Re: [PATCH v2] Bluetooth: le_supported_roles experimental feature

[Alain Michaud <alainmichaud@google.com>]

On Thu, Jul 2, 2020 at 11:01 AM Alain Michaud <alainmichaud@google.com> wrote:
>
> Resending as plaintext.
>
>
> On Thu, Jul 2, 2020 at 10:59 AM Alain Michaud <alainmichaud@google.com> wrote:
> >
> > Hi Marcel
> >
> > On Thu, Jul 2, 2020 at 9:18 AM Marcel Holtmann <marcel@holtmann.org> wrote:
> >>
> >> Hi Alain,
> >>
> >> > This patch adds an le_supported_roles features which allows a
> >> > clients to determine if the controller is able to support peripheral and
> >> > central connections separately and at the same time.
> >> >
> >> > Signed-off-by: Alain Michaud <alainm@chromium.org>
> >> > ---
> >> >
> >> > Changes in v2:
> >> > - Slight change of design based on offline feedback
> >> >
> >> > net/bluetooth/mgmt.c | 36 +++++++++++++++++++++++++++++++++++-
> >> > 1 file changed, 35 insertions(+), 1 deletion(-)
> >> >
> >> > diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> >> > index 5e9b9728eeac..c13fcc21745f 100644
> >> > --- a/net/bluetooth/mgmt.c
> >> > +++ b/net/bluetooth/mgmt.c
> >> > @@ -3753,10 +3753,36 @@ static const u8 debug_uuid[16] = {
> >> > };
> >> > #endif
> >> >
> >> > +/* 671b10b5-42c0-4696-9227-eb28d1b049d6 */
> >> > +static const u8 le_supported_roles[16] = {
> >> > +     0xd6, 0x49, 0xb0, 0xd1, 0x28, 0xeb, 0x27, 0x92,
> >> > +     0x96, 0x46, 0xc0, 0x42, 0xb5, 0x10, 0x1b, 0x67,
> >> > +};
> >> > +
> >> > +static u32 get_le_roles_flags(struct hci_dev *hdev)
> >> > +{
> >> > +     u32 flags = 0;
> >> > +
> >> > +     /* Central connections supported */
> >> > +     if (hdev->le_states[4] & 0x08)
> >> > +             flags |= BIT(0);
> >> > +
> >> > +     /* Peripheral connections supported */
> >> > +     if (hdev->le_states[4] & 0x40)
> >> > +             flags |= BIT(1);
> >> > +
> >> > +     /* Simult central and peripheral connections supported */
> >> > +     if (test_bit(HCI_QUIRK_VALID_LE_STATES, &hdev->quirks) &&
> >> > +         (hdev->le_states[3] & 0x10))
> >> > +             flags |= BIT(2);
> >> > +
> >> > +     return flags;
> >> > +}
> >>
> >> this is not what we can do here. The flags are defined like this.
> >>
> >>         The following bits are defined for the Flags parameter:
> >>
> >>                 0       Feature active
> >>                 1       Causes change in supported settings
> >>
> >> And I want these flags for generic handling of experimental features. Individual features can not overwrite it.
> >>
> >> So if you only want to support a the “read" functionality, then something like this please.
> >>
> >>         if ((hdev->le_states[4] & 0x08) &&      /* Central */
> >>             (hdev->le_states[4] & 0x40) &&      /* Peripheral */
> >>             (hdev->le_states[3] & 0x10) &&      /* Simultaneous */
> >>             test_bit(HCI_QUIRK_VALID_LE_STATES, &hdev->quirks))
> >>                 flags |= BIT(0);
> >>
> > OK, Since the userspace Api we discussed reports individual states, would you suggest if LE is supported that the Central and Peripheral roles are supported and just use this to query the simultaneous support? Also, seems like what you are suggesting looks a lot like v1.
> >
> >>
> >> > +
> >> > static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
> >> >                                 void *data, u16 data_len)
> >> > {
> >> > -     char buf[42];
> >> > +     char buf[44];
> >> >       struct mgmt_rp_read_exp_features_info *rp = (void *)buf;
> >> >       u16 idx = 0;
> >> >
> >> > @@ -3774,6 +3800,14 @@ static int read_exp_features_info(struct sock *sk, struct hci_dev *hdev,
> >> >       }
> >> > #endif
> >> >
> >> > +     if (hdev) {
> >> > +             memcpy(rp->features[idx].uuid, le_supported_roles,
> >> > +                    sizeof(le_supported_roles));
> >> > +
> >>
> >> And I would put it all here instead of a separate function.
> >>
> >> > +             rp->features[idx].flags = cpu_to_le32(get_le_roles_flags(hdev));
> >> > +             ++idx;
> >> > +     }
> >> > +
> >> >       rp->feature_count = cpu_to_le16(idx);
> >> >
> >> >       /* After reading the experimental features information, enable
> >>
> >> Regards
> >>
> >> Marcel
> >>