From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-comment-return-1473-cohuck=redhat.com@lists.oasis-open.org Sender: 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 B34E2986009 for ; Tue, 27 Oct 2020 11:20:56 +0000 (UTC) Date: Tue, 27 Oct 2020 07:20:24 -0400 From: "Michael S. Tsirkin" Message-ID: <20201027071957-mutt-send-email-mst@kernel.org> References: <61930337391bdfd23ed164288d998c04177bc839.1603435652.git.jie.deng@intel.com> <20201023115932-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: Subject: [virtio-comment] Re: [virtio-dev] Re: [PATCH v2] virtio-i2c: add the device specification Content-Type: text/plain; charset=us-ascii Content-Disposition: inline To: Jie Deng Cc: virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org List-ID: On Mon, Oct 26, 2020 at 09:22:07AM +0800, Jie Deng wrote: > On 2020/10/24 0:00, Michael S. Tsirkin wrote: > > > On Fri, Oct 23, 2020 at 02:51:25PM +0800, Jie Deng wrote: > > > + > > > +The driver queues requests to the virtqueues, and they are used by the > > > +device. The request is the representation of one segment of an I2C > > > +transaction. Each request is of form: > > > + > > > +\begin{lstlisting} > > > +struct virtio_i2c_req { > > > + le16 addr; > > > + le16 flags; > > > + le16 len; > > > + u8 buf[]; > > > + u8 status; > > > +}; > > > +\end{lstlisting} > > > + > > > +The \field{addr} is the address of the I2C slave device. > > > + > > > +The first bit of \field{flags} indicates whether it is a read or write request. > > > +It means a read request if the first bit of \field{flags} is set, otherwise > > > +it is a write request. The rest bits of \field{flags} are reserved. > > > > > > > So how does one creates a multi-segment transaction then? > > > The I2C doesn't support segments numbering and sorting. > So if one creates a multi-segment transaction, then he/she should keep the > segments in order. > > Thanks. Fine, but I see no flags to signal start/end of such a transaction. > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org > > This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. Subscribe: virtio-comment-subscribe@lists.oasis-open.org Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org List help: virtio-comment-help@lists.oasis-open.org List archive: https://lists.oasis-open.org/archives/virtio-comment/ Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists Committee: https://www.oasis-open.org/committees/virtio/ Join OASIS: https://www.oasis-open.org/join/