Retain the old policy in processor_idle, so that when CPU_IDLE is not
configured, old C-state policy will still be used. This provides a
clean gradual migration path from old acpi policy to new cpuidle
based policy.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Index: linux-2.6.23-rc6/drivers/acpi/processor_idle.c
===================================================================
--- linux-2.6.23-rc6.orig/drivers/acpi/processor_idle.c
+++ linux-2.6.23-rc6/drivers/acpi/processor_idle.c
@@ -65,14 +65,20 @@ ACPI_MODULE_NAME("processor_idle");
#define ACPI_PROCESSOR_FILE_POWER "power"
#define PM_TIMER_TICKS_TO_US(p) (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
#define PM_TIMER_TICK_NS (1000000000ULL/PM_TIMER_FREQUENCY)
-#define C2_OVERHEAD 1 /* 1us */
-#define C3_OVERHEAD 1 /* 1us */
static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
module_param(max_cstate, uint, 0000);
static unsigned int nocst __read_mostly;
module_param(nocst, uint, 0000);
+#ifndef CONFIG_CPU_IDLE
+
+#define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr);
+
+#endif
+
/*
* IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
* For now disable this. Probably a bug somewhere else.
@@ -447,7 +453,12 @@ static void acpi_processor_power_verify_
* Normalize the C2 latency to expidite policy
*/
cx->valid = 1;
+
+#ifdef CONFIG_CPU_IDLE
cx->latency_ticks = cx->latency;
+#else
+ cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#endif
return;
}
@@ -527,7 +538,12 @@ static void acpi_processor_power_verify_
* use this in our C3 policy
*/
cx->valid = 1;
+
+#ifdef CONFIG_CPU_IDLE
cx->latency_ticks = cx->latency;
+#else
+ cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#endif
return;
}
@@ -592,6 +608,20 @@ static int acpi_processor_get_power_info
pr->power.count = acpi_processor_power_verify(pr);
+#ifndef CONFIG_CPU_IDLE
+ /*
+ * Set Default Policy
+ * ------------------
+ * Now that we know which states are supported, set the default
+ * policy. Note that this policy can be changed dynamically
+ * (e.g. encourage deeper sleeps to conserve battery life when
+ * not on AC).
+ */
+ result = acpi_processor_set_power_policy(pr);
+ if (result)
+ return result;
+#endif
+
/*
* if one state of type C2 or C3 is available, mark this
* CPU as being "idle manageable"
@@ -708,6 +738,11 @@ static inline u32 ticks_elapsed(u32 t1,
return ((0xFFFFFFFF - t1) + t2);
}
+#ifdef CONFIG_CPU_IDLE
+
+#define C2_OVERHEAD 1 /* 1us */
+#define C3_OVERHEAD 1 /* 1us */
+
/**
* acpi_idle_bm_check - checks if bus master activity was detected
*/
@@ -1088,6 +1123,552 @@ int acpi_processor_cst_has_changed(struc
return ret;
}
+#else
+
+/*
+ * This code provides the older acpi behaviour when cpuidle is not configured.
+ * This will go away once CPU_IDLE has been fully integrated into the mainline
+ * kernel. -- Venki --
+ */
+#define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+#define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+static void (*pm_idle_save) (void) __read_mostly;
+
+/*
+ * bm_history -- bit-mask with a bit per jiffy of bus-master activity
+ * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
+ * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
+ * 100 HZ: 0x0000000F: 4 jiffies = 40ms
+ * reduce history for more aggressive entry into C3
+ */
+static unsigned int bm_history __read_mostly =
+ (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
+module_param(bm_history, uint, 0644);
+
+static void
+acpi_processor_power_activate(struct acpi_processor *pr,
+ struct acpi_processor_cx *new)
+{
+ struct acpi_processor_cx *old;
+
+ if (!pr || !new)
+ return;
+
+ old = pr->power.state;
+
+ if (old)
+ old->promotion.count = 0;
+ new->demotion.count = 0;
+
+ /* Cleanup from old state. */
+ if (old) {
+ switch (old->type) {
+ case ACPI_STATE_C3:
+ /* Disable bus master reload */
+ if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
+ break;
+ }
+ }
+
+ /* Prepare to use new state. */
+ switch (new->type) {
+ case ACPI_STATE_C3:
+ /* Enable bus master reload */
+ if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
+ break;
+ }
+
+ pr->power.state = new;
+
+ return;
+}
+
+static void acpi_safe_halt(void)
+{
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (!need_resched())
+ safe_halt();
+ current_thread_info()->status |= TS_POLLING;
+}
+
+static atomic_t c3_cpu_count;
+
+/* Common C-state entry for C2, C3, .. */
+static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
+{
+ if (cstate->space_id == ACPI_CSTATE_FFH) {
+ /* Call into architectural FFH based C-state */
+ acpi_processor_ffh_cstate_enter(cstate);
+ } else {
+ int unused;
+ /* IO port based C-state */
+ inb(cstate->address);
+ /* Dummy wait op - must do something useless after P_LVL2 read
+ because chipsets cannot guarantee that STPCLK# signal
+ gets asserted in time to freeze execution properly. */
+ unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ }
+}
+
+static void acpi_processor_idle(void)
+{
+ struct acpi_processor *pr = NULL;
+ struct acpi_processor_cx *cx = NULL;
+ struct acpi_processor_cx *next_state = NULL;
+ int sleep_ticks = 0;
+ u32 t1, t2 = 0;
+
+ /*
+ * Interrupts must be disabled during bus mastering calculations and
+ * for C2/C3 transitions.
