From: Johan Hovold <johan@kernel.org>
To: Balakrishna Godavarthi <bgodavar@codeaurora.org>
Cc: marcel@holtmann.org, johan.hedberg@gmail.com, johan@kernel.org,
mka@chromium.org, linux-kernel@vger.kernel.org,
linux-bluetooth@vger.kernel.org, hemantg@codeaurora.org,
linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v5 2/5] Bluetooth: hci_qca: Deassert RTS while baudrate change command
Date: Wed, 9 Jan 2019 15:52:24 +0100 [thread overview]
Message-ID: <20190109145224.GN14782@localhost> (raw)
In-Reply-To: <20181220144639.15928-3-bgodavar@codeaurora.org>
On Thu, Dec 20, 2018 at 08:16:36PM +0530, Balakrishna Godavarthi wrote:
> 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>
> ---
> drivers/bluetooth/hci_qca.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 5a07c2370289..1680ead6cc3d 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);
> +
This may not do what you want unless you also disable hardware flow
control.
Johan
next prev parent reply other threads:[~2019-01-09 14:52 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-20 14:46 [PATCH v5 0/5] Bug fixes for Qualcomm BT chip wcn3990 Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 1/5] Bluetooth: hci_qca: use wait_until_sent() for power pulses Balakrishna Godavarthi
2018-12-22 1:59 ` Matthias Kaehlcke
2018-12-26 6:31 ` Balakrishna Godavarthi
2018-12-26 22:21 ` Matthias Kaehlcke
2018-12-27 3:23 ` Balakrishna Godavarthi
2019-01-09 14:38 ` Johan Hovold
2019-01-10 14:48 ` Balakrishna Godavarthi
2019-01-11 0:55 ` Matthias Kaehlcke
2019-01-11 14:32 ` Balakrishna Godavarthi
2019-01-11 23:38 ` Matthias Kaehlcke
2019-01-14 10:25 ` Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 2/5] Bluetooth: hci_qca: Deassert RTS while baudrate change command Balakrishna Godavarthi
2018-12-22 0:31 ` Matthias Kaehlcke
2018-12-26 5:45 ` Balakrishna Godavarthi
2018-12-26 20:25 ` Matthias Kaehlcke
2018-12-27 3:20 ` Balakrishna Godavarthi
2019-01-09 14:52 ` Johan Hovold [this message]
2019-01-10 14:34 ` Balakrishna Godavarthi
2019-01-10 14:39 ` Johan Hovold
2019-01-10 14:52 ` Balakrishna Godavarthi
2019-01-11 1:37 ` Matthias Kaehlcke
2019-01-11 15:07 ` Balakrishna Godavarthi
2019-01-11 23:56 ` Matthias Kaehlcke
2019-01-14 14:52 ` Balakrishna Godavarthi
2019-01-15 23:46 ` Matthias Kaehlcke
2019-01-17 16:09 ` Johan Hovold
2019-01-17 17:21 ` Matthias Kaehlcke
2019-01-18 9:44 ` Johan Hovold
2019-01-19 0:31 ` Matthias Kaehlcke
2019-01-21 8:56 ` Johan Hovold
2019-01-22 21:39 ` Matthias Kaehlcke
2019-01-21 14:41 ` Balakrishna Godavarthi
2019-01-22 21:53 ` Matthias Kaehlcke
2019-01-23 12:57 ` Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 3/5] Bluetooth: hci_qca: Fix frame reassembly errors for wcn3990 Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 4/5] Bluetooth: hci_qca: Disable IBS state machine and flush Tx buffer Balakrishna Godavarthi
2018-12-20 14:46 ` [PATCH v5 5/5] Bluetooth: btqca: inject command complete event during fw download Balakrishna Godavarthi
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