arm: tegra: xmm: CP wakeup and system suspend

To handle race condition between CP wakeup and system suspend
following policy enforced:
1. If system suspend happens first, then buffer the CP wake
   request and will abort the suspend at the end of device suspend
   complete.
2. If CP wakeup happens first, then system suspend starts then abort
   the system suspend immediately.

Bug 938553
Bug 948198
Bug 943035

Signed-off-by: Seshendra Gadagottu<sgadagottu@nvidia.com>
Reviewed-on: http://git-master/r/83130
(cherry picked from commit b2bd06368d3f6e16e5a7dd81c76dda0293de301b)

Change-Id: Ic7024aa739472a666f1274ccd7c9722259d54fa5
Reviewed-on: http://git-master/r/93384
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Seshendra Gadagottu <sgadagottu@nvidia.com>
Reviewed-by: Vinayak Pane <vpane@nvidia.com>
Tested-by: Vinayak Pane <vpane@nvidia.com>
Reviewed-by: Steve Lin <stlin@nvidia.com>

1 files changed, 179 insertions, 86 deletions

diff --git a/arch/arm/mach-tegra/baseband-xmm-power.c b/arch/arm/mach-tegra/baseband-xmm-power.c
index 7d5c527cab80..dc8981337f35 100644
--- a/arch/arm/mach-tegra/baseband-xmm-power.c
+++ b/arch/arm/mach-tegra/baseband-xmm-power.c
@@ -30,6 +30,7 @@
 #include <linux/spinlock.h>
 #include <linux/usb.h>
 #include <linux/pm_runtime.h>
+#include <linux/suspend.h>
 #include <mach/usb_phy.h>
 #include "board.h"
 #include "devices.h"
@@ -105,6 +106,7 @@ static bool wakeup_pending;
 static bool modem_sleep_flag;
 static spinlock_t xmm_lock;
 static DEFINE_MUTEX(xmm_onoff_mutex);
+static bool system_suspending;
 
 static void baseband_xmm_power_L2_resume(void);
 static int baseband_xmm_power_driver_handle_resume(
@@ -187,7 +189,6 @@ static int baseband_xmm_power_on(struct platform_device *device)
 	ret = enable_irq_wake(gpio_to_irq(data->modem.xmm.ipc_ap_wake));
 	if (ret < 0)
 		pr_err("%s: enable_irq_wake error\n", __func__);
-
 	pr_debug("%s }\n", __func__);
 
 	return 0;
@@ -238,10 +239,12 @@ static int baseband_xmm_power_off(struct platform_device *device)
 	gpio_set_value(data->modem.xmm.bb_rst, 0);
 	mdelay(1);
 
-	spin_lock_irqsave(&xmm_lock, flags);
 	baseband_xmm_powerstate = BBXMM_PS_UNINIT;
-	wakeup_pending = false;
 	modem_sleep_flag = false;
+	CP_initiated_L2toL0 = false;
+	spin_lock_irqsave(&xmm_lock, flags);
+	wakeup_pending = false;
+	system_suspending = false;
 	spin_unlock_irqrestore(&xmm_lock, flags);
 	/* start registration process once again on xmm on */
 	register_hsic_device = true;
@@ -307,11 +310,9 @@ void baseband_xmm_set_power_status(unsigned int status)
 	int value = 0;
 	unsigned long flags;
 
