misc: mic: Enable OSPM suspend and resume support.

This patch enables support for OSPM suspend and resume in the MIC
driver. During a host suspend event, the driver performs an
orderly shutdown of the cards if they are online. Upon resume, any
cards that were previously online before suspend are rebooted.
The driver performs an orderly shutdown of the card primarily to
ensure that applications in the card are terminated and mounted
devices are safely un-mounted before the card is powered down in
the event of an OSPM suspend.

The driver makes use of the MIC daemon to accomplish OSPM suspend
and resume. The driver registers a PM notifier per MIC device.
The devices get notified synchronously during PM_SUSPEND_PREPARE and
PM_POST_SUSPEND phases.

During the PM_SUSPEND_PREPARE phase, the driver performs one of the
following three tasks.
1) If the card is 'offline', the driver sets the card to a
   'suspended' state and returns.
2) If the card is 'online', the driver initiates card shutdown by
   setting the card state to suspending. This notifies the MIC
   daemon which invokes shutdown and sets card state to 'suspended'.
   The driver returns after the shutdown is complete.
3) If the card is already being shutdown, possibly by a host user
   space application, the driver sets the card state to 'suspended'
   and returns after the shutdown is complete.

During the PM_POST_SUSPEND phase, the driver simply notifies the
daemon and returns. The daemon boots those cards that were previously
online during the suspend phase.

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
Signed-off-by: Harshavardhan R Kharche <harshavardhan.r.kharche@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 193 insertions, 5 deletions

diff --git a/drivers/misc/mic/host/mic_boot.c b/drivers/misc/mic/host/mic_boot.c
index 60c54d5c43c2..d56b8bf4eaf6 100644
--- a/drivers/misc/mic/host/mic_boot.c
+++ b/drivers/misc/mic/host/mic_boot.c
@@ -37,12 +37,13 @@ static void mic_reset(struct mic_device *mdev)
 
 #define MIC_RESET_TO (45)
 
+	INIT_COMPLETION(mdev->reset_wait);
 	mdev->ops->reset_fw_ready(mdev);
 	mdev->ops->reset(mdev);
 
 	for (i = 0; i < MIC_RESET_TO; i++) {
 		if (mdev->ops->is_fw_ready(mdev))
-			return;
+			goto done;
 		/*
 		 * Resets typically take 10s of seconds to complete.
 		 * Since an MMIO read is required to check if the
@@ -51,6 +52,8 @@ static void mic_reset(struct mic_device *mdev)
 		msleep(1000);
 	}
 	mic_set_state(mdev, MIC_RESET_FAILED);
+done:
+	complete_all(&mdev->reset_wait);
 }
 
 /* Initialize the MIC bootparams */
@@ -123,7 +126,8 @@ void mic_stop(struct mic_device *mdev, bool force)
 		if (MIC_RESET_FAILED == mdev->state)
 			goto unlock;
 		mic_set_shutdown_status(mdev, MIC_NOP);
-		mic_set_state(mdev, MIC_OFFLINE);
+		if (MIC_SUSPENDED != mdev->state)
+			mic_set_state(mdev, MIC_OFFLINE);
 	}
 unlock:
 	mutex_unlock(&mdev->mic_mutex);
@@ -165,7 +169,14 @@ void mic_shutdown_work(struct work_struct *work)
 	mutex_lock(&mdev->mic_mutex);
 	mic_set_shutdown_status(mdev, bootparam->shutdown_status);
 	bootparam->shutdown_status = 0;
-	if (MIC_SHUTTING_DOWN != mdev->state)
+
+	/*
+	 * if state is MIC_SUSPENDED, OSPM suspend is in progress. We do not
+	 * change the state here so as to prevent users from booting the card
+	 * during and after the suspend operation.
+	 */
+	if (MIC_SHUTTING_DOWN != mdev->state &&
+	    MIC_SUSPENDED != mdev->state)
 		mic_set_state(mdev, MIC_SHUTTING_DOWN);
 	mutex_unlock(&mdev->mic_mutex);
 }
@@ -183,3 +194,106 @@ void mic_reset_trigger_work(struct work_struct *work)
 
