On Mon, Jun 25, 2018 at 04:43:54PM -0700, Matthias Kaehlcke wrote:
> This is a nice improvement, a few remaining questions inline.
>
> On Mon, Jun 25, 2018 at 07:10:10PM +0530, Balakrishna Godavarthi wrote:
> > In function qca_setup, we set initial and operating speeds for Qualcomm
> > Bluetooth SoC's. This block of code is common across different
> > Qualcomm Bluetooth SoC's. Instead of duplicating the code, created
> > a wrapper function to set the speeds. So that future coming SoC's
> > can use these wrapper functions to set speeds.
> >
> > Signed-off-by: Balakrishna Godavarthi <bgodavar@xxxxxxxxxxxxxx>
> > ---
> > Changes in v8:
> > * common function to set INIT and operating speeds.
> > * moved hardware flow control to qca_set_speed().
> >
> > Changes in v7:
> > * initial patch
> > * created wrapper functions for init and operating speeds.
> > ---
> > drivers/bluetooth/hci_qca.c | 89 +++++++++++++++++++++++++++----------
> > 1 file changed, 65 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > index fe62420ef838..38b7dbe6c897 100644
> > --- a/drivers/bluetooth/hci_qca.c
> > +++ b/drivers/bluetooth/hci_qca.c
> > @@ -119,6 +119,11 @@ struct qca_data {
> > u64 votes_off;
> > };
> >
> > +enum qca_speed_type {
> > + QCA_INIT_SPEED = 1,
> > + QCA_OPER_SPEED
> > +};
> > +
> > struct qca_serdev {
> > struct hci_uart serdev_hu;
> > struct gpio_desc *bt_en;
> > @@ -923,6 +928,60 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
> > hci_uart_set_baudrate(hu, speed);
> > }
> >
> > +static unsigned int qca_get_speed(struct hci_uart *hu,
> > + enum qca_speed_type speed_type)
> > +{
> > + unsigned int speed = 0;
> > +
> > + if (speed_type == QCA_INIT_SPEED) {
> > + if (hu->init_speed)
> > + speed = hu->init_speed;
> > + else if (hu->proto->init_speed)
> > + speed = hu->proto->init_speed;
> > + } else {
> > + if (hu->oper_speed)
> > + speed = hu->oper_speed;
> > + else if (hu->proto->oper_speed)
> > + speed = hu->proto->oper_speed;
> > + }
> > +
> > + return speed;
> > +}
> > +
> > +static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
> > +{
> > + unsigned int speed, qca_baudrate;
> > + int ret;
> > +
> > + if (speed_type == QCA_INIT_SPEED) {
> > + speed = qca_get_speed(hu, QCA_INIT_SPEED);
> > + if (speed)
> > + host_set_baudrate(hu, speed);
> > + else
> > + bt_dev_err(hu->hdev, "Init speed should be non zero");
>
> The check for 'speed == 0' is done in multiple places. From this
> code I deduce that it is expected that both INIT and OPER speed are
> set to non-zero values. What happens if either of them is zero? Is the
> driver still operational?
>
> > + return 0;
> > + }
> > +
> > + speed = qca_get_speed(hu, QCA_OPER_SPEED);
> > + if (!speed) {
> > + bt_dev_err(hu->hdev, "operating speed should be non zero");
> > + return 0;
> > + }
> > +
> > + qca_baudrate = qca_get_baudrate_value(speed);
> > + bt_dev_info(hu->hdev, "Set UART speed to %d", speed);
> > + ret = qca_set_baudrate(hu->hdev, qca_baudrate);
> > + if (ret) {
> > + bt_dev_err(hu->hdev, "Failed to change the baudrate (%d)", ret);
> > + return ret;
> > + }
> > +
> > + host_set_baudrate(hu, speed);
> > +
> > + return ret;
> > +}
>
> In the discussion on "[v7,8/8] Bluetooth: hci_qca: Add support for
> Qualcomm Bluetooth chip wcn3990" you mentioned the possbility to move
> the hci_uart_set_flow_control() calls into _set_speed(). This seemed
> interesting but finally it isn't done in this series. Did you
> encounter that it is not feasible/desirable for some reason?
I got that half wrong. "[v8,7/7] Bluetooth: hci_qca: Add support for
Qualcomm Bluetooth chip wcn3990" adds the flow control calls to
_set_speed() however there are still_set_flow_control() calls in
qca_setup(), which confused/s me.
Could you provide a brief summary on the situations (relevant for this
driver) in which flow controls needs to be enabled/disabled?
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