-	pr_debug("%s\n", __func__);
-
 	if (baseband_xmm_powerstate == status)
 		return;
-
+	pr_debug("%s\n", __func__);
 	switch (status) {
 	case BBXMM_PS_L0:
 		if (modem_sleep_flag) {
@@ -320,6 +321,9 @@ void baseband_xmm_set_power_status(unsigned int status)
 			baseband_xmm_power_driver_handle_resume(data);
 		}
 		pr_info("L0\n");
+		baseband_xmm_powerstate = status;
+		if (!wake_lock_active(&wakelock))
+			wake_lock(&wakelock);
 		value = gpio_get_value(data->modem.xmm.ipc_hsic_active);
 		pr_debug("before L0 ipc_hsic_active=%d\n", value);
 		if (!value) {
@@ -330,16 +334,21 @@ void baseband_xmm_set_power_status(unsigned int status)
 			modem_power_on = false;
 			baseband_modem_power_on(data);
 		}
-
-		if (!wake_lock_active(&wakelock))
-			wake_lock(&wakelock);
-
 		pr_debug("gpio host active high->\n");
 		break;
 	case BBXMM_PS_L2:
 		pr_info("L2\n");
-		wake_unlock(&wakelock);
-		modem_sleep_flag = true;
+		baseband_xmm_powerstate = status;
+		spin_lock_irqsave(&xmm_lock, flags);
+		if (wakeup_pending) {
+			spin_unlock_irqrestore(&xmm_lock, flags);
+			baseband_xmm_power_L2_resume();
+		 } else {
+			spin_unlock_irqrestore(&xmm_lock, flags);
+			if (wake_lock_active(&wakelock))
+				wake_unlock(&wakelock);
+			modem_sleep_flag = true;
+		}
 		break;
 	case BBXMM_PS_L3:
 		if (baseband_xmm_powerstate == BBXMM_PS_L2TOL0) {
@@ -352,6 +361,10 @@ void baseband_xmm_set_power_status(unsigned int status)
 			}
 		}
 		pr_info("L3\n");
+		baseband_xmm_powerstate = status;
+		spin_lock_irqsave(&xmm_lock, flags);
+		system_suspending = false;
+		spin_unlock_irqrestore(&xmm_lock, flags);
 		if (wake_lock_active(&wakelock)) {
 			pr_info("%s: releasing wakelock before L3\n",
 				__func__);
@@ -361,16 +374,22 @@ void baseband_xmm_set_power_status(unsigned int status)
 		pr_debug("gpio host active low->\n");
 		break;
 	case BBXMM_PS_L2TOL0:
+		spin_lock_irqsave(&xmm_lock, flags);
+		system_suspending = false;
+		wakeup_pending = false;
+		spin_unlock_irqrestore(&xmm_lock, flags);
 		/* do this only from L2 state */
 		if (baseband_xmm_powerstate == BBXMM_PS_L2) {
 			baseband_xmm_powerstate = status;
 			pr_debug("BB XMM POWER STATE = %d\n", status);
 			baseband_xmm_power_L2_resume();
 		}
+		baseband_xmm_powerstate = status;
+		break;
 	default:
+		baseband_xmm_powerstate = status;
 		break;
 	}
-	baseband_xmm_powerstate = status;
 	pr_debug("BB XMM POWER STATE = %d\n", status);
 }
 EXPORT_SYMBOL_GPL(baseband_xmm_set_power_status);
@@ -378,10 +397,9 @@ EXPORT_SYMBOL_GPL(baseband_xmm_set_power_status);
 irqreturn_t baseband_xmm_power_ipc_ap_wake_irq(int irq, void *dev_id)
 {
 	int value;
+	struct baseband_power_platform_data *data = baseband_power_driver_data;
 
-	value = gpio_get_value(baseband_power_driver_data->
-				modem.xmm.ipc_ap_wake);
-
+	value = gpio_get_value(data->modem.xmm.ipc_ap_wake);
 	pr_debug("%s g(%d), wake_st(%d)\n", __func__, value, ipc_ap_wake_state);
 