+ */
+ local_irq_disable();
+
+ pr = processors[smp_processor_id()];
+ if (!pr) {
+ local_irq_enable();
+ return;
+ }
+
+ /*
+ * Check whether we truly need to go idle, or should
+ * reschedule:
+ */
+ if (unlikely(need_resched())) {
+ local_irq_enable();
+ return;
+ }
+
+ cx = pr->power.state;
+ if (!cx) {
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+ return;
+ }
+
+ /*
+ * Check BM Activity
+ * -----------------
+ * Check for bus mastering activity (if required), record, and check
+ * for demotion.
+ */
+ if (pr->flags.bm_check) {
+ u32 bm_status = 0;
+ unsigned long diff = jiffies - pr->power.bm_check_timestamp;
+
+ if (diff > 31)
+ diff = 31;
+
+ pr->power.bm_activity <<= diff;
+
+ acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+ if (bm_status) {
+ pr->power.bm_activity |= 0x1;
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
+ }
+ /*
+ * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
+ * the true state of bus mastering activity; forcing us to
+ * manually check the BMIDEA bit of each IDE channel.
+ */
+ else if (errata.piix4.bmisx) {
+ if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
+ || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
+ pr->power.bm_activity |= 0x1;
+ }
+
+ pr->power.bm_check_timestamp = jiffies;
+
+ /*
+ * If bus mastering is or was active this jiffy, demote
+ * to avoid a faulty transition. Note that the processor
+ * won't enter a low-power state during this call (to this
+ * function) but should upon the next.
+ *
+ * TBD: A better policy might be to fallback to the demotion
+ * state (use it for this quantum only) istead of
+ * demoting -- and rely on duration as our sole demotion
+ * qualification. This may, however, introduce DMA
+ * issues (e.g. floppy DMA transfer overrun/underrun).
+ */
+ if ((pr->power.bm_activity & 0x1) &&
+ cx->demotion.threshold.bm) {
+ local_irq_enable();
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /*
+ * Check for P_LVL2_UP flag before entering C2 and above on
+ * an SMP system. We do it here instead of doing it at _CST/P_LVL
+ * detection phase, to work cleanly with logical CPU hotplug.
+ */
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+ cx = &pr->power.states[ACPI_STATE_C1];
+#endif
+
+ /*
+ * Sleep:
+ * ------
+ * Invoke the current Cx state to put the processor to sleep.
+ */
+ if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (need_resched()) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return;
+ }
+ }
+
+ switch (cx->type) {
+
+ case ACPI_STATE_C1:
+ /*
+ * Invoke C1.
+ * Use the appropriate idle routine, the one that would
+ * be used without acpi C-states.
+ */
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+
+ /*
+ * TBD: Can't get time duration while in C1, as resumes
+ * go to an ISR rather than here. Need to instrument
+ * base interrupt handler.
+ *
+ * Note: the TSC better not stop in C1, sched_clock() will
+ * skew otherwise.
+ */
+ sleep_ticks = 0xFFFFFFFF;
+ break;
+
+ case ACPI_STATE_C2:
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Tell the scheduler that we are going deep-idle: */
+ sched_clock_idle_sleep_event();
+ /* Invoke C2 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C2, so notify users */
+ mark_tsc_unstable("possible TSC halt in C2");
+#endif
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks = ticks_elapsed(t1, t2);
+
+ /* Tell the scheduler how much we idled: */
+ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
+ /* Re-enable interrupts */
+ local_irq_enable();
+ /* Do not account our idle-switching overhead: */
+ sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
+
+ current_thread_info()->status |= TS_POLLING;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ case ACPI_STATE_C3:
+ /*
+ * disable bus master
+ * bm_check implies we need ARB_DIS
+ * !bm_check implies we need cache flush
+ * bm_control implies whether we can do ARB_DIS
+ *
+ * That leaves a case where bm_check is set and bm_control is
+ * not set. In that case we cannot do much, we enter C3
+ * without doing anything.
