Received-SPF: pass (google.com: domain of linux-bluetooth-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain;
        charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.60.0.2.21\))
Subject: Re: [PATCH v3 1/3] Bluetooth: add support to enumerate codec
 capabilities
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20210422141449.25155-1-kiran.k@intel.com>
Date:   Fri, 23 Apr 2021 09:58:16 +0200
Cc:     Bluetooth Kernel Mailing List <linux-bluetooth@vger.kernel.org>,
        Chethan T N <chethan.tumkur.narayan@intel.com>,
        Srivatsa Ravishankar <ravishankar.srivatsa@intel.com>
Content-Transfer-Encoding: 8BIT
Message-Id: <96E58F60-51DE-4D47-B0BC-3D988D16C401@holtmann.org>
References: <20210422141449.25155-1-kiran.k@intel.com>
To:     Kiran K <kiran.k@intel.com>
Precedence: bulk

Hi Kiran,

> add support to enumerate local supported codec capabilities
> 
> < HCI Command: Read Local Suppor.. (0x04|0x000e) plen 7
>        Codec: mSBC (0x05)
>        Logical Transport Type: 0x00
>        Direction: Input (Host to Controller) (0x00)
>> HCI Event: Command Complete (0x0e) plen 12
>      Read Local Supported Codec Capabilities (0x04|0x000e) ncmd 1
>        Status: Success (0x00)
>        Number of codec capabilities: 1
>         Capabilities #0:
>        00 00 11 15 02 33
> 
> Signed-off-by: Kiran K <kiran.k@intel.com>
> Signed-off-by: Chethan T N <chethan.tumkur.narayan@intel.com>
> Signed-off-by: Srivatsa Ravishankar <ravishankar.srivatsa@intel.com>
> ---
> * changes in v3
>  move codec enumeration into a new init function
> * changes in v2
>  add skb length check before accessing data
> 
> include/net/bluetooth/hci.h |  7 ++++
> net/bluetooth/hci_core.c    | 16 ++++++---
> net/bluetooth/hci_event.c   | 68 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 87 insertions(+), 4 deletions(-)
> 
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index ea4ae551c426..e3f7771fe84f 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -1314,6 +1314,13 @@ struct hci_rp_read_local_pairing_opts {
> 	__u8     max_key_size;
> } __packed;
> 
> +#define HCI_OP_READ_LOCAL_CODEC_CAPS	0x100e
> +struct hci_op_read_local_codec_caps {
> +	__u8	codec_id[5];
> +	__u8	transport;
> +	__u8	direction;
> +} __packed;
> +
> #define HCI_OP_READ_PAGE_SCAN_ACTIVITY	0x0c1b
> struct hci_rp_read_page_scan_activity {
> 	__u8     status;
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index fd12f1652bdf..9419bbf55d90 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -838,10 +838,6 @@ static int hci_init4_req(struct hci_request *req, unsigned long opt)
> 	if (hdev->commands[22] & 0x04)
> 		hci_set_event_mask_page_2(req);
> 
> -	/* Read local codec list if the HCI command is supported */
> -	if (hdev->commands[29] & 0x20)
> -		hci_req_add(req, HCI_OP_READ_LOCAL_CODECS, 0, NULL);
> -

that is not what I actually meant. The initial command to read the codec list can clearly stay in this init phase. Just the subsequent calls to read further details require an extra phase.

> 	/* Read local pairing options if the HCI command is supported */
> 	if (hdev->commands[41] & 0x08)
> 		hci_req_add(req, HCI_OP_READ_LOCAL_PAIRING_OPTS, 0, NULL);
> @@ -907,6 +903,15 @@ static int hci_init4_req(struct hci_request *req, unsigned long opt)
> 	return 0;
> }
> 
> +static int hci_init5_req(struct hci_request *req, unsigned long opt)
> +{
> +	struct hci_dev *hdev = req->hdev;
> +
> +	/* Read local codec list if the HCI command is supported */
> +	if (hdev->commands[29] & 0x20)
> +		hci_req_add(req, HCI_OP_READ_LOCAL_CODECS, 0, NULL);

So here instead you go through your list of codec ids and read its capabilities.

