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Date:   Fri, 03 Jan 2020 14:33:46 +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
Subject: Re: [PATCH v3 4/4] Bluetooth: hci_qca: Add HCI command timeout
 handling
In-Reply-To: <20200102190727.GB89495@google.com>
References: <20191225060317.5258-1-rjliao@codeaurora.org>
 <20191227072130.29431-1-rjliao@codeaurora.org>
 <20191227072130.29431-4-rjliao@codeaurora.org>
 <20200102190727.GB89495@google.com>
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在 2020-01-03 03:07，Matthias Kaehlcke 写道：
> Hi Rocky,
> 
> On Fri, Dec 27, 2019 at 03:21:30PM +0800, Rocky Liao wrote:
>> This patch adds the HCI command timeout handling, it will trigger 
>> btsoc
>> to report its memory dump via vendor specific events when hit the 
>> defined
>> max HCI command timeout count. After all the memory dump VSE are sent, 
>> the
>> btsoc will also send a HCI_HW_ERROR event to host and this will cause 
>> a new
>> hci down/up process and the btsoc will be re-initialized.
>> 
>> Signed-off-by: Rocky Liao <rjliao@codeaurora.org>
>> ---
>> 
>> Changes in v2:
>> - Fix build error
>> Changes in v3:
>> - Remove the function declaration
>> - Move the cmd_timeout() callback register to probe()
>> - Remove the redundant empty line
>> 
>>  drivers/bluetooth/hci_qca.c | 45 
>> +++++++++++++++++++++++++++++++++++++
>>  1 file changed, 45 insertions(+)
>> 
>> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
>> index ca0b38f065e5..026e2e2cdd30 100644
>> --- a/drivers/bluetooth/hci_qca.c
>> +++ b/drivers/bluetooth/hci_qca.c
>> @@ -47,6 +47,8 @@
>>  #define IBS_HOST_TX_IDLE_TIMEOUT_MS	2000
>>  #define CMD_TRANS_TIMEOUT_MS		100
>> 
>> +#define QCA_BTSOC_DUMP_CMD	0xFB
>> +
>>  /* susclk rate */
>>  #define SUSCLK_RATE_32KHZ	32768
>> 
>> @@ -56,6 +58,9 @@
>>  /* max retry count when init fails */
>>  #define QCA_MAX_INIT_RETRY_COUNT 3
>> 
>> +/* when hit the max cmd time out count, trigger btsoc dump */
>> +#define QCA_MAX_CMD_TIMEOUT_COUNT 3
> 
> nit: MAX_CMD_TIMEOUTS?
> 
> Similar to QCA_MAX_INIT_RETRY_COUNT on which I commented earlier I 
> don't
> think the 'QCA' prefix adds value here. The constant is defined in the 
> driver
> itself and isn't related to hardware.
> 

OK

>> +
>>  enum qca_flags {
>>  	QCA_IBS_ENABLED,
>>  	QCA_DROP_VENDOR_EVENT,
>> @@ -123,6 +128,8 @@ struct qca_data {
>>  	u64 rx_votes_off;
>>  	u64 votes_on;
>>  	u64 votes_off;
>> +
>> +	u32 cmd_timeout_cnt;
> 
> nit: cmd_timeouts?
> 
>>  };
>> 
>>  enum qca_speed_type {
>> @@ -1332,6 +1339,11 @@ static int qca_setup(struct hci_uart *hu)
>>  	if (!ret) {
>>  		set_bit(QCA_IBS_ENABLED, &qca->flags);
>>  		qca_debugfs_init(hdev);
>> +
>> +		/* clear the command time out count every time after
>> +		 * initializaiton done
>> +		 */
>> +		qca->cmd_timeout_cnt = 0;
>>  	} else if (ret == -ENOENT) {
>>  		/* No patch/nvm-config found, run with original fw/config */
>>  		ret = 0;
>> @@ -1462,6 +1474,38 @@ static int qca_power_off(struct hci_dev *hdev)
>>  	return 0;
>>  }
>> 
>> +static int qca_send_btsoc_dump_cmd(struct hci_uart *hu)
>> +{
>> +	int err = 0;
> 
> The variable is pointless, just return 0 at the end of the function.
> 
OK

>> +	struct sk_buff *skb = NULL;
>> +	struct qca_data *qca = hu->priv;
>> +
>> +	BT_DBG("hu %p sending btsoc dump command", hu);
>> +
>> +	skb = bt_skb_alloc(1, GFP_ATOMIC);
>> +	if (!skb) {
>> +		BT_ERR("Failed to allocate memory for qca dump command");
> 
> "These generic allocation functions all emit a stack dump on failure 
> when used
> without __GFP_NOWARN so there is no use in emitting an additional 
> failure
> message when NULL is returned."
> 
> Documentation/process/coding-style.rst
> 
> hence the logging is redundant, drop it.
> 

OK

>> +		return -ENOMEM;
>> +	}
>> +
>> +	skb_put_u8(skb, QCA_BTSOC_DUMP_CMD);
>> +
>> +	skb_queue_tail(&qca->txq, skb);
>> +
>> +	return err;
>> +}
>> +
>> +static void qca_cmd_timeout(struct hci_dev *hdev)
>> +{
>> +	struct hci_uart *hu = hci_get_drvdata(hdev);
>> +	struct qca_data *qca = hu->priv;
>> +
>> +	BT_ERR("hu %p hci cmd timeout count=0x%x", hu, 
>> ++qca->cmd_timeout_cnt);
> 
> Is there any particular reason to print the counter in hex instead of
> decimal?
> 
> Should this use bt_dev_err() since we have a hdev in this context?
> 

OK

>> +
>> +	if (qca->cmd_timeout_cnt >= QCA_MAX_CMD_TIMEOUT_COUNT)
>> +		qca_send_btsoc_dump_cmd(hu);
>> +}
>> +
>>  static int qca_regulator_enable(struct qca_serdev *qcadev)
>>  {
>>  	struct qca_power *power = qcadev->bt_power;
>> @@ -1605,6 +1649,7 @@ static int qca_serdev_probe(struct serdev_device 
>> *serdev)
>>  		hdev = qcadev->serdev_hu.hdev;
>>  		set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
>>  		hdev->shutdown = qca_power_off;
>> +		hdev->cmd_timeout = qca_cmd_timeout;
>>  	}
>> 
>>  out:	return err;
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
>> Forum, a Linux Foundation Collaborative Project