RE: [PATCH v11 04/10] Bluetooth: Allow querying of supported offload codecs over SCO socket

["K, Kiran" <kiran.k@intel.com>]

Hi Marcel,

> -----Original Message-----
> From: Marcel Holtmann <marcel@holtmann.org>
> Sent: Friday, July 30, 2021 7:44 PM
> To: K, Kiran <kiran.k@intel.com>
> Cc: linux-bluetooth@vger.kernel.org; Srivatsa, Ravishankar
> <ravishankar.srivatsa@intel.com>; Tumkur Narayan, Chethan
> <chethan.tumkur.narayan@intel.com>
> Subject: Re: [PATCH v11 04/10] Bluetooth: Allow querying of supported
> offload codecs over SCO socket
> 
> Hi Kiran,
> 
> > Add BT_CODEC option for getsockopt systemcall to get the details of
> > offload codecs supported over SCO socket
> >
> > Signed-off-by: Kiran K <kiran.k@intel.com>
> > Reviewed-by: Chethan T N <chethan.tumkur.narayan@intel.com>
> > Reviewed-by: Srivatsa Ravishankar <ravishankar.srivatsa@intel.com>
> > ---
> > * changes in v11:
> >  - Remove Kconfig related changes
> > * changes in v10:
> >  - In getsockopt, prepare data in advance and call copy_to_user
> >    istead of calling put_user on each field of struct bt_codec
> >
> > include/net/bluetooth/bluetooth.h | 20 +++++++
> > include/net/bluetooth/hci.h       |  4 ++
> > include/net/bluetooth/hci_core.h  |  1 +
> > net/bluetooth/sco.c               | 91 +++++++++++++++++++++++++++++++
> > 4 files changed, 116 insertions(+)
> >
> > diff --git a/include/net/bluetooth/bluetooth.h
> > b/include/net/bluetooth/bluetooth.h
> > index 9125effbf448..64cddff0c9c4 100644
> > --- a/include/net/bluetooth/bluetooth.h
> > +++ b/include/net/bluetooth/bluetooth.h
> > @@ -153,6 +153,26 @@ struct bt_voice {
> >
> > #define BT_SCM_PKT_STATUS	0x03
> >
> > +#define BT_CODEC	19
> > +
> > +struct	bt_codec_caps {
> > +	__u8	len;
> > +	__u8	data[];
> > +} __packed;
> > +
> > +struct bt_codec {
> > +	__u8	id;
> > +	__u16	cid;
> > +	__u16	vid;
> > +	__u8	data_path;
> > +	__u8	num_caps;
> > +} __packed;
> > +
> > +struct bt_codecs {
> > +	__u8		num_codecs;
> > +	struct bt_codec	codecs[];
> > +} __packed;
> > +
> > __printf(1, 2)
> > void bt_info(const char *fmt, ...);
> > __printf(1, 2)
> > diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> > index b4e35cf5f4b1..22e872e60ff8 100644
> > --- a/include/net/bluetooth/hci.h
> > +++ b/include/net/bluetooth/hci.h
> > @@ -2621,6 +2621,10 @@ static inline struct hci_sco_hdr
> *hci_sco_hdr(const struct sk_buff *skb)
> > #define hci_iso_data_len(h)		((h) & 0x3fff)
> > #define hci_iso_data_flags(h)		((h) >> 14)
> >
> > +/* codec transport types */
> > +#define TRANSPORT_ACL		0x00
> > +#define TRANSPORT_SCO_ESCO	0x01
> > +
> > /* le24 support */
> > static inline void hci_cpu_to_le24(__u32 val, __u8 dst[3]) { diff
> > --git a/include/net/bluetooth/hci_core.h
> > b/include/net/bluetooth/hci_core.h
> > index 6742e6ad7b37..71c409c8ab34 100644
> > --- a/include/net/bluetooth/hci_core.h
> > +++ b/include/net/bluetooth/hci_core.h
> > @@ -617,6 +617,7 @@ struct hci_dev {
> > 	int (*set_bdaddr)(struct hci_dev *hdev, const bdaddr_t *bdaddr);
> > 	void (*cmd_timeout)(struct hci_dev *hdev);
> > 	bool (*prevent_wake)(struct hci_dev *hdev);
> > +	int (*get_data_path_id)(struct hci_dev *hdev, __u8 *data_path);
> > };
> >
> > #define HCI_PHY_HANDLE(handle)	(handle & 0xff)
> > diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index
> > ffa2a77a3e4c..2f32693f09c1 100644
> > --- a/net/bluetooth/sco.c
> > +++ b/net/bluetooth/sco.c
> > @@ -953,6 +953,12 @@ static int sco_sock_getsockopt(struct socket *sock,
> int level, int optname,
> > 	struct bt_voice voice;
> > 	u32 phys;
> > 	int pkt_status;
> > +	int buf_len;
> > +	struct codec_list *c;
> > +	u8 num_codecs, i, __user *ptr;
> > +	struct hci_dev *hdev;
> > +	struct hci_codec_caps *caps;
> > +	struct bt_codec codec;
> >
> > 	BT_DBG("sk %p", sk);
> >
> > @@ -1017,6 +1023,91 @@ static int sco_sock_getsockopt(struct socket
> *sock, int level, int optname,
> > 			err = -EFAULT;
> > 		break;
> >
> > +	case BT_CODEC:
> > +		num_codecs = 0;
> > +		buf_len = 0;
> > +
> > +		hdev = hci_get_route(&sco_pi(sk)->dst, &sco_pi(sk)->src,
> BDADDR_BREDR);
> > +		if (!hdev) {
> > +			err = -EBADFD;
> > +			break;
> > +		}
> > +
> > +		if (!hdev->get_data_path_id) {
> > +			err = -EOPNOTSUPP;
> > +			break;
> > +		}
> 
> so I did say that this needs to be put behind an experimental feature setting.
> I am not committing to an userspace API until we have more feedback.

Ack.
> 
> Regards
> 
> Marcel

Regards,
Kiran