Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 2 Mar 2021 09:52:33 +0530
From:   Viresh Kumar <viresh.kumar@linaro.org>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Jie Deng <jie.deng@intel.com>,
        Linux I2C <linux-i2c@vger.kernel.org>,
        virtualization@lists.linux-foundation.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Wolfram Sang <wsa@kernel.org>,
        Jason Wang <jasowang@redhat.com>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        conghui.chen@intel.com, kblaiech@mellanox.com,
        jarkko.nikula@linux.intel.com,
        Sergey Semin <Sergey.Semin@baikalelectronics.ru>,
        Mike Rapoport <rppt@kernel.org>, loic.poulain@linaro.org,
        Tali Perry <tali.perry1@gmail.com>,
        Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= 
        <u.kleine-koenig@pengutronix.de>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        yu1.wang@intel.com, shuo.a.liu@intel.com
Subject: Re: [PATCH v5] i2c: virtio: add a virtio i2c frontend driver
Message-ID: <20210302042233.7ppagwjk3rah3uh3@vireshk-i7>
References: <00f826ffe1b6b4f5fb41de2b55ad6b8783b7ff45.1614579846.git.jie.deng@intel.com>
 <CAK8P3a1ZXbodV07TTErnQunCLWOBnzRiVdLCxBD743fn-6FbXg@mail.gmail.com>
 <20210302040114.rg6bb32g2bsivsgf@vireshk-i7>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210302040114.rg6bb32g2bsivsgf@vireshk-i7>
User-Agent: NeoMutt/20180716-391-311a52
Precedence: bulk

On 02-03-21, 09:31, Viresh Kumar wrote:
> On 01-03-21, 16:19, Arnd Bergmann wrote:
> > On Mon, Mar 1, 2021 at 7:41 AM Jie Deng <jie.deng@intel.com> wrote:
> > 
> > > --- /dev/null
> > > +++ b/include/uapi/linux/virtio_i2c.h
> > > @@ -0,0 +1,56 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-or-later WITH Linux-syscall-note */
> > > +/*
> > > + * Definitions for virtio I2C Adpter
> > > + *
> > > + * Copyright (c) 2021 Intel Corporation. All rights reserved.
> > > + */
> > > +
> > > +#ifndef _UAPI_LINUX_VIRTIO_I2C_H
> > > +#define _UAPI_LINUX_VIRTIO_I2C_H
> > 
> > Why is this a uapi header? Can't this all be moved into the driver
> > itself?
> > 
> > > +/**
> > > + * struct virtio_i2c_req - the virtio I2C request structure
> > > + * @out_hdr: the OUT header of the virtio I2C message
> > > + * @write_buf: contains one I2C segment being written to the device
> > > + * @read_buf: contains one I2C segment being read from the device
> > > + * @in_hdr: the IN header of the virtio I2C message
> > > + */
> > > +struct virtio_i2c_req {
> > > +       struct virtio_i2c_out_hdr out_hdr;
> > > +       u8 *write_buf;
> > > +       u8 *read_buf;
> > > +       struct virtio_i2c_in_hdr in_hdr;
> > > +};
> > 
> > In particular, this structure looks like it is only ever usable between
> > the transfer functions in the driver itself, it is shared with neither
> > user space nor the virtio host side.
> 
> Why is it so ? Won't you expect hypervisors or userspace apps to use
> these ?

This comment applies only for the first two structures as the third
one is never exchanged over virtio.

-- 
viresh