Bluetooth: hci_mrvl: Add serdev support for 88W8997

Add serdev support for the 88W8997 from NXP (previously Marvell). It
includes support for changing the baud rate. The command to change the
baud rate is taken from the user manual UM11483 Rev. 9 in section 7
(Bring-up of Bluetooth interfaces) from NXP.

Signed-off-by: Stefan Eichenberger <[e-mail]>
Signed-off-by: Francesco Dolcini <[e-mail]>
Signed-off-by: Luiz Augusto von Dentz <[e-mail]>

drivers/bluetooth/hci_mrvl.c

···
 #define MRVL_ACK 0x5A
 #define MRVL_NAK 0xBF
 #define MRVL_RAW_DATA 0x1F
+#define MRVL_SET_BAUDRATE 0xFC09
 
 enum {
 	STATE_CHIP_VER_PENDING,
 	STATE_FW_REQ_PENDING,
+	STATE_FW_LOADED,
 };
 
 struct mrvl_data {
···
 	if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
 		return -EUNATCH;
 
+	/* We might receive some noise when there is no firmware loaded. Therefore,
+	 * we drop data if the firmware is not loaded yet and if there is no fw load
+	 * request pending.
+	 */
+	if (!test_bit(STATE_FW_REQ_PENDING, &mrvl->flags) &&
+				!test_bit(STATE_FW_LOADED, &mrvl->flags))
+		return count;
+
 	mrvl->rx_skb = h4_recv_buf(hu->hdev, mrvl->rx_skb, data, count,
 				    mrvl_recv_pkts,
 				    ARRAY_SIZE(mrvl_recv_pkts));
···
 static int mrvl_setup(struct hci_uart *hu)
 {
 	int err;
+	struct mrvl_data *mrvl = hu->priv;
 
 	hci_uart_set_flow_control(hu, true);
 
···
 	hci_uart_wait_until_sent(hu);
 
 	if (hu->serdev)
-		serdev_device_set_baudrate(hu->serdev, 3000000);
+		serdev_device_set_baudrate(hu->serdev, hu->oper_speed);
 	else
-		hci_uart_set_baudrate(hu, 3000000);
+		hci_uart_set_baudrate(hu, hu->oper_speed);
 
 	hci_uart_set_flow_control(hu, false);
 
···
 	if (err)
 		return err;
 
+	set_bit(STATE_FW_LOADED, &mrvl->flags);
+
 	return 0;
 }
 
-static const struct hci_uart_proto mrvl_proto = {
+static int mrvl_set_baudrate(struct hci_uart *hu, unsigned int speed)
+{
+	int err;
+	struct mrvl_data *mrvl = hu->priv;
+	__le32 speed_le = cpu_to_le32(speed);
+
+	/* The firmware might be loaded by the Wifi driver over SDIO. We wait
+	 * up to 10s for the CTS to go up. Afterward, we know that the firmware
+	 * is ready.
+	 */
+	err = serdev_device_wait_for_cts(hu->serdev, true, 10000);
+	if (err) {
+		bt_dev_err(hu->hdev, "Wait for CTS failed with %d\n", err);
+		return err;
+	}
+
+	set_bit(STATE_FW_LOADED, &mrvl->flags);
+
+	err = __hci_cmd_sync_status(hu->hdev, MRVL_SET_BAUDRATE,
+				    sizeof(speed_le), &speed_le,
+				    HCI_INIT_TIMEOUT);
+	if (err) {
+		bt_dev_err(hu->hdev, "send command failed: %d", err);
+		return err;
+	}
+
+	serdev_device_set_baudrate(hu->serdev, speed);
+
+	/* We forcefully have to send a command to the bluetooth module so that
+	 * the driver detects it after a baudrate change. This is foreseen by
+	 * hci_serdev by setting HCI_UART_VND_DETECT which then causes a dummy
+	 * local version read.
+	 */
+	set_bit(HCI_UART_VND_DETECT, &hu->hdev_flags);
+
+	return 0;
+}
+
+static const struct hci_uart_proto mrvl_proto_8897 = {
 	.id		= HCI_UART_MRVL,
 	.name		= "Marvell",
 	.init_speed	= 115200,
+	.oper_speed	= 3000000,
 	.open		= mrvl_open,
 	.close		= mrvl_close,
 	.flush		= mrvl_flush,
···
 	.dequeue	= mrvl_dequeue,
 };
 
+static const struct hci_uart_proto mrvl_proto_8997 = {
+	.id		= HCI_UART_MRVL,
+	.name		= "Marvell 8997",
+	.init_speed	= 115200,
+	.oper_speed	= 3000000,
+	.open		= mrvl_open,
+	.close		= mrvl_close,
+	.flush		= mrvl_flush,
+	.set_baudrate   = mrvl_set_baudrate,
+	.recv		= mrvl_recv,
+	.enqueue	= mrvl_enqueue,
+	.dequeue	= mrvl_dequeue,
+};
+
 static int mrvl_serdev_probe(struct serdev_device *serdev)
 {
 	struct mrvl_serdev *mrvldev;
+	const struct hci_uart_proto *mrvl_proto = device_get_match_data(&serdev->dev);
 
 	mrvldev = devm_kzalloc(&serdev->dev, sizeof(*mrvldev), GFP_KERNEL);
 	if (!mrvldev)
 		return -ENOMEM;
 
+	mrvldev->hu.oper_speed = mrvl_proto->oper_speed;
+	if (mrvl_proto->set_baudrate)
+		of_property_read_u32(serdev->dev.of_node, "max-speed", &mrvldev->hu.oper_speed);
+
 	mrvldev->hu.serdev = serdev;
 	serdev_device_set_drvdata(serdev, mrvldev);
 
-	return hci_uart_register_device(&mrvldev->hu, &mrvl_proto);
+	return hci_uart_register_device(&mrvldev->hu, mrvl_proto);
 }
 
 static void mrvl_serdev_remove(struct serdev_device *serdev)
···
 }
 
 static const struct of_device_id __maybe_unused mrvl_bluetooth_of_match[] = {
-	{ .compatible = "mrvl,88w8897" },
+	{ .compatible = "mrvl,88w8897", .data = &mrvl_proto_8897},
+	{ .compatible = "mrvl,88w8997", .data = &mrvl_proto_8997},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, mrvl_bluetooth_of_match);
···
 {
 	serdev_device_driver_register(&mrvl_serdev_driver);
 
-	return hci_uart_register_proto(&mrvl_proto);
+	return hci_uart_register_proto(&mrvl_proto_8897);
 }
 
 int __exit mrvl_deinit(void)
 {
 	serdev_device_driver_unregister(&mrvl_serdev_driver);
 
-	return hci_uart_unregister_proto(&mrvl_proto);
+	return hci_uart_unregister_proto(&mrvl_proto_8897);
 }