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authorDeepthi Dharwar <deepthi@linux.vnet.ibm.com>2011-10-28 14:50:42 +0400
committerLen Brown <len.brown@intel.com>2011-11-07 06:13:58 +0400
commit46bcfad7a819bd17ac4e831b04405152d59784ab (patch)
tree20041e788154d103edff2699f88d4a30320e3ee2 /arch/arm/mach-kirkwood
parent4202735e8ab6ecfb0381631a0d0b58fefe0bd4e2 (diff)
downloadlinux-46bcfad7a819bd17ac4e831b04405152d59784ab.tar.xz
cpuidle: Single/Global registration of idle states
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>
Diffstat (limited to 'arch/arm/mach-kirkwood')
-rw-r--r--arch/arm/mach-kirkwood/cpuidle.c30
1 files changed, 16 insertions, 14 deletions
diff --git a/arch/arm/mach-kirkwood/cpuidle.c b/arch/arm/mach-kirkwood/cpuidle.c
index 358dd80b3a07..ffd690dc3d33 100644
--- a/arch/arm/mach-kirkwood/cpuidle.c
+++ b/arch/arm/mach-kirkwood/cpuidle.c
@@ -32,6 +32,7 @@ static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
/* Actual code that puts the SoC in different idle states */
static int kirkwood_enter_idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
int index)
{
struct timeval before, after;
@@ -68,28 +69,29 @@ static int kirkwood_enter_idle(struct cpuidle_device *dev,
static int kirkwood_init_cpuidle(void)
{
struct cpuidle_device *device;
-
- cpuidle_register_driver(&kirkwood_idle_driver);
+ struct cpuidle_driver *driver = &kirkwood_idle_driver;
device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
device->state_count = KIRKWOOD_MAX_STATES;
+ driver->state_count = KIRKWOOD_MAX_STATES;
/* Wait for interrupt state */
- device->states[0].enter = kirkwood_enter_idle;
- device->states[0].exit_latency = 1;
- device->states[0].target_residency = 10000;
- device->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
- strcpy(device->states[0].name, "WFI");
- strcpy(device->states[0].desc, "Wait for interrupt");
+ driver->states[0].enter = kirkwood_enter_idle;
+ driver->states[0].exit_latency = 1;
+ driver->states[0].target_residency = 10000;
+ driver->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
+ strcpy(driver->states[0].name, "WFI");
+ strcpy(driver->states[0].desc, "Wait for interrupt");
/* Wait for interrupt and DDR self refresh state */
- device->states[1].enter = kirkwood_enter_idle;
- device->states[1].exit_latency = 10;
- device->states[1].target_residency = 10000;
- device->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
- strcpy(device->states[1].name, "DDR SR");
- strcpy(device->states[1].desc, "WFI and DDR Self Refresh");
+ driver->states[1].enter = kirkwood_enter_idle;
+ driver->states[1].exit_latency = 10;
+ driver->states[1].target_residency = 10000;
+ driver->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
+ strcpy(driver->states[1].name, "DDR SR");
+ strcpy(driver->states[1].desc, "WFI and DDR Self Refresh");
+ cpuidle_register_driver(&kirkwood_idle_driver);
if (cpuidle_register_device(device)) {
printk(KERN_ERR "kirkwood_init_cpuidle: Failed registering\n");
return -EIO;