From mboxrd@z Thu Jan 1 00:00:00 1970 From: ccross@android.com (Colin Cross) Date: Fri, 30 Mar 2012 12:43:29 -0700 Subject: [PATCH 2/3] ARM: OMAP4: cpuidle: Use coupled cpuidle states to implement SMP cpuidle. In-Reply-To: <1333114048-26136-3-git-send-email-santosh.shilimkar@ti.com> References: <1333114048-26136-1-git-send-email-santosh.shilimkar@ti.com> <1333114048-26136-3-git-send-email-santosh.shilimkar@ti.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Mar 30, 2012 at 6:27 AM, Santosh Shilimkar wrote: > OMAP4 CPUDILE driver is converted mainly based on notes from the > coupled cpuidle patch series. > > The changes include : > - Register both CPUs and C-states to cpuidle driver. > - Set struct cpuidle_device.coupled_cpus > - Set struct cpuidle_device.safe_state to non coupled state. > - Set CPUIDLE_FLAG_COUPLED in struct cpuidle_state.flags for each > ?state that affects multiple cpus. > - Separate ->enter hooks for coupled & simple idle. > - CPU0 wait loop for CPU1 power transition. > - CPU1 wakeup mechanism for the idle exit. > - Enabling ARCH_NEEDS_CPU_IDLE_COUPLED for OMAP4. > > Thanks to Kevin Hilman and Colin Cross on the suggestions/fixes > on the intermediate version of this patch. > > Signed-off-by: Santosh Shilimkar > CC: Kevin Hilman > Cc: Colin Cross > --- > ?arch/arm/mach-omap2/Kconfig ? ? ? | ? ?1 + > ?arch/arm/mach-omap2/cpuidle44xx.c | ?167 ++++++++++++++++++++++--------------- > ?2 files changed, 101 insertions(+), 67 deletions(-) > > diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig > index e20c8ab..250786e 100644 > --- a/arch/arm/mach-omap2/Kconfig > +++ b/arch/arm/mach-omap2/Kconfig > @@ -54,6 +54,7 @@ config ARCH_OMAP4 > ? ? ? ?select PM_OPP if PM > ? ? ? ?select USB_ARCH_HAS_EHCI > ? ? ? ?select ARM_CPU_SUSPEND if PM > + ? ? ? select ARCH_NEEDS_CPU_IDLE_COUPLED if CPU_IDLE The "if CPU_IDLE" is not necessary, ARCH_NEEDS_CPU_IDLE_COUPLED is designed to have no effect if CPU_IDLE is not set. > > ?comment "OMAP Core Type" > ? ? ? ?depends on ARCH_OMAP2 > diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c > index f386cbe..5724393 100644 > --- a/arch/arm/mach-omap2/cpuidle44xx.c > +++ b/arch/arm/mach-omap2/cpuidle44xx.c > @@ -21,6 +21,7 @@ > ?#include "common.h" > ?#include "pm.h" > ?#include "prm.h" > +#include "clockdomain.h" > > ?#ifdef CONFIG_CPU_IDLE > > @@ -44,10 +45,11 @@ static struct cpuidle_params cpuidle_params_table[] = { > ?#define OMAP4_NUM_STATES ARRAY_SIZE(cpuidle_params_table) > > ?struct omap4_idle_statedata omap4_idle_data[OMAP4_NUM_STATES]; > -static struct powerdomain *mpu_pd, *cpu0_pd, *cpu1_pd; > +static struct powerdomain *mpu_pd, *cpu_pd[NR_CPUS]; > +static struct clockdomain *cpu_clkdm[NR_CPUS]; > > ?/** > - * omap4_enter_idle - Programs OMAP4 to enter the specified state > + * omap4_enter_idle_coupled_[simple/coupled] - OMAP4 cpuidle entry functions > ?* @dev: cpuidle device > ?* @drv: cpuidle driver > ?* @index: the index of state to be entered > @@ -56,34 +58,40 @@ static struct powerdomain *mpu_pd, *cpu0_pd, *cpu1_pd; > ?* specified low power state selected by the governor. > ?* Returns the amount of time spent in the low power state. > ?*/ > -static int omap4_enter_idle(struct cpuidle_device *dev, > +static int omap4_enter_idle_simple(struct cpuidle_device *dev, > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct cpuidle_driver *drv, > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?int index) > +{ > + ? ? ? local_fiq_disable(); > + ? ? ? omap_do_wfi(); > + ? ? ? local_fiq_enable(); > + > + ? ? ? return index; > +} > + > +static int omap4_enter_idle_coupled(struct cpuidle_device *dev, > ? ? ? ? ? ? ? ? ? ? ? ?struct cpuidle_driver *drv, > ? ? ? ? ? ? ? ? ? ? ? ?int index) > ?