PM / Domains: Remove cpuidle attach

The power domains code allows to tie a cpuidle state with a power domain.

Preventing the cpuidle framework to enter a specific idle state by disabling
from the power domain framework is a good idea. Unfortunately, the current
implementation has some gaps with a SMP system and a complex cpuidle
implementation. Enabling a power domain wakes up all the cpus even if a cpu
does not belong to the power domain.

There is some work to do a logical representation with the power domains of
the hardware dependencies (eg. a cpu belongs to a power domains, these power
domains belong to a higher power domain for a cluster, etc ...). A new code
relying on the genpd hierarchy to disable the idle states would make more
sense.

As the unique user of this code has been removed, let's wipe out this code
to prevent new user and to have a clean place to put a new implementation.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -122,19 +122,6 @@ static void genpd_sd_counter_inc(struct generic_pm_domain *genpd)
 	smp_mb__after_atomic();
 }
 
-static void genpd_recalc_cpu_exit_latency(struct generic_pm_domain *genpd)
-{
-	s64 usecs64;
-
-	if (!genpd->cpuidle_data)
-		return;
-
-	usecs64 = genpd->power_on_latency_ns;
-	do_div(usecs64, NSEC_PER_USEC);
-	usecs64 += genpd->cpuidle_data->saved_exit_latency;
-	genpd->cpuidle_data->idle_state->exit_latency = usecs64;
-}
-
 static int genpd_power_on(struct generic_pm_domain *genpd, bool timed)
 {
 	ktime_t time_start;
@@ -158,7 +145,6 @@ static int genpd_power_on(struct generic_pm_domain *genpd, bool timed)
 
 	genpd->power_on_latency_ns = elapsed_ns;
 	genpd->max_off_time_changed = true;
-	genpd_recalc_cpu_exit_latency(genpd);
 	pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
 		 genpd->name, "on", elapsed_ns);
 
@@ -222,13 +208,6 @@ static int __pm_genpd_poweron(struct generic_pm_domain *genpd)
 	    || (genpd->prepared_count > 0 && genpd->suspend_power_off))
 		return 0;
 
-	if (genpd->cpuidle_data) {
-		cpuidle_pause_and_lock();
-		genpd->cpuidle_data->idle_state->disabled = true;
-		cpuidle_resume_and_unlock();
-		goto out;
-	}
-
 	/*
 	 * The list is guaranteed not to change while the loop below is being
 	 * executed, unless one of the masters' .power_on() callbacks fiddles
@@ -381,21 +360,6 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
 			return -EAGAIN;
 	}
 
-	if (genpd->cpuidle_data) {
-		/*
-		 * If cpuidle_data is set, cpuidle should turn the domain off
-		 * when the CPU in it is idle.  In that case we don't decrement
-		 * the subdomain counts of the master domains, so that power is
-		 * not removed from the current domain prematurely as a result
-		 * of cutting off the masters' power.
-		 */
-		genpd->status = GPD_STATE_POWER_OFF;
-		cpuidle_pause_and_lock();
-		genpd->cpuidle_data->idle_state->disabled = false;
-		cpuidle_resume_and_unlock();
-		return 0;
-	}
-
 	if (genpd->power_off) {
 		int ret;
 
