Messages in this thread | | | Date | Tue, 4 Aug 2020 17:56:36 +0200 | From | Alexandre Belloni <> | Subject | Re: [PATCH v2 2/3] ARM: at91: pm: add per soc validation of pm modes |
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On 04/08/2020 15:45:40+0000, Claudiu.Beznea@microchip.com wrote: > > > On 04.08.2020 18:08, Alexandre Belloni wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > > > On 04/08/2020 15:00:38+0000, Claudiu.Beznea@microchip.com wrote: > >> > >> > >> On 04.08.2020 14:42, Alexandre Belloni wrote: > >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > >>> > >>> Hello, > >>> > >>> On 04/08/2020 14:07:37+0300, Claudiu Beznea wrote: > >>>> void __init at91rm9200_pm_init(void) > >>>> { > >>>> + static const int modes[] __initconst = { > >>> > >>> You don't need that to be static as it is now local to the function. > >>> > >>>> + AT91_PM_STANDBY, AT91_PM_ULP0 > >>>> + }; > >>>> + > >>>> if (!IS_ENABLED(CONFIG_SOC_AT91RM9200)) > >>>> return; > >>>> > >>>> + at91_pm_modes_validate(modes, ARRAY_SIZE(modes)); > >>> > >>> For rm9200 and at91sam9, I would not allow changing the pm_modes and > >>> simply enforce standby_mode = AT91_PM_STANDBY and suspend_mode = > >>> AT91_PM_ULP0.I don't think you have any user that ever changed that > >>> behaviour also that avoids increasing the boot time for those slow SoCs. > >> > >> OK, but bootargs is parsed at a moment when there is no information about > >> the machine that is running the code. And enforcing this in *_pm_init() > >> functions for rm9200 and at91sam9 may change suspend and standby mode that > >> user selected. If there is no user up to this moment there is still the > >> possibility of being one in the future. > >> > > > > So let's prevent users from doing that. Unused arguments are silently > > ignored which is exactly what we want to do. > > Can you share what are you thinking about? You want to not parse > atmel.pm_modes for this machines? >
Well, as you said, when parsing we don't know on which machine we are running so let's keep parsing it anyway.
> > You won't make me believe > > there is actually a use case for swapping the standby and suspend > > meanings. > What i want to say is this: > bootargs contains atmel.pm_modes=ulp0,standby > > this leads to > standby_mode=ulp0 > suspend_mode=standby > > But you want in code to force > standby_mode=standby > suspend_mode=ulp0 > > The question is: is this what you are thinking this should be done? >
Yes, I think we need to enforce standby_mode=standby and suspend_mode=ulp0 for rm9200 and at91sam9. This is how it always have been.
You have two ways of doing that:
Etiher you enforce the values after parsing, in at91rm9200_pm_init and at91sam9_pm_init. Or, when parsing your store the values in a different location than soc_pm.data and update soc_pm.data only in sama5_pm_init, sama5d2_pm_init and sam9x60_pm_init. I feel like the first solution is easier.
-- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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