[PATCH v2 1/3] usb: dwc3: gadget: increment request->actual once

[PATCH v2 1/3] usb: dwc3: gadget: increment request->actual once

[Felipe Balbi]

When using SG lists, we would end up setting
request->actual to:

	num_mapped_sgs * (request->length - count)

Let's fix that up by incrementing request->actual
only once.

Cc: <stable@vger.kernel.org>
Reported-by: Brian E Rogers <brian.e.rogers@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---

Changes since V1:
	- NONE

 drivers/usb/dwc3/gadget.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8f8c2157910e..863c306ebb69 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2013,14 +2013,6 @@ 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)
 		return 1;
 	if ((event->status & DEPEVT_STATUS_LST) &&
@@ -2040,6 +2032,7 @@ 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 {
@@ -2054,6 +2047,8 @@ 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);
@@ -2061,6 +2056,14 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 				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)
-- 
2.9.1

[PATCH v2 2/3] usb: dwc3: gadget: fix for short pkts during chained xfers

[Felipe Balbi]

DWC3 has one interesting peculiarity with chained
transfers. If we setup N chained transfers and we
get a short packet before processing all N TRBs,
DWC3 will (conditionally) issue a XferComplete or
XferInProgress event and retire all TRBs from the
one which got a short packet to the last without
clearing their HWO bits.

This means SW must clear HWO bit manually, which
this patch is doing.

Cc: <stable@vger.kernel.org>
Cc: Brian E Rogers <brian.e.rogers@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---

Changes since V1:
	- NONE

 drivers/usb/dwc3/gadget.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 863c306ebb69..241f5c7b34bf 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -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;
@@ -1964,6 +1965,19 @@ 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
@@ -1975,6 +1989,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 		 */
 		dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n",
 				dep->name, trb);
+
 	count = trb->size & DWC3_TRB_SIZE_MASK;
 
 	if (dep->direction) {
@@ -2036,10 +2051,13 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 	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;
@@ -2049,9 +2067,8 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 			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);
-- 
2.9.1

[PATCH v2 3/3] usb: dwc3: gadget: always cleanup all TRBs

[Felipe Balbi]

If we stop earlier due to short packet, we will
not be able to giveback all TRBs.

Cc: <stable@vger.kernel.org>
Cc: Brian E Rogers <brian.e.rogers@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---

Changes since V1:
	- Avoid a regression with non scatterlist transfers

 drivers/usb/dwc3/gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 241f5c7b34bf..eb820e4ab49d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2028,7 +2028,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 			s_pkt = 1;
 	}
 
-	if (s_pkt)
+	if (s_pkt && !chain)
 		return 1;
 	if ((event->status & DEPEVT_STATUS_LST) &&
 			(trb->ctrl & (DWC3_TRB_CTRL_LST |
-- 
2.9.1