diff mbox series

[v1,2/4] Bluetooth: hci_qca: Pull RTS line high for baudrate change command

Message ID 20181106120528.30342-3-bgodavar@codeaurora.org (mailing list archive)
State Not Applicable, archived
Delegated to: Andy Gross
Headers show
Series [v1,1/4] Bluetooth: hci_qca: use wait_until_sent() for power pulses | expand

Commit Message

Balakrishna Godavarthi Nov. 6, 2018, 12:05 p.m. UTC
This patch will pull the RTS line high instead of turning off the
flow control, while changing baudrate of host and chip.

Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
---
 drivers/bluetooth/hci_qca.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

Comments

Matthias Kaehlcke Nov. 14, 2018, 1:55 a.m. UTC | #1
On Tue, Nov 06, 2018 at 05:35:26PM +0530, Balakrishna Godavarthi wrote:
> This patch will pull the RTS line high instead of turning off the
> flow control, while changing baudrate of host and chip.

Please don't only describe what is changed, but also why this change
is necessary.

IIUC the BT chip honors flow control during baudrate changes, however
it sometimes sends 'garbage' which results in "Bluetooth: hci0: Frame
reassembly failed (-84)" messages.

> Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
> ---
>  drivers/bluetooth/hci_qca.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 051f081d1835..8301663f0004 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 +1087,14 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
>  		if (!speed)
>  			return 0;
>  
> +		/* Pulling RTS line to high is mandatory while sending change
> +		 * baudrate request to SoC and also while setting the host
> +		 * baudrate.
> +		 */

Instead of just stating that this is 'mandatory' explain why it is
needed. Also better say 'Deassert RTS' instead of the more lower level
'Pulling RTS line to high'. It could be something like 'Deassert RTS
to prevent the BT controller from sending garbage during the baudrate
change.'

> +		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 +1102,9 @@ 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;

Tested-by: Matthias Kaehlcke <mka@chromium.org>
Balakrishna Godavarthi Nov. 14, 2018, 6:32 a.m. UTC | #2
Hi Matthias,

On 2018-11-14 07:25, Matthias Kaehlcke wrote:
> On Tue, Nov 06, 2018 at 05:35:26PM +0530, Balakrishna Godavarthi wrote:
>> This patch will pull the RTS line high instead of turning off the
>> flow control, while changing baudrate of host and chip.
> 
> Please don't only describe what is changed, but also why this change
> is necessary.
> 
> IIUC the BT chip honors flow control during baudrate changes, however
> it sometimes sends 'garbage' which results in "Bluetooth: hci0: Frame
> reassembly failed (-84)" messages.
> 

[Bala]: will update the commit text.

>> Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
>> ---
>>  drivers/bluetooth/hci_qca.c | 23 ++++++++++++-----------
>>  1 file changed, 12 insertions(+), 11 deletions(-)
>> 
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index 051f081d1835..8301663f0004 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 +1087,14 @@ static int qca_set_speed(struct hci_uart *hu, 
>> enum qca_speed_type speed_type)
>>  		if (!speed)
>>  			return 0;
>> 
>> +		/* Pulling RTS line to high is mandatory while sending change
>> +		 * baudrate request to SoC and also while setting the host
>> +		 * baudrate.
>> +		 */
> 
> Instead of just stating that this is 'mandatory' explain why it is
> needed. Also better say 'Deassert RTS' instead of the more lower level
> 'Pulling RTS line to high'. It could be something like 'Deassert RTS
> to prevent the BT controller from sending garbage during the baudrate
> change.'
> 

[Bala]: will update the comment.

>> +		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 +1102,9 @@ 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;
> 
> Tested-by: Matthias Kaehlcke <mka@chromium.org>

Thanks for testing.
diff mbox series

Patch

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 051f081d1835..8301663f0004 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 +1087,14 @@  static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
 		if (!speed)
 			return 0;
 
+		/* Pulling RTS line to high is mandatory while sending change
+		 * baudrate request to SoC and also while setting the host
+		 * baudrate.
+		 */
+		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 +1102,9 @@  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;