC3_EP0_BOUNCE_SIZE	512
+#define DWC3_EP0_SETUP_SIZE	512
 #define DWC3_ENDPOINTS_NUM	32
 #define DWC3_XHCI_RESOURCES_NUM	2
 
@@ -761,12 +761,10 @@ struct dwc3_scratchpad_array {
 /**
  * struct dwc3 - representation of our controller
  * @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
  * @ep0_trb: dma address of ep0_trb
  * @ep0_usb_req: dummy req used while handling STD USB requests
- * @ep0_bounce_addr: dma address of ep0_bounce
  * @scratch_addr: dma address of scratchbuf
  * @ep0_in_setup: one control transfer is completed and enter setup phase
  * @lock: for synchronizing
@@ -859,13 +857,11 @@ struct dwc3_scratchpad_array {
 struct dwc3 {
 	struct dwc3_trb		*ep0_trb;
 	void			*bounce;
-	void			*ep0_bounce;
 	void			*zlp_buf;
 	void			*scratchbuf;
 	u8			*setup_buf;
 	dma_addr_t		ep0_trb_addr;
 	dma_addr_t		bounce_addr;
-	dma_addr_t		ep0_bounce_addr;
 	dma_addr_t		scratch_addr;
 	struct dwc3_request	ep0_usb_req;
 	struct completion	ep0_in_setup;
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 3ba2309c837f..04249243e4d3 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -836,7 +836,6 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 	struct usb_request	*ur;
 	struct dwc3_trb		*trb;
 	struct dwc3_ep		*ep0;
-	unsigned		transfer_size = 0;
 	unsigned		maxp;
 	unsigned		remaining_ur_length;
 	void			*buf;
@@ -849,9 +848,7 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 	ep0 = dwc->eps[0];
 
 	dwc->ep0_next_event = DWC3_EP0_NRDY_STATUS;
-
 	trb = dwc->ep0_trb;
-
 	trace_dwc3_complete_trb(ep0, trb);
 
 	r = next_request(&ep0->pending_list);
@@ -872,39 +869,17 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 	remaining_ur_length = ur->length;
 
 	length = trb->size & DWC3_TRB_SIZE_MASK;
-
 	maxp = ep0->endpoint.maxpacket;
+	transferred = ur->length - length;
+	ur->actual += transferred;
 
 	if (dwc->ep0_bounced) {
-		/*
-		 * Handle the first TRB before handling the bounce buffer if
-		 * the request length is greater than the bounce buffer size
-		 */
-		if (ur->length > DWC3_EP0_BOUNCE_SIZE) {
-			transfer_size = ALIGN(ur->length - maxp, maxp);
-			transferred = transfer_size - length;
-			buf = (u8 *)buf + transferred;
-			ur->actual += transferred;
-			remaining_ur_length -= transferred;
-
-			trb++;
-			length = trb->size & DWC3_TRB_SIZE_MASK;
-
-			ep0->trb_enqueue = 0;
-		}
-
-		transfer_size = roundup((ur->length - transfer_size),
-					maxp);
-
-		transferred = min_t(u32, remaining_ur_length,
-				    transfer_size - length);
-		memcpy(buf, dwc->ep0_bounce, transferred);
-	} else {
-		transferred = ur->length - length;
+		trb++;
+		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+		ep0->trb_enqueue = 0;
+		dwc->ep0_bounced = false;
 	}
 
-	ur->actual += transferred;
-
 	if ((epnum & 1) && ur->actual < ur->length) {
 		/* for some reason we did not get everything out */
 
@@ -1006,8 +981,8 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 		ret = dwc3_ep0_start_trans(dep);
 	} else if (!IS_ALIGNED(req->request.length, dep->endpoint.maxpacket)
 			&& (dep->number == 0)) {
-		u32	transfer_size = 0;
 		u32	maxpacket;
+		u32	rem;
 
 		ret = usb_gadget_map_request_by_dev(dwc->sysdev,
 				&req->request, dep->number);
@@ -1015,23 +990,19 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
 			return;
 
 		maxpacket = dep->endpoint.maxpacket;
-
-		if (req->request.length > DWC3_EP0_BOUNCE_SIZE) {
-			transfer_size = ALIGN(req->request.length - maxpacket,
-					      maxpacket);
-			dwc3_ep0_prepare_one_trb(dep, req->request.dma,
-						   transfer_size,
-						   DWC3_TRBCTL_CONTROL_DATA,
-						   true);
-		}
-
-		transfer_size = roundup((req->request.length - transfer_size),
-					maxpacket);
-
+		rem = req->request.length % maxpacket;
 		dwc->ep0_bounced = true;
 
