From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 511B0C5478C for ; Tue, 27 Feb 2024 09:02:42 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 9EBC6C6107 for ; Tue, 27 Feb 2024 09:02:41 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 84971986531 for ; Tue, 27 Feb 2024 09:02:41 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id 6BADA9863B6; Tue, 27 Feb 2024 09:02:41 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 5C7439863DE for ; Tue, 27 Feb 2024 09:02:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: Osw8U546MxaX4u1xeKb5dg-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709024557; x=1709629357; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=FlpacEWacryyrIlJZOoZ2EmsNR8IKw7FDvlRQtzIliY=; b=aHAs9MmuOCmIi4RrPyqNC5wSyVF0AsFIIwGIBSu4jE6L5sF9mSKpuj19IoCjRzstG0 7vOv9oKxp9e2oZfOgWsDDRN+ZjMiWswZaaXAfncG8ZYNAj19PO0Q+jPjbe6ZdbfZ+/Wr +GLGHnXBbPYJslIXqse9DNhMdmuqF+4iY4qlNMiS8eVxmqhEK1nzmEtAqQV8RX5nMBt+ vuBENmpA95SShyZjiO+ysg9OzgdTx8U90O6UUP55VOe9i663Qy1IPNS+G+aHNtxPrGKk YtmEpAqyrALnROXO67d0hFJhfM3p/9QE5xHFP3crJjlko/BobEDCYab5m6IluCxdn8sk xTjg== X-Forwarded-Encrypted: i=1; AJvYcCW7ZtiKbbswnV6TZsWA6WIlBO02PpyD7Dp+8hbHYOKlV5CBUbQjIQ3knbhiBfBGv/JlZk3Ypr4k58Kjr1wFtBbXAT3WFlleaSfUd1phKJDC X-Gm-Message-State: AOJu0YygSvrB+ZonFpjBLOR7SCuLqZjyEla2UndoqalMCTkEc9YW2sIt EJFGBC8bMtu4dGn2dEPANsmPbIaw5mqS62LUmim/UFy/X5uIbVa2yc/hkzp9usbH8aqXeNPI7Nr gf09/fQzND0u7+5krazXT/lhQ8Bn98kVGhWenCG/APgCBk7jqRYZQjpqMr+gz2EsCaA== X-Received: by 2002:ac8:7cb5:0:b0:42e:71bf:fb92 with SMTP id z21-20020ac87cb5000000b0042e71bffb92mr8237053qtv.40.1709024556884; Tue, 27 Feb 2024 01:02:36 -0800 (PST) X-Google-Smtp-Source: AGHT+IEktM+QuiKRjrNahkKKCp6g6mPsIdmLJBBljJdl/Jpj1OjlZw9vIz8CtyenrJ+CoAmXDtw3rw== X-Received: by 2002:ac8:7cb5:0:b0:42e:71bf:fb92 with SMTP id z21-20020ac87cb5000000b0042e71bffb92mr8237041qtv.40.1709024556554; Tue, 27 Feb 2024 01:02:36 -0800 (PST) Date: Tue, 27 Feb 2024 10:02:33 +0100 From: Matias Ezequiel Vara Larsen To: Cornelia Huck Cc: Marc Kleine-Budde , Mikhail Golubev-Ciuchea , virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org, linux-can@vger.kernel.org, Harald Mommer Message-ID: References: <20230609142243.199074-1-Mikhail.Golubev-Ciuchea@opensynergy.com> <20240221-acts-decade-76d3d69e8e4d-mkl@pengutronix.de> <20240221-juggling-uproar-9518b4901f41-mkl@pengutronix.de> <877circsh3.fsf@redhat.com> MIME-Version: 1.0 In-Reply-To: <877circsh3.fsf@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: Re: [virtio-dev] Re: [virtio-comment] [RFC PATCH v3] virtio-can: Device specification. On Mon, Feb 26, 2024 at 01:36:40PM +0100, Cornelia Huck wrote: > On Wed, Feb 21 2024, Marc Kleine-Budde wrote: > > > On 21.02.2024 14:16:54, Matias Ezequiel Vara Larsen wrote: > >> On Wed, Feb 21, 2024 at 01:49:31PM +0100, Marc Kleine-Budde wrote: > >> > On 21.02.2024 11:37:58, Matias Ezequiel Vara Larsen wrote: > >> > > > > +The length of the \field{sdu} is determined by the \field{length}. > >> > > > > + > >> > > > > +The type of a CAN message identifier is determined by \field{flags}. The > >> > > > > +3 most significant bits of \field{can_id} do not bear the information > >> > > > > +about the type of the CAN message identifier and are 0. > >> > > > > + > >> > > > > +The device MUST reject any CAN frame type for which support has not been > >> > > > > +negotiated with VIRTIO_CAN_RESULT_NOT_OK in \field{result} and MUST NOT > >> > > > > +schedule the message for transmission. A CAN frame with an undefined bit > >> > > > > +set in \field{flags} is treated like a CAN frame for which support has > >> > > > > +not been negotiated. > >> > > > > + > >> > > > > +The device MUST reject any CAN frame for which \field{can_id} or > >> > > > > +\field{sdu} length are out of range or the CAN controller is in an > >> > > > > +invalid state with VIRTIO_CAN_RESULT_NOT_OK in \field{result} and MUST > >> > > > > +NOT schedule the message for transmission. > >> > > > > + > >> > > I am not very familiar with CAN but how does the device figure out that > >> > > the can_id is out of range? > >> > > >> > In classical CAN we have the standard CAN frames, which have an 11 bit > >> > ID, and there are extended CAN frames, which have 29 bits ID. Extended > >> > frames are signaled with VIRTIO_CAN_FLAGS_EXTENDED set. > >> > > >> > So if a standard frame uses more than 11 Bits of CAN-ID, it's considered > >> > out of range. > > > > Another option would be an extended frame (VIRTIO_CAN_FLAGS_EXTENDED > > set) and using more than 29 bits. > > > >> Thanks Marc for the explanation. Do you think that it would be > >> worthwhile to add that to the spec at some point? > > > > Yes that makes sense as it clarifies what's meant by out of range for > > CAN-IDs, for the valid length a reference to > > \item[VIRTIO_CAN_F_CAN_CLASSIC (0)] and \item[VIRTIO_CAN_F_CAN_FD (1)] > > might be added. > > [virtio mailing lists are supposedly down for migration right now, I > hope there's some kind of backfill happening later...] > > If the question comes up, it does make sense to add a > clarification... as the virtio-can spec is already voted upon and > merged, we'd need a patch on top. Not sure if it would qualify as an > editorial update or a vote would be needed, best to see it first :) > I will submit two patches regarding the changes proposed in this thread. Matias --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org