[PATCH V4 4/9] ARM: tegra: pm: add platform suspend support
Joseph Lo
josephl at nvidia.com
Wed Mar 20 06:26:39 EDT 2013
On Wed, 2013-03-20 at 01:07 +0800, Stephen Warren wrote:
> On 03/18/2013 02:13 AM, Joseph Lo wrote:
> > Adding suspend to RAM support for Tegra platform. There are three suspend
> > mode for Tegra. The difference were below.
> >
> > * LP2: CPU voltage off
> > * LP1: CPU voltage off, DRAM in self-refresh
> > * LP0: CPU + Core voltage off, DRAM in self-refresh
> >
> > After this patch, the LP2 suspend mode will be supported.
>
> > diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
> > index c84505c..024f355 100644
> > --- a/arch/arm/mach-tegra/common.c
> > +++ b/arch/arm/mach-tegra/common.c
> > @@ -66,6 +66,7 @@ void __init tegra_dt_init_irq(void)
> > tegra_init_irq();
> > irqchip_init();
> > tegra_legacy_irq_syscore_init();
> > + tegra_init_suspend();
>
> Does that have to be part of tegra_dt_init_irq()? Can't we initialize
> suspend support in some later hook. init_irq() should just initialize IRQs.
>
I can re-check the sequence later.
> > diff --git a/arch/arm/mach-tegra/pmc.c b/arch/arm/mach-tegra/pmc.c
>
> > -void set_power_timers(unsigned long us_on, unsigned long us_off)
> > +static void set_power_timers(u32 us_on, u32 us_off, unsigned long rate)
> > {
> > unsigned long long ticks;
> > unsigned long long pclk;
> > - unsigned long rate;
> > static unsigned long tegra_last_pclk;
> >
> > - rate = clk_get_rate(tegra_pclk);
> > -
> > if (WARN_ON_ONCE(rate <= 0))
> > pclk = 100000000;
> > else
>
> I don't think the code compiles after that?
>
> The code must both compile and execute correctly after each patch is
> applied, without relying on any future patches.
>
It's OK. I had checked this before sending the patch.
> > +void tegra_pmc_pm_set(enum tegra_suspend_mode mode)
> > +{
> > + u32 reg;
> > + unsigned long rate = 0;
> > +
> > + reg = tegra_pmc_readl(PMC_CTRL);
> > + reg |= TEGRA_POWER_CPU_PWRREQ_OE;
> > + reg &= ~TEGRA_POWER_EFFECT_LP0;
> > +
> > + switch (mode) {
> > + case TEGRA_SUSPEND_LP2:
> > + rate = clk_get_rate(tegra_pclk);
>
> That isn't used anywhere.
>
It will pass to set_power_timers().
> > +void tegra_pmc_suspend_init(void)
> > +{
> > + u32 reg;
> > +
> > + /* Always enable CPU power request; just normal polarity is supported */
> > + reg = tegra_pmc_readl(PMC_CTRL);
> > + BUG_ON(reg & TEGRA_POWER_CPU_PWRREQ_POLARITY);
>
> Why is that comment true? What does it take to support arbitrary
> polarity; just flipping the OE bit in the register?
Hmm. You are right. I think this is redundant if we support different
polarity setting. We should also add it into DT binding. So we can just
flip the OE bit here.
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