[virtio-comment] Clarifying the language of VIRTIO_RPMB_REQ_PROGRAM_KEY

[virtio-comment] Clarifying the language of VIRTIO_RPMB_REQ_PROGRAM_KEY

[Alex Bennée]

Hi,

In the virtio-rpmb part of the spec it says:

  The operation of a virtio RPMB device is driven by the requests placed on the virtqueue.
    The type of request can be program key (VIRTIO_RPMB_REQ_PROGRAM_KEY),
    get write counter (VIRTIO_RPMB_REQ_GET_WRITE_COUNTER),
    write (VIRTIO_RPMB_REQ_DATA_WRITE), and read (VIRTIO_RPMB_REQ_DATA_READ).
    A program key or write request can also combine with a
    result read (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result.

but later on:

  VIRTIO_RPMB_REQ_RESULT_READ
     requests for a returned result. It is used following with VIRTIO_RPMB_REQ_PROGRAM_KEY or VIRTIO_RPMB_REQ_DATA_WRITE request types for a returned result in one or multiple RPMB frames. If it’s not requested, the device will not return result frame to the driver.

So which is it? I can't quite see how a VIRTIO_RPMB_REQ_RESULT_READ can
be combined with the other requests because they are not overlapping
bits so maybe the working should be:

  A program key or write request can be followed by a result read (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result.

Is that is what is intended?

-- 
Alex Bennée

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[virtio-comment] RE: Clarifying the language of VIRTIO_RPMB_REQ_PROGRAM_KEY

[Huang, Yang]

>   A program key or write request can be followed by a result read
> (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result.
> 
> Is that is what is intended?

Yes.

RPMB Read/Get Write Counter implicitly requests for a result, so that VIRTIO_RPMB_REQ_RESULT_READ is not required.
Actually, it's aligned with the JEDEC spec.


> -----Original Message-----
> From: Alex Bennée <alex.bennee@linaro.org>
> Sent: Friday, June 12, 2020 11:41 PM
> To: virtio-comment@lists.oasis-open.org
> Cc: Huang, Yang <yang.huang@intel.com>; Zhu, Bing <bing.zhu@intel.com>;
> Winkler, Tomas <tomas.winkler@intel.com>
> Subject: Clarifying the language of VIRTIO_RPMB_REQ_PROGRAM_KEY
> 
> 
> Hi,
> 
> In the virtio-rpmb part of the spec it says:
> 
>   The operation of a virtio RPMB device is driven by the requests placed on the
> virtqueue.
>     The type of request can be program key (VIRTIO_RPMB_REQ_PROGRAM_KEY),
>     get write counter (VIRTIO_RPMB_REQ_GET_WRITE_COUNTER),
>     write (VIRTIO_RPMB_REQ_DATA_WRITE), and read
> (VIRTIO_RPMB_REQ_DATA_READ).
>     A program key or write request can also combine with a
>     result read (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result.
> 
> but later on:
> 
>   VIRTIO_RPMB_REQ_RESULT_READ
>      requests for a returned result. It is used following with
> VIRTIO_RPMB_REQ_PROGRAM_KEY or VIRTIO_RPMB_REQ_DATA_WRITE
> request types for a returned result in one or multiple RPMB frames. If it’s not
> requested, the device will not return result frame to the driver.
> 
> So which is it? I can't quite see how a VIRTIO_RPMB_REQ_RESULT_READ can be
> combined with the other requests because they are not overlapping bits so
> maybe the working should be:
> 
>   A program key or write request can be followed by a result read
> (VIRTIO_RPMB_REQ_RESULT_READ) for a returned result.
> 
> Is that is what is intended?
> 
> --
> Alex Bennée