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cpuidle: Single/Global registration of idle states

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This patch makes the cpuidle_states structure global (single copy)
instead of per-cpu. The statistics needed on per-cpu basis
by the governor are kept per-cpu. This simplifies the cpuidle
subsystem as state registration is done by single cpu only.
Having single copy of cpuidle_states saves memory. Rare case
of asymmetric C-states can be handled within the cpuidle driver
and architectures such as POWER do not have asymmetric C-states.

Having single/global registration of all the idle states,
dynamic C-state transitions on x86 are handled by
the boot cpu. Here, the boot cpu  would disable all the devices,
re-populate the states and later enable all the devices,
irrespective of the cpu that would receive the notification first.

Reference:
https://lkml.org/lkml/2011/4/25/83

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Deepthi Dharwar
2011-10-28 16:20:42 +05:30
committed by Len Brown
parent 4202735e8a
commit 46bcfad7a8
16 changed files with 438 additions and 206 deletions
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18
arch/sh/kernel/cpu/shmobile/cpuidle.c
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@@ -25,6 +25,7 @@ static unsigned long cpuidle_mode[] = {
};
static int cpuidle_sleep_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
unsigned long allowed_mode = arch_hwblk_sleep_mode();
@@ -64,19 +65,19 @@ static struct cpuidle_driver cpuidle_driver = {
void sh_mobile_setup_cpuidle(void)
{
struct cpuidle_device *dev = &cpuidle_dev;
struct cpuidle_driver *drv = &cpuidle_driver;
struct cpuidle_state *state;
int i;
cpuidle_register_driver(&cpuidle_driver);
for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
dev->states[i].name[0] = '\0';
dev->states[i].desc[0] = '\0';
drv->states[i].name[0] = '\0';
drv->states[i].desc[0] = '\0';
}
i = CPUIDLE_DRIVER_STATE_START;
state = &dev->states[i++];
state = &drv->states[i++];
snprintf(state->name, CPUIDLE_NAME_LEN, "C1");
strncpy(state->desc, "SuperH Sleep Mode", CPUIDLE_DESC_LEN);
state->exit_latency = 1;
@@ -86,10 +87,10 @@ void sh_mobile_setup_cpuidle(void)
state->flags |= CPUIDLE_FLAG_TIME_VALID;
state->enter = cpuidle_sleep_enter;
dev->safe_state_index = i-1;
drv->safe_state_index = i-1;
if (sh_mobile_sleep_supported & SUSP_SH_SF) {
state = &dev->states[i++];
state = &drv->states[i++];
snprintf(state->name, CPUIDLE_NAME_LEN, "C2");
strncpy(state->desc, "SuperH Sleep Mode [SF]",
CPUIDLE_DESC_LEN);
@@ -102,7 +103,7 @@ void sh_mobile_setup_cpuidle(void)
}
if (sh_mobile_sleep_supported & SUSP_SH_STANDBY) {
state = &dev->states[i++];
state = &drv->states[i++];
snprintf(state->name, CPUIDLE_NAME_LEN, "C3");
strncpy(state->desc, "SuperH Mobile Standby Mode [SF]",
CPUIDLE_DESC_LEN);
@@ -114,7 +115,10 @@ void sh_mobile_setup_cpuidle(void)
state->enter = cpuidle_sleep_enter;
}
drv->state_count = i;
dev->state_count = i;
cpuidle_register_driver(&cpuidle_driver);
cpuidle_register_device(dev);
}