+ */
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ if (atomic_inc_return(&c3_cpu_count) ==
+ num_online_cpus()) {
+ /*
+ * All CPUs are trying to go to C3
+ * Disable bus master arbitration
+ */
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
+ }
+ } else if (!pr->flags.bm_check) {
+ /* SMP with no shared cache... Invalidate cache */
+ ACPI_FLUSH_CPU_CACHE();
+ }
+
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Invoke C3 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ /* Tell the scheduler that we are going deep-idle: */
+ sched_clock_idle_sleep_event();
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ /* Enable bus master arbitration */
+ atomic_dec(&c3_cpu_count);
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
+ }
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C3, so notify users */
+ mark_tsc_unstable("TSC halts in C3");
+#endif
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks = ticks_elapsed(t1, t2);
+ /* Tell the scheduler how much we idled: */
+ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
+ /* Re-enable interrupts */
+ local_irq_enable();
+ /* Do not account our idle-switching overhead: */
+ sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
+
+ current_thread_info()->status |= TS_POLLING;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ default:
+ local_irq_enable();
+ return;
+ }
+ cx->usage++;
+ if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
+ cx->time += sleep_ticks;
+
+ next_state = pr->power.state;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /* Don't do promotion/demotion */
+ if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
+ next_state = cx;
+ goto end;
+ }
+#endif
+
+ /*
+ * Promotion?
+ * ----------
+ * Track the number of longs (time asleep is greater than threshold)
+ * and promote when the count threshold is reached. Note that bus
+ * mastering activity may prevent promotions.
+ * Do not promote above max_cstate.
+ */
+ if (cx->promotion.state &&
+ ((cx->promotion.state - pr->power.states) <= max_cstate)) {
+ if (sleep_ticks > cx->promotion.threshold.ticks &&
+ cx->promotion.state->latency <= system_latency_constraint()) {
+ cx->promotion.count++;
+ cx->demotion.count = 0;
+ if (cx->promotion.count >=
+ cx->promotion.threshold.count) {
+ if (pr->flags.bm_check) {
+ if (!
+ (pr->power.bm_activity & cx->
+ promotion.threshold.bm)) {
+ next_state =
+ cx->promotion.state;
+ goto end;
+ }
+ } else {
+ next_state = cx->promotion.state;
+ goto end;
+ }
+ }
+ }
+ }
+
+ /*
+ * Demotion?
+ * ---------
+ * Track the number of shorts (time asleep is less than time threshold)
+ * and demote when the usage threshold is reached.
+ */
+ if (cx->demotion.state) {
+ if (sleep_ticks < cx->demotion.threshold.ticks) {
+ cx->demotion.count++;
+ cx->promotion.count = 0;
+ if (cx->demotion.count >= cx->demotion.threshold.count) {
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+ }
+
+ end:
+ /*
+ * Demote if current state exceeds max_cstate
+ * or if the latency of the current state is unacceptable
+ */
+ if ((pr->power.state - pr->power.states) > max_cstate ||
+ pr->power.state->latency > system_latency_constraint()) {
+ if (cx->demotion.state)
+ next_state = cx->demotion.state;
+ }
+
+ /*
+ * New Cx State?
+ * -------------
+ * If we're going to start using a new Cx state we must clean up
+ * from the previous and prepare to use the new.
+ */
+ if (next_state != pr->power.state)
+ acpi_processor_power_activate(pr, next_state);
+}
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr)
+{
+ unsigned int i;
+ unsigned int state_is_set = 0;
+ struct acpi_processor_cx *lower = NULL;
+ struct acpi_processor_cx *higher = NULL;
+ struct acpi_processor_cx *cx;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ /*
+ * This function sets the default Cx state policy (OS idle handler).
+ * Our scheme is to promote quickly to C2 but more conservatively
+ * to C3. We're favoring C2 for its characteristics of low latency
+ * (quick response), good power savings, and ability to allow bus
+ * mastering activity. Note that the Cx state policy is completely
+ * customizable and can be altered dynamically.
