Re: [Qemu-ppc] [Qemu-devel] [PATCH 1/4] ppc4xx_i2c: Rewrite PPC4xx I2C emulation

[Philippe Mathieu-Daudé]

Hi Zoltan,

On 06/06/2018 11:03 AM, BALATON Zoltan wrote:
> On Wed, 6 Jun 2018, David Gibson wrote:
>> On Mon, Jun 04, 2018 at 01:50:40AM +0200, BALATON Zoltan wrote:
>>> I2C emulation currently is just enough for U-Boot to access SPD
>>> EEPROMs but features that guests use to access I2C devices are not
>>> correctly emulated. Rewrite to implement missing features to make it
>>> work with all clients.
>>>
>>> Signed-off-by: BALATON Zoltan <address@hidden>
>>> ---
>>> Maybe this could be split up into more patches but because the
>>> previous implementation was wrong only allowing U-Boot to pass and no
>>> clients could access I2C devices before this rewrite it probably does
>>> not worth to try to make it a lot of small changes instead of dropping
>>> the previous hack and rewrite following features of real hardware more
>>> closely. (It turns out that each client driver accesses I2C in a
>>> different way so we need to implement almost all features of the
>>> hardware to please everyone.)
>>
>> The trouble is that because I don't really have a good test setup for
>> this, I'm pretty reluctant to apply such a total rewrite without acks
>> from more people who've tested it.  That or reviewing the changes
>> myself, which I can't really do when it's in one big lump like this.
> 
> OK, I've sent a v2 where this patch is split up to smaller pieces that
> are hopefully easier to review. However this i2c emulation was only a
> stub originally which was hacked together to make U-Boot happy when
> added the sam460ex machine and this is the first version that attempts
> to really model the device so that guests can also use it. Therefore I
> think there's not a high chance of breaking anything important. I've
> tested this with AROS, Linux, AmigaOS and MorphOS and they seem to be
> able to read the RTC so it should work better than the previous version.

Are those images publicly accessible? (thinking about adding acceptance
qtests).

> (Only AROS boots fully on sam460ex of these yet, others still need some
> more work.)