Re: [PATCH v6 4/4] Bluetooth: hci_bcm: Support pcm params in dts

[Abhishek Pandit-Subedi]

On Mon, Nov 18, 2019 at 9:44 PM Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
>
> Hi Abhishek,
>
> > BCM chips may require configuration of PCM to operate correctly and
> > there is a vendor specific HCI command to do this. Add support in the
> > hci_bcm driver to parse this from devicetree and configure the chip.
> >
> > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
> > ---
> >
> > Changes in v6:
> > - Added btbcm_read_pcm_int_params and change pcm params to first read
> >  the pcm params before setting it
> >
> > Changes in v5:
> > - Rename parameters to bt-* and read as integer instead of bytestring
> > - Update documentation with defaults and put values in header
> > - Changed patch order
> >
> > Changes in v4:
> > - Fix incorrect function name in hci_bcm
> >
> > Changes in v3:
> > - Change disallow baudrate setting to return -EBUSY if called before
> >  ready. bcm_proto is no longer modified and is back to being const.
> > - Changed btbcm_set_pcm_params to btbcm_set_pcm_int_params
> > - Changed brcm,sco-routing to brcm,bt-sco-routing
> >
> > Changes in v2:
> > - Use match data to disallow baudrate setting
> > - Parse pcm parameters by name instead of as a byte string
> > - Fix prefix for dt-bindings commit
> >
> > drivers/bluetooth/hci_bcm.c | 57 +++++++++++++++++++++++++++++++++++++
> > 1 file changed, 57 insertions(+)
> >
> > diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
> > index ee40003008d8..2ce3fac2c5dd 100644
> > --- a/drivers/bluetooth/hci_bcm.c
> > +++ b/drivers/bluetooth/hci_bcm.c
> > @@ -25,6 +25,7 @@
> > #include <linux/pm_runtime.h>
> > #include <linux/serdev.h>
> >
> > +#include <dt-bindings/bluetooth/brcm.h>
> > #include <net/bluetooth/bluetooth.h>
> > #include <net/bluetooth/hci_core.h>
> >
> > @@ -88,6 +89,7 @@ struct bcm_device_data {
> >  *    used to disable flow control during runtime suspend and system sleep
> >  * @is_suspended: whether flow control is currently disabled
> >  * @no_early_set_baudrate: don't set_baudrate before setup()
> > + * @pcm_params: PCM and routing parameters
> >  */
> > struct bcm_device {
> >       /* Must be the first member, hci_serdev.c expects this. */
> > @@ -122,6 +124,8 @@ struct bcm_device {
> >       bool                    is_suspended;
> > #endif
> >       bool                    no_early_set_baudrate;
> > +
> > +     struct bcm_set_pcm_int_params   pcm_params;
> > };
> >
> > /* generic bcm uart resources */
> > @@ -541,6 +545,7 @@ static int bcm_flush(struct hci_uart *hu)
> > static int bcm_setup(struct hci_uart *hu)
> > {
> >       struct bcm_data *bcm = hu->priv;
> > +     struct bcm_set_pcm_int_params p;
> >       char fw_name[64];
> >       const struct firmware *fw;
> >       unsigned int speed;
> > @@ -594,6 +599,31 @@ static int bcm_setup(struct hci_uart *hu)
> >                       host_set_baudrate(hu, speed);
> >       }
> >
> > +     /* PCM parameters if any*/
> > +     err = btbcm_read_pcm_int_params(hu->hdev, &p);
> > +     if (!err) {
> > +             if (bcm->dev->pcm_params.routing == 0xff)
> > +                     bcm->dev->pcm_params.routing = p.routing;
> > +             if (bcm->dev->pcm_params.rate == 0xff)
> > +                     bcm->dev->pcm_params.rate = p.rate;
> > +             if (bcm->dev->pcm_params.frame_sync == 0xff)
> > +                     bcm->dev->pcm_params.frame_sync = p.frame_sync;
> > +             if (bcm->dev->pcm_params.sync_mode == 0xff)
> > +                     bcm->dev->pcm_params.sync_mode = p.sync_mode;
> > +             if (bcm->dev->pcm_params.clock_mode == 0xff)
> > +                     bcm->dev->pcm_params.clock_mode = p.clock_mode;
>
> Frankly, I wouldnât bother here. If the read HCI command failed, then we abort bcm_setup and fail the whole procedure. These commands have been around the first Broadcom chips and you can assume they are present. And if at some point they do fail, I want to know about it.
Ok -- will change to return error if it fails.

>
> > +
> > +             /* Write only when there are changes */
> > +             if (memcmp(&p, &bcm->dev->pcm_params, sizeof(p)))
> > +                     err = btbcm_write_pcm_int_params(hu->hdev,
> > +                                                      &bcm->dev->pcm_params);
> > +
> > +             if (err)
> > +                     bt_dev_warn(hu->hdev, "BCM: Write pcm params failed (%d)",
> > +                                 err);
> > +     } else
> > +             bt_dev_warn(hu->hdev, "BCM: Read pcm params failed (%d)", err);
> > +
> > finalize:
> >       release_firmware(fw);
> >
> > @@ -1128,9 +1158,36 @@ static int bcm_acpi_probe(struct bcm_device *dev)
> > }
> > #endif /* CONFIG_ACPI */
> >
> > +static int property_read_u8(struct device *dev, const char *prop, u8 *value)
> > +{
> > +     int err;
> > +     u32 tmp;
> > +
> > +     err = device_property_read_u32(dev, prop, &tmp);
> > +
> > +     if (!err)
> > +             *value = (u8)tmp;
> > +
> > +     return err;
> > +}
>
> I think this really needs to be done in the generic property code if this is wanted.
Yes, this should be device_property_read_u8. For some reason, I
thought that wasn't working before (I'll have to retest it with
straight integer values).

>
> > +
> > static int bcm_of_probe(struct bcm_device *bdev)
> > {
> >       device_property_read_u32(bdev->dev, "max-speed", &bdev->oper_speed);
> > +
> > +     memset(&bdev->pcm_params, 0xff, sizeof(bdev->pcm_params));
>
> Scrap this memset. We will read the values first.

I added this memset is bcm_of_probe occurs before patchram and without
setting some magic value in the pcm_params, we don't know which values
are valid (since 0 has some meaning in the params).
It doesn't make sense to me to read pcm params outside setup (I want
patchram to complete first) and it doesn't make sense to do property
reads inside setup.


>
> > +
> > +     property_read_u8(bdev->dev, "brcm,bt-sco-routing",
> > +                      &bdev->pcm_params.routing);
> > +     property_read_u8(bdev->dev, "brcm,bt-pcm-interface-rate",
> > +                      &bdev->pcm_params.rate);
> > +     property_read_u8(bdev->dev, "brcm,bt-pcm-frame-type",
> > +                      &bdev->pcm_params.frame_sync);
> > +     property_read_u8(bdev->dev, "brcm,bt-pcm-sync-mode",
> > +                      &bdev->pcm_params.sync_mode);
> > +     property_read_u8(bdev->dev, "brcm,bt-pcm-clock-mode",
> > +                      &bdev->pcm_params.clock_mode);
> > +
> >       return 0;
> > }
>
> Regards
>
> Marcel
>