arm: tegra: baseband: Discard modem remote wakeup in L3 transition

There is race between USB autopm and system PM. The device's upstream
port may not be ready if USB autopm is triggered by modem remote wakeup
GPIO during the L3 to L0 or L0/L2 to L3 transition.

Bug 955162

Reviewed-on: http://git-master/r/91369
(cherry picked from commit b668f74e93a4ae33b380744a8ac28c098456b459)

Change-Id: I1a9c2dadb530144aa8741370247272b6962fe777
Signed-off-by: Steve Lin <stlin@nvidia.com>
Reviewed-on: http://git-master/r/96593
Reviewed-by: Automatic_Commit_Validation_User

1 files changed, 155 insertions, 74 deletions

diff --git a/arch/arm/mach-tegra/tegra_usb_modem_power.c b/arch/arm/mach-tegra/tegra_usb_modem_power.c
index bcfbbab4832e..88543397f974 100644
--- a/arch/arm/mach-tegra/tegra_usb_modem_power.c
+++ b/arch/arm/mach-tegra/tegra_usb_modem_power.c
@@ -26,6 +26,9 @@
 #include <linux/gpio.h>
 #include <linux/usb.h>
 #include <linux/err.h>
+#include <linux/pm_runtime.h>
+#include <linux/suspend.h>
+#include <linux/slab.h>
 #include <linux/wakelock.h>
 #include <mach/tegra_usb_modem_power.h>
 
@@ -43,10 +46,11 @@ struct tegra_usb_modem {
 	struct delayed_work recovery_work;	/* modem recovery work */
 	const struct tegra_modem_operations *ops;	/* modem operations */
 	unsigned int capability;	/* modem capability */
+	int system_suspend;	/* system suspend flag */
+	struct notifier_block pm_notifier;	/* pm event notifier */
+	struct notifier_block usb_notifier;	/* usb event notifier */
 };
 
-static struct tegra_usb_modem tegra_mdm;
-
 /* supported modems */
 static const struct usb_device_id modem_list[] = {
 	{USB_DEVICE(0x1983, 0x0310),	/* Icera 450 rev1 */
@@ -68,11 +72,14 @@ static irqreturn_t tegra_usb_modem_wake_thread(int irq, void *data)
 	wake_lock_timeout(&modem->wake_lock, HZ);
 	mutex_lock(&modem->lock);
 	if (modem->udev) {
-		usb_lock_device(modem->udev);
 		pr_info("modem wake (%u)\n", ++(modem->wake_cnt));
-		if (usb_autopm_get_interface(modem->intf) == 0)
-			usb_autopm_put_interface_async(modem->intf);
-		usb_unlock_device(modem->udev);
+
+		if (!modem->system_suspend) {
+			usb_lock_device(modem->udev);
+			if (usb_autopm_get_interface(modem->intf) == 0)
+				usb_autopm_put_interface_async(modem->intf);
+			usb_unlock_device(modem->udev);
+		}
 	}
 	mutex_unlock(&modem->lock);
 
@@ -92,7 +99,8 @@ static void tegra_usb_modem_recovery(struct work_struct *ws)
 	mutex_unlock(&modem->lock);
 }
 
-static void device_add_handler(struct usb_device *udev)
+static void device_add_handler(struct tegra_usb_modem *modem,
+			       struct usb_device *udev)
 {
 	const struct usb_device_descriptor *desc = &udev->descriptor;
 	struct usb_interface *intf = usb_ifnum_to_if(udev, 0);
@@ -100,153 +108,222 @@ static void device_add_handler(struct usb_device *udev)
 
 	if (id) {
 		/* hold wakelock to ensure ril has enough time to restart */
-		wake_lock_timeout(&tegra_mdm.wake_lock, HZ*10);
+		wake_lock_timeout(&modem->wake_lock, HZ * 10);
 
 		pr_info("Add device %d <%s %s>\n", udev->devnum,
 			udev->manufacturer, udev->product);
 
-		mutex_lock(&tegra_mdm.lock);
-		tegra_mdm.udev = udev;
-		tegra_mdm.intf = intf;
-		tegra_mdm.vid = desc->idVendor;
-		tegra_mdm.pid = desc->idProduct;
-		tegra_mdm.wake_cnt = 0;
-		tegra_mdm.capability = id->driver_info;
-		mutex_unlock(&tegra_mdm.lock);
+		mutex_lock(&modem->lock);
+		modem->udev = udev;
+		modem->intf = intf;
+		modem->vid = desc->idVendor;
+		modem->pid = desc->idProduct;
+		modem->wake_cnt = 0;
+		modem->capability = id->driver_info;
+		mutex_unlock(&modem->lock);
 
 		pr_info("persist_enabled: %u\n", udev->persist_enabled);
 
-		if (tegra_mdm.capability & TEGRA_MODEM_AUTOSUSPEND) {
+#ifdef CONFIG_PM
+		if (modem->capability & TEGRA_MODEM_AUTOSUSPEND) {
+			pm_runtime_set_autosuspend_delay(&udev->dev, 2000);
 			usb_enable_autosuspend(udev);
 			pr_info("enable autosuspend for %s %s\n",
 				udev->manufacturer, udev->product);
 		}
+#endif
 	}
 }
 
