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Commit ad88a05b authored by Xiaozhe Shi's avatar Xiaozhe Shi Committed by Abhijeet Dharmapurikar
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power: qpnp-smbcharger: fix race condition in APSD rerun 



Currently there is a race condition in the rerun_aspd_work routine. The
driver only checks whether the USBIN_UV status is high after forcing
USBIN undervoltage before allowing the source detect interrupt to change
the USB status. If the falling edge of the SRC_DET interrupt induced
by the APSD rerun algorithm is handled after the rerun algorithm clears
the flag to ignore USBIN_UV and SRC_DET interrupts, it can cause
problems by invoking the USB removal code path. This ends up allowing the
subsequent rising edge of the source interrupt to trigger yet another
APSD rerun, creating an infinite loop of APSD reruns.

Fix this by waiting for the falling edge of the source detect interrupt
during the APSD rerun algorithm before allowing the USB to be detected
the second time.

CRs-Fixed: 823770
Change-Id: I434113c9475368bc543d396be016cc641e9ee540
Signed-off-by: default avatarXiaozhe Shi <xiaozhes@codeaurora.org>
Signed-off-by: default avatarAbhijeet Dharmapurikar <adharmap@codeaurora.org>
parent 24d8f022

drivers/power/qpnp-smbcharger.c

+29 −13
Original line number Diff line number Diff line
@@ -232,9 +232,11 @@ struct smbchg_chip { 
	unsigned long			first_aicl_seconds;

	int				aicl_irq_count;

	struct mutex			usb_status_lock;

	/* apsd workaround */

	struct work_struct		rerun_apsd_work;

	bool				apsd_rerun;

	bool				apsd_rerun_ignore_uv_irq;

	struct completion		apsd_src_det_lowered;



	struct led_classdev		led_cdev;

};
@@ -4342,6 +4344,7 @@ unlock: 
	mutex_unlock(&chip->usb_status_lock);

}



#define APSD_LOWERED_TIMEOUT_MS		1000

static void rerun_apsd_work(struct work_struct *work)

{

	int rc, tries = 0;
@@ -4358,6 +4361,12 @@ static void rerun_apsd_work(struct work_struct *work) 


	pr_smb(PR_STATUS, "Rerunning APSD\n");

	pr_smb(PR_MISC, "Allow only 9V chargers\n");

	if (!is_src_detect_high(chip)) {

		pr_smb(PR_STATUS, "source detect is already low\n");

		goto abort;

	} else {

		reinit_completion(&chip->apsd_src_det_lowered);

	}

	chip->apsd_rerun_ignore_uv_irq = true;

	rc = smbchg_sec_masked_write(chip,

			chip->usb_chgpth_base + USBIN_CHGR_CFG,
@@ -4367,16 +4376,14 @@ static void rerun_apsd_work(struct work_struct *work) 
		goto abort;

	}



	usb_uv = is_usb_uv(chip);

	while (!usb_uv && tries++ < 5) {

		msleep(20); /* sleep for UV condition to happen */

		usb_uv = is_usb_uv(chip);

	}

	if (!usb_uv) {

		pr_err("USB didnt go to UV after 9V aborting\n");

	rc = wait_for_completion_interruptible_timeout(

				&chip->apsd_src_det_lowered,

				msecs_to_jiffies(APSD_LOWERED_TIMEOUT_MS));

	if (rc <= 0) {

		pr_smb(PR_STATUS, "no src_det falling=%d\n", rc);

		if (is_src_detect_high(chip))

			goto abort;

	}



	pr_smb(PR_MISC, "Allow 5V-9V\n");

	rc = smbchg_sec_masked_write(chip,

			chip->usb_chgpth_base + USBIN_CHGR_CFG,
@@ -4394,6 +4401,7 @@ static void rerun_apsd_work(struct work_struct *work) 
		usb_uv = is_usb_uv(chip);

	}

	if (usb_uv) {

		pr_smb(PR_MISC, "USB was removed during rerun\n");

		/* looks like USB was removed */

		update_usb_status(chip, 0, 0);

		goto abort;
@@ -4502,16 +4510,23 @@ static irqreturn_t src_detect_handler(int irq, void *_chip) 
{

	struct smbchg_chip *chip = _chip;

	bool usb_present = is_usb_present(chip);

	bool src_detect = is_src_detect_high(chip);



	pr_smb(PR_STATUS,

		"%s chip->usb_present = %d usb_present = %d apsd_rerun_ignore_uv_irq=%d\n",

		"%s chip->usb_present = %d usb_present = %d src_detect = %d apsd_rerun_ignore_uv_irq=%d\n",

		chip->apsd_rerun_ignore_uv_irq ? "Ignoring":"",

		chip->usb_present, usb_present, chip->apsd_rerun_ignore_uv_irq);

		chip->usb_present, usb_present, src_detect,

		chip->apsd_rerun_ignore_uv_irq);



	if (chip->apsd_rerun_ignore_uv_irq)

	if (chip->apsd_rerun_ignore_uv_irq) {

		if (!src_detect) {

			pr_smb(PR_STATUS, "APSD rerun: src_detect low\n");

			complete_all(&chip->apsd_src_det_lowered);

		}

		goto out;

	}



	if (is_src_detect_high(chip)) {

	if (src_detect) {

		if (usb_present || chip->apsd_rerun)

			update_usb_status(chip, usb_present, chip->apsd_rerun);

	} else if (chip->usb_present) {
@@ -5876,6 +5891,7 @@ static int smbchg_probe(struct spmi_device *spmi) 
			smbchg_parallel_usb_en_work);

	INIT_DELAYED_WORK(&chip->vfloat_adjust_work, smbchg_vfloat_adjust_work);

	INIT_DELAYED_WORK(&chip->hvdcp_det_work, smbchg_hvdcp_det_work);

	init_completion(&chip->apsd_src_det_lowered);

	chip->vadc_dev = vadc_dev;

	chip->spmi = spmi;

	chip->dev = &spmi->dev;