 	mic_stop(mdev, false);
 }
+
+/**
+ * mic_complete_resume - Complete MIC Resume after an OSPM suspend/hibernate
+ * event.
+ * @mdev: pointer to mic_device instance
+ *
+ * RETURNS: None.
+ */
+void mic_complete_resume(struct mic_device *mdev)
+{
+	if (mdev->state != MIC_SUSPENDED) {
+		dev_warn(mdev->sdev->parent, "state %d should be %d\n",
+			 mdev->state, MIC_SUSPENDED);
+		return;
+	}
+
+	/* Make sure firmware is ready */
+	if (!mdev->ops->is_fw_ready(mdev))
+		mic_stop(mdev, true);
+
+	mutex_lock(&mdev->mic_mutex);
+	mic_set_state(mdev, MIC_OFFLINE);
+	mutex_unlock(&mdev->mic_mutex);
+}
+
+/**
+ * mic_prepare_suspend - Handle suspend notification for the MIC device.
+ * @mdev: pointer to mic_device instance
+ *
+ * RETURNS: None.
+ */
+void mic_prepare_suspend(struct mic_device *mdev)
+{
+	int rc;
+
+#define MIC_SUSPEND_TIMEOUT (60 * HZ)
+
+	mutex_lock(&mdev->mic_mutex);
+	switch (mdev->state) {
+	case MIC_OFFLINE:
+		/*
+		 * Card is already offline. Set state to MIC_SUSPENDED
+		 * to prevent users from booting the card.
+		 */
+		mic_set_state(mdev, MIC_SUSPENDED);
+		mutex_unlock(&mdev->mic_mutex);
+		break;
+	case MIC_ONLINE:
+		/*
+		 * Card is online. Set state to MIC_SUSPENDING and notify
+		 * MIC user space daemon which will issue card
+		 * shutdown and reset.
+		 */
+		mic_set_state(mdev, MIC_SUSPENDING);
+		mutex_unlock(&mdev->mic_mutex);
+		rc = wait_for_completion_timeout(&mdev->reset_wait,
+						MIC_SUSPEND_TIMEOUT);
+		/* Force reset the card if the shutdown completion timed out */
+		if (!rc) {
+			mutex_lock(&mdev->mic_mutex);
+			mic_set_state(mdev, MIC_SUSPENDED);
+			mutex_unlock(&mdev->mic_mutex);
+			mic_stop(mdev, true);
+		}
+		break;
+	case MIC_SHUTTING_DOWN:
+		/*
+		 * Card is shutting down. Set state to MIC_SUSPENDED
+		 * to prevent further boot of the card.
+		 */
+		mic_set_state(mdev, MIC_SUSPENDED);
+		mutex_unlock(&mdev->mic_mutex);
+		rc = wait_for_completion_timeout(&mdev->reset_wait,
+						MIC_SUSPEND_TIMEOUT);
+		/* Force reset the card if the shutdown completion timed out */
+		if (!rc)
+			mic_stop(mdev, true);
+		break;
+	default:
+		mutex_unlock(&mdev->mic_mutex);
+		break;
+	}
+}
+
+/**
+ * mic_suspend - Initiate MIC suspend. Suspend merely issues card shutdown.
+ * @mdev: pointer to mic_device instance
+ *
+ * RETURNS: None.
+ */
+void mic_suspend(struct mic_device *mdev)
+{
+	struct mic_bootparam *bootparam = mdev->dp;
+	s8 db = bootparam->h2c_shutdown_db;
+
+	mutex_lock(&mdev->mic_mutex);
+	if (MIC_SUSPENDING == mdev->state && db != -1) {
+		bootparam->shutdown_card = 1;
+		mdev->ops->send_intr(mdev, db);
+		mic_set_state(mdev, MIC_SUSPENDED);
+	}
+	mutex_unlock(&mdev->mic_mutex);
+}
diff --git a/drivers/misc/mic/host/mic_device.h b/drivers/misc/mic/host/mic_device.h
index dcba2a59e77f..3574cc375bb9 100644
--- a/drivers/misc/mic/host/mic_device.h
+++ b/drivers/misc/mic/host/mic_device.h
@@ -23,6 +23,7 @@
 
 #include <linux/cdev.h>
 #include <linux/idr.h>
+#include <linux/notifier.h>
 
 #include "mic_intr.h"
 
@@ -75,6 +76,7 @@ enum mic_stepping {
  * @state: MIC state.
  * @shutdown_status: MIC status reported by card for shutdown/crashes.
  * @state_sysfs: Sysfs dirent for notifying ring 3 about MIC state changes.
+ * @reset_wait: Waitqueue for sleeping while reset completes.
  * @log_buf_addr: Log buffer address for MIC.
  * @log_buf_len: Log buffer length address for MIC.
  * @dp: virtio device page
@@ -83,6 +85,7 @@ enum mic_stepping {
  * @shutdown_cookie: shutdown cookie.
  * @cdev: Character device for MIC.
  * @vdev_list: list of virtio devices.
+ * @pm_notifier: Handles PM notifications from the OS.
  */
 struct mic_device {
 	struct mic_mw mmio;
@@ -110,6 +113,7 @@ struct mic_device {
 	u8 state;
 	u8 shutdown_status;
 	struct sysfs_dirent *state_sysfs;
+	struct completion reset_wait;
 	void *log_buf_addr;
 	int *log_buf_len;
 	void *dp;
@@ -118,6 +122,7 @@ struct mic_device {
 	struct mic_irq *shutdown_cookie;
 	struct cdev cdev;
 	struct list_head vdev_list;
+	struct notifier_block pm_notifier;
 };
 
 /**
@@ -192,4 +197,7 @@ void mic_create_debug_dir(struct mic_device *dev);
 void mic_delete_debug_dir(struct mic_device *dev);
 void __init mic_init_debugfs(void);
 void mic_exit_debugfs(void);
+void mic_prepare_suspend(struct mic_device *mdev);
+void mic_complete_resume(struct mic_device *mdev);
+void mic_suspend(struct mic_device *mdev);
 #endif
diff --git a/drivers/misc/mic/host/mic_main.c b/drivers/misc/mic/host/mic_main.c
index ca06aa9b7114..b3520859abd3 100644
--- a/drivers/misc/mic/host/mic_main.c
+++ b/drivers/misc/mic/host/mic_main.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/poll.h>
+#include <linux/suspend.h>
 
