[PATCH dev-5.2 0/2] i2c: aspeed: Add H/W timeout support

[Jae Hyun Yoo]

Hi Andrew,

On 9/4/2019 5:54 PM, Jae Hyun Yoo wrote:
> On 9/4/2019 5:10 PM, Andrew Jeffery wrote:
>>
>>
>> On Thu, 5 Sep 2019, at 09:10, Jae Hyun Yoo wrote:
>>> Hi Andrew,
>>>
>>> On 9/4/2019 4:12 PM, Andrew Jeffery wrote:
>>>> On Thu, 5 Sep 2019, at 08:31, Jae Hyun Yoo wrote:
>>>>> Hi Joel,
>>>>>
>>>>> On 9/4/2019 3:54 PM, Joel Stanley wrote:
>>>>>> Hi Jae,
>>>>>>
>>>>>> On Wed, 4 Sep 2019 at 20:08, Jae Hyun Yoo 
>>>>>> <jae.hyun.yoo at linux.intel.com> wrote:
>>>>>>>
>>>>>>> In case of multi-master environment, if a peer master incorrectly 
>>>>>>> handles
>>>>>>> a bus in the middle of a transaction, I2C hardware hangs in slave 
>>>>>>> state
>>>>>>> and it can't escape from the slave state, so this commit adds slave
>>>>>>> inactive timeout support to recover the bus in the case.
>>>>>>>
>>>>>>> By applying this change, SDA data-low and SCL clock-low timeout 
>>>>>>> feature
>>>>>>> also could be enabled which was disabled previously.
>>>>>>
>>>>>> Please consider sending your RFC patches to the upstream list. You
>>>>>> have a big backlog of patches now.
>>>>>
>>>>> Thanks for the reminding. I can't send the RFC patches yet because 
>>>>> QEMU
>>>>> H/W model isn't ready yet. I'm still waiting for the fix from Cedric.
>>>>
>>>> QEMU shouldn't be preventing you from sending patches upstream, rather
>>>> it prevents us from enabling the buffer mode support in the OpenBMC
>>>> kernel tree. You should be sending all patches upstream as early as 
>>>> possible.
>>>
>>> I met a QEMU issue when I was upstreaming a patch set last year:
>>> https://lists.ozlabs.org/pipermail/linux-aspeed/2018-September/000750.html 
>>>
>>>
>>> If OpenBMC community accepts the QEMU issue, I can submit the RFC
>>> patches to upstream. Will submit the patch set soon to linux tree.
>>
>> Ah, didn't realise it was Guenter that ran into it. We have some 
>> changes[1] in
>> Cedric's aspeed-4.2 qemu tree - do you mind testing it out? If those 
>> patches
>> resolve the issue Maybe we could point Guenter at that tree, though 
>> really we
>> should get the fixes upstream so this isn't an issue.
>>
>> [1] 
>> https://github.com/legoater/qemu/compare/59dda66ab756e52e6a9c1ef89660d30b3769f63c...aspeed-4.2 
>>
>>
> 
> Okay. I'll give it a try.

I've tested I2C buffer mode support in QEMU using:
git://github.com/legoater/qemu.git
SRCBRANCH = "aspeed-4.2"
SRCREV = "1b31d645c448858eb7d11d463a4cb77df0ee7923"

Checked that I2C buffer mode works on the latest QEMU H/W model.
Thanks Cedric, Eddie for the H/W model implementation.

I'll submit all I2C backlog patches into linux upstream.

Cheers,
Jae