usb: dwc3: gadget: track number of TRBs per request

commit 09fe1f8d7e2f461275b1cdd832f2cfa5e9be346d upstream

This will help us remove the wait_event() from our ->dequeue().

Cc: Fei Yang <fei.yang@intel.com>
Cc: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: linux-usb@vger.kernel.org
Cc: stable@vger.kernel.org # 4.19.y
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
(cherry picked from commit 09fe1f8d7e2f461275b1cdd832f2cfa5e9be346d)
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/usb/dwc3/core.h

@@ -847,6 +847,7 @@ struct dwc3_hwparams {
  * @epnum: endpoint number to which this request refers
  * @trb: pointer to struct dwc3_trb
  * @trb_dma: DMA address of @trb
+ * @num_trbs: number of TRBs used by this request
  * @needs_extra_trb: true when request needs one extra TRB (either due to ZLP
  *	or unaligned OUT)
  * @direction: IN or OUT direction flag
@@ -867,6 +868,8 @@ struct dwc3_request {
 	struct dwc3_trb		*trb;
 	dma_addr_t		trb_dma;
 
+	unsigned		num_trbs;
+
 	unsigned		needs_extra_trb:1;
 	unsigned		direction:1;
 	unsigned		mapped:1;

drivers/usb/dwc3/gadget.c

@@ -1041,6 +1041,8 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
 		req->trb_dma = dwc3_trb_dma_offset(dep, trb);
 	}
 
+	req->num_trbs++;
+
 	__dwc3_prepare_one_trb(dep, trb, dma, length, chain, node,
 			stream_id, short_not_ok, no_interrupt);
 }
@@ -1075,6 +1077,7 @@ static void dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
 
 			/* Now prepare one extra TRB to align transfer size */
 			trb = &dep->trb_pool[dep->trb_enqueue];
+			req->num_trbs++;
 			__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr,
 					maxp - rem, false, 1,
 					req->request.stream_id,
@@ -1119,6 +1122,7 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
 
 		/* Now prepare one extra TRB to align transfer size */
 		trb = &dep->trb_pool[dep->trb_enqueue];
+		req->num_trbs++;
 		__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, maxp - rem,
 				false, 1, req->request.stream_id,
 				req->request.short_not_ok,
@@ -1135,6 +1139,7 @@ static void dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
 
 		/* Now prepare one extra TRB to handle ZLP */
 		trb = &dep->trb_pool[dep->trb_enqueue];
+		req->num_trbs++;
 		__dwc3_prepare_one_trb(dep, trb, dwc->bounce_addr, 0,
 				false, 1, req->request.stream_id,
 				req->request.short_not_ok,
@@ -2231,6 +2236,7 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
 	dwc3_ep_inc_deq(dep);
 
 	trace_dwc3_complete_trb(dep, trb);
+	req->num_trbs--;
 
 	/*
 	 * If we're in the middle of series of chained TRBs and we