Bluetooth: hci_bcm: Add suspend/resume runtime PM functions

Adds autosuspend runtime functionality to BCM UART driver.
Autosuspend is enabled at end of bcm_setup.

bcm_device_lock is used for system sleep functions as they can be
called at any time.
bcm_device_lock is not held for runtime suspend functions as this
is only enabled as long as platform device is opened.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_bcm.c

@@ -33,6 +33,7 @@
 #include <linux/tty.h>
 #include <linux/interrupt.h>
 #include <linux/dmi.h>
+#include <linux/pm_runtime.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -40,6 +41,8 @@
 #include "btbcm.h"
 #include "hci_uart.h"
 
+#define BCM_AUTOSUSPEND_DELAY	5000 /* default autosleep delay */
+
 struct bcm_device {
 	struct list_head	list;
 
@@ -160,6 +163,10 @@ static irqreturn_t bcm_host_wake(int irq, void *data)
 
 	bt_dev_dbg(bdev, "Host wake IRQ");
 
+	pm_runtime_get(&bdev->pdev->dev);
+	pm_runtime_mark_last_busy(&bdev->pdev->dev);
+	pm_runtime_put_autosuspend(&bdev->pdev->dev);
+
 	return IRQ_HANDLED;
 }
 
@@ -183,6 +190,12 @@ static int bcm_request_irq(struct bcm_data *bcm)
 			goto unlock;
 
 		device_init_wakeup(&bdev->pdev->dev, true);
+
+		pm_runtime_set_autosuspend_delay(&bdev->pdev->dev,
+						 BCM_AUTOSUSPEND_DELAY);
+		pm_runtime_use_autosuspend(&bdev->pdev->dev);
+		pm_runtime_set_active(&bdev->pdev->dev);
+		pm_runtime_enable(&bdev->pdev->dev);
 	}
 
 unlock:
@@ -198,7 +211,7 @@ static const struct bcm_set_sleep_mode default_sleep_params = {
 	.bt_wake_active = 1,	/* BT_WAKE active mode: 1 = high, 0 = low */
 	.host_wake_active = 0,	/* HOST_WAKE active mode: 1 = high, 0 = low */
 	.allow_host_sleep = 1,	/* Allow host sleep in SCO flag */
-	.combine_modes = 0,	/* Combine sleep and LPM flag */
+	.combine_modes = 1,	/* Combine sleep and LPM flag */
 	.tristate_control = 0,	/* Allow tri-state control of UART tx flag */
 	/* Irrelevant USB flags */
 	.usb_auto_sleep = 0,
@@ -284,6 +297,9 @@ static int bcm_close(struct hci_uart *hu)
 	if (bcm_device_exists(bdev)) {
 		bcm_gpio_set_power(bdev, false);
 #ifdef CONFIG_PM
+		pm_runtime_disable(&bdev->pdev->dev);
+		pm_runtime_set_suspended(&bdev->pdev->dev);
+
 		if (device_can_wakeup(&bdev->pdev->dev)) {
 			devm_free_irq(&bdev->pdev->dev, bdev->irq, bdev);
 			device_init_wakeup(&bdev->pdev->dev, false);
@@ -400,6 +416,15 @@ static int bcm_recv(struct hci_uart *hu, const void *data, int count)
 		bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
 		bcm->rx_skb = NULL;
 		return err;
+	} else if (!bcm->rx_skb) {
+		/* Delay auto-suspend when receiving completed packet */
+		mutex_lock(&bcm_device_lock);
+		if (bcm->dev && bcm_device_exists(bcm->dev)) {
+			pm_runtime_get(&bcm->dev->pdev->dev);
+			pm_runtime_mark_last_busy(&bcm->dev->pdev->dev);
+			pm_runtime_put_autosuspend(&bcm->dev->pdev->dev);
+		}
+		mutex_unlock(&bcm_device_lock);
 	}
 
 	return count;
@@ -421,8 +446,27 @@ static int bcm_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 static struct sk_buff *bcm_dequeue(struct hci_uart *hu)
 {
 	struct bcm_data *bcm = hu->priv;
+	struct sk_buff *skb = NULL;
+	struct bcm_device *bdev = NULL;
+
+	mutex_lock(&bcm_device_lock);
+
+	if (bcm_device_exists(bcm->dev)) {
+		bdev = bcm->dev;
+		pm_runtime_get_sync(&bdev->pdev->dev);
+		/* Shall be resumed here */
+	}
+
+	skb = skb_dequeue(&bcm->txq);
+
+	if (bdev) {
+		pm_runtime_mark_last_busy(&bdev->pdev->dev);
+		pm_runtime_put_autosuspend(&bdev->pdev->dev);
+	}
 
-	return skb_dequeue(&bcm->txq);
+	mutex_unlock(&bcm_device_lock);
+
+	return skb;
 }
 
 #ifdef CONFIG_PM
@@ -490,7 +534,8 @@ static int bcm_suspend(struct device *dev)
 	if (!bdev->hu)
 		goto unlock;
 
-	bcm_suspend_device(dev);
+	if (pm_runtime_active(dev))
+		bcm_suspend_device(dev);
 
 	if (device_may_wakeup(&bdev->pdev->dev)) {
 		error = enable_irq_wake(bdev->irq);
@@ -530,6 +575,10 @@ static int bcm_resume(struct device *dev)
 unlock:
 	mutex_unlock(&bcm_device_lock);
 
+	pm_runtime_disable(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
 	return 0;
 }
 #endif
@@ -750,7 +799,10 @@ MODULE_DEVICE_TABLE(acpi, bcm_acpi_match);
 #endif
 
 /* Platform suspend and resume callbacks */
-static SIMPLE_DEV_PM_OPS(bcm_pm_ops, bcm_suspend, bcm_resume);
+static const struct dev_pm_ops bcm_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(bcm_suspend, bcm_resume)
+	SET_RUNTIME_PM_OPS(bcm_suspend_device, bcm_resume_device, NULL)
+};
 
 static struct platform_driver bcm_driver = {
 	.probe = bcm_probe,