Re: [PATCH v7 4/8] Bluetooth: btqca: Redefine qca_uart_setup() to generic function.

[Balakrishna Godavarthi <bgodavar@codeaurora.org>]

Hi Matthias,

On 2018-06-21 05:03, Matthias Kaehlcke wrote:
> Hi Balakrishna,
> 
> On Wed, Jun 20, 2018 at 04:23:25PM +0530, Balakrishna Godavarthi wrote:
>> Hi Matthias,
>> 
>> On 2018-06-20 01:33, Matthias Kaehlcke wrote:
>> > On Tue, Jun 19, 2018 at 12:39:07PM +0530, Balakrishna Godavarthi wrote:
>> > > Hi Matthias,
>> > >
>> > > Please find my comments inline.
>> > >
>> > > On 2018-06-19 02:49, Matthias Kaehlcke wrote:
>> > > > On Sat, Jun 16, 2018 at 11:57:14AM +0530, Balakrishna Godavarthi wrote:
>> > > >
>> > > > > @@ -337,19 +337,20 @@ int qca_uart_setup(struct hci_dev *hdev,
>> > > > > uint8_t baudrate)
>> > > > >
>> > > > >  	config.user_baud_rate = baudrate;
>> > > > >
>> > > > > -	/* Get QCA version information */
>> > > > > -	err = qca_read_soc_version(hdev, &rome_ver);
>> > > > > -	if (err < 0 || rome_ver == 0) {
>> > > > > -		bt_dev_err(hdev, "QCA Failed to get version %d", err);
>> > > > > -		return err;
>> > > > > +	if (!soc_ver) {
>> > > > > +		/* Get QCA version information */
>> > > > > +		err = qca_read_soc_version(hdev, &soc_ver);
>> > > > > +		if (err < 0 || soc_ver == 0) {
>> > > > > +			bt_dev_err(hdev, "QCA Failed to get version %d", err);
>> > > > > +			return err;
>> > > > > +		}
>> > > > > +		bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);
>> > > > >  	}
>> > > >
>> > > > Why is this needed? A caller that passes in soc_ver = 0 could just
>> > > > call qca_read_soc_version() themselves.
>> > > [Bala]: hci_qca support two chip one ROME (already up-streamed) and
>> > > other
>> > > wcn3990.
>> > >         there setup sequence differs.
>> > >
>> > >         wcn3900:
>> > >         1. set baudrate to 115200
>> > >         2. read soc version
>> > >         3. set baudarte to 3.2Mbps
>> > >         4. download firmware. (calls qca_uart_setup)
>> > >
>> > >        ROME:
>> > >        1. set baudrate to 3.0 mbps
>> > >        2. calls qca_uart_setup to read soc version and download
>> > > firmware.
>> > >
>> > >       so to make use of existing function qca_setup_uart(). passing
>> > > soc_ver
>> > > as argument.
>> > >       if soc_ver is zero, then read soc version (i.e. for ROME chip).
>> > >
>> > >       Pls let me know, if you have any queries.
>> >
>> > I don't really understand this argumentation. Let's look at the code
>> > at the end of this series, where both Rome and wcn3900 are supported:
>> >
>> > https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1045608/6/drivers/bluetooth/hci_qca.c#1059
>> >
>> > The version could be read (for Rome only) after setting the operating
>> > speed:
>> 
>> [Bala]: yes we can read SoC version after setting operating baud rate. 
>> an
>> advice from SoC vendor that, read SoC version before setting operating
>> speed.
>>         one advantage from reading SoC version before setting 
>> operating
>> baudrate,it will helps us to understand whether the soc is responding 
>> to any
>> commands in default baud rate
>>         before setting operating speed.
> 
> Is the recommendation for Rome or wcn3990? I was referring to Rome and
> the current code sets the operating speed and then reads the SoC
> version (inside qca_uart_setup())
> 

[Bala]: my statement is wrt to wcn3990. yes, ROME will set operating 
speed and read version.

