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

Hi Marcel,

-----Original Message-----
From: Marcel Holtmann <marcel@holtmann.org>
Sent: Friday, July 30, 2021 7:44 PM
To: K, Kiran <redacted>
Cc: linux-bluetooth@vger.kernel.org; Srivatsa, Ravishankar
[off-list ref]; Tumkur Narayan, Chethan
[off-list ref]
Subject: Re: [PATCH v11 04/10] Bluetooth: Allow querying of supported
offload codecs over SCO socket

Hi Kiran,

quoted

Add BT_CODEC option for getsockopt systemcall to get the details of
offload codecs supported over SCO socket

Signed-off-by: Kiran K <redacted>
Reviewed-by: Chethan T N <redacted>
Reviewed-by: Srivatsa Ravishankar <redacted>
---
* 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)

quoted

#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,

quoted

	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,

quoted

			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);

quoted

+		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