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Commit 9c63b661 authored by Udipto Goswami's avatar Udipto Goswami Committed by Gerrit - the friendly Code Review server
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phy-msm-usb: Add mutex for protecting msm_otg_reset 



While booting up with charger connected, there is a chance
that msm_otg_reset getting called two times from two paths,
one from apsd re-run and another as part of udc_bind. This
could create a race condition leading to clocks being not
enabled while accessing registers causing to NOC error.

Fix this by introducing mutex lock in msm_otg_reset for
protecting both the thread's execution.

Change-Id: Ie20eded91bbe37f1ed672b7b926f6e5f31fb0235
Signed-off-by: default avatarUdipto Goswami <ugoswami@codeaurora.org>
parent 1ece9bbc

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

+11 −3
Original line number Diff line number Diff line 
/* Copyright (c) 2009-2019, Linux Foundation. All rights reserved.

/* Copyright (c) 2009-2020, Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and
@@ -890,6 +890,7 @@ static int msm_otg_reset(struct usb_phy *phy) 
	u32 val = 0;

	u32 ulpi_val = 0;



	mutex_lock(&motg->lock);

	msm_otg_dbg_log_event(&motg->phy, "USB RESET", phy->otg->state,

			get_pm_runtime_counter(phy->dev));

	/*
@@ -898,10 +899,13 @@ static int msm_otg_reset(struct usb_phy *phy) 
	 * USB BAM reset on other cases e.g. USB cable disconnections.

	 * If hardware reported error then it must be reset for recovery.

	 */

	if (motg->err_event_seen)

	if (motg->err_event_seen) {

		dev_info(phy->dev, "performing USB h/w reset for recovery\n");

	else if (pdata->disable_reset_on_disconnect && motg->reset_counter)

	} else if (pdata->disable_reset_on_disconnect &&

				motg->reset_counter) {

		mutex_unlock(&motg->lock);

		return 0;

	}



	motg->reset_counter++;
@@ -916,6 +920,7 @@ static int msm_otg_reset(struct usb_phy *phy) 
			enable_irq(motg->phy_irq);



		enable_irq(motg->irq);

		mutex_unlock(&motg->lock);

		return ret;

	}
@@ -926,6 +931,7 @@ static int msm_otg_reset(struct usb_phy *phy) 
	ret = msm_otg_link_reset(motg);

	if (ret) {

		dev_err(phy->dev, "link reset failed\n");

		mutex_unlock(&motg->lock);

		return ret;

	}
@@ -982,6 +988,7 @@ static int msm_otg_reset(struct usb_phy *phy) 


	if (phy->otg->state == OTG_STATE_UNDEFINED && motg->rm_pulldown)

		msm_chg_block_on(motg);

	mutex_unlock(&motg->lock);



	return 0;

}
@@ -4171,6 +4178,7 @@ static int msm_otg_probe(struct platform_device *pdev) 
	motg->pdev = pdev;

	motg->dbg_idx = 0;

	motg->dbg_lock = __RW_LOCK_UNLOCKED(lck);

	mutex_init(&motg->lock);



	if (motg->pdata->bus_scale_table) {

		motg->bus_perf_client =

include/linux/usb/msm_hsusb.h

+2 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 *

 * Copyright (C) 2008 Google, Inc.

 * Author: Brian Swetland <swetland@google.com>

 * Copyright (c) 2009-2019, The Linux Foundation. All rights reserved.

 * Copyright (c) 2009-2020, The Linux Foundation. All rights reserved.

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and
@@ -188,6 +188,7 @@ struct msm_otg { 
	struct usb_phy phy;

	struct msm_otg_platform_data *pdata;

	struct platform_device *pdev;

	struct mutex lock;

	int irq;

	int async_irq;

	int phy_irq;