linux-kernel - [PATCH 4/6] usb: bdc: Fix bug causing crash after multiple disconnects

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Message-Id: <1561064991-16874-5-git-send-email-alcooperx@gmail.com>
Date:   Thu, 20 Jun 2019 17:09:49 -0400
From:   Al Cooper <alcooperx@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Al Cooper <alcooperx@...il.com>, devicetree@...r.kernel.org,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, Luis Chamberlain <mcgrof@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>
Subject: [PATCH 4/6] usb: bdc: Fix bug causing crash after multiple disconnects

Multiple connects/disconnects can cause a crash on the second
disconnect. The driver had a problem where it would try to send
endpoint commands after it was disconnected which is not allowed
by the hardware. The fix is to only allow the endpoint commands
when the endpoint is connected. This will also fix issues that
showed up when using configfs to create gadgets.

Signed-off-by: Al Cooper <alcooperx@...il.com>
---
 drivers/usb/gadget/udc/bdc/bdc_core.c |  4 ++++
 drivers/usb/gadget/udc/bdc/bdc_ep.c   | 16 ++++++++++------
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/udc/bdc/bdc_core.c b/drivers/usb/gadget/udc/bdc/bdc_core.c
index c794890d785b..15e28790142d 100644
--- a/drivers/usb/gadget/udc/bdc/bdc_core.c
+++ b/drivers/usb/gadget/udc/bdc/bdc_core.c
@@ -282,6 +282,7 @@ static void bdc_mem_init(struct bdc *bdc, bool reinit)
 	 * in that case reinit is passed as 1
 	 */
 	if (reinit) {
+		int i;
 		/* Enable interrupts */
 		temp = bdc_readl(bdc->regs, BDC_BDCSC);
 		temp |= BDC_GIE;
@@ -291,6 +292,9 @@ static void bdc_mem_init(struct bdc *bdc, bool reinit)
 		/* Initialize SRR to 0 */
 		memset(bdc->srr.sr_bds, 0,
 					NUM_SR_ENTRIES * sizeof(struct bdc_bd));
+		/* clear ep flags to avoid post disconnect stops/deconfigs */
+		for (i = 1; i < bdc->num_eps; ++i)
+			bdc->bdc_ep_array[i]->flags = 0;
 	} else {
 		/* One time initiaization only */
 		/* Enable status report function pointers */
diff --git a/drivers/usb/gadget/udc/bdc/bdc_ep.c b/drivers/usb/gadget/udc/bdc/bdc_ep.c
index a4d9b5e1e50e..3f34d10939d0 100644
--- a/drivers/usb/gadget/udc/bdc/bdc_ep.c
+++ b/drivers/usb/gadget/udc/bdc/bdc_ep.c
@@ -615,7 +615,6 @@ int bdc_ep_enable(struct bdc_ep *ep)
 	}
 	bdc_dbg_bd_list(bdc, ep);
 	/* only for ep0: config ep is called for ep0 from connect event */
-	ep->flags |= BDC_EP_ENABLED;
 	if (ep->ep_num == 1)
 		return ret;
 
@@ -759,10 +758,13 @@ static int ep_dequeue(struct bdc_ep *ep, struct bdc_req *req)
 					__func__, ep->name, start_bdi, end_bdi);
 	dev_dbg(bdc->dev, "ep_dequeue ep=%p ep->desc=%p\n",
 						ep, (void *)ep->usb_ep.desc);
-	/* Stop the ep to see where the HW is ? */
-	ret = bdc_stop_ep(bdc, ep->ep_num);
-	/* if there is an issue with stopping ep, then no need to go further */
-	if (ret)
+	/* if still connected, stop the ep to see where the HW is ? */
+	if (!(bdc_readl(bdc->regs, BDC_USPC) & BDC_PST_MASK)) {
+		ret = bdc_stop_ep(bdc, ep->ep_num);
+		/* if there is an issue, then no need to go further */
+		if (ret)
+			return 0;
+	} else
 		return 0;
 
 	/*
@@ -1911,7 +1913,9 @@ static int bdc_gadget_ep_disable(struct usb_ep *_ep)
 		__func__, ep->name, ep->flags);
 
 	if (!(ep->flags & BDC_EP_ENABLED)) {
-		dev_warn(bdc->dev, "%s is already disabled\n", ep->name);
+		if (bdc->gadget.speed != USB_SPEED_UNKNOWN)
+			dev_warn(bdc->dev, "%s is already disabled\n",
+				 ep->name);
 		return 0;
 	}
 	spin_lock_irqsave(&bdc->lock, flags);
-- 
1.9.0.138.g2de3478