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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-02-06 18:41:06 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-02-11 23:34:57 +0100
commitbc721c1e4517a5110c4b0ae2e80345d3db6425fc (patch)
tree63075ae59344fdd693f13dc0b9736f283719846e /drivers/idle/intel_idle.c
parent40ab82e08d789d8f4437fec63142b40120c1c50f (diff)
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intel_idle: Clean up definitions of cpuidle callbacks
Add proper kerneldoc descriptions to intel_idle() and intel_idle_s2idle(), annotate the latter with __cpuidle and reorder the declarations of local variables in both of them to reflect the mwait_idle_with_hints() arguments order. No intentional functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/idle/intel_idle.c')
-rw-r--r--drivers/idle/intel_idle.c39
1 files changed, 27 insertions, 12 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 8d66efc53b89..5adc058c705d 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -892,19 +892,28 @@ static struct cpuidle_state dnv_cstates[] = {
};
/**
- * intel_idle
- * @dev: cpuidle_device
- * @drv: cpuidle driver
- * @index: index of cpuidle state
+ * intel_idle - Ask the processor to enter the given idle state.
+ * @dev: cpuidle device of the target CPU.
+ * @drv: cpuidle driver (assumed to point to intel_idle_driver).
+ * @index: Target idle state index.
+ *
+ * Use the MWAIT instruction to notify the processor that the CPU represented by
+ * @dev is idle and it can try to enter the idle state corresponding to @index.
+ *
+ * If the local APIC timer is not known to be reliable in the target idle state,
+ * enable one-shot tick broadcasting for the target CPU before executing MWAIT.
+ *
+ * Optionally call leave_mm() for the target CPU upfront to avoid wakeups due to
+ * flushing user TLBs.
*
* Must be called under local_irq_disable().
*/
static __cpuidle int intel_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
- unsigned long ecx = 1; /* break on interrupt flag */
struct cpuidle_state *state = &drv->states[index];
unsigned long eax = flg2MWAIT(state->flags);
+ unsigned long ecx = 1; /* break on interrupt flag */
bool uninitialized_var(tick);
int cpu = smp_processor_id();
@@ -937,16 +946,22 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev,
}
/**
- * intel_idle_s2idle - simplified "enter" callback routine for suspend-to-idle
- * @dev: cpuidle_device
- * @drv: cpuidle driver
- * @index: state index
+ * intel_idle_s2idle - Ask the processor to enter the given idle state.
+ * @dev: cpuidle device of the target CPU.
+ * @drv: cpuidle driver (assumed to point to intel_idle_driver).
+ * @index: Target idle state index.
+ *
+ * Use the MWAIT instruction to notify the processor that the CPU represented by
+ * @dev is idle and it can try to enter the idle state corresponding to @index.
+ *
+ * Invoked as a suspend-to-idle callback routine with frozen user space, frozen
+ * scheduler tick and suspended scheduler clock on the target CPU.
*/
-static void intel_idle_s2idle(struct cpuidle_device *dev,
- struct cpuidle_driver *drv, int index)
+static __cpuidle void intel_idle_s2idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv, int index)
{
- unsigned long ecx = 1; /* break on interrupt flag */
unsigned long eax = flg2MWAIT(drv->states[index].flags);
+ unsigned long ecx = 1; /* break on interrupt flag */
mwait_idle_with_hints(eax, ecx);
}