{ > ? ? ? ?struct omap4_idle_statedata *cx = > ? ? ? ? ? ? ? ? ? ? ? ?cpuidle_get_statedata(&dev->states_usage[index]); > - ? ? ? u32 cpu1_state; > ? ? ? ?int cpu_id = smp_processor_id(); > > ? ? ? ?local_fiq_disable(); > > + ? ? ? clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id); > + > ? ? ? ?/* > - ? ? ? ?* CPU0 has to stay ON (i.e in C1) until CPU1 is OFF state. > + ? ? ? ?* CPU0 has to wait and stay ON until CPU1 is OFF state. > ? ? ? ? * This is necessary to honour hardware recommondation > ? ? ? ? * of triggeing all the possible low power modes once CPU1 is > ? ? ? ? * out of coherency and in OFF mode. > - ? ? ? ?* Update dev->last_state so that governor stats reflects right > - ? ? ? ?* data. > ? ? ? ? */ > - ? ? ? cpu1_state = pwrdm_read_pwrst(cpu1_pd); > - ? ? ? if (cpu1_state != PWRDM_POWER_OFF) { > - ? ? ? ? ? ? ? index = drv->safe_state_index; > - ? ? ? ? ? ? ? cx = cpuidle_get_statedata(&dev->states_usage[index]); > + ? ? ? if (dev->cpu == 0) { > + ? ? ? ? ? ? ? while (pwrdm_read_pwrst(cpu_pd[1]) != PWRDM_POWER_OFF) > + ? ? ? ? ? ? ? ? ? ? ? cpu_relax(); If something goes wrong in the core coupled code or in the cpu 1 power state transition, this will hang forever and be hard to debug. It might be worth adding a timeout with a BUG_ON. > ? ? ? ?} > > - ? ? ? if (index > 0) > - ? ? ? ? ? ? ? clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id); > - > ? ? ? ?/* > ? ? ? ? * Call idle CPU PM enter notifier chain so that > ? ? ? ? * VFP and per CPU interrupt context is saved. > @@ -91,25 +99,35 @@ static int omap4_enter_idle(struct cpuidle_device *dev, > ? ? ? ?if (cx->cpu_state == PWRDM_POWER_OFF) > ? ? ? ? ? ? ? ?cpu_pm_enter(); This should never get called without cpu_state == PWRDM_POWER_OFF, and even if it did, calling cpu_pm_enter shouldn't hurt anything. It would be clearer to unconditionally call cpu_pm_enter(). > > - ? ? ? pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); > - ? ? ? omap_set_pwrdm_state(mpu_pd, cx->mpu_state); > - > - ? ? ? /* > - ? ? ? ?* Call idle CPU cluster PM enter notifier chain > - ? ? ? ?* to save GIC and wakeupgen context. > - ? ? ? ?*/ > - ? ? ? if ((cx->mpu_state == PWRDM_POWER_RET) && > - ? ? ? ? ? ? ? (cx->mpu_logic_state == PWRDM_POWER_OFF)) > - ? ? ? ? ? ? ? ? ? ? ? cpu_cluster_pm_enter(); > + ? ? ? if (dev->cpu == 0) { > + ? ? ? ? ? ? ? pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); > + ? ? ? ? ? ? ? omap_set_pwrdm_state(mpu_pd, cx->mpu_state); > + > + ? ? ? ? ? ? ? /* > + ? ? ? ? ? ? ? ?* Call idle CPU cluster PM enter notifier chain > + ? ? ? ? ? ? ? ?* to save GIC and wakeupgen context. > + ? ? ? ? ? ? ? ?*/ > + ? ? ? ? ? ? ? if ((cx->mpu_state == PWRDM_POWER_RET) && > + ? ? ? ? ? ? ? ? ? ? ? (cx->mpu_logic_state == PWRDM_POWER_OFF)) > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? cpu_cluster_pm_enter(); > + ? ? ? } > > ? ? ? ?omap4_enter_lowpower(dev->cpu, cx->cpu_state); > > + ? ? ? if (dev->cpu == 0) { > + ? ? ? ? ? ? ? /* Wakeup CPU1 only if it is not offlined */ > + ? ? ? ? ? ? ? if (cpumask_test_cpu(1, cpu_online_mask)) { > + ? ? ? ? ? ? ? ? ? ? ? clkdm_wakeup(cpu_clkdm[1]); > + ? ? ? ? ? ? ? ? ? ? ? clkdm_allow_idle(cpu_clkdm[1]); > + ? ? ? ? ? ? ? } > + ? ? ? } > + > ? ? ? ?/* > ? ? ? ? * Call idle CPU PM exit notifier chain to restore > ? ? ? ? * VFP and per CPU IRQ context. Only CPU0 state is > ? ? ? ? * considered since CPU1 is managed by CPU hotplug. > ? ? ? ? */ This comment is no longer accurate? cpu_pm_enter is called on cpu 1 above. > - ? ? ? if (pwrdm_read_prev_pwrst(cpu0_pd) == PWRDM_POWER_OFF) > + ? ? ? if (pwrdm_read_prev_pwrst(cpu_pd[dev->cpu]) == PWRDM_POWER_OFF) > ? ? ? ? ? ? ? ?cpu_pm_exit(); This should get called unconditionally. It's not explicitly stated, but the cpu_pm_* api expects cpu_pm_exit() to be called after cpu_pm_enter(), even if the low power state was not entered. Otherwise, a cpu_pm_enter notifier that disables the hardware will not get a chance to re-enable it.