From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us.padl.com (us.padl.com [216.154.215.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE0E227A91D; Fri, 5 Jun 2026 01:14:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.154.215.154 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780622054; cv=none; b=BztTgN/Byl+Adb0ETkGk0lmwgQXoQT+4oPtj3RTOk70hAHDYCDfwRnqnR1E31gYCxc9/vKMhaVSBOxUJ55Vdu5foyzNEN3TMHqNuBeygd+bfNc5A+9vfy496+j0Kk/CYJdSbEneZy4CR3r7tvMhn2a05DJTz7bjvD/1BMHdvJ9E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780622054; c=relaxed/simple; bh=DrfrjKEiOQMi4PdJ4tlqIf5bMHmaoVxpAStGpcKRSzc=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=txK6xQkU6sEiyNsXjgcbPlBVgD+HrngSimttoW4tyi4n5TCMvlcmsKsciT0iFCVGsom9XmyM8SMrVFACc7o5nekg53g/jqmd3YBCmbWu8LubAsm6+RYHQ+fc9SLrSLGdvTYiZvpONVcojNePq3tcudRXGL51EybvdOsokkKWpns= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=padl.com; spf=pass smtp.mailfrom=padl.com; dkim=pass (2048-bit key) header.d=padl.com header.i=@padl.com header.b=oDmkyogF; arc=none smtp.client-ip=216.154.215.154 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=padl.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=padl.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=padl.com header.i=@padl.com header.b="oDmkyogF" Received: from smtpclient.apple (border.lukktone.com [139.130.100.52]) by us.padl.com (Postfix) with ESMTPSA id 2831C60937; Thu, 4 Jun 2026 21:14:07 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=padl.com; s=default; t=1780622051; bh=DrfrjKEiOQMi4PdJ4tlqIf5bMHmaoVxpAStGpcKRSzc=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=oDmkyogFljIzJqXnVOl8N6/Z1kZ8rd/mJgU/o0OrOpVUeL8DjCpBOfUpS0pR0IKxn 4Ulg+dMVm8mI5d598F3TyKPE9gre0i6QECupfnwYmae7zkb74kYp3+v/7qdWhZPc89 8xlnQl18znnEZMBZ7wLva1NbgYrVBqnhxYeB13mFqcaxMbguXpY5KhEMRmPwHDvzUm MWpfb8ssI7lKribphXyl89P+batCi/NwOgz27KyR4RCupNVR+pDPCodmbnjT3niroz ZqCKdTG1QrdOG0NVcWtrpw7xc0wzre/SnHbyl0xpha357iFkxy6EcyVeLj4V2nc6RL Ur4T9AVp8AHbA== Content-Type: text/plain; charset=utf-8 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.700.81\)) Subject: Re: [PATCH net-next 0/2] net: dsa: mv88e6xxx: add support for dcb pcp app From: Luke Howard In-Reply-To: <4d6e6d83-af79-4a06-9736-d6d81e705a61@lunn.ch> Date: Fri, 5 Jun 2026 11:13:55 +1000 Cc: Cedric Jehasse , cedric.jehasse@luminex.be, Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Russell King , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Max Hunter , Kieran Tyrrell , Nikolay Aleksandrov Content-Transfer-Encoding: quoted-printable Message-Id: References: <20260604-net-next-mv88e6xxx-pcp-prio-v1-0-f9d10fe6cdc8@luminex.be> <02BDD59A-30A9-46F9-8413-28A867B50CD5@padl.com> <4d6e6d83-af79-4a06-9736-d6d81e705a61@lunn.ch> To: Andrew Lunn X-Mailer: Apple Mail (2.3826.700.81) Hi Andrew, > I don't know enough about AVB, so this might not apply here.... >=20 > What does the pure software version of AVB look like? Is there a need > to configure these parameters? If not, why not? If there is, what API > is currently used? Qdisc configuration for AVB is described here [1] albeit with reversed = numbering of TCs. CBS parameters are usually managed dynamically by SRP = (in user space), but static configuration as shown in the link would be = common for automative AVB/TSN. > Ideally, the user should not need to know if some functionality has > been accelerated by offloading it to hardware. They just configure it > using the standard Linux model of the feature. Absolutely, and that was the model I used when building a SRP daemon, = which I first tested with the software bridge and some i210s. One issue is that AVB is typically configured using MQPRIO, which = configures egress queue mapping. The Marvell switches support ingress = queue mapping (the subject of this patch), although there is a special = case for AVB traffic which does allow for egress queue mapping. The main issue is that inbound frames belonging to AVB TCs that do _not_ = have a SRP-managed DA must be dropped. This permits those queues=E2=80=99 = CBS bandwidth to be reserved for AVB streams.Marvell implements this = with the STATIC_AVB_NRL entry state, combined with an ingress port flag = that enables the packet filtering. My patch mapped the Marvell model to the software bridge, i.e. new = IFLA_BRPORT and MDB flags. However, Nikolay (correctly) points out that = these are unidiomatic for Linux. My understanding is that these should likely be managed with tc-flower. = The SRP daemon would manage tc-flower entries along with the MDB when an = AVB stream is admitted. Unfortunately, implemetning this in mv88e6xxx = would be more complicated: it would either require intercepting the = tc-flower requests and mapping them to native AVB admission control = (which may be fragile), or adding PCP/DA matching to the TCAM = implementation (which may not be sufficiently performant, more research = is needed). Luke [1] https://tsn.readthedocs.io/avb.html