-		dwc3_ep0_prepare_one_trb(dep, dwc->ep0_bounce_addr,
-					 transfer_size, DWC3_TRBCTL_CONTROL_DATA,
+		/* prepare normal TRB */
+		dwc3_ep0_prepare_one_trb(dep, req->request.dma,
+					 req->request.length,
+					 DWC3_TRBCTL_CONTROL_DATA,
+					 true);
+
+		/* Now prepare one extra TRB to align transfer size */
+		dwc3_ep0_prepare_one_trb(dep, dwc->bounce_addr,
+					 maxpacket - rem,
+					 DWC3_TRBCTL_CONTROL_DATA,
 					 false);
 		ret = dwc3_ep0_start_trans(dep);
 	} else {
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 4787d6f449fa..4dc80729ae11 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -171,7 +171,6 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 		int status)
 {
 	struct dwc3			*dwc = dep->dwc;
-	unsigned int			unmap_after_complete = false;
 
 	req->started = false;
 	list_del(&req->list);
@@ -181,19 +180,8 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 	if (req->request.status == -EINPROGRESS)
 		req->request.status = status;
 
-	/*
-	 * NOTICE we don't want to unmap before calling ->complete() if we're
-	 * dealing with a bounced ep0 request. If we unmap it here, we would end
-	 * up overwritting the contents of req->buf and this could confuse the
-	 * gadget driver.
-	 */
-	if (dwc->ep0_bounced && dep->number <= 1) {
-		dwc->ep0_bounced = false;
-		unmap_after_complete = true;
-	} else {
-		usb_gadget_unmap_request_by_dev(dwc->sysdev,
-				&req->request, req->direction);
-	}
+	usb_gadget_unmap_request_by_dev(dwc->sysdev,
+					&req->request, req->direction);
 
 	trace_dwc3_gadget_giveback(req);
 
@@ -201,10 +189,6 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 	usb_gadget_giveback_request(&dep->endpoint, &req->request);
 	spin_lock(&dwc->lock);
 
-	if (unmap_after_complete)
-		usb_gadget_unmap_request_by_dev(dwc->sysdev,
-				&req->request, req->direction);
-
 	if (dep->number > 1)
 		pm_runtime_put(dwc->dev);
 }
@@ -3153,32 +3137,23 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 		goto err0;
 	}
 
-	dwc->setup_buf = kzalloc(DWC3_EP0_BOUNCE_SIZE, GFP_KERNEL);
+	dwc->setup_buf = kzalloc(DWC3_EP0_SETUP_SIZE, GFP_KERNEL);
 	if (!dwc->setup_buf) {
 		ret = -ENOMEM;
 		goto err1;
 	}
 
-	dwc->ep0_bounce = dma_alloc_coherent(dwc->sysdev,
-			DWC3_EP0_BOUNCE_SIZE, &dwc->ep0_bounce_addr,
-			GFP_KERNEL);
-	if (!dwc->ep0_bounce) {
-		dev_err(dwc->dev, "failed to allocate ep0 bounce buffer\n");
-		ret = -ENOMEM;
-		goto err2;
-	}
-
 	dwc->zlp_buf = kzalloc(DWC3_ZLP_BUF_SIZE, GFP_KERNEL);
 	if (!dwc->zlp_buf) {
 		ret = -ENOMEM;
-		goto err3;
+		goto err2;
 	}
 
 	dwc->bounce = dma_alloc_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE,
 			&dwc->bounce_addr, GFP_KERNEL);
 	if (!dwc->bounce) {
 		ret = -ENOMEM;
-		goto err4;
+		goto err3;
 	}
 
 	init_completion(&dwc->ep0_in_setup);
@@ -3218,7 +3193,7 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 
 	ret = dwc3_gadget_init_endpoints(dwc, dwc->num_eps);
 	if (ret)
-		goto err5;
+		goto err4;
 
 	ret = usb_add_gadget_udc(dwc->dev, &dwc->gadget);
 	if (ret) {
@@ -3228,16 +3203,14 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 
 	return 0;
 err5:
-	dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
-			dwc->bounce_addr);
+	dwc3_gadget_free_endpoints(dwc);
 
 err4:
-	kfree(dwc->zlp_buf);
+	dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
+			dwc->bounce_addr);
 
 err3:
-	dwc3_gadget_free_endpoints(dwc);
-	dma_free_coherent(dwc->sysdev, DWC3_EP0_BOUNCE_SIZE,
-			dwc->ep0_bounce, dwc->ep0_bounce_addr);
+	kfree(dwc->zlp_buf);
 
 err2:
 	kfree(dwc->setup_buf);
@@ -3260,9 +3233,6 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
 
 	dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
 			dwc->bounce_addr);
-	dma_free_coherent(dwc->sysdev, DWC3_EP0_BOUNCE_SIZE,
-			dwc->ep0_bounce, dwc->ep0_bounce_addr);
-
 	kfree(dwc->setup_buf);
 	kfree(dwc->zlp_buf);