Bluetooth: hci_intel: Implement LPM suspend/resume

Add LPM PM suspend/resume/host_wake LPM functions.
A LPM transaction is composed with a LPM request and ack/response.
Host can send a LPM suspend/resume request to the controller which
should respond with a LPM ack.
If resume is requested by the controller (irq), host has to send a LPM
ack once resumed.

Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/bluetooth/hci_intel.c b/drivers/bluetooth/hci_intel.c
index 5d53185..2e15ca5 100644 (file)
--- a/drivers/bluetooth/hci_intel.c
+++ b/drivers/bluetooth/hci_intel.c
@@ -46,12 +46,17 @@
 #define STATE_BOOTING          4
 #define STATE_LPM_ENABLED      5
 #define STATE_TX_ACTIVE                6
+#define STATE_SUSPENDED                7
+#define STATE_LPM_TRANSACTION  8
 
+#define HCI_LPM_WAKE_PKT 0xf0
 #define HCI_LPM_PKT 0xf1
 #define HCI_LPM_MAX_SIZE 10
 #define HCI_LPM_HDR_SIZE HCI_EVENT_HDR_SIZE
 
 #define LPM_OP_TX_NOTIFY 0x00
+#define LPM_OP_SUSPEND_ACK 0x02
+#define LPM_OP_RESUME_ACK 0x03
 
 struct hci_lpm_pkt {
        __u8 opcode;
@@ -129,6 +134,143 @@ static int intel_wait_booting(struct hci_uart *hu)
        return err;
 }
 
