Bluetooth: Add USB autosuspend support to btusb driver

This patch adds support of USB autosuspend to the btusb driver.

If the device doesn't support remote wakeup, simple support based on
up/down is provided. If the device supports remote wakeup, additional
support for autosuspend while the interface is up is provided. This is
done by queueing URBs in an anchor structure and waking the device up
from a work queue on sending. Reception triggers remote wakeup.

The last busy facility of the USB autosuspend code is used. To close
a race between autosuspend and transmission, a counter of ongoing
transmissions is maintained.

Add #ifdefs for CONFIG_PM as necessary.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Tested-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 124db8c..7ba91aa 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -35,7 +35,7 @@
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
 
-#define VERSION "0.5"
+#define VERSION "0.6"
 
 static int ignore_dga;
 static int ignore_csr;
@@ -145,6 +145,7 @@
 #define BTUSB_INTR_RUNNING	0
 #define BTUSB_BULK_RUNNING	1
 #define BTUSB_ISOC_RUNNING	2
+#define BTUSB_SUSPENDING	3
 
 struct btusb_data {
 	struct hci_dev       *hdev;
@@ -157,11 +158,15 @@
 	unsigned long flags;
 
 	struct work_struct work;
+	struct work_struct waker;
 
 	struct usb_anchor tx_anchor;
 	struct usb_anchor intr_anchor;
 	struct usb_anchor bulk_anchor;
 	struct usb_anchor isoc_anchor;
+	struct usb_anchor deferred;
+	int tx_in_flight;
+	spinlock_t txlock;
 
 	struct usb_endpoint_descriptor *intr_ep;
 	struct usb_endpoint_descriptor *bulk_tx_ep;
@@ -174,8 +179,23 @@
 	unsigned int sco_num;
 	int isoc_altsetting;
 	int suspend_count;
+	int did_iso_resume:1;
 };
 
+static int inc_tx(struct btusb_data *data)
+{
+	unsigned long flags;
+	int rv;
+
+	spin_lock_irqsave(&data->txlock, flags);
+	rv = test_bit(BTUSB_SUSPENDING, &data->flags);
+	if (!rv)
+		data->tx_in_flight++;
+	spin_unlock_irqrestore(&data->txlock, flags);
+
+	return rv;
+}
+
 static void btusb_intr_complete(struct urb *urb)
 {
 	struct hci_dev *hdev = urb->context;
@@ -202,6 +222,7 @@
 	if (!test_bit(BTUSB_INTR_RUNNING, &data->flags))
 		return;
 
+	usb_mark_last_busy(data->udev);
 	usb_anchor_urb(urb, &data->intr_anchor);
 
 	err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -325,6 +346,7 @@
 
 	urb->transfer_flags |= URB_FREE_BUFFER;
 
+	usb_mark_last_busy(data->udev);
 	usb_anchor_urb(urb, &data->bulk_anchor);
 
 	err = usb_submit_urb(urb, mem_flags);
@@ -463,6 +485,33 @@
 {
 	struct sk_buff *skb = urb->context;
 	struct hci_dev *hdev = (struct hci_dev *) skb->dev;
+	struct btusb_data *data = hdev->driver_data;
+
+	BT_DBG("%s urb %p status %d count %d", hdev->name,
+					urb, urb->status, urb->actual_length);
+
+	if (!test_bit(HCI_RUNNING, &hdev->flags))
+		goto done;
+
+	if (!urb->status)
+		hdev->stat.byte_tx += urb->transfer_buffer_length;
+	else
+		hdev->stat.err_tx++;
+
+done:
+	spin_lock(&data->txlock);
+	data->tx_in_flight--;
+	spin_unlock(&data->txlock);
+
+	kfree(urb->setup_packet);
+
+	kfree_skb(skb);
+}
+
+static void btusb_isoc_tx_complete(struct urb *urb)
+{
+	struct sk_buff *skb = urb->context;
+	struct hci_dev *hdev = (struct hci_dev *) skb->dev;
 
 	BT_DBG("%s urb %p status %d count %d", hdev->name,
 					urb, urb->status, urb->actual_length);
@@ -488,11 +537,17 @@
 
 	BT_DBG("%s", hdev->name);
 
+	err = usb_autopm_get_interface(data->intf);
+	if (err < 0)
+		return err;
+
+	data->intf->needs_remote_wakeup = 1;
+
 	if (test_and_set_bit(HCI_RUNNING, &hdev->flags))
-		return 0;
+		goto done;
 
 	if (test_and_set_bit(BTUSB_INTR_RUNNING, &data->flags))
-		return 0;
+		goto done;
 
 	err = btusb_submit_intr_urb(hdev, GFP_KERNEL);
 	if (err < 0)
@@ -507,17 +562,28 @@
 	set_bit(BTUSB_BULK_RUNNING, &data->flags);
 	btusb_submit_bulk_urb(hdev, GFP_KERNEL);
 