+ */
+
+ /* startup state */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (!state_is_set)
+ pr->power.state = cx;
+ state_is_set++;
+ break;
+ }
+
+ if (!state_is_set)
+ return -ENODEV;
+
+ /* demotion */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (lower) {
+ cx->demotion.state = lower;
+ cx->demotion.threshold.ticks = cx->latency_ticks;
+ cx->demotion.threshold.count = 1;
+ if (cx->type == ACPI_STATE_C3)
+ cx->demotion.threshold.bm = bm_history;
+ }
+
+ lower = cx;
+ }
+
+ /* promotion */
+ for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (higher) {
+ cx->promotion.state = higher;
+ cx->promotion.threshold.ticks = cx->latency_ticks;
+ if (cx->type >= ACPI_STATE_C2)
+ cx->promotion.threshold.count = 4;
+ else
+ cx->promotion.threshold.count = 10;
+ if (higher->type == ACPI_STATE_C3)
+ cx->promotion.threshold.bm = bm_history;
+ }
+
+ higher = cx;
+ }
+
+ return 0;
+}
+
+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+ int result = 0;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ if (nocst) {
+ return -ENODEV;
+ }
+
+ if (!pr->flags.power_setup_done)
+ return -ENODEV;
+
+ /* Fall back to the default idle loop */
+ pm_idle = pm_idle_save;
+ synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
+
+ pr->flags.power = 0;
+ result = acpi_processor_get_power_info(pr);
+ if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
+ pm_idle = acpi_processor_idle;
+
+ return result;
+}
+
+#ifdef CONFIG_SMP
+static void smp_callback(void *v)
+{
+ /* we already woke the CPU up, nothing more to do */
+}
+
+/*
+ * This function gets called when a part of the kernel has a new latency
+ * requirement. This means we need to get all processors out of their C-state,
+ * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
+ * wakes them all right up.
+ */
+static int acpi_processor_latency_notify(struct notifier_block *b,
+ unsigned long l, void *v)
+{
+ smp_call_function(smp_callback, NULL, 0, 1);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block acpi_processor_latency_notifier = {
+ .notifier_call = acpi_processor_latency_notify,
+};
+
+#endif
+
+#endif
+
int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
{
@@ -1104,6 +1685,9 @@ int __cpuinit acpi_processor_power_init(
"ACPI: processor limited to max C-state %d\n",
max_cstate);
first_run++;
+#if !defined (CONFIG_CPU_IDLE) && defined (CONFIG_SMP)
+ register_latency_notifier(&acpi_processor_latency_notifier);
+#endif
}
if (!pr)
@@ -1127,10 +1711,12 @@ int __cpuinit acpi_processor_power_init(
* platforms that only support C1.
*/
if ((pr->flags.power) && (!boot_option_idle_override)) {
+#ifdef CONFIG_CPU_IDLE
acpi_processor_setup_cpuidle(pr);
pr->power.dev.cpu = pr->id;
if (cpuidle_register_device(&pr->power.dev))
return -EIO;
+#endif
printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
for (i = 1; i <= pr->power.count; i++)
@@ -1138,6 +1724,13 @@ int __cpuinit acpi_processor_power_init(
printk(" C%d[C%d]", i,
pr->power.states[i].type);
printk(")\n");
+
+#ifndef CONFIG_CPU_IDLE
+ if (pr->id == 0) {
+ pm_idle_save = pm_idle;
+ pm_idle = acpi_processor_idle;
+ }
+#endif
}
/* 'power' [R] */
@@ -1157,12 +1750,33 @@ int __cpuinit acpi_processor_power_init(
int acpi_processor_power_exit(struct acpi_processor *pr,
struct acpi_device *device)
{
+#ifdef CONFIG_CPU_IDLE
if ((pr->flags.power) && (!boot_option_idle_override))
cpuidle_unregister_device(&pr->power.dev);
+#endif
pr->flags.power_setup_done = 0;
if (acpi_device_dir(device))
remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
acpi_device_dir(device));
+
+#ifndef CONFIG_CPU_IDLE
+
+ /* Unregister the idle handler when processor #0 is removed. */
+ if (pr->id == 0) {
+ pm_idle = pm_idle_save;
+
+ /*
+ * We are about to unload the current idle thread pm callback
+ * (pm_idle), Wait for all processors to update cached/local
+ * copies of pm_idle before proceeding.
+ */
+ cpu_idle_wait();
+#ifdef CONFIG_SMP
+ unregister_latency_notifier(&acpi_processor_latency_notifier);
+#endif
+ }
+#endif
+
return 0;
}
-
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