On 01/30/13 19:04, Jon Hunter wrote: > When booting with device-tree for OMAP3 and AM335x devices and a gptimer > is used as the clocksource (which is always the case for AM335x), a > gptimer located in a power domain that is not always-on is selected. > Ideally we should use a gptimer located in a power domain that is always > on (such as the wake-up domain) so that time can be maintained during a > kernel suspend without keeping on additional power domains unnecessarily. > > In order to fix this so that we can select a gptimer located in a power > domain that is always-on, the following changes were made ... > 1. Currently, only when selecting a gptimer to use for a clockevent > timer, do we pass a timer property that can be used to select a > specific gptimer. Change this so that we can pass a property when > selecting a gptimer to use for a clocksource timer too. > 2. Currently, when selecting either a gptimer to use for a clockevent > timer or a clocksource timer and no timer property is passed, then > the first available timer is selected regardless of the properties > it has. Change this so that if no properties are passed, then a timer > that does not have additional features (such as always-on, dsp-irq, > pwm, and secure) is selected. > > Please note that using a gptimer for both clocksource and clockevents > can have a system power impact during idle. The reason being is that > OMAP and AMxxx devices typically only have one gptimer in a power domain > that is always-on. Therefore when the kernel is idle both the clocksource > and clockevent timers will be active and this will keep additional power > domains on. During kernel suspend, only the clocksource timer is active > and therefore, it is better to use a gptimer in a power domain that is > always-on for clocksource. This should explain the gptimer number switch in the #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) section below, right? I would really like to see that clearly stated in the commit message. For instance: ... it is better to use a gptimer in a power domain that is always-on for clocksource. Therefore we switch to use the first gptimer for clocksource and the second for clockevents. > > Signed-off-by: Jon Hunter <jon-hunter@xxxxxx> Apart from above, Acked-by: Igor Grinberg <grinberg@xxxxxxxxxxxxxx> > --- > arch/arm/mach-omap2/timer.c | 32 +++++++++++++++++++++----------- > 1 file changed, 21 insertions(+), 11 deletions(-) > > diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c > index af20be7..acf9f82 100644 > --- a/arch/arm/mach-omap2/timer.c > +++ b/arch/arm/mach-omap2/timer.c [...] > @@ -557,19 +567,19 @@ void __init omap##name##_sync32k_timer_init(void) \ > #if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP4) || \ > defined(CONFIG_SOC_OMAP5) > OMAP_SYS_32K_TIMER_INIT(2, 1, "timer_32k_ck", "ti,timer-alwon", > - 2, "timer_sys_ck"); > + 2, "timer_sys_ck", NULL); > #endif > > #ifdef CONFIG_ARCH_OMAP3 > OMAP_SYS_32K_TIMER_INIT(3, 1, "timer_32k_ck", "ti,timer-alwon", > - 2, "timer_sys_ck"); > + 2, "timer_sys_ck", NULL); > OMAP_SYS_32K_TIMER_INIT(3_secure, 12, "secure_32k_fck", "ti,timer-secure", > - 2, "timer_sys_ck"); > + 2, "timer_sys_ck", NULL); > #endif /* CONFIG_ARCH_OMAP3 */ > > #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) > -OMAP_SYS_GP_TIMER_INIT(3, 1, "timer_sys_ck", "ti,timer-alwon", > - 2, "timer_sys_ck"); > +OMAP_SYS_GP_TIMER_INIT(3, 2, "timer_sys_ck", NULL, > + 1, "timer_sys_ck", "ti,timer-alwon"); > #endif > > #ifdef CONFIG_ARCH_OMAP4 > -- Regards, Igor. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