@@ -1433,105 +1397,6 @@ out:
 	return ret;
 }
 
-/**
- * pm_genpd_attach_cpuidle - Connect the given PM domain with cpuidle.
- * @genpd: PM domain to be connected with cpuidle.
- * @state: cpuidle state this domain can disable/enable.
- *
- * Make a PM domain behave as though it contained a CPU core, that is, instead
- * of calling its power down routine it will enable the given cpuidle state so
- * that the cpuidle subsystem can power it down (if possible and desirable).
- */
-int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int state)
-{
-	struct cpuidle_driver *cpuidle_drv;
-	struct gpd_cpuidle_data *cpuidle_data;
-	struct cpuidle_state *idle_state;
-	int ret = 0;
-
-	if (IS_ERR_OR_NULL(genpd) || state < 0)
-		return -EINVAL;
-
-	mutex_lock(&genpd->lock);
-
-	if (genpd->cpuidle_data) {
-		ret = -EEXIST;
-		goto out;
-	}
-	cpuidle_data = kzalloc(sizeof(*cpuidle_data), GFP_KERNEL);
-	if (!cpuidle_data) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	cpuidle_drv = cpuidle_driver_ref();
-	if (!cpuidle_drv) {
-		ret = -ENODEV;
-		goto err_drv;
-	}
-	if (cpuidle_drv->state_count <= state) {
-		ret = -EINVAL;
-		goto err;
-	}
-	idle_state = &cpuidle_drv->states[state];
-	if (!idle_state->disabled) {
-		ret = -EAGAIN;
-		goto err;
-	}
-	cpuidle_data->idle_state = idle_state;
-	cpuidle_data->saved_exit_latency = idle_state->exit_latency;
-	genpd->cpuidle_data = cpuidle_data;
-	genpd_recalc_cpu_exit_latency(genpd);
-
- out:
-	mutex_unlock(&genpd->lock);
-	return ret;
-
- err:
-	cpuidle_driver_unref();
-
- err_drv:
-	kfree(cpuidle_data);
-	goto out;
-}
-
-/**
- * pm_genpd_detach_cpuidle - Remove the cpuidle connection from a PM domain.
- * @genpd: PM domain to remove the cpuidle connection from.
- *
- * Remove the cpuidle connection set up by pm_genpd_attach_cpuidle() from the
- * given PM domain.
- */
-int pm_genpd_detach_cpuidle(struct generic_pm_domain *genpd)
-{
-	struct gpd_cpuidle_data *cpuidle_data;
-	struct cpuidle_state *idle_state;
-	int ret = 0;
-
-	if (IS_ERR_OR_NULL(genpd))
-		return -EINVAL;
-
-	mutex_lock(&genpd->lock);
-
-	cpuidle_data = genpd->cpuidle_data;
-	if (!cpuidle_data) {
-		ret = -ENODEV;
-		goto out;
-	}
-	idle_state = cpuidle_data->idle_state;
-	if (!idle_state->disabled) {
-		ret = -EAGAIN;
-		goto out;
-	}
-	idle_state->exit_latency = cpuidle_data->saved_exit_latency;
-	cpuidle_driver_unref();
-	genpd->cpuidle_data = NULL;
-	kfree(cpuidle_data);
-
- out:
-	mutex_unlock(&genpd->lock);
-	return ret;
-}
-
 /* Default device callbacks for generic PM domains. */
 
 /**

include/linux/pm_domain.h

@@ -15,7 +15,6 @@
 #include <linux/err.h>
 #include <linux/of.h>
 #include <linux/notifier.h>
-#include <linux/cpuidle.h>
 
 /* Defines used for the flags field in the struct generic_pm_domain */
 #define GENPD_FLAG_PM_CLK	(1U << 0) /* PM domain uses PM clk */
@@ -38,11 +37,6 @@ struct gpd_dev_ops {
 	bool (*active_wakeup)(struct device *dev);
 };
 
-struct gpd_cpuidle_data {
-	unsigned int saved_exit_latency;
-	struct cpuidle_state *idle_state;
-};
-
 struct generic_pm_domain {
 	struct dev_pm_domain domain;	/* PM domain operations */
 	struct list_head gpd_list_node;	/* Node in the global PM domains list */
@@ -68,7 +62,6 @@ struct generic_pm_domain {
 	s64 max_off_time_ns;	/* Maximum allowed "suspended" time. */
 	bool max_off_time_changed;
 	bool cached_power_down_ok;
-	struct gpd_cpuidle_data *cpuidle_data;
 	int (*attach_dev)(struct generic_pm_domain *domain,
 			  struct device *dev);
 	void (*detach_dev)(struct generic_pm_domain *domain,
@@ -131,8 +124,6 @@ extern int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 				  struct generic_pm_domain *new_subdomain);
 extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 				     struct generic_pm_domain *target);
-extern int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int state);
-extern int pm_genpd_detach_cpuidle(struct generic_pm_domain *genpd);
 extern void pm_genpd_init(struct generic_pm_domain *genpd,
 			  struct dev_power_governor *gov, bool is_off);
 
@@ -172,14 +163,6 @@ static inline int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 {
 	return -ENOSYS;
 }
-static inline int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int st)
-{
-	return -ENOSYS;
-}
-static inline int pm_genpd_detach_cpuidle(struct generic_pm_domain *genpd)
-{
-	return -ENOSYS;
-}
 static inline void pm_genpd_init(struct generic_pm_domain *genpd,
 				 struct dev_power_governor *gov, bool is_off)
 {