+done:
+	usb_autopm_put_interface(data->intf);
 	return 0;
 
 failed:
 	clear_bit(BTUSB_INTR_RUNNING, &data->flags);
 	clear_bit(HCI_RUNNING, &hdev->flags);
+	usb_autopm_put_interface(data->intf);
 	return err;
 }
 
+static void btusb_stop_traffic(struct btusb_data *data)
+{
+	usb_kill_anchored_urbs(&data->intr_anchor);
+	usb_kill_anchored_urbs(&data->bulk_anchor);
+	usb_kill_anchored_urbs(&data->isoc_anchor);
+}
+
 static int btusb_close(struct hci_dev *hdev)
 {
 	struct btusb_data *data = hdev->driver_data;
+	int err;
 
 	BT_DBG("%s", hdev->name);
 
@@ -527,13 +593,16 @@
 	cancel_work_sync(&data->work);
 
 	clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
-	usb_kill_anchored_urbs(&data->isoc_anchor);
-
 	clear_bit(BTUSB_BULK_RUNNING, &data->flags);
-	usb_kill_anchored_urbs(&data->bulk_anchor);
-
 	clear_bit(BTUSB_INTR_RUNNING, &data->flags);
-	usb_kill_anchored_urbs(&data->intr_anchor);
+
+	btusb_stop_traffic(data);
+	err = usb_autopm_get_interface(data->intf);
+	if (err < 0)
+		return 0;
+
+	data->intf->needs_remote_wakeup = 0;
+	usb_autopm_put_interface(data->intf);
 
 	return 0;
 }
@@ -620,7 +689,7 @@
 		urb->dev      = data->udev;
 		urb->pipe     = pipe;
 		urb->context  = skb;
-		urb->complete = btusb_tx_complete;
+		urb->complete = btusb_isoc_tx_complete;
 		urb->interval = data->isoc_tx_ep->bInterval;
 
 		urb->transfer_flags  = URB_ISO_ASAP;
@@ -631,12 +700,21 @@
 				le16_to_cpu(data->isoc_tx_ep->wMaxPacketSize));
 
 		hdev->stat.sco_tx++;
-		break;
+		goto skip_waking;
 
 	default:
 		return -EILSEQ;
 	}
 
+	err = inc_tx(data);
+	if (err) {
+		usb_anchor_urb(urb, &data->deferred);
+		schedule_work(&data->waker);
+		err = 0;
+		goto done;
+	}
+
+skip_waking:
 	usb_anchor_urb(urb, &data->tx_anchor);
 
 	err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -644,10 +722,13 @@
 		BT_ERR("%s urb %p submission failed", hdev->name, urb);
 		kfree(urb->setup_packet);
 		usb_unanchor_urb(urb);
+	} else {
+		usb_mark_last_busy(data->udev);
 	}
 
 	usb_free_urb(urb);
 
+done:
 	return err;
 }
 
@@ -719,8 +800,19 @@
 {
 	struct btusb_data *data = container_of(work, struct btusb_data, work);
 	struct hci_dev *hdev = data->hdev;
+	int err;
 
 	if (hdev->conn_hash.sco_num > 0) {
+		if (!data->did_iso_resume) {
+			err = usb_autopm_get_interface(data->isoc);
+			if (err < 0) {
+				clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
+				usb_kill_anchored_urbs(&data->isoc_anchor);
+				return;
+			}
+
+			data->did_iso_resume = 1;
+		}
 		if (data->isoc_altsetting != 2) {
 			clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
 			usb_kill_anchored_urbs(&data->isoc_anchor);
@@ -740,9 +832,25 @@
 		usb_kill_anchored_urbs(&data->isoc_anchor);
 
 		__set_isoc_interface(hdev, 0);
+		if (data->did_iso_resume) {
+			data->did_iso_resume = 0;
+			usb_autopm_put_interface(data->isoc);
+		}
 	}
 }
 
+static void btusb_waker(struct work_struct *work)
+{
+	struct btusb_data *data = container_of(work, struct btusb_data, waker);
+	int err;
+
+	err = usb_autopm_get_interface(data->intf);
+	if (err < 0)
+		return;
+
+	usb_autopm_put_interface(data->intf);
+}
+
 static int btusb_probe(struct usb_interface *intf,
 				const struct usb_device_id *id)
 {
@@ -812,11 +920,14 @@
 	spin_lock_init(&data->lock);
 
