Re: [PATCH v1 4/4] Bluetooth: hci_qca: Fix frame reassembly errors for wcn3990

[Balakrishna Godavarthi]

Hi Matthias,

On 2018-11-15 01:06, Matthias Kaehlcke wrote:
> On Tue, Nov 06, 2018 at 05:35:28PM +0530, Balakrishna Godavarthi wrote:
> > [  176.929612] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly 
> > failed (-84)
> > [  176.945734] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly 
> > failed (-84)
> > [  176.953298] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly 
> > failed (-84)
> > [  177.010660] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly 
> > failed (-84)
> > [  177.067633] Bluetooth: hci_qca.c:qca_recv() hci0: Frame reassembly 
> > failed (-84)
> >
> > The above errors log on console due to receiving of stray bytes
> > when wcn3990 boot up's i.e. when during initial setup procedure.
>
> Please shortly introduce the topic instead of starting with the log
> messages.
[Bala]:  will update.

> > Signed-off-by: Balakrishna Godavarthi <bgodavar@xxxxxxxxxxxxxx>
> > ---
> >  drivers/bluetooth/hci_qca.c | 20 +++++++++++++++++++-
> >  1 file changed, 19 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > index 97b57e0f4725..341f80606574 100644
> > --- a/drivers/bluetooth/hci_qca.c
> > +++ b/drivers/bluetooth/hci_qca.c
> > @@ -56,6 +56,7 @@
> >
> >  /* Controller states */
> >  #define STATE_IN_BAND_SLEEP_ENABLED	1
> > +#define STATE_DISCARD_RX		2
> >
> >  #define IBS_WAKE_RETRANS_TIMEOUT_MS	100
> >  #define IBS_TX_IDLE_TIMEOUT_MS		2000
> > @@ -511,6 +512,7 @@ static int qca_open(struct hci_uart *hu)
> >  		} else {
> >  			hu->init_speed = qcadev->init_speed;
> >  			hu->oper_speed = qcadev->oper_speed;
> > +			set_bit(STATE_DISCARD_RX, &qca->flags);
> >  			ret = qca_power_setup(hu, true);
> >  			if (ret) {
> >  				destroy_workqueue(qca->workqueue);
> > @@ -903,6 +905,13 @@ static int qca_recv(struct hci_uart *hu, const 
> > void *data, int count)
> >  	if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
> >  		return -EUNATCH;
> >
> > +	/* We discard Rx data received while device is in booting
> > +	 * stage, this is due multiple baudrate switch is causing
> > +	 * UART to read some garbage data.
> > +	 */
>
> This isn't entirely correct. I saw frame reassembly errors before
> qca_wcn3990_init() is called, i.e. no baudrate changes. Some of the
> garbage seems to be sent shortly after powering on the controller.

[Bala]: yes your correct, will update the comment.

> > +	if (test_bit(STATE_DISCARD_RX, &qca->flags))
> > +		return 0;
> > +
> >  	qca->rx_skb = h4_recv_buf(hu->hdev, qca->rx_skb, data, count,
> >  				  qca_recv_pkts, ARRAY_SIZE(qca_recv_pkts));
> >  	if (IS_ERR(qca->rx_skb)) {
> > @@ -1192,10 +1201,12 @@ static int qca_setup(struct hci_uart *hu)
> >  		set_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks);
> >  		clear_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
> >  		hu->hdev->shutdown = qca_power_off;
> > +
> >  		ret = qca_wcn3990_init(hu);
> >  		if (ret)
> >  			return ret;
> >
> > +		clear_bit(STATE_DISCARD_RX, &qca->flags);
> >  		ret = qca_read_soc_version(hdev, &soc_ver);
> >  		if (ret)
> >  			return ret;
> > @@ -1278,8 +1289,15 @@ static void qca_power_shutdown(struct hci_uart 
> > *hu)
> >  	struct serdev_device *serdev = hu->serdev;
> >  	unsigned char cmd = QCA_WCN3990_POWEROFF_PULSE;
> >
> > -	host_set_baudrate(hu, 2400);
> > +	/* From this point we go into power off state,
> > +	 * disable IBS and discard all the queued data.
> > +	 */
> > +	clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
> > +	set_bit(STATE_DISCARD_RX, &qca->flags);
> > +	qca_flush(hu);
> > +
> >  	hci_uart_set_flow_control(hu, true);
> > +	host_set_baudrate(hu, 2400);
> >  	serdev_device_write(serdev, &cmd, sizeof(cmd), 0);
> >  	serdev_device_wait_until_sent(serdev, 0);
> >  	hci_uart_set_flow_control(hu, false);
>
> This change won't win a beauty price, but it seems it is needed to
> suppress the 'frame reassembly' spam, unless the controller can be
> convinced to stop sending garbage in the first place.
[Bala]: This is due to serdev_open function call before we trun on the 
regulators.
        where we don't have control over serdev open and close calls.

> Tested-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>

[Bala]: Thanks for testing.

--
Regards
Balakrishna.