> +	return 0;
> +}
> static int __hci_init(struct hci_dev *hdev)
> {
> 	int err;
> @@ -937,6 +942,9 @@ static int __hci_init(struct hci_dev *hdev)
> 	if (err < 0)
> 		return err;
> 
> +	err = __hci_req_sync(hdev, hci_init5_req, 0, HCI_INIT_TIMEOUT, NULL);
> +	if (err < 0)
> +		return err;
> 	/* This function is only called when the controller is actually in
> 	 * configured state. When the controller is marked as unconfigured,
> 	 * this initialization procedure is not run.
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 5e99968939ce..a4b905a76c1b 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -887,6 +887,70 @@ static void hci_cc_read_data_block_size(struct hci_dev *hdev,
> 	       hdev->block_cnt, hdev->block_len);
> }
> 
> +static void hci_cc_read_local_codecs(struct hci_dev *hdev,
> +				     struct sk_buff *skb)
> +{
> +	__u8 num_codecs;
> +	struct hci_op_read_local_codec_caps caps;
> +
> +	if (skb->len < sizeof(caps))
> +		return;
> +
> +	bt_dev_dbg(hdev, "status 0x%2.2x", skb->data[0]);
> +
> +	if (skb->data[0])
> +		return;
> +
> +	/* enumerate standard codecs */
> +	skb_pull(skb, 1);
> +
> +	if (skb->len < 1)
> +		return;
> +
> +	num_codecs = skb->data[0];
> +
> +	bt_dev_dbg(hdev, "Number of standard codecs: %u", num_codecs);
> +
> +	skb_pull(skb, 1);
> +
> +	if (skb->len < num_codecs)
> +		return;
> +
> +	while (num_codecs--) {
> +		caps.codec_id[0] = skb->data[0];
> +		caps.transport = 0x00;
> +		caps.direction = 0x00;
> +
> +		hci_send_cmd(hdev, HCI_OP_READ_LOCAL_CODEC_CAPS, sizeof(caps),
> +			     &caps);
> +

Here you just store the codec ids.

> +		skb_pull(skb, 1);
> +	}
> +
> +	/* enumerate vendor specific codecs */
> +	if (skb->len < 1)
> +		return;
> +
> +	num_codecs = skb->data[0];
> +	skb_pull(skb, 1);
> +
> +	bt_dev_dbg(hdev, "Number of vendor specific codecs: %u", num_codecs);
> +
> +	if (skb->len < (num_codecs * 4))
> +		return;
> +
> +	while (num_codecs--) {
> +		caps.codec_id[0] = 0xFF;
> +		memcpy(&caps.codec_id[1], skb->data, 4);
> +		caps.transport = 0x00;
> +		caps.direction = 0x00;
> +
> +		hci_send_cmd(hdev, HCI_OP_READ_LOCAL_CODEC_CAPS, sizeof(caps),
> +			     &caps);
> +		skb_pull(skb, 4);
> +	}
> +}
> +
> static void hci_cc_read_clock(struct hci_dev *hdev, struct sk_buff *skb)
> {
> 	struct hci_rp_read_clock *rp = (void *) skb->data;
> @@ -3437,6 +3501,10 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb,
> 		hci_cc_read_data_block_size(hdev, skb);
> 		break;
> 
> +	case HCI_OP_READ_LOCAL_CODECS:
> +		hci_cc_read_local_codecs(hdev, skb);
> +		break;
> +
> 	case HCI_OP_READ_FLOW_CONTROL_MODE:
> 		hci_cc_read_flow_control_mode(hdev, skb);
> 		break;

Regards

Marcel