kernel-ark/drivers/cpuidle/cpuidle-pseries.c
Daniel Lezcano b82b6cca48 cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logic
The only place where the time is invalid is when the ACPI_CSTATE_FFH entry
method is not set. Otherwise for all the drivers, the time can be correctly
measured.

Instead of duplicating the CPUIDLE_FLAG_TIME_VALID flag in all the drivers
for all the states, just invert the logic by replacing it by the flag
CPUIDLE_FLAG_TIME_INVALID, hence we can set this flag only for the acpi idle
driver, remove the former flag from all the drivers and invert the logic with
this flag in the different governor.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-11-12 21:17:27 +01:00

271 lines
5.6 KiB
C

/*
* cpuidle-pseries - idle state cpuidle driver.
* Adapted from drivers/idle/intel_idle.c and
* drivers/acpi/processor_idle.c
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/cpuidle.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <asm/paca.h>
#include <asm/reg.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/runlatch.h>
#include <asm/plpar_wrappers.h>
struct cpuidle_driver pseries_idle_driver = {
.name = "pseries_idle",
.owner = THIS_MODULE,
};
static int max_idle_state;
static struct cpuidle_state *cpuidle_state_table;
static inline void idle_loop_prolog(unsigned long *in_purr)
{
ppc64_runlatch_off();
*in_purr = mfspr(SPRN_PURR);
/*
* Indicate to the HV that we are idle. Now would be
* a good time to find other work to dispatch.
*/
get_lppaca()->idle = 1;
}
static inline void idle_loop_epilog(unsigned long in_purr)
{
u64 wait_cycles;
wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
wait_cycles += mfspr(SPRN_PURR) - in_purr;
get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
get_lppaca()->idle = 0;
if (irqs_disabled())
local_irq_enable();
ppc64_runlatch_on();
}
static int snooze_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
unsigned long in_purr;
idle_loop_prolog(&in_purr);
local_irq_enable();
set_thread_flag(TIF_POLLING_NRFLAG);
while (!need_resched()) {
HMT_low();
HMT_very_low();
}
HMT_medium();
clear_thread_flag(TIF_POLLING_NRFLAG);
smp_mb();
idle_loop_epilog(in_purr);
return index;
}
static void check_and_cede_processor(void)
{
/*
* Ensure our interrupt state is properly tracked,
* also checks if no interrupt has occurred while we
* were soft-disabled
*/
if (prep_irq_for_idle()) {
cede_processor();
#ifdef CONFIG_TRACE_IRQFLAGS
/* Ensure that H_CEDE returns with IRQs on */
if (WARN_ON(!(mfmsr() & MSR_EE)))
__hard_irq_enable();
#endif
}
}
static int dedicated_cede_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
unsigned long in_purr;
idle_loop_prolog(&in_purr);
get_lppaca()->donate_dedicated_cpu = 1;
HMT_medium();
check_and_cede_processor();
get_lppaca()->donate_dedicated_cpu = 0;
idle_loop_epilog(in_purr);
return index;
}
static int shared_cede_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
unsigned long in_purr;
idle_loop_prolog(&in_purr);
/*
* Yield the processor to the hypervisor. We return if
* an external interrupt occurs (which are driven prior
* to returning here) or if a prod occurs from another
* processor. When returning here, external interrupts
* are enabled.
*/
check_and_cede_processor();
idle_loop_epilog(in_purr);
return index;
}
/*
* States for dedicated partition case.
*/
static struct cpuidle_state dedicated_states[] = {
{ /* Snooze */
.name = "snooze",
.desc = "snooze",
.exit_latency = 0,
.target_residency = 0,
.enter = &snooze_loop },
{ /* CEDE */
.name = "CEDE",
.desc = "CEDE",
.exit_latency = 10,
.target_residency = 100,
.enter = &dedicated_cede_loop },
};
/*
* States for shared partition case.
*/
static struct cpuidle_state shared_states[] = {
{ /* Shared Cede */
.name = "Shared Cede",
.desc = "Shared Cede",
.exit_latency = 0,
.target_residency = 0,
.enter = &shared_cede_loop },
};
static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
unsigned long action, void *hcpu)
{
int hotcpu = (unsigned long)hcpu;
struct cpuidle_device *dev =
per_cpu(cpuidle_devices, hotcpu);
if (dev && cpuidle_get_driver()) {
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
cpuidle_pause_and_lock();
cpuidle_enable_device(dev);
cpuidle_resume_and_unlock();
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
cpuidle_pause_and_lock();
cpuidle_disable_device(dev);
cpuidle_resume_and_unlock();
break;
default:
return NOTIFY_DONE;
}
}
return NOTIFY_OK;
}
static struct notifier_block setup_hotplug_notifier = {
.notifier_call = pseries_cpuidle_add_cpu_notifier,
};
/*
* pseries_cpuidle_driver_init()
*/
static int pseries_cpuidle_driver_init(void)
{
int idle_state;
struct cpuidle_driver *drv = &pseries_idle_driver;
drv->state_count = 0;
for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
/* Is the state not enabled? */
if (cpuidle_state_table[idle_state].enter == NULL)
continue;
drv->states[drv->state_count] = /* structure copy */
cpuidle_state_table[idle_state];
drv->state_count += 1;
}
return 0;
}
/*
* pseries_idle_probe()
* Choose state table for shared versus dedicated partition
*/
static int pseries_idle_probe(void)
{
if (cpuidle_disable != IDLE_NO_OVERRIDE)
return -ENODEV;
if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
if (lppaca_shared_proc(get_lppaca())) {
cpuidle_state_table = shared_states;
max_idle_state = ARRAY_SIZE(shared_states);
} else {
cpuidle_state_table = dedicated_states;
max_idle_state = ARRAY_SIZE(dedicated_states);
}
} else
return -ENODEV;
return 0;
}
static int __init pseries_processor_idle_init(void)
{
int retval;
retval = pseries_idle_probe();
if (retval)
return retval;
pseries_cpuidle_driver_init();
retval = cpuidle_register(&pseries_idle_driver, NULL);
if (retval) {
printk(KERN_DEBUG "Registration of pseries driver failed.\n");
return retval;
}
register_cpu_notifier(&setup_hotplug_notifier);
printk(KERN_DEBUG "pseries_idle_driver registered\n");
return 0;
}
device_initcall(pseries_processor_idle_init);