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Message-ID: <52173745.9060309@linux.vnet.ibm.com>
Date: Fri, 23 Aug 2013 15:49:49 +0530
From: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
CC: rjw@...k.pl, daniel.lezcano@...aro.org,
linux-kernel@...r.kernel.org, dongsheng.wang@...escale.com,
preeti@...ux.vnet.ibm.com, srivatsa.bhat@...ux.vnet.ibm.com,
scottwood@...escale.com, linux-pm@...ts.linux-foundation.org,
linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH V4 3/5] powerpc/cpuidle: Generic powerpc backend cpuidle
driver.
Hi Bartlomiej,
Thanks for the review.
On 08/22/2013 04:26 PM, Bartlomiej Zolnierkiewicz wrote:
>
> Hi,
>
> On Thursday, August 22, 2013 11:00:29 AM Deepthi Dharwar wrote:
>> This patch involves moving the current pseries_idle backend driver code
>> from pseries/processor_idle.c to drivers/cpuidle/cpuidle-powerpc.c,
>> and making the backend code generic enough to be able to extend this
>> driver code for both powernv and pseries.
>>
>> It enables the support for pseries platform, such that going forward the same code
>> with minimal efforts can be re-used for a common driver on powernv
>> and can be further extended to support cpuidle idle state mgmt for the rest
>> of the powerpc platforms in the future. This removes a lot of code duplicacy,
>> making the code elegant.
>
> This patch mixes the code movement with the actual code changes which is
> not a good practice as it makes review more difficult and is generally bad
> from the long term maintainance POV.
>
> Please split this patch on code movement and code changes parts.
Sure. I shall do so.
> V4 of this patch now also seems to contain changes which I posted on
> Tuesday as a part of dev->state_count removal patchset:
>
> http://permalink.gmane.org/gmane.linux.power-management.general/37392
> http://permalink.gmane.org/gmane.linux.power-management.general/37393
>
> so some work probably got duplicated. :(
>
Sorry about that. I have been re-writing this driver over the last few
weeks and this cleanup was on my to-do list since V1 as pointed out by
Daniel. I have missed seeing your cleanup.
Thanks for patch !
Regards,
Deepthi
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>
>> Signed-off-by: Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>
>> ---
>> arch/powerpc/include/asm/paca.h | 23 +
>> arch/powerpc/include/asm/processor.h | 2
>> arch/powerpc/platforms/pseries/Kconfig | 9 -
>> arch/powerpc/platforms/pseries/Makefile | 1
>> arch/powerpc/platforms/pseries/processor_idle.c | 360 -----------------------
>> drivers/cpuidle/Kconfig | 7
>> drivers/cpuidle/Makefile | 2
>> drivers/cpuidle/cpuidle-powerpc.c | 304 +++++++++++++++++++
>> 8 files changed, 337 insertions(+), 371 deletions(-)
>> delete mode 100644 arch/powerpc/platforms/pseries/processor_idle.c
>> create mode 100644 drivers/cpuidle/cpuidle-powerpc.c
>>
>> diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
>> index 77c91e7..7bd83ff 100644
>> --- a/arch/powerpc/include/asm/paca.h
>> +++ b/arch/powerpc/include/asm/paca.h
>> @@ -175,6 +175,29 @@ extern void setup_paca(struct paca_struct *new_paca);
>> extern void allocate_pacas(void);
>> extern void free_unused_pacas(void);
>>
>> +#ifdef CONFIG_PPC_BOOK3S
>> +#define get_lppaca_is_shared_proc() get_paca()->lppaca_ptr->shared_proc
>> +static inline void set_lppaca_idle(u8 idle)
>> +{
>> + get_paca()->lppaca_ptr->idle = idle;
>> +}
>> +
>> +static inline void add_lppaca_wait_state(u64 cycles)
>> +{
>> + get_paca()->lppaca_ptr->wait_state_cycles += cycles;
>> +}
>> +
>> +static inline void set_lppaca_donate_dedicated_cpu(u8 value)
>> +{
>> + get_paca()->lppaca_ptr->donate_dedicated_cpu = value;
>> +}
>> +#else
>> +#define get_lppaca_is_shared_proc() -1
>> +static inline void set_lppaca_idle(u8 idle) { }
>> +static inline void add_lppaca_wait_state(u64 cycles) { }
>> +static inline void set_lppaca_donate_dedicated_cpu(u8 value) { }
>> +#endif
>> +
>> #else /* CONFIG_PPC64 */
>>
>> static inline void allocate_pacas(void) { };
>> diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
>> index e378ccc..5f57c56 100644
>> --- a/arch/powerpc/include/asm/processor.h
>> +++ b/arch/powerpc/include/asm/processor.h
>> @@ -430,7 +430,7 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
>> extern int powersave_nap; /* set if nap mode can be used in idle loop */
>> extern void power7_nap(void);
>>
>> -#ifdef CONFIG_PSERIES_IDLE
>> +#ifdef CONFIG_CPU_IDLE_POWERPC
>> extern void update_smt_snooze_delay(int cpu, int residency);
>> #else
>> static inline void update_smt_snooze_delay(int cpu, int residency) {}
>> diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
>> index 62b4f80..bb59bb0 100644
>> --- a/arch/powerpc/platforms/pseries/Kconfig
>> +++ b/arch/powerpc/platforms/pseries/Kconfig
>> @@ -119,12 +119,3 @@ config DTL
>> which are accessible through a debugfs file.
