linux-kernel - [PATCH 3/4] usb: dwc2: drd: fix sleeping while spinlock atomic context

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Date:   Fri, 24 Jul 2020 14:37:47 +0200
From:   Amelie Delaunay <amelie.delaunay@...com>
To:     Minas Harutyunyan <hminas@...opsys.com>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>
CC:     <linux-usb@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        Fabrice Gasnier <fabrice.gasnier@...com>,
        Amelie Delaunay <amelie.delaunay@...com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Subject: [PATCH 3/4] usb: dwc2: drd: fix sleeping while spinlock atomic context

If GINTSTS.CURMODE is not yet reflecting the expecting mode after calling
dwc2_force_mode, we enter in the dwc2_wait_for_mode function while under
spinlock atomic context.
To avoid this situation, move the call to dwc2_force_mode after the
spinlock atomic context.

Fixes: bc0f0d4a5853 ("usb: dwc2: override PHY input signals with usb role switch support")
Reported-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
---
 drivers/usb/dwc2/drd.c | 27 +++++++--------------------
 1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 5099841b1417..2d4176f5788e 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -70,6 +70,7 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 {
 	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
 	unsigned long flags;
+	int already = 0;
 
 	/* Skip session not in line with dr_mode */
 	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
@@ -88,26 +89,9 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 	spin_lock_irqsave(&hsotg->lock, flags);
 
 	if (role == USB_ROLE_HOST) {
-		if (dwc2_ovr_avalid(hsotg, true))
-			goto unlock;
-
-		if (hsotg->dr_mode == USB_DR_MODE_OTG)
-			/*
-			 * This will raise a Connector ID Status Change
-			 * Interrupt - connID A
-			 */
-			dwc2_force_mode(hsotg, true);
+		already = dwc2_ovr_avalid(hsotg, true);
 	} else if (role == USB_ROLE_DEVICE) {
-		if (dwc2_ovr_bvalid(hsotg, true))
-			goto unlock;
-
-		if (hsotg->dr_mode == USB_DR_MODE_OTG)
-			/*
-			 * This will raise a Connector ID Status Change
-			 * Interrupt - connID B
-			 */
-			dwc2_force_mode(hsotg, false);
-
+		already = dwc2_ovr_bvalid(hsotg, true);
 		/* This clear DCTL.SFTDISCON bit */
 		dwc2_hsotg_core_connect(hsotg);
 	} else {
@@ -120,9 +104,12 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 		}
 	}
 
-unlock:
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
+	if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
+		/* This will raise a Connector ID Status Change Interrupt */
+		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
+
 	dev_dbg(hsotg->dev, "%s-session valid\n",
 		role == USB_ROLE_NONE ? "No" :
 		role == USB_ROLE_HOST ? "A" : "B");
-- 
2.17.1