 	if (ipc_ap_wake_state < IPC_AP_WAKE_IRQ_READY) {
@@ -417,66 +435,63 @@ irqreturn_t baseband_xmm_power_ipc_ap_wake_irq(int irq, void *dev_id)
 	} else {
 		if (!value) {
 			pr_debug("%s - falling\n", __func__);
-			/* [ver < 1130] gpio protocol falling edge */
-			if (modem_ver < XMM_MODEM_VER_1130) {
-				pr_debug("gpio host wakeup done <-\n");
-				value = gpio_get_value
-					(baseband_power_driver_data->
-					modem.xmm.ipc_bb_wake);
-				if (value) {
-					/* Clear the slave wakeup request */
-					gpio_set_value
-						(baseband_power_driver_data->
-						modem.xmm.ipc_bb_wake, 0);
-					pr_debug("gpio slave wakeup done ->\n");
-				}
+			/* First check it a CP ack or CP wake  */
+			value = gpio_get_value
+				(data->modem.xmm.ipc_bb_wake);
+			if (value) {
+				pr_debug("cp ack for bb_wake\n");
+				ipc_ap_wake_state = IPC_AP_WAKE_L;
+				return IRQ_HANDLED;
 			}
-			/* [ver >= 1130] gpio protocol falling edge */
-			if (modem_ver >= XMM_MODEM_VER_1130) {
-				if (baseband_xmm_powerstate == BBXMM_PS_L2) {
+			spin_lock(&xmm_lock);
+			wakeup_pending = true;
+			if (system_suspending) {
+				spin_unlock(&xmm_lock);
+				pr_info("Set wakeup_pending = 1 in system_"
+					" suspending!!!\n");
+			} else {
+				if (baseband_xmm_powerstate ==
+							BBXMM_PS_L3) {
+					spin_unlock(&xmm_lock);
+					pr_info(" CP L3 -> L0\n");
+				} else if (baseband_xmm_powerstate ==
+							BBXMM_PS_L2) {
 					CP_initiated_L2toL0 = true;
+					spin_unlock(&xmm_lock);
 					baseband_xmm_set_power_status
-						(BBXMM_PS_L2TOL0);
-				} else if (baseband_xmm_powerstate ==
-								BBXMM_PS_L3) {
-					spin_lock(&xmm_lock);
-					wakeup_pending = true;
+					(BBXMM_PS_L2TOL0);
+				} else {
+					CP_initiated_L2toL0 = true;
 					spin_unlock(&xmm_lock);
-					pr_info("CP L3 -> L0\n");
 				}
 			}
 			/* save gpio state */
 			ipc_ap_wake_state = IPC_AP_WAKE_L;
 		} else {
 			pr_debug("%s - rising\n", __func__);
-			/* [ver >= 1130] gpio protocol rising edge */
-			if (modem_ver >= XMM_MODEM_VER_1130) {
-				pr_debug("gpio host wakeup done <-\n");
-				value = gpio_get_value
-					(baseband_power_driver_data->
-					modem.xmm.ipc_bb_wake);
-				if (value) {
-					/* Clear the slave wakeup request */
-					gpio_set_value
-						(baseband_power_driver_data->
-						modem.xmm.ipc_bb_wake, 0);
-					pr_debug("gpio slave wakeup done ->\n");
-					if (reenable_autosuspend && usbdev) {
-						reenable_autosuspend = false;
-						queue_work(workqueue,
-							&autopm_resume_work);
-					}
-				}
-				if ((baseband_xmm_powerstate ==
-							BBXMM_PS_L2TOL0) ||
-					(baseband_xmm_powerstate ==
-							BBXMM_PS_L3TOL0))
-					baseband_xmm_set_power_status(
-							BBXMM_PS_L0);
-				else
-					pr_info("%s:no state"
-						"change required\n", __func__);
+			value = gpio_get_value
+				(data->modem.xmm.ipc_hsic_active);
+			if (!value) {
+				pr_info("host active low: ignore request\n");
+				ipc_ap_wake_state = IPC_AP_WAKE_H;
+				return IRQ_HANDLED;
+			}
+			value = gpio_get_value
+				(data->modem.xmm.ipc_bb_wake);
+			if (value) {
+				/* Clear the slave wakeup request */
+				gpio_set_value
+				(data->modem.xmm.ipc_bb_wake, 0);
+				pr_debug("gpio slave wakeup done ->\n");
+			}
+			if (reenable_autosuspend && usbdev) {
+					reenable_autosuspend = false;
+				queue_work(workqueue,
+					&autopm_resume_work);
 			}
+			modem_sleep_flag = false;
+			baseband_xmm_set_power_status(
+					BBXMM_PS_L0);
 			/* save gpio state */
 			ipc_ap_wake_state = IPC_AP_WAKE_H;
 		}
@@ -561,14 +576,21 @@ static void baseband_xmm_power_L2_resume(void)
 {
 	struct baseband_power_platform_data *data = baseband_power_driver_data;
 	int value;
-	int delay = 1000; /* maxmum delay in msec */
+	int delay = 10000; /* maxmum delay in msec */
+	unsigned long flags;
 
 	pr_debug("%s\n", __func__);
 
 	if (!baseband_power_driver_data)
 		return;
 
