[virtio-comment] Re: [virtio-dev] Re: [PATCH v2] virtio-i2c: add the device specification

[Jie Deng <jie.deng@intel.com>]

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.

>
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