Re: RFC: Proper suspend-to-ram implementation of Ingenic SoCs

[Paul Cercueil <paul@crapouillou.net>]

Hi Zhou,

Le jeu., juil. 14 2022 at 00:13:22 +0800, Zhou Yanjie 
<zhouyanjie@wanyeetech.com> a écrit :
> Hi Paul,
> 
> On 2022/7/14 上午12:08, Paul Cercueil wrote:
>> Hi Mike,
>> [...]
>> 
>>> If I comment the "wait" instruction, it will exit the suspend 
>>> process \x7f\x7fimmediately. And yes, I don't think it suspended properly.
>> 
>> Ok. I was suggesting to try that since it would show if the crash 
>> \x7fhappens when a particular device gets suspended.
>> 
>> Are you certain that your wakeup IRQ is unmasked?
>> 
>> [...]
>> 
>>>>>>  I'm afraid the above didn't work for me. Have you tested 
>>>>>> \x7f\x7f\x7f\x7f\x7fsuspend-to-ram in person on a X series SoC?
>>>> 
>>>>  I didn't test on X-series, I mostly work with JZ. But that part 
>>>> of \x7f\x7f\x7fthe design didn't change since the JZ4740.
>>>> 
>>>>  Cheers,
>>>>  -Paul
>>>> 
>>>> 
>>> 
>>> 
>>> To be honest, I never owned a board with a JZ series SoC. And sorry 
>>> \x7f\x7ffor assuming the suspend-to-ram is unusable on all Ingenic SoCs. 
>>> \x7f\x7fIIRC, all the JZ series SoCs have external DRAM, while the X 
>>> series \x7f\x7fSoCs have internal DRAM. Also Ingenic advertised the power 
>>> saving \x7f\x7ffeatures of the X series SoCs heavily. Things might be 
>>> different \x7f\x7fsince it may involve additional power management.
>> 
>> Even if the 3.x method you were describing works, the currently 
>> \x7fupstream method should work as well, and if it doesn't, we probably 
>> \x7fshould try to figure why.
>> 
>> I remember doing some tests on the JZ4770 some years ago, and I 
>> would \x7fget a power consumption of 7mA when suspended - that's for 
>> the whole \x7fboard, measured at the 3.7V battery, so about 0.026 W. 
>> The only things \x7fpowered ON then are the RAM chips and the SoC's RTC 
>> module.
>> 
>>> At the time of writing the last sentence of the email, Dr. Zhou 
>>> just \x7f\x7fpointed out that it may has something to do with the secure 
>>> boot \x7f\x7ffeature introduced in the X series SoC, although the feature 
>>> is not \x7f\x7fenabled. I already mailed my X1000E & X1501 boards to Dr. 
>>> Zhou for \x7f\x7ffurther tests. You may want to get a X1000(E) board 
>>> (e.g. halley2) \x7f\x7fand test this by yourself.
>> 
>> I do have a Cu1000-Neo board, but I have never used it, I wouldn't 
>> \x7fknow how to test this.
>> 
> 
> The CU1000-Neo board does not lead out the wakeup pins, maybe it can 
> be tested with GKD350 (X1830)?

Well any GPIO can act as a wakeup pin, really. "The" wakeup pin is 
actually masked during suspend unless you specify it as wakeup-enable.
See: 
https://github.com/torvalds/linux/blob/master/arch/mips/boot/dts/ingenic/gcw0.dts#L231

Cheers,
-Paul