From: Viresh Kumar <viresh.kumar@linaro.org>
To: Jie Deng <jie.deng@intel.com>
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: Thu, 25 Feb 2021 12:51:14 +0530 [thread overview]
Message-ID: <20210225072114.iwmtaexl3dkihlba@vireshk-i7> (raw)
In-Reply-To: <7c5e44c534b3fd07b855af22d8d4b78bc44cd7a4.1602465440.git.jie.deng@intel.com>
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 ?
--
viresh
next prev parent reply other threads:[~2021-02-25 7:21 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 [this message]
2021-02-26 2:46 ` Jie Deng
2021-02-26 4:21 ` Viresh Kumar
2021-02-26 6:36 ` Jie Deng
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