Re: [PATCH] soc: ti: pm33xx: Enable DS0 for the platforms on which it is functional

[J, KEERTHY]

On 8/22/2018 1:07 PM, Johan Hovold wrote:
> On Wed, Aug 22, 2018 at 09:34:09AM +0200, Johan Hovold wrote:
> > On Wed, Aug 22, 2018 at 11:02:31AM +0530, Keerthy wrote:
> > > Enable DS0 for only those platforms on which it is functional
> > >
> > > Signed-off-by: Keerthy <j-keerthy@xxxxxx>
> > > ---
> > >   arch/arm/mach-omap2/pm33xx-core.c    | 5 +++++
> > >   drivers/soc/ti/pm33xx.c              | 9 +++++++++
> > >   include/linux/platform_data/pm33xx.h | 2 ++
> > >   3 files changed, 16 insertions(+)
> > >
> > > diff --git a/arch/arm/mach-omap2/pm33xx-core.c b/arch/arm/mach-omap2/pm33xx-core.c
> > > index f4971e4..f0f6e8e 100644
> > > --- a/arch/arm/mach-omap2/pm33xx-core.c
> > > +++ b/arch/arm/mach-omap2/pm33xx-core.c
> > > @@ -135,6 +135,11 @@ static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
> > >   {
> > >   	int ret = 0;
> > >   
> > > +	if (!(args & WFI_FLAG_DEEP_SLEEP0)) {
> > > +		pr_err("DS0 mode not supported\n");
> > > +		return -ENOTSUPP;
> > > +	}
> > > +
> > >   	amx3_pre_suspend_common();
> > >   	scu_power_mode(scu_base, SCU_PM_POWEROFF);
> > >   	ret = cpu_suspend(args, fn);
> > > diff --git a/drivers/soc/ti/pm33xx.c b/drivers/soc/ti/pm33xx.c
> > > index d0dab32..53238d7 100644
> > > --- a/drivers/soc/ti/pm33xx.c
> > > +++ b/drivers/soc/ti/pm33xx.c
> > > @@ -324,6 +324,15 @@ static int am33xx_pm_probe(struct platform_device *pdev)
> > >   	suspend_wfi_flags |= WFI_FLAG_SAVE_EMIF;
> > >   	suspend_wfi_flags |= WFI_FLAG_WAKE_M3;
> > >   
> > > +	/*
> > > +	 * Deep Sleep0 mode is currently functional only on am437x-gp-evm,
> > > +	 * am33xx-evm and boneblack family. Hence set the DS0 flag
> > > +	 */
> > > +	if (of_machine_is_compatible("ti,am437x-gp-evm") ||
> > > +	    of_machine_is_compatible("ti,am335x-bone-black") ||
> > > +	    of_machine_is_compatible("ti,am335x-evm"))
> > > +		suspend_wfi_flags |= WFI_FLAG_DEEP_SLEEP0;
> >
> > What about other (out-of-tree) machines which supports DS0 and which
> > this change would break?
> >
> > I think this needs to be a blacklist if anything.
> >
> > Please also expand in the commit message why you think this is needed.

Currently when one does echo mem > /sys/power/state on unsuppored 
machines there can be a crash or a hang. So bail out with a message.

> > Last, what tree is this against? There's no am43xx_suspend() in
> > linux-next (and you add compatibles above for am33xx too).
>
> Sorry, there is indeed an am43xx_suspend(), but you are adding
> compatibles for am33xx which use am33xx_suspend().

am33xx_pm_probe is a common probe function for both am33 and am43.
AFAIK for am33 family am335x-evm and am335x-bone-black support Deep 
Sleep mode. For am43 family am43tx-gp-evm alone supports at the moment.

Can you let me know of other am33 machines that support DS0 mode?
I could have simply used ti,am33xx compatible which covers entire am33 
family but then am33xx-bone (bone white) does not support this mode.

> Johan