linux-kernel - Re: [PATCH v3] bluetooth: hci_qca: Fix qca6390 enable failure after warm reboot

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Message-ID: <4c5c9fd8-e90c-c7e2-8f21-edad3c3ca7ff@codeaurora.org>
Date:   Thu, 28 May 2020 13:04:25 +0800
From:   Zijun Hu <zijuhu@...eaurora.org>
To:     Matthias Kaehlcke <mka@...omium.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, bgodavar@...eaurora.org,
        c-hbandi@...eaurora.org, hemantg@...eaurora.org,
        rjliao@...eaurora.org
Subject: Re: [PATCH v3] bluetooth: hci_qca: Fix qca6390 enable failure after
 warm reboot



On 5/28/2020 12:48 AM, Matthias Kaehlcke wrote:
> Hi Zijun,
> 
> On Wed, May 27, 2020 at 10:32:39AM +0800, Zijun Hu wrote:
>> Warm reboot can not restore qca6390 controller baudrate
>> to default due to lack of controllable BT_EN pin or power
>> supply, so fails to download firmware after warm reboot.
>>
>> Fixed by sending EDL_SOC_RESET VSC to reset controller
>> within added device shutdown implementation.
>>
>> Signed-off-by: Zijun Hu <zijuhu@...eaurora.org>
>> ---
>>  drivers/bluetooth/hci_qca.c | 29 +++++++++++++++++++++++++++++
>>  1 file changed, 29 insertions(+)
>>
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index e4a6823..4b6f8b6 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> @@ -1975,6 +1975,34 @@ static void qca_serdev_remove(struct serdev_device *serdev)
>>  	hci_uart_unregister_device(&qcadev->serdev_hu);
>>  }
>>  
>> +static void qca_serdev_shutdown(struct device *dev)
>> +{
>> +	int ret;
>> +	int timeout = msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS);
>> +	struct serdev_device *serdev = to_serdev_device(dev);
>> +	struct qca_serdev *qcadev = serdev_device_get_drvdata(serdev);
>> +	const u8 ibs_wake_cmd[] = { 0xFD };
>> +	const u8 edl_reset_soc_cmd[] = { 0x01, 0x00, 0xFC, 0x01, 0x05 };
>> +
>> +	if (qcadev->btsoc_type == QCA_QCA6390) {
>> +		serdev_device_write_flush(serdev);
>> +		serdev_device_write_buf(serdev,
>> +				ibs_wake_cmd, sizeof(ibs_wake_cmd));
>> +		serdev_device_wait_until_sent(serdev, timeout);
> 
> Why no check of the return value of serdev_device_write_buf() here,
> does it make sense to continue if sending the wakeup command failed?
> 
i will correct it at v4 patch
> Couldn't serdev_device_write() be used instead of the _write_buf() +
> _wait_until_sent() combo?
> 
i don't think so, serdev_device_write() is not appropriate at here.
serdev_device_write_wakeup() should be used to release completion hold
by serdev_device_write(), however @hci_serdev_client_ops doesn't use
serdev_device_write_wakeup() to implement its write_wakeup operation.
we don't want to touch common hci_serdev.c code.

>> +		usleep_range(8000, 10000);
>> +
>> +		serdev_device_write_flush(serdev);
> 
> I suppose the flush is done because _wait_until_sent() could have timed out.
> Another reason to use _device_write() (if suitable), since it returns
> -ETIMEDOUT in that case?
>
flush is prefixed at write operation to speed up
shutdown procedure in case of unexpected data injected
during waiting for controller wakeup.
the combo have been used and i just follow it>> +		ret = serdev_device_write_buf(serdev,
>> +				edl_reset_soc_cmd, sizeof(edl_reset_soc_cmd));
>> +		if (ret < 0) {
>> +			BT_ERR("QCA send EDL_RESET_REQ error: %d", ret);
>> +			return;
>> +		}
>> +		serdev_device_wait_until_sent(serdev, timeout);
>> +		usleep_range(8000, 10000);
>> +	}
>> +}
>> +
>>  static int __maybe_unused qca_suspend(struct device *dev)
>>  {
>>  	struct hci_dev *hdev = container_of(dev, struct hci_dev, dev);
>> @@ -2100,6 +2128,7 @@ static struct serdev_device_driver qca_serdev_driver = {
>>  		.name = "hci_uart_qca",
>>  		.of_match_table = of_match_ptr(qca_bluetooth_of_match),
>>  		.acpi_match_table = ACPI_PTR(qca_bluetooth_acpi_match),
>> +		.shutdown = qca_serdev_shutdown,
>>  		.pm = &qca_pm_ops,
>>  	},
>>  };
>> -- 
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
>>

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project