>> > https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1045608/6/drivers/bluetooth/hci_qca.c#1111
>> >
>> > I concede that having two "if (qcadev->btsoc_type == XYZ)" branches in
>> > qca_setup() is kinda ugly, but I think it's still better than the
>> > conditional call of qca_read_soc_version() in qca_uart_setup().
>> 
>> [Bala]: we require an if-else block  for soc type.As wcn3900 support
>> hardware flow control where as ROME is not supporting hardware flow 
>> control.
> 
> Since you mention if-else and flow control I'm not sure if you
> understood correctly what I suggested. My suggestion is to add
> something like this:
> 
> if (qcadev->btsoc_type == QCA_ROME) {
> 	ret = qca_read_soc_version(hdev, &soc_ver);
> 	if (ret < 0 || soc_ver == 0) {
> 	   	// Note mka@: we might want to skip this log,
> 		// qca_read_soc_version() already logs in all error paths
> 		bt_dev_err(hdev, "Failed to get version %d", ret);
> 		return ret;
> 	}
> }
> 
> right here:
> 
> https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/1045608/6/drivers/bluetooth/hci_qca.c#1111
> 
> which is functionally equivalent to the current code.
> 
> You could even do the error check in the common code (just checking
> for 'soc_ver == 0', assuming that qca_read_soc_version() doesn't set
> it to something different in case of error).
> 
> Anyway, I won't insist if you prefer it as is and Marcel is ok with it.

[Bala]: thanks for clarifying my doubt, but if remove the 
qca_read_soc_version() from qca_uart_setup() and handle it qca_setup().
         in that case, we will have common blocks of code, when we 
integrate wcn3990 into existing qca_setup()

        static int qca_setup(struct hci_uart *hu)
       {
         ...

         qcadev = serdev_device_get_drvdata(hu->serdev);

         /* Patch downloading has to be done without IBS mode */
         clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);

         /* Setup initial baudrate */
         speed = qca_get_speed(hu, QCA_INIT_SPEED);
         if (speed)
                 qca_set_speed(hu, speed, QCA_INIT_SPEED);

         if (qcadev->btsoc_type == QCA_WCN3990) {
                 bt_dev_dbg(hdev, "setting up wcn3990");
                 hci_uart_set_flow_control(hu, true);
                 ret = qca_send_vendor_cmd(hdev, 
QCA_WCN3990_POWERON_PULSE);
                 if (ret) {
                         bt_dev_err(hdev, "failed to send power on 
command");
                         return ret;
                 }

                 serdev_device_close(hu->serdev);
                 ret = serdev_device_open(hu->serdev);
                 if (ret) {
                         bt_dev_err(hdev, "failed to open port");
                         return ret;
                 }

                 msleep(100);
                 speed = qca_get_speed(hu, QCA_INIT_SPEED);
                 if (speed)
                         qca_set_speed(hu, speed, QCA_INIT_SPEED);

                 hci_uart_set_flow_control(hu, false);
         } else {
                 bt_dev_info(hdev, "ROME setup");
                 /* Setup user speed if needed */
                 speed = qca_get_speed(hu, QCA_OPER_SPEED);
                 if (speed) {
                         ret = qca_set_speed(hu, speed, QCA_OPER_SPEED);
                         if (ret)
                                 return ret;

                         qca_baudrate = qca_get_baudrate_value(speed);
                 }
         }

         ret = qca_read_soc_version(hdev, &soc_ver);
         if (ret < 0 || soc_ver == 0) {
                 bt_dev_err(hdev, "Failed to get version %d", ret);
                 return ret;
         }
         bt_dev_info(hdev, "wcn3990 controller version 0x%08x", soc_ver);


         if (qcadev->btsoc_type == QCA_WCN3990) {
                 hci_uart_set_flow_control(hu, true);
                 /* Setup user speed if needed */
                 speed = qca_get_speed(hu, QCA_OPER_SPEED);
                 if (speed) {
                         ret = qca_set_speed(hu, speed, QCA_OPER_SPEED);
                         if (ret)
                                 return ret;

                 qca_baudrate = qca_get_baudrate_value(speed);

         }

         /* Setup patch / NVM configurations */
         ret = qca_uart_setup(hdev, qca_baudrate, qcadev->btsoc_type, 
soc_ver);
         if (!ret) {
                 set_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
                 qca_debugfs_init(hdev);
         } else if (ret == -ENOENT) {
                 /* No patch/nvm-config found, run with original 
fw/config */
                 ret = 0;
         } else if (ret == -EAGAIN) {
                 /*
       ...
       }


-- 
Regards
Balakrishna.