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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
Download Patch File Download Diff File Expand all files Collapse all files
arch/arm/mach-davinci/cpuidle.c
+21 -18
View File
@@ -78,6 +78,7 @@ static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = {
/* Actual code that puts the SoC in different idle states */
static int davinci_enter_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
@@ -109,6 +110,7 @@ static int __init davinci_cpuidle_probe(struct platform_device *pdev)
{
int ret;
struct cpuidle_device *device;
struct cpuidle_driver *driver = &davinci_idle_driver;
struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
device = &per_cpu(davinci_cpuidle_device, smp_processor_id());
@@ -120,32 +122,33 @@ static int __init davinci_cpuidle_probe(struct platform_device *pdev)
ddr2_reg_base = pdata->ddr2_ctlr_base;
ret = cpuidle_register_driver(&davinci_idle_driver);
if (ret) {
dev_err(&pdev->dev, "failed to register driver\n");
return ret;
}
/* Wait for interrupt state */
device->states[0].enter = davinci_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 = davinci_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 = davinci_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 = davinci_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");
if (pdata->ddr2_pdown)
davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN;
cpuidle_set_statedata(&device->states_usage[1], &davinci_states[1]);
device->state_count = DAVINCI_CPUIDLE_MAX_STATES;
driver->state_count = DAVINCI_CPUIDLE_MAX_STATES;
ret = cpuidle_register_driver(&davinci_idle_driver);
if (ret) {
dev_err(&pdev->dev, "failed to register driver\n");
return ret;
}
ret = cpuidle_register_device(device);
if (ret) {