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Subject: Re: [PATCH v2 1/3] Bluetooth: add support to enumerate codec
 capabilities
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20210412083538.18600-1-kiran.k@intel.com>
Date:   Tue, 13 Apr 2021 21:14:33 +0200
Cc:     "open list:BLUETOOTH DRIVERS" <linux-bluetooth@vger.kernel.org>,
        "Srivatsa, Ravishankar" <ravishankar.srivatsa@intel.com>,
        Chethan T N <chethan.tumkur.narayan@intel.com>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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Message-Id: <3434AC21-8C36-435D-9D0F-3597FE434D54@holtmann.org>
References: <20210412083538.18600-1-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 v2
>  add skb->len check before accessing event data
> 
> include/net/bluetooth/hci.h |  7 ++++
> net/bluetooth/hci_event.c   | 68 +++++++++++++++++++++++++++++++++++++
> 2 files changed, 75 insertions(+)
> 
> 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_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);
> +
> +		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);
> +	}

instead of sending hci_send_cmd here, I rather do this in a separate init stage. Since you want to cache the codec values anyway, start doing it now.

Regards

Marcel