Bluetooth: btusb: Use the cmd_timeout method to reset the Intel BT chip

If the platform provides it, use the reset gpio to reset the Intel BT
chip, as part of cmd_timeout handling. This has been found helpful on
Intel bluetooth controllers where the firmware gets stuck and the only
way out is a hard reset pin provided by the platform.

Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 4761499..5de0c2e 100644 (file)
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -29,6 +29,7 @@
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
 #include <linux/suspend.h>
+#include <linux/gpio/consumer.h>
 #include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -439,6 +440,7 @@ static const struct dmi_system_id btusb_needs_reset_resume_table[] = {
 #define BTUSB_BOOTING          9
 #define BTUSB_DIAG_RUNNING     10
 #define BTUSB_OOB_WAKE_ENABLED 11
+#define BTUSB_HW_RESET_ACTIVE  12
 
 struct btusb_data {
        struct hci_dev       *hdev;
@@ -476,6 +478,8 @@ struct btusb_data {
        struct usb_endpoint_descriptor *diag_tx_ep;
        struct usb_endpoint_descriptor *diag_rx_ep;
 
+       struct gpio_desc *reset_gpio;
+
        __u8 cmdreq_type;
        __u8 cmdreq;
 
@@ -489,8 +493,41 @@ struct btusb_data {
        int (*setup_on_usb)(struct hci_dev *hdev);
 
        int oob_wake_irq;   /* irq for out-of-band wake-on-bt */
+       unsigned cmd_timeout_cnt;
 };
 
+
+static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
+{
+       struct btusb_data *data = hci_get_drvdata(hdev);
+       struct gpio_desc *reset_gpio = data->reset_gpio;
+
+       if (++data->cmd_timeout_cnt < 5)
+               return;
+
+       if (!reset_gpio) {
+               bt_dev_err(hdev, "No way to reset. Ignoring and continuing");
+               return;
+       }
+
+       /*
+        * Toggle the hard reset line if the platform provides one. The reset
+        * is going to yank the device off the USB and then replug. So doing
+        * once is enough. The cleanup is handled correctly on the way out
+        * (standard USB disconnect), and the new device is detected cleanly
+        * and bound to the driver again like it should be.
+        */
+       if (test_and_set_bit(BTUSB_HW_RESET_ACTIVE, &data->flags)) {
+               bt_dev_err(hdev, "last reset failed? Not resetting again");
+               return;
+       }
+
+       bt_dev_err(hdev, "Initiating HW reset via gpio");
+       gpiod_set_value(reset_gpio, 1);
+       mdelay(100);
+       gpiod_set_value(reset_gpio, 0);
+}
+
 static inline void btusb_free_frags(struct btusb_data *data)
 {
        unsigned long flags;
@@ -2915,6 +2952,7 @@ static int btusb_probe(struct usb_interface *intf,
                       const struct usb_device_id *id)
 {
        struct usb_endpoint_descriptor *ep_desc;
+       struct gpio_desc *reset_gpio;
        struct btusb_data *data;
        struct hci_dev *hdev;
        unsigned ifnum_base;
@@ -3028,6 +3066,15 @@ static int btusb_probe(struct usb_interface *intf,
 
        SET_HCIDEV_DEV(hdev, &intf->dev);
 
+       reset_gpio = gpiod_get_optional(&data->udev->dev, "reset",
+                                       GPIOD_OUT_LOW);
+       if (IS_ERR(reset_gpio)) {
+               err = PTR_ERR(reset_gpio);
+               goto out_free_dev;
+       } else if (reset_gpio) {
+               data->reset_gpio = reset_gpio;
+       }
+
        hdev->open   = btusb_open;
        hdev->close  = btusb_close;
        hdev->flush  = btusb_flush;
@@ -3082,6 +3129,7 @@ static int btusb_probe(struct usb_interface *intf,
                hdev->shutdown = btusb_shutdown_intel;
                hdev->set_diag = btintel_set_diag_mfg;
                hdev->set_bdaddr = btintel_set_bdaddr;
+               hdev->cmd_timeout = btusb_intel_cmd_timeout;
                set_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks);
                set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
                set_bit(HCI_QUIRK_NON_PERSISTENT_DIAG, &hdev->quirks);
@@ -3094,6 +3142,7 @@ static int btusb_probe(struct usb_interface *intf,
                hdev->hw_error = btintel_hw_error;
                hdev->set_diag = btintel_set_diag;
                hdev->set_bdaddr = btintel_set_bdaddr;
+               hdev->cmd_timeout = btusb_intel_cmd_timeout;
                set_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks);
                set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
                set_bit(HCI_QUIRK_NON_PERSISTENT_DIAG, &hdev->quirks);
@@ -3226,6 +3275,8 @@ static int btusb_probe(struct usb_interface *intf,
        return 0;
 
 out_free_dev:
+       if (data->reset_gpio)
+               gpiod_put(data->reset_gpio);
        hci_free_dev(hdev);
        return err;
 }
@@ -3269,6 +3320,9 @@ static void btusb_disconnect(struct usb_interface *intf)
        if (data->oob_wake_irq)
                device_init_wakeup(&data->udev->dev, false);
 
+       if (data->reset_gpio)
+               gpiod_put(data->reset_gpio);
+
        hci_free_dev(hdev);
 }