[PATCH AUTOSEL 6.14 09/31] usb: dwc3: gadget: Refactor loop to avoid NULL endpoints

[Sasha Levin <sashal@kernel.org>]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit eafba0205426091354f050381c32ad1567c35844 ]

Prepare the gadget driver to handle the reserved endpoints that will be
not allocated at the initialisation time.

While at it, add a warning where the NULL endpoint should never happen.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20250212193116.2487289-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/dwc3/gadget.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 89a4dc8ebf948..1c3d153ea73f7 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -547,6 +547,7 @@ static int dwc3_gadget_set_xfer_resource(struct dwc3_ep *dep)
 int dwc3_gadget_start_config(struct dwc3 *dwc, unsigned int resource_index)
 {
 	struct dwc3_gadget_ep_cmd_params params;
+	struct dwc3_ep		*dep;
 	u32			cmd;
 	int			i;
 	int			ret;
@@ -563,8 +564,13 @@ int dwc3_gadget_start_config(struct dwc3 *dwc, unsigned int resource_index)
 		return ret;
 
 	/* Reset resource allocation flags */
-	for (i = resource_index; i < dwc->num_eps && dwc->eps[i]; i++)
-		dwc->eps[i]->flags &= ~DWC3_EP_RESOURCE_ALLOCATED;
+	for (i = resource_index; i < dwc->num_eps; i++) {
+		dep = dwc->eps[i];
+		if (!dep)
+			continue;
+
+		dep->flags &= ~DWC3_EP_RESOURCE_ALLOCATED;
+	}
 
 	return 0;
 }
@@ -751,9 +757,11 @@ void dwc3_gadget_clear_tx_fifos(struct dwc3 *dwc)
 
 	dwc->last_fifo_depth = fifo_depth;
 	/* Clear existing TXFIFO for all IN eps except ep0 */
-	for (num = 3; num < min_t(int, dwc->num_eps, DWC3_ENDPOINTS_NUM);
-	     num += 2) {
+	for (num = 3; num < min_t(int, dwc->num_eps, DWC3_ENDPOINTS_NUM); num += 2) {
 		dep = dwc->eps[num];
+		if (!dep)
+			continue;
+
 		/* Don't change TXFRAMNUM on usb31 version */
 		size = DWC3_IP_IS(DWC3) ? 0 :
 			dwc3_readl(dwc->regs, DWC3_GTXFIFOSIZ(num >> 1)) &
@@ -3703,6 +3711,8 @@ static bool dwc3_gadget_endpoint_trbs_complete(struct dwc3_ep *dep,
 
 		for (i = 0; i < DWC3_ENDPOINTS_NUM; i++) {
 			dep = dwc->eps[i];
+			if (!dep)
+				continue;
 
 			if (!(dep->flags & DWC3_EP_ENABLED))
 				continue;
@@ -3852,6 +3862,10 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 	u8			epnum = event->endpoint_number;
 
 	dep = dwc->eps[epnum];
+	if (!dep) {
+		dev_warn(dwc->dev, "spurious event, endpoint %u is not allocated\n", epnum);
+		return;
+	}
 
 	if (!(dep->flags & DWC3_EP_ENABLED)) {
 		if ((epnum > 1) && !(dep->flags & DWC3_EP_TRANSFER_STARTED))
-- 
2.39.5