+	/* claim the wakelock here to avoid any system suspend */
+	if (!wake_lock_active(&wakelock))
+		wake_lock(&wakelock);
 	modem_sleep_flag = false;
+	spin_lock_irqsave(&xmm_lock, flags);
+	wakeup_pending = false;
+	spin_unlock_irqrestore(&xmm_lock, flags);
 
 	if (CP_initiated_L2toL0)  {
 		pr_info("CP L2->L0\n");
@@ -577,17 +599,24 @@ static void baseband_xmm_power_L2_resume(void)
 	} else {
 		/* set the slave wakeup request */
 		pr_info("AP L2->L0\n");
-		gpio_set_value(data->modem.xmm.ipc_bb_wake, 1);
-		pr_debug("waiting for host wakeup from CP...\n");
-		do {
-			mdelay(1);
-			value = gpio_get_value(data->modem.xmm.ipc_ap_wake);
-			delay--;
-		} while ((value) && (delay));
-		if (delay)
-			pr_debug("gpio host wakeup low <-\n");
-		else
-			pr_info("!!AP L2->L0 Failed\n");
+		value = gpio_get_value(data->modem.xmm.ipc_ap_wake);
+		if (value) {
+			pr_debug("waiting for host wakeup from CP...\n");
+			/* wake bb */
+			gpio_set_value(data->modem.xmm.ipc_bb_wake, 1);
+			do {
+				mdelay(1);
+				value = gpio_get_value(
+					data->modem.xmm.ipc_ap_wake);
+				delay--;
+			} while ((value) && (delay));
+			if (delay)
+				pr_debug("gpio host wakeup low <-\n");
+			else
+				pr_info("!!AP L2->L0 Failed\n");
+		} else {
+			pr_info("CP already ready\n");
+		}
 	}
 }
 
@@ -771,6 +800,63 @@ static struct notifier_block usb_xmm_nb = {
 	.notifier_call = usb_xmm_notify,
 };
 
+static int baseband_xmm_power_pm_notifier_event(struct notifier_block *this,
+					unsigned long event, void *ptr)
+{
+	struct baseband_power_platform_data *data = baseband_power_driver_data;
+	unsigned long flags;
+
+	if (!data)
+		return NOTIFY_DONE;
+
+	pr_debug("%s: event %ld\n", __func__, event);
+	switch (event) {
+	case PM_SUSPEND_PREPARE:
+		pr_debug("%s : PM_SUSPEND_PREPARE\n", __func__);
+		if (wake_lock_active(&wakelock)) {
+			pr_info("%s: wakelock was active, aborting suspend\n",
+					__func__);
+			return NOTIFY_STOP;
+		}
+
+		spin_lock_irqsave(&xmm_lock, flags);
+		if (wakeup_pending) {
+			wakeup_pending = false;
+			spin_unlock_irqrestore(&xmm_lock, flags);
+			pr_info("%s : XMM busy : Abort system suspend\n",
+				 __func__);
+			return NOTIFY_STOP;
+		}
+		system_suspending = true;
+		spin_unlock_irqrestore(&xmm_lock, flags);
+		return NOTIFY_OK;
+	case PM_POST_SUSPEND:
+		pr_debug("%s : PM_POST_SUSPEND\n", __func__);
+		spin_lock_irqsave(&xmm_lock, flags);
+		system_suspending = false;
+		if (wakeup_pending &&
+			(baseband_xmm_powerstate == BBXMM_PS_L2)) {
+			wakeup_pending = false;
+			spin_unlock_irqrestore(&xmm_lock, flags);
+			pr_info("%s : Service Pending CP wakeup\n",
+				__func__);
+			CP_initiated_L2toL0 = true;
+			baseband_xmm_set_power_status
+				(BBXMM_PS_L2TOL0);
+			return NOTIFY_OK;
+		}
+		wakeup_pending = false;
+		spin_unlock_irqrestore(&xmm_lock, flags);
+		return NOTIFY_OK;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block baseband_xmm_power_pm_notifier = {
+	.notifier_call = baseband_xmm_power_pm_notifier_event,
+};
+
+
 static int baseband_xmm_power_driver_probe(struct platform_device *device)
 {
 	struct baseband_power_platform_data *data
@@ -846,7 +932,7 @@ static int baseband_xmm_power_driver_probe(struct platform_device *device)
 		}
 		err = enable_irq_wake(gpio_to_irq(data->modem.xmm.ipc_ap_wake));
 		if (err < 0)
-			 pr_err("%s: enable_irq_wake error\n", __func__);
+			pr_err("%s: enable_irq_wake error\n", __func__);
 		ipc_ap_wake_state = IPC_AP_WAKE_IRQ_READY;
 		if (modem_ver >= XMM_MODEM_VER_1130) {
 			pr_debug("%s: ver > 1130: AP_WAKE_INIT1\n", __func__);
@@ -883,12 +969,14 @@ static int baseband_xmm_power_driver_probe(struct platform_device *device)
 	/* init state variables */
 	register_hsic_device = true;
 	CP_initiated_L2toL0 = false;
-	spin_lock_irqsave(&xmm_lock, flags);
 	baseband_xmm_powerstate = BBXMM_PS_UNINIT;
+	spin_lock_irqsave(&xmm_lock, flags);
 	wakeup_pending = false;
+	system_suspending = false;
 	spin_unlock_irqrestore(&xmm_lock, flags);
 
