linux-kernel - Re: [PATCH v3 2/4] Bluetooth: hci_qca: Retry btsoc initialize when it fails

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Message-ID: <20200102184116.GA89495@google.com>
Date:   Thu, 2 Jan 2020 10:41:16 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Rocky Liao <rjliao@...eaurora.org>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v3 2/4] Bluetooth: hci_qca: Retry btsoc initialize when
 it fails

Hi Rocky,

On Fri, Dec 27, 2019 at 03:21:28PM +0800, Rocky Liao wrote:
> This patch adds the retry of btsoc initialization when it fails. There are
> reports that the btsoc initialization may fail on some platforms but the
> repro ratio is very low. The failure may be caused by UART, platform HW or
> the btsoc itself but it's very difficlut to root cause, given the repro
> ratio is very low. Add a retry for the btsoc initialization will resolve
> most of the failures and make Bluetooth finally works.

Is this problem specific to a certain chipset?

What are the symptoms?

> Signed-off-by: Rocky Liao <rjliao@...eaurora.org>
> ---
> 
> Changes in v2: None
> Changes in v3: None
> 
>  drivers/bluetooth/hci_qca.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 43fd84028786..45042aa27fa4 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -53,6 +53,9 @@
>  /* Controller debug log header */
>  #define QCA_DEBUG_HANDLE	0x2EDC
>  
> +/* max retry count when init fails */
> +#define QCA_MAX_INIT_RETRY_COUNT 3

nit: MAX_RETRIES or MAX_INIT_RETRIES?

The QCA prefix just adds noise here IMO, there's no need to disambiguate
the constant from other retries since it is defined in hci_qca.c.

> +
>  enum qca_flags {
>  	QCA_IBS_ENABLED,
>  	QCA_DROP_VENDOR_EVENT,
> @@ -1257,7 +1260,9 @@ static int qca_setup(struct hci_uart *hu)
>  {
>  	struct hci_dev *hdev = hu->hdev;
>  	struct qca_data *qca = hu->priv;
> +	struct qca_serdev *qcadev;
>  	unsigned int speed, qca_baudrate = QCA_BAUDRATE_115200;
> +	unsigned int init_retry_count = 0;

nit: the name is a bit clunky, how about 'retries'?

>  	enum qca_btsoc_type soc_type = qca_soc_type(hu);
>  	const char *firmware_name = qca_get_firmware_name(hu);
>  	int ret;
> @@ -1275,6 +1280,7 @@ static int qca_setup(struct hci_uart *hu)
>  	 */
>  	set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
>  
> +retry:
>  	if (qca_is_wcn399x(soc_type)) {
>  		bt_dev_info(hdev, "setting up wcn3990");
>  
> @@ -1293,6 +1299,12 @@ static int qca_setup(struct hci_uart *hu)
>  			return ret;
>  	} else {
>  		bt_dev_info(hdev, "ROME setup");
> +		if (hu->serdev) {
> +			qcadev = serdev_device_get_drvdata(hu->serdev);
> +			gpiod_set_value_cansleep(qcadev->bt_en, 1);
> +			/* Controller needs time to bootup. */
> +			msleep(150);

Shouldn't this be in qca_power_on(), analogous to the power off code from
"[1/4]Bluetooth: hci_qca: Add QCA Rome power off support to the
qca_power_off()"?

qca_power_on() should then also be called for ROME. If you opt for this it
should be done in a separate patch, or possibly merged into the one
mentioned above.

> +		}
>  		qca_set_speed(hu, QCA_INIT_SPEED);
>  	}
>  
> @@ -1329,6 +1341,20 @@ static int qca_setup(struct hci_uart *hu)
>  		 * patch/nvm-config is found, so run with original fw/config.
>  		 */
>  		ret = 0;
> +	} else {
> +		if (init_retry_count < QCA_MAX_INIT_RETRY_COUNT) {
> +			qca_power_off(hdev);
> +			if (hu->serdev) {
> +				serdev_device_close(hu->serdev);
> +				ret = serdev_device_open(hu->serdev);
> +				if (ret) {
> +					bt_dev_err(hu->hdev, "open port fail");

nit: "failed to open port"