Re: [PATCH v2 1/3] Bluetooth: hci_qca: use wait_until_sent() for power pulses

Matthias Kaehlcke
2018-11-26T19:05:19Z

On Thu, Nov 22, 2018 at 05:45:10PM +0530, Balakrishna Godavarthi wrote:
> wcn3990 requires a power pulse to turn ON/OFF along with
> regulators. Sometimes we are observing the power pulses are sent
> out with some time delay, due to queuing these commands. This is
> causing synchronization issues with chip, which intern delay the
> chip setup or may end up with communication issues.
>
> Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
> ---
> v2:
> * Updated function qca_send_power_pulse()
> * addressed reviewer comments.

These unspecific descriptions require people to open v1, read through
the comments and assume you addressed all of them. Better describe
briefly what the actual changes are.

> v1:
> * initial patch
>
> ---
> drivers/bluetooth/hci_qca.c | 37 +++++++++++++------------------------
> 1 file changed, 13 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index f036c8f98ea3..f5dd323c1967 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1013,11 +1013,9 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
> hci_uart_set_baudrate(hu, speed);
> }
>
> -static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
> +static int qca_send_power_pulse(struct hci_uart *hu, u8 cmd)
> {
> - struct hci_uart *hu = hci_get_drvdata(hdev);
> - struct qca_data *qca = hu->priv;
> - struct sk_buff *skb;
> + int ret;
>
> /* These power pulses are single byte command which are sent
> * at required baudrate to wcn3990. On wcn3990, we have an external
> @@ -1029,19 +1027,16 @@ static int qca_send_power_pulse(struct hci_dev *hdev, u8 cmd)
> * save power. Disabling hardware flow control is mandatory while
> * sending power pulses to SoC.
> */
> - bt_dev_dbg(hdev, "sending power pulse %02x to SoC", cmd);
> -
> - skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
> - if (!skb)
> - return -ENOMEM;
> -
> + bt_dev_dbg(hu->hdev, "sending power pulse %02x to SoC", cmd);
> hci_uart_set_flow_control(hu, true);
> + ret = serdev_device_write(hu->serdev, &cmd, sizeof(cmd), 0);
> + if (ret < 0) {
> + bt_dev_err(hu->hdev, "failed to send power pulse %02x to SoC",
> + cmd);

Re-enable flow control? The controller or serial port might be in a
non-operational state anyway, but better not complicate matters
further.

Cheers

Matthias