-static void device_remove_handler(struct usb_device *udev)
+static void device_remove_handler(struct tegra_usb_modem *modem,
+				  struct usb_device *udev)
 {
 	const struct usb_device_descriptor *desc = &udev->descriptor;
 
-	if (desc->idVendor == tegra_mdm.vid &&
-	    desc->idProduct == tegra_mdm.pid) {
+	if (desc->idVendor == modem->vid &&
+	    desc->idProduct == modem->pid) {
 		pr_info("Remove device %d <%s %s>\n", udev->devnum,
 			udev->manufacturer, udev->product);
 
-		mutex_lock(&tegra_mdm.lock);
-		tegra_mdm.udev = NULL;
-		tegra_mdm.intf = NULL;
-		tegra_mdm.vid = 0;
-		mutex_unlock(&tegra_mdm.lock);
+		mutex_lock(&modem->lock);
+		modem->udev = NULL;
+		modem->intf = NULL;
+		modem->vid = 0;
+		mutex_unlock(&modem->lock);
 
-		if (tegra_mdm.capability & TEGRA_MODEM_RECOVERY)
-			queue_delayed_work(tegra_mdm.wq,
-					   &tegra_mdm.recovery_work, HZ * 10);
+		if (modem->capability & TEGRA_MODEM_RECOVERY)
+			queue_delayed_work(modem->wq,
+					   &modem->recovery_work, HZ * 10);
 	}
 }
 
-static int usb_notify(struct notifier_block *self, unsigned long action,
-		      void *blob)
+static int mdm_usb_notifier(struct notifier_block *notifier,
+			    unsigned long usb_event,
+			    void *udev)
 {
-	switch (action) {
+	struct tegra_usb_modem *modem =
+		container_of(notifier, struct tegra_usb_modem, usb_notifier);
+
+	switch (usb_event) {
 	case USB_DEVICE_ADD:
-		device_add_handler(blob);
+		device_add_handler(modem, udev);
 		break;
 	case USB_DEVICE_REMOVE:
-		device_remove_handler(blob);
+		device_remove_handler(modem, udev);
 		break;
 	}
-
 	return NOTIFY_OK;
 }
 
-static struct notifier_block usb_nb = {
-	.notifier_call = usb_notify,
-};
+static int mdm_pm_notifier(struct notifier_block *notifier,
+			   unsigned long pm_event,
+			   void *unused)
+{
+	struct tegra_usb_modem *modem =
+		container_of(notifier, struct tegra_usb_modem, pm_notifier);
 
-static int tegra_usb_modem_probe(struct platform_device *pdev)
+	mutex_lock(&modem->lock);
+	if (!modem->udev) {
+		mutex_unlock(&modem->lock);
+		return NOTIFY_DONE;
+	}
+
+	pr_info("%s: event %ld\n", __func__, pm_event);
+	switch (pm_event) {
+	case PM_SUSPEND_PREPARE:
+		if (wake_lock_active(&modem->wake_lock)) {
+			pr_warn("%s: wakelock was active, aborting suspend\n",
+				__func__);
+			return NOTIFY_STOP;
+		}
+
+		modem->system_suspend = 1;
+		mutex_unlock(&modem->lock);
+		return NOTIFY_OK;
+	case PM_POST_SUSPEND:
+		modem->system_suspend = 0;
+		mutex_unlock(&modem->lock);
+		return NOTIFY_OK;
+	}
+
+	mutex_unlock(&modem->lock);
+	return NOTIFY_DONE;
+}
+
+static int mdm_init(struct tegra_usb_modem *modem, struct platform_device *pdev)
 {
 	struct tegra_usb_modem_power_platform_data *pdata =
 	    pdev->dev.platform_data;
-	int ret;
-
-	if (!pdata) {
-		dev_dbg(&pdev->dev, "platform_data not available\n");
-		return -EINVAL;
-	}
+	int ret = 0;
 
 	/* get modem operations from platform data */
-	tegra_mdm.ops = (const struct tegra_modem_operations *)pdata->ops;
+	modem->ops = (const struct tegra_modem_operations *)pdata->ops;
 
-	if (tegra_mdm.ops) {
+	if (modem->ops) {
 		/* modem init */
-		if (tegra_mdm.ops->init) {
-			ret = tegra_mdm.ops->init();
+		if (modem->ops->init) {
+			ret = modem->ops->init();
 			if (ret)
 				return ret;
 		}
 
 		/* start modem */
-		if (tegra_mdm.ops->start)
-			tegra_mdm.ops->start();
+		if (modem->ops->start)
+			modem->ops->start();
 	}
 
-	mutex_init(&(tegra_mdm.lock));
-	wake_lock_init(&(tegra_mdm.wake_lock), WAKE_LOCK_SUSPEND,
+	mutex_init(&(modem->lock));
+	wake_lock_init(&modem->wake_lock, WAKE_LOCK_SUSPEND,
 		       "tegra_usb_mdm_lock");
 
