From e978aa7d7d57d04eb5f88a7507c4fb98577def77 Mon Sep 17 00:00:00 2001 From: Deepthi Dharwar Date: Fri, 28 Oct 2011 16:20:09 +0530 Subject: cpuidle: Move dev->last_residency update to driver enter routine; remove dev->last_state Cpuidle governor only suggests the state to enter using the governor->select() interface, but allows the low level driver to override the recommended state. The actual entered state may be different because of software or hardware demotion. Software demotion is done by the back-end cpuidle driver and can be accounted correctly. Current cpuidle code uses last_state field to capture the actual state entered and based on that updates the statistics for the state entered. Ideally the driver enter routine should update the counters, and it should return the state actually entered rather than the time spent there. The generic cpuidle code should simply handle where the counters live in the sysfs namespace, not updating the counters. Reference: https://lkml.org/lkml/2011/3/25/52 Signed-off-by: Deepthi Dharwar Signed-off-by: Trinabh Gupta Tested-by: Jean Pihet Reviewed-by: Kevin Hilman Acked-by: Arjan van de Ven Acked-by: Kevin Hilman Signed-off-by: Len Brown --- arch/arm/mach-at91/cpuidle.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'arch/arm/mach-at91/cpuidle.c') diff --git a/arch/arm/mach-at91/cpuidle.c b/arch/arm/mach-at91/cpuidle.c index 1cfeac1..4696a0d 100644 --- a/arch/arm/mach-at91/cpuidle.c +++ b/arch/arm/mach-at91/cpuidle.c @@ -33,7 +33,7 @@ static struct cpuidle_driver at91_idle_driver = { /* Actual code that puts the SoC in different idle states */ static int at91_enter_idle(struct cpuidle_device *dev, - struct cpuidle_state *state) + int index) { struct timeval before, after; int idle_time; @@ -41,10 +41,10 @@ static int at91_enter_idle(struct cpuidle_device *dev, local_irq_disable(); do_gettimeofday(&before); - if (state == &dev->states[0]) + if (index == 0) /* Wait for interrupt state */ cpu_do_idle(); - else if (state == &dev->states[1]) { + else if (index == 1) { asm("b 1f; .align 5; 1:"); asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ saved_lpr = sdram_selfrefresh_enable(); @@ -55,7 +55,9 @@ static int at91_enter_idle(struct cpuidle_device *dev, local_irq_enable(); idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + (after.tv_usec - before.tv_usec); - return idle_time; + + dev->last_residency = idle_time; + return index; } /* Initialize CPU idle by registering the idle states */ -- cgit v1.1 From 46bcfad7a819bd17ac4e831b04405152d59784ab Mon Sep 17 00:00:00 2001 From: Deepthi Dharwar Date: Fri, 28 Oct 2011 16:20:42 +0530 Subject: 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 Signed-off-by: Trinabh Gupta Tested-by: Jean Pihet Reviewed-by: Kevin Hilman Acked-by: Arjan van de Ven Acked-by: Kevin Hilman Signed-off-by: Len Brown --- arch/arm/mach-at91/cpuidle.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) (limited to 'arch/arm/mach-at91/cpuidle.c') diff --git a/arch/arm/mach-at91/cpuidle.c b/arch/arm/mach-at91/cpuidle.c index 4696a0d..93178f6 100644 --- a/arch/arm/mach-at91/cpuidle.c +++ b/arch/arm/mach-at91/cpuidle.c @@ -33,6 +33,7 @@ static struct cpuidle_driver at91_idle_driver = { /* Actual code that puts the SoC in different idle states */ static int at91_enter_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) { struct timeval before, after; @@ -64,27 +65,29 @@ static int at91_enter_idle(struct cpuidle_device *dev, static int at91_init_cpuidle(void) { struct cpuidle_device *device; - - cpuidle_register_driver(&at91_idle_driver); + struct cpuidle_driver *driver = &at91_idle_driver; device = &per_cpu(at91_cpuidle_device, smp_processor_id()); device->state_count = AT91_MAX_STATES; + driver->state_count = AT91_MAX_STATES; /* Wait for interrupt state */ - device->states[0].enter = at91_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 = at91_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 RAM self refresh state */ - device->states[1].enter = at91_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, "RAM_SR"); - strcpy(device->states[1].desc, "WFI and RAM Self Refresh"); + driver->states[1].enter = at91_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, "RAM_SR"); + strcpy(driver->states[1].desc, "WFI and RAM Self Refresh"); + + cpuidle_register_driver(&at91_idle_driver); if (cpuidle_register_device(device)) { printk(KERN_ERR "at91_init_cpuidle: Failed registering\n"); -- cgit v1.1