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Date: Tue, 03 Feb 2015 22:15:47 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM list <linux-pm@...r.kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Len Brown <len.brown@...el.com>,
Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 2/2] ACPI / cpuidle: Common callback routine for entering states
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
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@...el.com>
---
drivers/acpi/processor_idle.c | 118 ++++++++++++++++--------------------------
1 file changed, 45 insertions(+), 73 deletions(-)
Index: linux-pm/drivers/acpi/processor_idle.c
===================================================================
--- linux-pm.orig/drivers/acpi/processor_idle.c
+++ linux-pm/drivers/acpi/processor_idle.c
@@ -737,74 +737,17 @@ static bool acpi_idle_fallback_to_c1(str
!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 cpu
}
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_
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++;
--
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