Re: [PATCH 2/2] Bluetooth: btusb: Support Bluetooth Reset for Mediatek Chip.

This change enable Mediatek reset mechanism via USB, it's a specific
reset mechanism with Mediatek chips. To handle error recovery, it use
the cmd_timoeut to reset Mediatek Bluetooth.

Signed-off-by: mark-yw.chen <redacted>
---
drivers/bluetooth/btusb.c | 145 ++++++++++++++++++++++++++++++++++++++
1 file changed, 145 insertions(+)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 2a55ae0a5f8c..acc23afbfe0f 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c

@@ -3075,6 +3075,18 @@ static int btusb_shutdown_intel_new(struct hci_dev *hdev)

	return 0;
}

+/* UHW CR mapping */
+#define BT_MISC			0x70002510
+#define BT_SUBSYS_RST		0x70002610
+#define UDMA_INT_STA_BT		0x74000024
+#define UDMA_INT_STA_BT1	0x74000308
+#define BT_WDT_STATUS		0x740003A0
+#define EP_RST_OPT		0x74011890
+#define EP_RST_IN_OUT_OPT	0x00010001
+#define BT_RST_DONE		0x00000100
+#define BT_RESET_WAIT_MS	100
+#define BT_RESET_NUM_TRIES	10
+
#define FIRMWARE_MT7663		"mediatek/mt7663pr2h.bin"
#define FIRMWARE_MT7668		"mediatek/mt7668pr2h.bin"

@@ -3649,6 +3661,59 @@ static int btusb_mtk_func_query(struct hci_dev *hdev)

	return status;
}

+static int btusb_mtk_uhw_reg_write(struct btusb_data *data, u32 reg, u32 val)
+{
+	int pipe, err, size = sizeof(u32);
+	u8 buf[4];
+
+	buf[0] = (val & 0x00ff);
+	buf[1] = ((val >> 8) & 0x00ff);
+	buf[2] = ((val >> 16) & 0x00ff);
+	buf[3] = ((val >> 24) & 0x00ff);

+
+	pipe = usb_rcvctrlpipe(data->udev, 0);
+	err = usb_control_msg(data->udev, pipe, 0x01,
+			      0xDE,
+			      reg >> 16, reg & 0xffff,
+			      buf, size, USB_CTRL_SET_TIMEOUT);
+	if (err < 0) {
+		BT_ERR("Failed to read uhw reg(%d)", err);
+		goto err_free_buf;
+	}
+
+	*val = get_unaligned_le32(buf);
+	BT_INFO("%s: reg=%x, value=0x%08x", __func__, reg, *val);
+
+err_free_buf:
+	kfree(buf);
+
+	return err;
+}
+
static int btusb_mtk_reg_read(struct btusb_data *data, u32 reg, u32 *val)
{
	int pipe, err, size = sizeof(u32);

@@ -3728,6 +3793,7 @@ static int btusb_mtk_setup(struct hci_dev *hdev)

			 dev_id & 0xffff, (fw_version & 0xff) + 1);
		err = btusb_mtk_setup_firmware_79xx(hdev, fw_bin_name);

+		btusb_mtk_uhw_reg_write(data, EP_RST_OPT, EP_RST_IN_OUT_OPT);

		/* Enable Bluetooth protocol */
		param = 1;
		wmt_params.op = BTMTK_WMT_FUNC_CTRL;

@@ -3851,6 +3917,84 @@ static int btusb_mtk_shutdown(struct hci_dev *hdev)

	return 0;
}

+static void btusb_mtk_cmd_timeout(struct hci_dev *hdev)
+{
+	struct btusb_data *data = hci_get_drvdata(hdev);
+	u32 val;
+	int err, retry = 0;
+
+	/*
+	 * Toggle the bluetooth reset via usb. It's mediatek spicific reset
+	 * mechanism, and the reset flow won't replug the USB. Thus, it must
+	 * handle the urb transaction, such as stop_traffic and submit_urb.
+	 * After bluetooth reset completed, we will re-download the firmware
+	 * and send hw_err to host.
+	 */

+
+		retry++;
+		msleep(BT_RESET_WAIT_MS);
+	} while (retry < BT_RESET_NUM_TRIES);
+
+	btusb_mtk_id_get(data, 0x70010200, &val);
+	bt_dev_info(hdev, "device id (%x)", val);
+
+	err = btusb_mtk_setup(hdev);
+	if (err < 0) {
+		bt_dev_err(hdev, "mtk_setup failed, err = %d", err);
+		return;
+	}
+	hci_reset_dev(hdev);
+
+	if (enable_autosuspend)
+		usb_enable_autosuspend(data->udev);
+
+	clear_bit(BTUSB_HW_RESET_ACTIVE, &data->flags);
+}
+
static int btusb_recv_bulk_mtk(struct btusb_data *data, void *buffer, int count)
{
	struct sk_buff *skb;

@@ -4736,6 +4880,7 @@ static int btusb_probe(struct usb_interface *intf,

		hdev->shutdown = btusb_mtk_shutdown;
		hdev->manufacturer = 70;
		data->recv_bulk = btusb_recv_bulk_mtk;
+		hdev->cmd_timeout = btusb_mtk_cmd_timeout;
		set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
	}