Peter Zijlstra
2022-Jun-14 22:12 UTC
[PATCH 34.5/36] cpuidle,omap4: Push RCU-idle into omap4_enter_lowpower()
On Mon, Jun 13, 2022 at 03:39:05PM +0300, Tony Lindgren wrote:> OMAP4 uses full SoC suspend modes as idle states, as such it needs the > whole power-domain and clock-domain code from the idle path. > > All that code is not suitable to run with RCU disabled, as such push > RCU-idle deeper still. > > Signed-off-by: Tony Lindgren <tony at atomide.com> > --- > > Peter here's one more for your series, looks like this is needed to avoid > warnings similar to what you did for omap3.Thanks Tony! I've had a brief look at omap2_pm_idle() and do I understand it right that something like the below patch would reduce it to a simple 'WFI'? What do I do with the rest of that code, because I don't think this thing has a cpuidle driver to take over, effectively turning it into dead code. --- a/arch/arm/mach-omap2/pm24xx.c +++ b/arch/arm/mach-omap2/pm24xx.c @@ -126,10 +126,20 @@ static int omap2_allow_mpu_retention(voi return 1; } -static void omap2_enter_mpu_retention(void) +static void omap2_do_wfi(void) { const int zero = 0; + /* WFI */ + asm("mcr p15, 0, %0, c7, c0, 4" : : "r" (zero) : "memory", "cc"); +} + +#if 0 +/* + * possible cpuidle implementation between WFI and full_retention above + */ +static void omap2_enter_mpu_retention(void) +{ /* The peripherals seem not to be able to wake up the MPU when * it is in retention mode. */ if (omap2_allow_mpu_retention()) { @@ -146,8 +157,7 @@ static void omap2_enter_mpu_retention(vo pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_ON); } - /* WFI */ - asm("mcr p15, 0, %0, c7, c0, 4" : : "r" (zero) : "memory", "cc"); + omap2_do_wfi(); pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_ON); } @@ -161,6 +171,7 @@ static int omap2_can_sleep(void) return 1; } +#endif static void omap2_pm_idle(void) { @@ -169,6 +180,7 @@ static void omap2_pm_idle(void) if (omap_irq_pending()) return; +#if 0 error = cpu_cluster_pm_enter(); if (error || !omap2_can_sleep()) { omap2_enter_mpu_retention(); @@ -179,6 +191,9 @@ static void omap2_pm_idle(void) out_cpu_cluster_pm: cpu_cluster_pm_exit(); +#else + omap2_do_wfi(); +#endif } static void __init prcm_setup_regs(void)