[PATCH] soc: imx: gpcv2: Assert reset before ungating clock

[Marek Vasut]

On 7/17/21 1:32 AM, Lucas Stach wrote:
> Hi Marek,

Hi,

> Am Donnerstag, dem 01.07.2021 um 00:59 +0200 schrieb Marek Vasut:
>> In case the power domain clock are ungated before the reset is asserted,
>> the system might freeze completely. However, the MX8MM GPUMIX and VPUMIX
>> domains require different reset deassertion timing, and incorrect reset
>> deassertion timing also leads to hang.
>>
>> Add per-domain reset_{,de}assert_early flags which allow fine-grained
>> control of the reset assertion and deassertion sequence. Currently, on
>> MX8MM, the behavior is as follows and aligned with NXP downstream ATF
>> fork:
>> - VPUMIX: reset assert, reset deassert, domain power up
>> - GPUMIX: reset assert, domain power on, reset deassert
>>
> This patch should now be necessary, as my testing over the last few
> days showed that the VPUMIX isn't actually different and copes just
> fine with the reset being asserted early, just like the GPUMIX domain.

Yes, this patch is absolutely essential, otherwise the system hangs at 
random, as explained in the commit message.