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ACPI / cpuidle: Common callback routine for entering states 

Introduce a common ->enter callback routine for the ACPI cpuidle
driver, acpi_idle_enter(), which helps to reduce code complexity,
size and duplication and prevents theoretically possible failues that
an incorrect routine may be run to enter the given idle state due to
a firmware bug (eg. when _CST returns a different set of states for
each processor).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2015-02-03 21:55:11 +01:00
parent d2cecb3d66
commit 6491bc0c61
1 changed files with 45 additions and 73 deletions
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118
drivers/acpi/processor_idle.c
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@ -737,74 +737,17 @@ static bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
!pr->flags.has_cst;
}
/**
* acpi_idle_enter_simple - enters a CPU idle state without BM handling
* @dev: the target CPU
* @drv: cpuidle driver with cpuidle state information
* @index: the index of suggested state
*/
static int acpi_idle_enter_simple(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
struct acpi_processor *pr;
struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
pr = __this_cpu_read(processors);
if (unlikely(!pr))
return -EINVAL;
if (cx->type != ACPI_STATE_C1 && acpi_idle_fallback_to_c1(pr)) {
index = CPUIDLE_DRIVER_STATE_START;
cx = per_cpu(acpi_cstate[index], dev->cpu);
}
lapic_timer_state_broadcast(pr, cx, 1);
if (cx->type == ACPI_STATE_C3)
ACPI_FLUSH_CPU_CACHE();
acpi_idle_do_entry(cx);
lapic_timer_state_broadcast(pr, cx, 0);
return index;
}
static int c3_cpu_count;
static DEFINE_RAW_SPINLOCK(c3_lock);
/**
* acpi_idle_enter_bm - enters C3 with proper BM handling
* @dev: the target CPU
* @drv: cpuidle driver containing state data
* @index: the index of suggested state
*
* If BM is detected, the deepest non-C3 idle state is entered instead.
* @pr: Target processor
* @cx: Target state context
*/
static int acpi_idle_enter_bm(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
static void acpi_idle_enter_bm(struct acpi_processor *pr,
struct acpi_processor_cx *cx)
{
struct acpi_processor *pr;
struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
pr = __this_cpu_read(processors);
if (unlikely(!pr))
return -EINVAL;
if (acpi_idle_fallback_to_c1(pr))
return acpi_idle_enter_simple(dev, drv, CPUIDLE_DRIVER_STATE_START);
if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
if (drv->safe_state_index >= 0) {
return drv->states[drv->safe_state_index].enter(dev,
drv, drv->safe_state_index);
} else {
acpi_safe_halt();
return -EBUSY;
}
}
acpi_unlazy_tlb(smp_processor_id());
/*
@ -842,6 +785,45 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
}
lapic_timer_state_broadcast(pr, cx, 0);
}
static int acpi_idle_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
struct acpi_processor *pr;
pr = __this_cpu_read(processors);
if (unlikely(!pr))
return -EINVAL;
if (cx->type != ACPI_STATE_C1) {
if (acpi_idle_fallback_to_c1(pr)) {
index = CPUIDLE_DRIVER_STATE_START;
cx = per_cpu(acpi_cstate[index], dev->cpu);
} else if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check) {
if (cx->bm_sts_skip || !acpi_idle_bm_check()) {
acpi_idle_enter_bm(pr, cx);
return index;
} else if (drv->safe_state_index >= 0) {
index = drv->safe_state_index;
cx = per_cpu(acpi_cstate[index], dev->cpu);
} else {
acpi_safe_halt();
return -EBUSY;
}
}
}
lapic_timer_state_broadcast(pr, cx, 1);
if (cx->type == ACPI_STATE_C3)
ACPI_FLUSH_CPU_CACHE();
acpi_idle_do_entry(cx);
lapic_timer_state_broadcast(pr, cx, 0);
return index;
}
@ -936,22 +918,12 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
state->exit_latency = cx->latency;
state->target_residency = cx->latency * latency_factor;
state->enter = acpi_idle_enter;
state->flags = 0;
switch (cx->type) {
case ACPI_STATE_C1:
case ACPI_STATE_C2:
state->enter = acpi_idle_enter_simple;
if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) {
state->enter_dead = acpi_idle_play_dead;
drv->safe_state_index = count;
break;
case ACPI_STATE_C3:
state->enter = pr->flags.bm_check ?
acpi_idle_enter_bm :
acpi_idle_enter_simple;
break;
}
count++;