-	/* create work queue */
-	tegra_mdm.wq = create_workqueue("tegra_usb_mdm_queue");
-	INIT_DELAYED_WORK(&(tegra_mdm.recovery_work), tegra_usb_modem_recovery);
+	/* create work queue platform_driver_registe*/
+	modem->wq = create_workqueue("tegra_usb_mdm_queue");
+	INIT_DELAYED_WORK(&(modem->recovery_work), tegra_usb_modem_recovery);
 
 	/* create threaded irq for remote wakeup */
 	if (gpio_is_valid(pdata->wake_gpio)) {
 		/* get remote wakeup gpio from platform data */
-		tegra_mdm.wake_gpio = pdata->wake_gpio;
+		modem->wake_gpio = pdata->wake_gpio;
 
-		ret = gpio_request(tegra_mdm.wake_gpio, "usb_mdm_wake");
+		ret = gpio_request(modem->wake_gpio, "usb_mdm_wake");
 		if (ret)
 			return ret;
 
-		tegra_gpio_enable(tegra_mdm.wake_gpio);
+		tegra_gpio_enable(modem->wake_gpio);
 
 		/* enable IRQ for remote wakeup */
-		tegra_mdm.irq = gpio_to_irq(tegra_mdm.wake_gpio);
+		modem->irq = gpio_to_irq(modem->wake_gpio);
 
 		ret =
-		    request_threaded_irq(tegra_mdm.irq, NULL,
+		    request_threaded_irq(modem->irq, NULL,
 					 tegra_usb_modem_wake_thread,
 					 pdata->flags, "tegra_usb_mdm_wake",
-					 &tegra_mdm);
+					 modem);
 		if (ret < 0) {
 			dev_err(&pdev->dev, "%s: request_threaded_irq error\n",
 				__func__);
 			return ret;
 		}
 
-		ret = enable_irq_wake(tegra_mdm.irq);
+		ret = enable_irq_wake(modem->irq);
 		if (ret) {
 			dev_err(&pdev->dev, "%s: enable_irq_wake error\n",
 				__func__);
-			free_irq(tegra_mdm.irq, &tegra_mdm);
+			free_irq(modem->irq, modem);
 			return ret;
 		}
 	}
 
-	usb_register_notify(&usb_nb);
-	dev_info(&pdev->dev, "Initialized tegra_usb_modem_power\n");
+	modem->pm_notifier.notifier_call = mdm_pm_notifier;
+	modem->usb_notifier.notifier_call = mdm_usb_notifier;
 
-	return 0;
+	usb_register_notify(&modem->usb_notifier);
+	register_pm_notifier(&modem->pm_notifier);
+
+	return ret;
+}
+
+static int tegra_usb_modem_probe(struct platform_device *pdev)
+{
+	struct tegra_usb_modem_power_platform_data *pdata =
+	    pdev->dev.platform_data;
+	struct tegra_usb_modem *modem;
+	int ret = 0;
+
+	if (!pdata) {
+		dev_dbg(&pdev->dev, "platform_data not available\n");
+		return -EINVAL;
+	}
+
+	modem = kzalloc(sizeof(struct tegra_usb_modem), GFP_KERNEL);
+	if (!modem) {
+		dev_dbg(&pdev->dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	ret = mdm_init(modem, pdev);
+	if (ret) {
+		kfree(modem);
+		return ret;
+	}
+
+	dev_set_drvdata(&pdev->dev, modem);
+
+	return ret;
 }
 
 static int __exit tegra_usb_modem_remove(struct platform_device *pdev)
 {
-	usb_unregister_notify(&usb_nb);
+	struct tegra_usb_modem *modem = platform_get_drvdata(pdev);
 
-	if (tegra_mdm.irq) {
-		disable_irq_wake(tegra_mdm.irq);
-		free_irq(tegra_mdm.irq, &tegra_mdm);
+	unregister_pm_notifier(&modem->pm_notifier);
+	usb_unregister_notify(&modem->usb_notifier);
+
+	if (modem->irq) {
+		disable_irq_wake(modem->irq);
+		free_irq(modem->irq, modem);
 	}
+	kfree(modem);
 	return 0;
 }
 
@@ -254,17 +331,21 @@ static int __exit tegra_usb_modem_remove(struct platform_device *pdev)
 static int tegra_usb_modem_suspend(struct platform_device *pdev,
 				   pm_message_t state)
 {
+	struct tegra_usb_modem *modem = platform_get_drvdata(pdev);
+
 	/* send L3 hint to modem */
-	if (tegra_mdm.ops && tegra_mdm.ops->suspend)
-		tegra_mdm.ops->suspend();
+	if (modem->ops && modem->ops->suspend)
+		modem->ops->suspend();
 	return 0;
 }
 
 static int tegra_usb_modem_resume(struct platform_device *pdev)
 {
+	struct tegra_usb_modem *modem = platform_get_drvdata(pdev);
+
 	/* send L3->L0 hint to modem */
-	if (tegra_mdm.ops && tegra_mdm.ops->resume)
-		tegra_mdm.ops->resume();
+	if (modem->ops && modem->ops->resume)
+		modem->ops->resume();
 	return 0;
 }
 #endif