 	usb_register_notify(&usb_xmm_nb);
+	register_pm_notifier(&baseband_xmm_power_pm_notifier);
 
 	pr_debug("%s }\n", __func__);
 	return 0;
@@ -907,6 +995,7 @@ static int baseband_xmm_power_driver_remove(struct platform_device *device)
 	if (!data)
 		return 0;
 
+	unregister_pm_notifier(&baseband_xmm_power_pm_notifier);
 	usb_unregister_notify(&usb_xmm_nb);
 
 	/* free work structure */
@@ -956,29 +1045,31 @@ static int baseband_xmm_power_driver_handle_resume(
 	}
 
 	modem_sleep_flag = false;
+	spin_lock_irqsave(&xmm_lock, flags);
+	wakeup_pending = false;
+	spin_unlock_irqrestore(&xmm_lock, flags);
 
 	/* L3->L0 */
 	baseband_xmm_set_power_status(BBXMM_PS_L3TOL0);
 	value = gpio_get_value(data->modem.xmm.ipc_ap_wake);
 	if (value) {
 		pr_info("AP L3 -> L0\n");
+		pr_debug("waiting for host wakeup...\n");
 		/* wake bb */
 		gpio_set_value(data->modem.xmm.ipc_bb_wake, 1);
-
-		pr_debug("waiting for host wakeup...\n");
 		do {
 			mdelay(1);
-			value = gpio_get_value(data->modem.xmm.ipc_ap_wake);
+			value = gpio_get_value(
+				data->modem.xmm.ipc_ap_wake);
 			delay--;
 		} while ((value) && (delay));
 		if (delay)
 			pr_debug("gpio host wakeup low <-\n");
+		else
+			pr_info("!!AP L3->L0 Failed\n");
+
 	} else {
 		pr_info("CP L3 -> L0\n");
-		spin_lock_irqsave(&xmm_lock, flags);
-		/* Clear wakeup pending flag */
-		wakeup_pending = false;
-		spin_unlock_irqrestore(&xmm_lock, flags);
 	}
 	reenable_autosuspend = true;
 
@@ -986,6 +1077,7 @@ static int baseband_xmm_power_driver_handle_resume(
 
 }
 
+
 #ifdef CONFIG_PM
 static int baseband_xmm_power_driver_suspend(struct device *dev)
 {
@@ -1012,6 +1104,7 @@ static int baseband_xmm_power_suspend_noirq(struct device *dev)
 
 	pr_debug("%s\n", __func__);
 	spin_lock_irqsave(&xmm_lock, flags);
+	system_suspending = false;
 	if (wakeup_pending) {
 		wakeup_pending = false;
 		spin_unlock_irqrestore(&xmm_lock, flags);