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Date:   Fri, 03 Jan 2020 14:31:46 +0800
From:   rjliao@codeaurora.org
To:     Matthias Kaehlcke <mka@chromium.org>
Cc:     marcel@holtmann.org, johan.hedberg@gmail.com,
        linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org,
        linux-arm-msm@vger.kernel.org,
        linux-bluetooth-owner@vger.kernel.org
Subject: Re: [PATCH v3 2/4] Bluetooth: hci_qca: Retry btsoc initialize when it
 fails
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References: <20191225060317.5258-1-rjliao@codeaurora.org>
 <20191227072130.29431-1-rjliao@codeaurora.org>
 <20191227072130.29431-2-rjliao@codeaurora.org>
 <20200102184116.GA89495@google.com>
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在 2020-01-03 02:41，Matthias Kaehlcke 写道：

> 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?

It's reported on Rome so far but I think the patch is potentially 
helpful for
wcn399x as well.

The symptoms is the firmware downloading failed due to the UART write 
timed out.

>> Signed-off-by: Rocky Liao <rjliao@codeaurora.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.
> 

There is no qca_power_on() func and wcn399x is calling 
qca_wcn3990_init() to
do power on, I prefer to not do this change this time. If it's needed it 
should
be a new patch to add qca_power_on() which supports both Rome and 
wcn399x.

>> +        }
>> 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"