From: Jie Deng <jie.deng@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-i2c@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, mst@redhat.com,
jasowang@redhat.com, wsa+renesas@sang-engineering.com,
wsa@kernel.org, andriy.shevchenko@linux.intel.com,
jarkko.nikula@linux.intel.com, jdelvare@suse.de,
Sergey.Semin@baikalelectronics.ru, krzk@kernel.org,
rppt@kernel.org, loic.poulain@linaro.org, tali.perry1@gmail.com,
bjorn.andersson@linaro.org, shuo.a.liu@intel.com,
conghui.chen@intel.com, yu1.wang@intel.com,
"Alex Bennée" <alex.bennee@linaro.org>,
"Vincent Guittot" <vincent.guittot@linaro.org>
Subject: Re: [PATCH v4] i2c: virtio: add a virtio i2c frontend driver
Date: Fri, 26 Feb 2021 10:46:03 +0800 [thread overview]
Message-ID: <a580de35-787e-4024-3c80-0a101b1a6d3b@intel.com> (raw)
In-Reply-To: <20210225072114.iwmtaexl3dkihlba@vireshk-i7>
On 2021/2/25 15:21, Viresh Kumar wrote:
> On 12-10-20, 09:55, Jie Deng wrote:
>> Add an I2C bus driver for virtio para-virtualization.
>>
>> The controller can be emulated by the backend driver in
>> any device model software by following the virtio protocol.
>>
>> This driver communicates with the backend driver through a
>> virtio I2C message structure which includes following parts:
>>
>> - Header: i2c_msg addr, flags, len.
>> - Data buffer: the pointer to the I2C msg data.
>> - Status: the processing result from the backend.
>>
>> People may implement different backend drivers to emulate
>> different controllers according to their needs. A backend
>> example can be found in the device model of the open source
>> project ACRN. For more information, please refer to
>> https://projectacrn.org.
>> diff --git a/include/uapi/linux/virtio_i2c.h b/include/uapi/linux/virtio_i2c.h
>> new file mode 100644
>> index 0000000..7413e45
>> --- /dev/null
>> +++ b/include/uapi/linux/virtio_i2c.h
>> @@ -0,0 +1,31 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause */
>> +/*
>> + * Definitions for virtio I2C Adpter
>> + *
>> + * Copyright (c) 2020 Intel Corporation. All rights reserved.
>> + */
>> +
>> +#ifndef _UAPI_LINUX_VIRTIO_I2C_H
>> +#define _UAPI_LINUX_VIRTIO_I2C_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/virtio_ids.h>
>> +#include <linux/virtio_config.h>
>> +
>> +/**
>> + * struct virtio_i2c_hdr - the virtio I2C message header structure
>> + * @addr: i2c_msg addr, the slave address
>> + * @flags: i2c_msg flags
>> + * @len: i2c_msg len
>> + */
>> +struct virtio_i2c_hdr {
>> + __le16 addr;
>> + __le16 flags;
>> + __le16 len;
>> +};
> Hi Jie,
>
> I am a bit confused about the header and the format in which data is being
> processed here. When I look at the specification present here:
>
> https://lists.oasis-open.org/archives/virtio-comment/202009/msg00021.html
>
> it talks about
>
> struct virtio_i2c_out_hdr {
> le16 addr;
> le16 padding;
> le32 flags;
> };
> struct virtio_i2c_in_hdr {
> u8 status;
> };
>
> struct virtio_i2c_req {
> struct virtio_i2c_out_hdr out_hdr;
> u8 write_buf [];
> u8 read_buf [];
> struct virtio_i2c_in_hdr in_hdr;
> };
>
> while what we have above is completely different. What am I missing ?
This v4 was the old version before the specification was acked by the
virtio tc.
Following is the latest specification.
https://raw.githubusercontent.com/oasis-tcs/virtio-spec/master/virtio-i2c.tex
I will send the v5 since the host/guest ABI changes.
Thanks.
next prev parent reply other threads:[~2021-02-26 2:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-12 1:55 [PATCH v4] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2020-10-12 5:45 ` kernel test robot
2020-11-25 9:35 ` Michael S. Tsirkin
2020-11-26 2:00 ` Jie Deng
2021-02-25 7:21 ` Viresh Kumar
2021-02-26 2:46 ` Jie Deng [this message]
2021-02-26 4:21 ` Viresh Kumar
2021-02-26 6:36 ` Jie Deng
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