Bluetooth: Add delayed init sequence support for UART controllers

This patch makes it possible to have UART drivers perform an internal
initialization before calling hci_register_dev. This allows moving a lot
of init code from user space (hciattach) to the kernel side, thereby
creating a more controlled/robust initialization process.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

2 files changed, 43 insertions, 1 deletions

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index b6d1f200401a..74e0966b3ead 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -156,6 +156,35 @@ restart:
         return 0;
 }
 
+static void hci_uart_init_work(struct work_struct *work)
+{
+        struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
+        int err;
+
+        if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
+                return;
+
+        err = hci_register_dev(hu->hdev);
+        if (err < 0) {
+                BT_ERR("Can't register HCI device");
+                hci_free_dev(hu->hdev);
+                hu->hdev = NULL;
+                hu->proto->close(hu);
+        }
+
+        set_bit(HCI_UART_REGISTERED, &hu->flags);
+}
+
+int hci_uart_init_ready(struct hci_uart *hu)
+{
+        if (!test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
+                return -EALREADY;
+
+        schedule_work(&hu->init_ready);
+
+        return 0;
+}
+
 /* ------- Interface to HCI layer ------ */
 /* Initialize device */
 static int hci_uart_open(struct hci_dev *hdev)
@@ -264,6 +293,8 @@ static int hci_uart_tty_open(struct tty_struct *tty)
         hu->tty = tty;
         tty->receive_room = 65536;
 
+        INIT_WORK(&hu->init_ready, hci_uart_init_work);
+
         spin_lock_init(&hu->rx_lock);
 
         /* Flush any pending characters in the driver and line discipline. */
@@ -302,7 +333,8 @@ static void hci_uart_tty_close(struct tty_struct *tty)
 
         if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
                 if (hdev) {
-                        hci_unregister_dev(hdev);
+                        if (test_bit(HCI_UART_REGISTERED, &hu->flags))
+                                hci_unregister_dev(hdev);
                         hci_free_dev(hdev);
                 }
                 hu->proto->close(hu);
@@ -402,12 +434,17 @@ static int hci_uart_register_dev(struct hci_uart *hu)
         else
                 hdev->dev_type = HCI_BREDR;
 
+        if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
+                return 0;
+
         if (hci_register_dev(hdev) < 0) {
                 BT_ERR("Can't register HCI device");
                 hci_free_dev(hdev);
                 return -ENODEV;
         }
 
+        set_bit(HCI_UART_REGISTERED, &hu->flags);
+
         return 0;
 }
 
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index aaf9d7de1b9f..fffa61ff5cb1 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -47,6 +47,7 @@
 #define HCI_UART_RAW_DEVICE     0
 #define HCI_UART_RESET_ON_INIT  1
 #define HCI_UART_CREATE_AMP     2
+#define HCI_UART_INIT_PENDING   3
 
 struct hci_uart;
 
@@ -66,6 +67,8 @@ struct hci_uart {
         unsigned long           flags;
         unsigned long           hdev_flags;
 
+        struct work_struct      init_ready;
+
         struct hci_uart_proto   *proto;
         void                    *priv;
 
@@ -76,6 +79,7 @@ struct hci_uart {
 
 /* HCI_UART proto flag bits */
 #define HCI_UART_PROTO_SET      0
+#define HCI_UART_REGISTERED     1
 
 /* TX states  */
 #define HCI_UART_SENDING        1
@@ -84,6 +88,7 @@ struct hci_uart {
 int hci_uart_register_proto(struct hci_uart_proto *p);
 int hci_uart_unregister_proto(struct hci_uart_proto *p);
 int hci_uart_tx_wakeup(struct hci_uart *hu);
+int hci_uart_init_ready(struct hci_uart *hu);
 
 #ifdef CONFIG_BT_HCIUART_H4
 int h4_init(void);