diff mbox series

[v3,2/4] Bluetooth: hci_qca: Deassert RTS while baudrate change command

Message ID 20181130150247.26294-3-bgodavar@codeaurora.org (mailing list archive)
State Not Applicable, archived
Headers show
Series Bug fixes for Qualcomm BT chip wcn3990 | expand

Commit Message

Balakrishna Godavarthi Nov. 30, 2018, 3:02 p.m. UTC 
This patch will help to stop frame reassembly errors while changing
the baudrate. This is because host send a change baudrate request
command to the chip with 115200 bps, Whereas chip will change their
UART clocks to the enable for new baudrate and sends the response
for the change request command with newer baudrate, On host side
we are still operating in 115200 bps which results of reading garbage
data. Here we are pulling RTS line, so that chip we will wait to send data
to host until host change its baudrate.

Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
---
v3:
 * Updated comments in code to be more specific.
v2:
 * updated commit text and comments.
v1:
 * initial patch
---
 drivers/bluetooth/hci_qca.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index f5dd323c1967..253b5bae30c2 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -963,7 +963,6 @@  static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
 	struct hci_uart *hu = hci_get_drvdata(hdev);
 	struct qca_data *qca = hu->priv;
 	struct sk_buff *skb;
-	struct qca_serdev *qcadev;
 	u8 cmd[] = { 0x01, 0x48, 0xFC, 0x01, 0x00 };
 
 	if (baudrate > QCA_BAUDRATE_3200000)
@@ -977,13 +976,6 @@  static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
 		return -ENOMEM;
 	}
 
-	/* Disabling hardware flow control is mandatory while
-	 * sending change baudrate request to wcn3990 SoC.
-	 */
-	qcadev = serdev_device_get_drvdata(hu->serdev);
-	if (qcadev->btsoc_type == QCA_WCN3990)
-		hci_uart_set_flow_control(hu, true);
-
 	/* Assign commands to change baudrate and packet type. */
 	skb_put_data(skb, cmd, sizeof(cmd));
 	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
@@ -999,9 +991,6 @@  static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
 	schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS));
 	set_current_state(TASK_RUNNING);
 
-	if (qcadev->btsoc_type == QCA_WCN3990)
-		hci_uart_set_flow_control(hu, false);
-
 	return 0;
 }
 
@@ -1086,6 +1075,7 @@  static int qca_check_speeds(struct hci_uart *hu)
 static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
 {
 	unsigned int speed, qca_baudrate;
+	struct qca_serdev *qcadev;
 	int ret;
 
 	if (speed_type == QCA_INIT_SPEED) {
@@ -1097,6 +1087,15 @@  static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
 		if (!speed)
 			return 0;
 
+		/* Deassert RTS while changing the baudrate of chip and host.
+		 * This will prevent chip from transmitting its response with
+		 * the new baudrate while the host port is still operating at
+		 * the old speed.
+		 */
+		qcadev = serdev_device_get_drvdata(hu->serdev);
+		if (qcadev->btsoc_type == QCA_WCN3990)
+			serdev_device_set_rts(hu->serdev, false);
+
 		qca_baudrate = qca_get_baudrate_value(speed);
 		bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed);
 		ret = qca_set_baudrate(hu->hdev, qca_baudrate);
@@ -1104,6 +1103,9 @@  static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
 			return ret;
 
 		host_set_baudrate(hu, speed);
+
+		if (qcadev->btsoc_type == QCA_WCN3990)
+			serdev_device_set_rts(hu->serdev, true);
 	}
 
 	return 0;