 #include <linux/mic_common.h>
 #include "../common/mic_dev.h"
@@ -187,6 +188,43 @@ static enum mic_hw_family mic_get_family(struct pci_dev *pdev)
 }
 
 /**
+* mic_pm_notifier: Notifier callback function that handles
+* PM notifications.
+*
+* @notifier_block: The notifier structure.
+* @pm_event: The event for which the driver was notified.
+* @unused: Meaningless. Always NULL.
+*
+* returns NOTIFY_DONE
+*/
+static int mic_pm_notifier(struct notifier_block *notifier,
+		unsigned long pm_event, void *unused)
+{
+	struct mic_device *mdev = container_of(notifier,
+		struct mic_device, pm_notifier);
+
+	switch (pm_event) {
+	case PM_HIBERNATION_PREPARE:
+		/* Fall through */
+	case PM_SUSPEND_PREPARE:
+		mic_prepare_suspend(mdev);
+		break;
+	case PM_POST_HIBERNATION:
+		/* Fall through */
+	case PM_POST_SUSPEND:
+		/* Fall through */
+	case PM_POST_RESTORE:
+		mic_complete_resume(mdev);
+		break;
+	case PM_RESTORE_PREPARE:
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+/**
  * mic_device_init - Allocates and initializes the MIC device structure
  *
  * @mdev: pointer to mic_device instance
@@ -194,9 +232,11 @@ static enum mic_hw_family mic_get_family(struct pci_dev *pdev)
  *
  * returns none.
  */
-static void
+static int
 mic_device_init(struct mic_device *mdev, struct pci_dev *pdev)
 {
+	int rc;
+
 	mdev->family = mic_get_family(pdev);
 	mdev->stepping = pdev->revision;
 	mic_ops_init(mdev);
@@ -205,7 +245,20 @@ mic_device_init(struct mic_device *mdev, struct pci_dev *pdev)
 	mdev->irq_info.next_avail_src = 0;
 	INIT_WORK(&mdev->reset_trigger_work, mic_reset_trigger_work);
 	INIT_WORK(&mdev->shutdown_work, mic_shutdown_work);
+	init_completion(&mdev->reset_wait);
 	INIT_LIST_HEAD(&mdev->vdev_list);
+	mdev->pm_notifier.notifier_call = mic_pm_notifier;
+	rc = register_pm_notifier(&mdev->pm_notifier);
+	if (rc) {
+		dev_err(&pdev->dev, "register_pm_notifier failed rc %d\n",
+			rc);
+		goto register_pm_notifier_fail;
+	}
+	return 0;
+register_pm_notifier_fail:
+	flush_work(&mdev->shutdown_work);
+	flush_work(&mdev->reset_trigger_work);
+	return rc;
 }
 
 /**
@@ -224,6 +277,7 @@ static void mic_device_uninit(struct mic_device *mdev)
 	kfree(mdev->bootmode);
 	flush_work(&mdev->reset_trigger_work);
 	flush_work(&mdev->shutdown_work);
+	unregister_pm_notifier(&mdev->pm_notifier);
 }
 
 /**
@@ -253,7 +307,11 @@ static int mic_probe(struct pci_dev *pdev,
 		goto ida_fail;
 	}
 
-	mic_device_init(mdev, pdev);
+	rc = mic_device_init(mdev, pdev);
+	if (rc) {
+		dev_err(&pdev->dev, "mic_device_init failed rc %d\n", rc);
+		goto device_init_fail;
+	}
 
 	rc = pci_enable_device(pdev);
 	if (rc) {
@@ -376,6 +434,7 @@ disable_device:
 	pci_disable_device(pdev);
 uninit_device:
 	mic_device_uninit(mdev);
+device_init_fail:
 	ida_simple_remove(&g_mic_ida, mdev->id);
 ida_fail:
 	kfree(mdev);
diff --git a/drivers/misc/mic/host/mic_sysfs.c b/drivers/misc/mic/host/mic_sysfs.c
index 75746adfb155..6dd864e4a617 100644
--- a/drivers/misc/mic/host/mic_sysfs.c
+++ b/drivers/misc/mic/host/mic_sysfs.c
@@ -33,6 +33,8 @@ static const char * const mic_state_string[] = {
 	[MIC_ONLINE] = "online",
 	[MIC_SHUTTING_DOWN] = "shutting_down",
 	[MIC_RESET_FAILED] = "reset_failed",
+	[MIC_SUSPENDING] = "suspending",
+	[MIC_SUSPENDED] = "suspended",
 };
 
 /*
@@ -156,6 +158,11 @@ state_store(struct device *dev, struct device_attribute *attr,
 		goto done;
 	}
 
+	if (sysfs_streq(buf, "suspend")) {
+		mic_suspend(mdev);
+		goto done;
+	}
+
 	count = -EINVAL;
 done:
 	return count;