+static int intel_wait_lpm_transaction(struct hci_uart *hu)
+{
+       struct intel_data *intel = hu->priv;
+       int err;
+
+       err = wait_on_bit_timeout(&intel->flags, STATE_LPM_TRANSACTION,
+                                 TASK_INTERRUPTIBLE,
+                                 msecs_to_jiffies(1000));
+
+       if (err == 1) {
+               bt_dev_err(hu->hdev, "LPM transaction interrupted");
+               return -EINTR;
+       }
+
+       if (err) {
+               bt_dev_err(hu->hdev, "LPM transaction timeout");
+               return -ETIMEDOUT;
+       }
+
+       return err;
+}
+
+static int intel_lpm_suspend(struct hci_uart *hu)
+{
+       static const u8 suspend[] = { 0x01, 0x01, 0x01 };
+       struct intel_data *intel = hu->priv;
+       struct sk_buff *skb;
+
+       if (!test_bit(STATE_LPM_ENABLED, &intel->flags) ||
+           test_bit(STATE_SUSPENDED, &intel->flags))
+               return 0;
+
+       if (test_bit(STATE_TX_ACTIVE, &intel->flags))
+               return -EAGAIN;
+
+       bt_dev_dbg(hu->hdev, "Suspending");
+
+       skb = bt_skb_alloc(sizeof(suspend), GFP_KERNEL);
+       if (!skb) {
+               bt_dev_err(hu->hdev, "Failed to alloc memory for LPM packet");
+               return -ENOMEM;
+       }
+
+       memcpy(skb_put(skb, sizeof(suspend)), suspend, sizeof(suspend));
+       bt_cb(skb)->pkt_type = HCI_LPM_PKT;
+
+       set_bit(STATE_LPM_TRANSACTION, &intel->flags);
+
+       skb_queue_tail(&intel->txq, skb);
+       hci_uart_tx_wakeup(hu);
+
+       intel_wait_lpm_transaction(hu);
+       /* Even in case of failure, continue and test the suspended flag */
+
+       clear_bit(STATE_LPM_TRANSACTION, &intel->flags);
+
+       if (!test_bit(STATE_SUSPENDED, &intel->flags)) {
+               bt_dev_err(hu->hdev, "Device suspend error");
+               return -EINVAL;
+       }
+
+       bt_dev_dbg(hu->hdev, "Suspended");
+
+       hci_uart_set_flow_control(hu, true);
+
+       return 0;
+}
+
+static int intel_lpm_resume(struct hci_uart *hu)
+{
+       struct intel_data *intel = hu->priv;
+       struct sk_buff *skb;
+
+       if (!test_bit(STATE_LPM_ENABLED, &intel->flags) ||
+           !test_bit(STATE_SUSPENDED, &intel->flags))
+               return 0;
+
+       bt_dev_dbg(hu->hdev, "Resuming");
+
+       hci_uart_set_flow_control(hu, false);
+
+       skb = bt_skb_alloc(0, GFP_KERNEL);
+       if (!skb) {
+               bt_dev_err(hu->hdev, "Failed to alloc memory for LPM packet");
+               return -ENOMEM;
+       }
+
+       bt_cb(skb)->pkt_type = HCI_LPM_WAKE_PKT;
+
+       set_bit(STATE_LPM_TRANSACTION, &intel->flags);
+
+       skb_queue_tail(&intel->txq, skb);
+       hci_uart_tx_wakeup(hu);
+
+       intel_wait_lpm_transaction(hu);
+       /* Even in case of failure, continue and test the suspended flag */
+
+       clear_bit(STATE_LPM_TRANSACTION, &intel->flags);
+
+       if (test_bit(STATE_SUSPENDED, &intel->flags)) {
+               bt_dev_err(hu->hdev, "Device resume error");
+               return -EINVAL;
+       }
+
+       bt_dev_dbg(hu->hdev, "Resumed");
+
+       return 0;
+}
+
+static int intel_lpm_host_wake(struct hci_uart *hu)
+{
+       static const u8 lpm_resume_ack[] = { LPM_OP_RESUME_ACK, 0x00 };
+       struct intel_data *intel = hu->priv;
+       struct sk_buff *skb;
+
+       hci_uart_set_flow_control(hu, false);
+
+       clear_bit(STATE_SUSPENDED, &intel->flags);
+
+       skb = bt_skb_alloc(sizeof(lpm_resume_ack), GFP_KERNEL);
+       if (!skb) {
+               bt_dev_err(hu->hdev, "Failed to alloc memory for LPM packet");
+               return -ENOMEM;
+       }
+
+       memcpy(skb_put(skb, sizeof(lpm_resume_ack)), lpm_resume_ack,
+              sizeof(lpm_resume_ack));
+       bt_cb(skb)->pkt_type = HCI_LPM_PKT;
+
+       skb_queue_tail(&intel->txq, skb);
+       hci_uart_tx_wakeup(hu);
+
+       bt_dev_dbg(hu->hdev, "Resumed by controller");
+
+       return 0;
+}
+
 static irqreturn_t intel_irq(int irq, void *dev_id)
 {
        struct intel_device *idev = dev_id;
@@ -800,12 +942,28 @@ static void intel_recv_lpm_notify(struct hci_dev *hdev, int value)
 static int intel_recv_lpm(struct hci_dev *hdev, struct sk_buff *skb)
 {
        struct hci_lpm_pkt *lpm = (void *)skb->data;
+       struct hci_uart *hu = hci_get_drvdata(hdev);
+       struct intel_data *intel = hu->priv;
 
        switch (lpm->opcode) {
        case LPM_OP_TX_NOTIFY:
                if (lpm->dlen)
                        intel_recv_lpm_notify(hdev, lpm->data[0]);
                break;
+       case LPM_OP_SUSPEND_ACK:
+               set_bit(STATE_SUSPENDED, &intel->flags);
+               if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags)) {
+                       smp_mb__after_atomic();
+                       wake_up_bit(&intel->flags, STATE_LPM_TRANSACTION);
+               }
+               break;
+       case LPM_OP_RESUME_ACK:
+               clear_bit(STATE_SUSPENDED, &intel->flags);
+               if (test_and_clear_bit(STATE_LPM_TRANSACTION, &intel->flags)) {
+                       smp_mb__after_atomic();
+                       wake_up_bit(&intel->flags, STATE_LPM_TRANSACTION);
+               }
+               break;
        default:
                bt_dev_err(hdev, "Unknown LPM opcode (%02x)", lpm->opcode);
                break;