[RFC][PATCH 1/2] cpuidle: Drop disabled field from struct cpuidle_state

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

After recent cpuidle updates the disabled field in struct
cpuidle_state is only used by two drivers (intel_idle and shmobile
cpuidle) for marking unusable idle states, but that may as well be
achieved with the help of a state flag, so define an "unusable" idle
state flag, CPUIDLE_FLAG_UNUSABLE, make the drivers in question use
it instead of the disable field and make the core set
CPUIDLE_STATE_DISABLED_BY_DRIVER for the idle states with that flag
set.

After the above changes, the disabled field in struct cpuidle_state
is not used any more, so drop it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 arch/sh/kernel/cpu/shmobile/cpuidle.c |    8 ++++----
 drivers/cpuidle/cpuidle.c             |    2 +-
 drivers/cpuidle/poll_state.c          |    1 -
 drivers/idle/intel_idle.c             |    6 +++---
 include/linux/cpuidle.h               |    2 +-
 5 files changed, 9 insertions(+), 10 deletions(-)

Index: linux-pm/drivers/idle/intel_idle.c
===================================================================
--- linux-pm.orig/drivers/idle/intel_idle.c
+++ linux-pm/drivers/idle/intel_idle.c
@@ -1291,8 +1291,8 @@ static void sklh_idle_state_table_update
 			return;
 	}
 
-	skl_cstates[5].disabled = 1;	/* C8-SKL */
-	skl_cstates[6].disabled = 1;	/* C9-SKL */
+	skl_cstates[5].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C8-SKL */
+	skl_cstates[6].flags |= CPUIDLE_FLAG_UNUSABLE;	/* C9-SKL */
 }
 /*
  * intel_idle_state_table_update()
@@ -1355,7 +1355,7 @@ static void __init intel_idle_cpuidle_dr
 			continue;
 
 		/* if state marked as disabled, skip it */
-		if (cpuidle_state_table[cstate].disabled != 0) {
+		if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_UNUSABLE) {
 			pr_debug("state %s is disabled\n",
 				 cpuidle_state_table[cstate].name);
 			continue;
Index: linux-pm/include/linux/cpuidle.h
===================================================================
--- linux-pm.orig/include/linux/cpuidle.h
+++ linux-pm/include/linux/cpuidle.h
@@ -54,7 +54,6 @@ struct cpuidle_state {
 	unsigned int	exit_latency; /* in US */
 	int		power_usage; /* in mW */
 	unsigned int	target_residency; /* in US */
-	bool		disabled; /* disabled on all CPUs */
 
 	int (*enter)	(struct cpuidle_device *dev,
 			struct cpuidle_driver *drv,
@@ -77,6 +76,7 @@ struct cpuidle_state {
 #define CPUIDLE_FLAG_POLLING	BIT(0) /* polling state */
 #define CPUIDLE_FLAG_COUPLED	BIT(1) /* state applies to multiple cpus */
 #define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */
+#define CPUIDLE_FLAG_UNUSABLE	BIT(3) /* avoid using this state */
 
 struct cpuidle_device_kobj;
 struct cpuidle_state_kobj;
Index: linux-pm/arch/sh/kernel/cpu/shmobile/cpuidle.c
===================================================================
--- linux-pm.orig/arch/sh/kernel/cpu/shmobile/cpuidle.c
+++ linux-pm/arch/sh/kernel/cpu/shmobile/cpuidle.c
@@ -67,7 +67,7 @@ static struct cpuidle_driver cpuidle_dri
 			.enter = cpuidle_sleep_enter,
 			.name = "C2",
 			.desc = "SuperH Sleep Mode [SF]",
-			.disabled = true,
+			.flags = CPUIDLE_FLAG_UNUSABLE,
 		},
 		{
 			.exit_latency = 2300,
@@ -76,7 +76,7 @@ static struct cpuidle_driver cpuidle_dri
 			.enter = cpuidle_sleep_enter,
 			.name = "C3",
 			.desc = "SuperH Mobile Standby Mode [SF]",
-			.disabled = true,
+			.flags = CPUIDLE_FLAG_UNUSABLE,
 		},
 	},
 	.safe_state_index = 0,
@@ -86,10 +86,10 @@ static struct cpuidle_driver cpuidle_dri
 int __init sh_mobile_setup_cpuidle(void)
 {
 	if (sh_mobile_sleep_supported & SUSP_SH_SF)
-		cpuidle_driver.states[1].disabled = false;
+		cpuidle_driver.states[1].flags = CPUIDLE_FLAG_NONE;
 
 	if (sh_mobile_sleep_supported & SUSP_SH_STANDBY)
-		cpuidle_driver.states[2].disabled = false;
+		cpuidle_driver.states[2].flags = CPUIDLE_FLAG_NONE;
 
 	return cpuidle_register(&cpuidle_driver, NULL);
 }
Index: linux-pm/drivers/cpuidle/cpuidle.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/cpuidle.c
+++ linux-pm/drivers/cpuidle/cpuidle.c
@@ -570,7 +570,7 @@ static int __cpuidle_register_device(str
 		return -EINVAL;
 
 	for (i = 0; i < drv->state_count; i++)
-		if (drv->states[i].disabled)
+		if (drv->states[i].flags & CPUIDLE_FLAG_UNUSABLE)
 			dev->states_usage[i].disable |= CPUIDLE_STATE_DISABLED_BY_DRIVER;
 
 	per_cpu(cpuidle_devices, dev->cpu) = dev;
Index: linux-pm/drivers/cpuidle/poll_state.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/poll_state.c
+++ linux-pm/drivers/cpuidle/poll_state.c
@@ -53,7 +53,6 @@ void cpuidle_poll_state_init(struct cpui
 	state->target_residency_ns = 0;
 	state->power_usage = -1;
 	state->enter = poll_idle;
-	state->disabled = false;
 	state->flags = CPUIDLE_FLAG_POLLING;
 }
 EXPORT_SYMBOL_GPL(cpuidle_poll_state_init);