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Date: Thu, 23 May 2024 14:17:41 +0100
From: Simon Horman <horms@kernel.org>
To: Ying Hsu <yinghsu@chromium.org>
Cc: linux-bluetooth@vger.kernel.org, luiz.dentz@gmail.com,
	pmenzel@molgen.mpg.de, chromeos-bluetooth-upstreaming@chromium.org,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	Marcel Holtmann <marcel@holtmann.org>,
	Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH v2] Bluetooth: Add vendor-specific packet classification
 for ISO data
Message-ID: <20240523131741.GN883722@kernel.org>
References: <20240523060934.2883716-1-yinghsu@chromium.org>
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In-Reply-To: <20240523060934.2883716-1-yinghsu@chromium.org>

On Thu, May 23, 2024 at 06:09:31AM +0000, Ying Hsu wrote:
> When HCI raw sockets are opened, the Bluetooth kernel module doesn't
> track CIS/BIS connections. User-space applications have to identify
> ISO data by maintaining connection information and look up the mapping
> for each ACL data packet received. Besides, btsnoop log captured in
> kernel couldn't tell ISO data from ACL data in this case.
> 
> To avoid additional lookups, this patch introduces vendor-specific
> packet classification for Intel BT controllers to distinguish
> ISO data packets from ACL data packets.
> 
> Signed-off-by: Ying Hsu <yinghsu@chromium.org>
> ---
> Tested LE audio unicast recording on a ChromeOS device with Intel AX211
> 
> Changes in v2:
> - Adds vendor-specific packet classificaton in hci_dev.
> - Keeps reclassification in hci_recv_frame.
> 
>  drivers/bluetooth/btusb.c        | 19 +++++++++++++++++++
>  include/net/bluetooth/hci_core.h |  1 +
>  net/bluetooth/hci_core.c         | 16 ++++++++++++++++
>  3 files changed, 36 insertions(+)
> 
> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> index 79aefdb3324d..75561e749c50 100644
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -966,6 +966,24 @@ static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
>  	gpiod_set_value_cansleep(reset_gpio, 0);
>  }
>  
> +#define BT_USB_INTEL_ISODATA_HANDLE_BASE 0x900
> +
> +static u8 btusb_intel_classify_pkt_type(struct hci_dev *hdev, struct sk_buff *skb)
> +{
> +	/*
> +	 * Distinguish ISO data packets form ACL data packets
> +	 * based on their conneciton handle value range.

nit: connection

> +	 */
> +	if (hci_skb_pkt_type(skb) == HCI_ACLDATA_PKT) {
> +		__u16 handle = __le16_to_cpu(hci_acl_hdr(skb)->handle);
> +
> +		if (hci_handle(handle) >= BT_USB_INTEL_ISODATA_HANDLE_BASE)
> +			return HCI_ISODATA_PKT;
> +	}
> +
> +	return hci_skb_pkt_type(skb);
> +}
> +
>  #define RTK_DEVCOREDUMP_CODE_MEMDUMP		0x01
>  #define RTK_DEVCOREDUMP_CODE_HW_ERR		0x02
>  #define RTK_DEVCOREDUMP_CODE_CMD_TIMEOUT	0x03

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