Re: [PATCH i2c-next v6] i2c: aspeed: Handle master/slave combined irq events properly

From: CÃdric Le Goater
Date: Thu Sep 13 2018 - 12:51:39 EST


On 09/13/2018 05:57 PM, Guenter Roeck wrote:
> On Thu, Sep 13, 2018 at 05:48:59PM +0200, CÃdric Le Goater wrote:
>> On 09/13/2018 03:33 PM, Guenter Roeck wrote:
> [ ... ]
>>>>> Â /*
>>>>> ÂÂ * The state machine needs some refinement. It is only used to track
>>>>> ÂÂ * invalid STOP commands for the moment.
>>>>> @@ -188,7 +215,7 @@ static void aspeed_i2c_bus_handle_cmd(AspeedI2CBus *bus, uint64_t value)
>>>>> Â {
>>>>> ÂÂÂÂÂ bus->cmd &= ~0xFFFF;
>>>>> ÂÂÂÂÂ bus->cmd |= value & 0xFFFF;
>>>>> -ÂÂÂ bus->intr_status = 0;> +ÂÂÂ bus->intr_status &= I2CD_INTR_RX_DONE;
>>>>
>>>> it deserves a comment to understand which scenario we are trying to handle.
>>>> ÂÂ
>>>
>>> Ok. FWIW, I wonder if intr_status should be touched here in the first place,
>>> but I neither have the hardware nor a datasheet, so I don't know if any bits
>>> are auto-cleared.
>>
>> I just pushed a patch on my branch with some more explanation :
>>
>> https://github.com/legoater/qemu/commits/aspeed-3.1
>>
> That seems to suggest that none of the status bits auto-clears, and that
> the above code clearing intr_status should be removed entirely.
> Am I missing something ?

You are right. I just pushed another version of the previous patch with this
new hunk :

@@ -188,7 +200,6 @@ static void aspeed_i2c_bus_handle_cmd(As
{
bus->cmd &= ~0xFFFF;
bus->cmd |= value & 0xFFFF;
- bus->intr_status = 0;

if (bus->cmd & I2CD_M_START_CMD) {
uint8_t state = aspeed_i2c_get_state(bus) & I2CD_MACTIVE ?


The QEMU palmetto and witherspoon machines seem to behave fine. Can you give
it a try ?

Thanks,

C.