On Fri, Jan 18, 2019 at 04:31:09PM -0800, Matthias Kaehlcke wrote:
> On Fri, Jan 18, 2019 at 10:44:16AM +0100, Johan Hovold wrote:
> > On Thu, Jan 17, 2019 at 09:21:09AM -0800, Matthias Kaehlcke wrote:
> >
> > > I observed that the qcom_geni_serial driver doesn't raise RTS with
> > > flow control disabled. It seems we have to investigate why that's the
> > > case. I agree that the driver should be platform agnostic.
> >
> > Sounds like a driver bug, unless the hardware is just "odd". The
> > driver implementation of this looks very non-standard judging from a
> > quick peek.
> >
> > In fact, qcom_geni_serial_get_mctrl() is currently a no-op if hardware
> > flow control is not enabled:
> >
> > if (uart_console(uport) || !uart_cts_enabled(uport))
> > return;
> >
> > Perhaps dropping the !uart_cts_enabled() test is sufficient.
>
> Thanks for taking a look Johan, that was indeed the problem (also
> in set_mctrl()). I posted a fix:
> https://lore.kernel.org/patchwork/patch/1033611/
Nice (I did mean set_mctrl() above, as I think you noticed).
> Balakrishna, the following (applied on top of your patch) works for me
> with the UART patch above:
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 9d5e41f159c78f..60bfdf01f72841 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -1080,7 +1080,7 @@ static int qca_set_speed(struct hci_uart *hu, enum
> qca_speed_type speed_type)
> {
> unsigned int speed, qca_baudrate;
> struct qca_serdev *qcadev;
> - int ret;
> + int ret = 0;
>
> if (speed_type == QCA_INIT_SPEED) {
> speed = qca_get_speed(hu, QCA_INIT_SPEED);
> @@ -1097,22 +1097,27 @@ static int qca_set_speed(struct hci_uart *hu, enum
> qca_speed_type speed_type)
> * the old speed.
> */
> qcadev = serdev_device_get_drvdata(hu->serdev);
> - if (qcadev->btsoc_type == QCA_WCN3990)
> + if (qcadev->btsoc_type == QCA_WCN3990) {
> + hci_uart_set_flow_control(hu, true);
Wow, yeah, this parameter inversion is indeed confusing...
> serdev_device_set_rts(hu->serdev, false);
> + }
But looking at hci_uart_set_flow_control() now, it actually also
deasserts RTS. So all you need here is the hci_uart_set_flow_control()
call.
And that makes the inversion make a bit more sense too, even if the
naming is a bit unfortunate with respect to
serdev_device_set_flow_control() at least.
> qca_baudrate = qca_get_baudrate_value(speed);
> bt_dev_dbg(hu->hdev, "Set UART speed to %d", speed);
> ret = qca_set_baudrate(hu->hdev, qca_baudrate);
> if (ret)
> - return ret;
> + goto out;
>
> host_set_baudrate(hu, speed);
>
> - if (qcadev->btsoc_type == QCA_WCN3990)
> +out:
> + if (qcadev->btsoc_type == QCA_WCN3990) {
> + hci_uart_set_flow_control(hu, false);
> serdev_device_set_rts(hu->serdev, true);
> + }
And same here.
Johan