 	INIT_WORK(&data->work, btusb_work);
+	INIT_WORK(&data->waker, btusb_waker);
+	spin_lock_init(&data->txlock);
 
 	init_usb_anchor(&data->tx_anchor);
 	init_usb_anchor(&data->intr_anchor);
 	init_usb_anchor(&data->bulk_anchor);
 	init_usb_anchor(&data->isoc_anchor);
+	init_usb_anchor(&data->deferred);
 
 	hdev = hci_alloc_dev();
 	if (!hdev) {
@@ -941,6 +1052,7 @@
 	hci_free_dev(hdev);
 }
 
+#ifdef CONFIG_PM
 static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct btusb_data *data = usb_get_intfdata(intf);
@@ -950,22 +1062,44 @@
 	if (data->suspend_count++)
 		return 0;
 
+	spin_lock_irq(&data->txlock);
+	if (!(interface_to_usbdev(intf)->auto_pm && data->tx_in_flight)) {
+		set_bit(BTUSB_SUSPENDING, &data->flags);
+		spin_unlock_irq(&data->txlock);
+	} else {
+		spin_unlock_irq(&data->txlock);
+		data->suspend_count--;
+		return -EBUSY;
+	}
+
 	cancel_work_sync(&data->work);
 
+	btusb_stop_traffic(data);
 	usb_kill_anchored_urbs(&data->tx_anchor);
 
-	usb_kill_anchored_urbs(&data->isoc_anchor);
-	usb_kill_anchored_urbs(&data->bulk_anchor);
-	usb_kill_anchored_urbs(&data->intr_anchor);
-
 	return 0;
 }
 
+static void play_deferred(struct btusb_data *data)
+{
+	struct urb *urb;
+	int err;
+
+	while ((urb = usb_get_from_anchor(&data->deferred))) {
+		err = usb_submit_urb(urb, GFP_ATOMIC);
+		if (err < 0)
+			break;
+
+		data->tx_in_flight++;
+	}
+	usb_scuttle_anchored_urbs(&data->deferred);
+}
+
 static int btusb_resume(struct usb_interface *intf)
 {
 	struct btusb_data *data = usb_get_intfdata(intf);
 	struct hci_dev *hdev = data->hdev;
-	int err;
+	int err = 0;
 
 	BT_DBG("intf %p", intf);
 
@@ -973,13 +1107,13 @@
 		return 0;
 
 	if (!test_bit(HCI_RUNNING, &hdev->flags))
-		return 0;
+		goto done;
 
 	if (test_bit(BTUSB_INTR_RUNNING, &data->flags)) {
 		err = btusb_submit_intr_urb(hdev, GFP_NOIO);
 		if (err < 0) {
 			clear_bit(BTUSB_INTR_RUNNING, &data->flags);
-			return err;
+			goto failed;
 		}
 	}
 
@@ -987,9 +1121,10 @@
 		err = btusb_submit_bulk_urb(hdev, GFP_NOIO);
 		if (err < 0) {
 			clear_bit(BTUSB_BULK_RUNNING, &data->flags);
-			return err;
-		} else
-			btusb_submit_bulk_urb(hdev, GFP_NOIO);
+			goto failed;
+		}
+
+		btusb_submit_bulk_urb(hdev, GFP_NOIO);
 	}
 
 	if (test_bit(BTUSB_ISOC_RUNNING, &data->flags)) {
@@ -999,16 +1134,35 @@
 			btusb_submit_isoc_urb(hdev, GFP_NOIO);
 	}
 
+	spin_lock_irq(&data->txlock);
+	play_deferred(data);
+	clear_bit(BTUSB_SUSPENDING, &data->flags);
+	spin_unlock_irq(&data->txlock);
+	schedule_work(&data->work);
+
 	return 0;
+
+failed:
+	usb_scuttle_anchored_urbs(&data->deferred);
+done:
+	spin_lock_irq(&data->txlock);
+	clear_bit(BTUSB_SUSPENDING, &data->flags);
+	spin_unlock_irq(&data->txlock);
+
+	return err;
 }
+#endif
 
 static struct usb_driver btusb_driver = {
 	.name		= "btusb",
 	.probe		= btusb_probe,
 	.disconnect	= btusb_disconnect,
+#ifdef CONFIG_PM
 	.suspend	= btusb_suspend,
 	.resume		= btusb_resume,
+#endif
 	.id_table	= btusb_table,
+	.supports_autosuspend = 1,
 };
 
 static int __init btusb_init(void)