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
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.
On 26-02-21, 10:46, Jie Deng wrote:
> 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.
Okay, now it makes some sense :)
I am interested in this stuff, if possible please keep me Cc'd for following
versions, thanks.
--
viresh
On 2021/2/26 12:21, Viresh Kumar wrote:
> On 26-02-21, 10:46, Jie Deng wrote:
>> 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.
> Okay, now it makes some sense :)
>
> I am interested in this stuff, if possible please keep me Cc'd for following
> versions, thanks.
Sure. I will add you to the Cc list.