linux-kernel - [PATCH 1/2] usb: dwc2: add ep enabled flag to avoid double enable/disable

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Date:	Mon, 30 Nov 2015 13:21:27 +0800
From:	changbin.du@...el.com
To:	johnyoun@...opsys.com
Cc:	gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Du, Changbin" <changbin.du@...el.com>
Subject: [PATCH 1/2] usb: dwc2: add ep enabled flag to avoid double enable/disable

From: "Du, Changbin" <changbin.du@...el.com>

Enabling a already enabled ep is illegal, because the ep may has trbs
running. Reprogram the ep may break running transfer. So udc driver
must avoid this happening by return an error -EBUSY. Gadget function
driver also should avoid such things, but that is out of udc driver.

Similarly, disable a disabled ep makes no sense, but no need return
an error here.

Signed-off-by: Du, Changbin <changbin.du@...el.com>
---
 drivers/usb/dwc2/core.h   |  1 +
 drivers/usb/dwc2/gadget.c | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index a66d3cb..cf7eccd 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -162,6 +162,7 @@ struct dwc2_hsotg_ep {
 	unsigned char           mc;
 	unsigned char           interval;
 
+	unsigned int		enabled:1;
 	unsigned int            halted:1;
 	unsigned int            periodic:1;
 	unsigned int            isochronous:1;
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 0abf73c..586bbcd 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -2423,6 +2423,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 	/* enable, but don't activate EP0in */
 	dwc2_writel(dwc2_hsotg_ep0_mps(hsotg->eps_out[0]->ep.maxpacket) |
 	       DXEPCTL_USBACTEP, hsotg->regs + DIEPCTL0);
+	hsotg->eps_out[0]->enabled = 1;
 
 	dwc2_hsotg_enqueue_setup(hsotg);
 
@@ -2680,6 +2681,14 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 		return -EINVAL;
 	}
 
+	spin_lock_irqsave(&hsotg->lock, flags);
+	if (hs_ep->enabled) {
+		dev_warn(hsotg->dev, "%s: ep %s already enabled\n",
+			__func__, hs_ep->name);
+		ret = -EBUSY;
+		goto error;
+	}
+
 	mps = usb_endpoint_maxp(desc);
 
 	/* note, we handle this here instead of dwc2_hsotg_set_ep_maxpacket */
@@ -2690,7 +2699,6 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 	dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x from 0x%08x\n",
 		__func__, epctrl, epctrl_reg);
 
-	spin_lock_irqsave(&hsotg->lock, flags);
 
 	epctrl &= ~(DXEPCTL_EPTYPE_MASK | DXEPCTL_MPS_MASK);
 	epctrl |= DXEPCTL_MPS(mps);
@@ -2806,6 +2814,8 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 	/* enable the endpoint interrupt */
 	dwc2_hsotg_ctrl_epint(hsotg, index, dir_in, 1);
 
+	hs_ep->enabled = 1;
+
 error:
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 	return ret;
@@ -2835,6 +2845,11 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
 	epctrl_reg = dir_in ? DIEPCTL(index) : DOEPCTL(index);
 
 	spin_lock_irqsave(&hsotg->lock, flags);
+	if (!hs_ep->enabled) {
+		dev_warn(hsotg->dev, "%s: ep %s already disabled\n",
+			__func__, hs_ep->name);
+		goto out;
+	}
 
 	hsotg->fifo_map &= ~(1<<hs_ep->fifo_index);
 	hs_ep->fifo_index = 0;
@@ -2854,6 +2869,9 @@ static int dwc2_hsotg_ep_disable(struct usb_ep *ep)
 	/* terminate all requests with shutdown */
 	kill_all_requests(hsotg, hs_ep, -ESHUTDOWN);
 
+	hs_ep->enabled = 0;
+
+out:
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 	return 0;
 }
-- 
2.5.0

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