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author | Deepthi Dharwar <deepthi@linux.vnet.ibm.com> | 2011-10-28 14:50:42 +0400 |
---|---|---|
committer | Len Brown <len.brown@intel.com> | 2011-11-07 06:13:58 +0400 |
commit | 46bcfad7a819bd17ac4e831b04405152d59784ab (patch) | |
tree | 20041e788154d103edff2699f88d4a30320e3ee2 /arch/arm/mach-kirkwood | |
parent | 4202735e8ab6ecfb0381631a0d0b58fefe0bd4e2 (diff) | |
download | linux-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.c | 30 |
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; |