Re: [Xen-devel] [RFC PATCH 22/31] xen/arm: Add Xen changes to SCPI protocol

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

Hi Julien, Stefano

On Tue, Dec 5, 2017 at 11:41 PM, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
>
>
> On 05/12/2017 21:20, Stefano Stabellini wrote:
>>
>> On Thu, 9 Nov 2017, Oleksandr Tyshchenko wrote:
>>>
>>> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>>>
>>> Modify the direct ported SCPI Message Protocol driver to be
>>> functional inside Xen.
>>>
>>> As SCPI Message protocol driver expects mailbox to be registed,
>>> find and initialize mailbox before probing it.
>>>
>>> Include "wrappers.h" which contains all required things the direct
>>> ported code relies on.
>>>
>>> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>>> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>>> CC: Julien Grall <julien.grall@xxxxxxxxxx>
>>
>>
>> As far as drivers ported from Linux go, this looks pretty clean in terms
>> of changes and nasty glue code required to get it to work.
>>
>> The wrappers.h header is not too bad. The question remains on whether we
>> should keep the #if 0 to retain "textual compatibility" with Linux, or
>> we should just bite the bullet and apply the changes. If we commit them
>> as a separate patch, we can always dig out the difference between the
>> original driver and the Xen version using git.
>>
>> Julien, what do you think?
>
>
> When I see the diff of that series:
>
>  50 files changed, 4822 insertions(+), 862 deletions(-)
>
> this is a rather huge series for benefits that we still don't know (e.g we
> don't have any numbers). Based on the current discussion, it looks like the
> design will change quite a lot. So in entire honesty, I haven't spent and
> will not spend much times look at the code itself until we get an agreement
> on the benefits.
>
> However I had a brief look at the code and I raised quiet a few time the
> eyebrow at the glue code. I saw that mutex was converted spinlock without
> any justification (see patch #20).
>
> Anyway, Oleksandr promised to come back with numbers and investigating the
> discussion. We should probably wait that before looking at this series in
> more details.
Yes, I am working on getting numbers. We will resume discussion when I
provide them.

>
> Cheers,
>
> --
> Julien Grall



-- 
Regards,

Oleksandr Tyshchenko

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