On 08/07/2019 00:08, Dmitry Osipenko wrote: > The PCLK clock is running off SCLK, which is a critical clock that is > very unlikely to randomly change its rate. It's also a bit clumsy (and > apparently incorrect) to query the clock's rate with interrupts being > disabled because clk_get_rate() takes a mutex and that's the case during > suspend/cpuidle entering. Lastly, it's better to always fully reprogram > PMC state because it's not obvious whether it could be changed after SC7.
I agree with the first part, but I would drop the last sentence because I see no evidence of this. Maybe Peter can confirm. > Signed-off-by: Dmitry Osipenko <[email protected]> > --- > drivers/soc/tegra/pmc.c | 26 +++++++++++--------------- > 1 file changed, 11 insertions(+), 15 deletions(-) > > diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c > index 9f9c1c677cf4..532e0ada012b 100644 > --- a/drivers/soc/tegra/pmc.c > +++ b/drivers/soc/tegra/pmc.c > @@ -1433,6 +1433,7 @@ void tegra_pmc_set_suspend_mode(enum tegra_suspend_mode > mode) > void tegra_pmc_enter_suspend_mode(enum tegra_suspend_mode mode) > { > unsigned long long rate = 0; > + u64 ticks; > u32 value; > > switch (mode) { > @@ -1441,7 +1442,7 @@ void tegra_pmc_enter_suspend_mode(enum > tegra_suspend_mode mode) > break; > > case TEGRA_SUSPEND_LP2: > - rate = clk_get_rate(pmc->clk); > + rate = pmc->rate; There is another call to clk_get_rate() that could be removed as well. > break; > > default: > @@ -1451,26 +1452,20 @@ void tegra_pmc_enter_suspend_mode(enum > tegra_suspend_mode mode) > if (WARN_ON_ONCE(rate == 0)) > rate = 100000000; > > - if (rate != pmc->rate) { > - u64 ticks; > - > - ticks = pmc->cpu_good_time * rate + USEC_PER_SEC - 1; > - do_div(ticks, USEC_PER_SEC); > - tegra_pmc_writel(pmc, ticks, PMC_CPUPWRGOOD_TIMER); > - > - ticks = pmc->cpu_off_time * rate + USEC_PER_SEC - 1; > - do_div(ticks, USEC_PER_SEC); > - tegra_pmc_writel(pmc, ticks, PMC_CPUPWROFF_TIMER); > + ticks = pmc->cpu_good_time * rate + USEC_PER_SEC - 1; > + do_div(ticks, USEC_PER_SEC); > + tegra_pmc_writel(pmc, ticks, PMC_CPUPWRGOOD_TIMER); You could go a step further and update the cpu_good_time/cpu_off_time to be ticks and calculated once during probe and recalculated if tegra_pmc_set_suspend_mode is called. I am not sure why we really need to pass mode to tegra_pmc_enter_suspend_mode() seeing as the mode is stored in the pmc struct. > > - wmb(); > - > - pmc->rate = rate; > - } > + ticks = pmc->cpu_off_time * rate + USEC_PER_SEC - 1; > + do_div(ticks, USEC_PER_SEC); > + tegra_pmc_writel(pmc, ticks, PMC_CPUPWROFF_TIMER); > > value = tegra_pmc_readl(pmc, PMC_CNTRL); > value &= ~PMC_CNTRL_SIDE_EFFECT_LP0; > value |= PMC_CNTRL_CPU_PWRREQ_OE; > tegra_pmc_writel(pmc, value, PMC_CNTRL); > + > + wmb(); > } > #endif > > @@ -2082,6 +2077,7 @@ static int tegra_pmc_probe(struct platform_device *pdev) > pmc->clk = NULL; > } > > + pmc->rate = clk_get_rate(pmc->clk); You should check the value returned is not 0 here. Cheers Jon -- nvpublic
