Commit 81ca96c8 authored Feb 06, 2014 by Saket Saurabh

phy_msm_usb: Fix crash when switching from peripheral to host mode



When system boots up, USB driver waits using wait_for_completion()
event for the initial VBUS state notification from PMIC.
Once VBUS initial state is reported to USB after PMIC driver
initialization, USB sets the completion variable pmic_vbus_done
to value 1. Later wait_for_completion() event sets the variable
pmic_vbus_done to value 0.

For USB cable disconnect/connect events, PMIC notifies to USB
through msm_otg_set_vbus_state() and USB queues msm_otg_sm_work()
to process the disconnect/connect events. For the crash scenario,
as the variable pmic_vbus_done value is set to zero, hence USB
returns from msm_otg_set_vbus_state() without queuing the
msm_otg_sm_work() due to which USB disconnect event is not processed
and crash happens when USB switching from peripheral to host mode.

Fixing the issue using a static flag init which will be initialized
to false. Once VBUS initial state is reported to USB after PMIC
driver initialization, set the static flag init to true.

CRs-Fixed: 607067
Change-Id: Id229537f9223a031f68b793725021225e13376a7
Signed-off-by: Saket Saurabh <ssaurabh@codeaurora.org>

parent ddc46d3a

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

+4 −2

Original line number	Diff line number	Diff line
		@@ -3447,6 +3447,7 @@ static irqreturn_t msm_otg_irq(int irq, void *data)
		static void msm_otg_set_vbus_state(int online)
		{
		struct msm_otg *motg = the_msm_otg;
		static bool init;

		if (online) {
		pr_debug("PMIC: BSV set\n");
		@@ -3463,11 +3464,12 @@ static void msm_otg_set_vbus_state(int online)
		* completion in UNDEFINED state. Process
		* the initial VBUS event in ID_GND state.
		*/
		if (pmic_vbus_init.done)
		if (init)
		return;
		}

		if (!pmic_vbus_init.done) {
		if (!init) {
		init = true;
		complete(&pmic_vbus_init);
		pr_debug("PMIC: BSV init complete\n");
		return;