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Commit d5779648 authored by Vijayavardhan Vennapusa's avatar Vijayavardhan Vennapusa Committed by Gerrit - the friendly Code Review server
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USB: phy-msm-qusb: Fix race conditions during fast PI/PO 



During fast cable connect/disconnect, there is chance that
set_suspend() called as part of USB entering low power mode
and PMIC driver asking to remove pulldowns race each other.
This could cause unclocked access and results in crash. Fix this
issue by using mutex to avoid crash due to the race mentioned.

Change-Id: I1babb545d40b8761774cbdd3a57258ed6bc77398
Signed-off-by: default avatarVijayavardhan Vennapusa <vvreddy@codeaurora.org>
Signed-off-by: default avatarChandana Kishori Chiluveru <cchiluve@codeaurora.org>
parent e036a3df

drivers/usb/phy/phy-msm-qusb.c

+10 −0
Original line number Diff line number Diff line
@@ -149,6 +149,7 @@ struct qusb_phy { 
	int			*emu_dcm_reset_seq;

	int			emu_dcm_reset_seq_len;

	bool			put_into_high_z_state;

	struct mutex		phy_lock;

};



static void qusb_phy_enable_clocks(struct qusb_phy *qphy, bool on)
@@ -665,6 +666,7 @@ static int qusb_phy_set_suspend(struct usb_phy *phy, int suspend) 


			qusb_phy_enable_clocks(qphy, false);

		} else { /* Disconnect case */

			mutex_lock(&qphy->phy_lock);

			/* Disable all interrupts */

			writel_relaxed(0x00,

				qphy->base + QUSB2PHY_PORT_INTR_CTRL);
@@ -680,6 +682,7 @@ static int qusb_phy_set_suspend(struct usb_phy *phy, int suspend) 
				qusb_phy_enable_power(qphy, false);

			else

				dev_dbg(phy->dev, "race with rm_pulldown. Keep ldo ON\n");

			mutex_unlock(&qphy->phy_lock);



			/*

			 * Set put_into_high_z_state to true so next USB
@@ -744,11 +747,13 @@ static int qusb_phy_dpdm_regulator_enable(struct regulator_dev *rdev) 
	dev_dbg(qphy->phy.dev, "%s dpdm_enable:%d\n",

				__func__, qphy->dpdm_enable);



	mutex_lock(&qphy->phy_lock);

	if (!qphy->dpdm_enable) {

		ret = qusb_phy_enable_power(qphy, true);

		if (ret < 0) {

			dev_dbg(qphy->phy.dev,

				"dpdm regulator enable failed:%d\n", ret);

			mutex_unlock(&qphy->phy_lock);

			return ret;

		}

		qphy->dpdm_enable = true;
@@ -796,6 +801,7 @@ static int qusb_phy_dpdm_regulator_enable(struct regulator_dev *rdev) 
			qusb_phy_gdsc(qphy, false);

		}

	}

	mutex_unlock(&qphy->phy_lock);



	return ret;

}
@@ -808,6 +814,7 @@ static int qusb_phy_dpdm_regulator_disable(struct regulator_dev *rdev) 
	dev_dbg(qphy->phy.dev, "%s dpdm_enable:%d\n",

				__func__, qphy->dpdm_enable);



	mutex_lock(&qphy->phy_lock);

	if (qphy->dpdm_enable) {

		if (!qphy->cable_connected) {

			if (qphy->tcsr_clamp_dig_n)
@@ -819,11 +826,13 @@ static int qusb_phy_dpdm_regulator_disable(struct regulator_dev *rdev) 
				dev_dbg(qphy->phy.dev,

					"dpdm regulator disable failed:%d\n",

					ret);

				mutex_unlock(&qphy->phy_lock);

				return ret;

			}

		}

		qphy->dpdm_enable = false;

	}

	mutex_unlock(&qphy->phy_lock);



	return ret;

}
@@ -1144,6 +1153,7 @@ static int qusb_phy_probe(struct platform_device *pdev) 
		return PTR_ERR(qphy->vdda18);

	}



	mutex_init(&qphy->phy_lock);

	platform_set_drvdata(pdev, qphy);



	qphy->phy.label			= "msm-qusb-phy";