>>
>> Say N if you are unsure.
>> -
>> -config PSERIES_IDLE
>> - bool "Cpuidle driver for pSeries platforms"
>> - depends on CPU_IDLE
>> - depends on PPC_PSERIES
>> - default y
>> - help
>> - Select this option to enable processor idle state management
>> - through cpuidle subsystem.
>> diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
>> index 8ae0103..4b22379 100644
>> --- a/arch/powerpc/platforms/pseries/Makefile
>> +++ b/arch/powerpc/platforms/pseries/Makefile
>> @@ -21,7 +21,6 @@ obj-$(CONFIG_HCALL_STATS) += hvCall_inst.o
>> obj-$(CONFIG_CMM) += cmm.o
>> obj-$(CONFIG_DTL) += dtl.o
>> obj-$(CONFIG_IO_EVENT_IRQ) += io_event_irq.o
>> -obj-$(CONFIG_PSERIES_IDLE) += processor_idle.o
>>
>> ifeq ($(CONFIG_PPC_PSERIES),y)
>> obj-$(CONFIG_SUSPEND) += suspend.o
>> diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
>> deleted file mode 100644
>> index c905b99..0000000
>> --- a/arch/powerpc/platforms/pseries/processor_idle.c
>> +++ /dev/null
>> @@ -1,360 +0,0 @@
>> -/*
>> - * processor_idle - idle state cpuidle driver.
>> - * Adapted from drivers/idle/intel_idle.c and
>> - * drivers/acpi/processor_idle.c
>> - *
>> - */
>> -
>> -#include <linux/kernel.h>
>> -#include <linux/module.h>
>> -#include <linux/init.h>
>> -#include <linux/moduleparam.h>
>> -#include <linux/cpuidle.h>
>> -#include <linux/cpu.h>
>> -#include <linux/notifier.h>
>> -
>> -#include <asm/paca.h>
>> -#include <asm/reg.h>
>> -#include <asm/machdep.h>
>> -#include <asm/firmware.h>
>> -#include <asm/runlatch.h>
>> -#include <asm/plpar_wrappers.h>
>> -
>> -struct cpuidle_driver pseries_idle_driver = {
>> - .name = "pseries_idle",
>> - .owner = THIS_MODULE,
>> -};
>> -
>> -#define MAX_IDLE_STATE_COUNT 2
>> -
>> -static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
>> -static struct cpuidle_device __percpu *pseries_cpuidle_devices;
>> -static struct cpuidle_state *cpuidle_state_table;
>> -
>> -static inline void idle_loop_prolog(unsigned long *in_purr)
>> -{
>> - *in_purr = mfspr(SPRN_PURR);
>> - /*
>> - * Indicate to the HV that we are idle. Now would be
>> - * a good time to find other work to dispatch.
>> - */
>> - get_lppaca()->idle = 1;
>> -}
>> -
>> -static inline void idle_loop_epilog(unsigned long in_purr)
>> -{
>> - get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr;
>> - get_lppaca()->idle = 0;
>> -}
>> -
>> -static int snooze_loop(struct cpuidle_device *dev,
>> - struct cpuidle_driver *drv,
>> - int index)
>> -{
>> - unsigned long in_purr;
>> - int cpu = dev->cpu;
>> -
>> - idle_loop_prolog(&in_purr);
>> - local_irq_enable();
>> - set_thread_flag(TIF_POLLING_NRFLAG);
>> -
>> - while ((!need_resched()) && cpu_online(cpu)) {
>> - ppc64_runlatch_off();
>> - HMT_low();
>> - HMT_very_low();
>> - }
>> -
>> - HMT_medium();
>> - clear_thread_flag(TIF_POLLING_NRFLAG);
>> - smp_mb();
>> -
>> - idle_loop_epilog(in_purr);
>> -
>> - return index;
>> -}
>> -
>> -static void check_and_cede_processor(void)
>> -{
>> - /*
>> - * Ensure our interrupt state is properly tracked,
>> - * also checks if no interrupt has occurred while we
>> - * were soft-disabled
>> - */
>> - if (prep_irq_for_idle()) {
>> - cede_processor();
>> -#ifdef CONFIG_TRACE_IRQFLAGS
>> - /* Ensure that H_CEDE returns with IRQs on */
>> - if (WARN_ON(!(mfmsr() & MSR_EE)))
>> - __hard_irq_enable();
>> -#endif
>> - }
>> -}
>> -
>> -static int dedicated_cede_loop(struct cpuidle_device *dev,
>> - struct cpuidle_driver *drv,
>> - int index)
>> -{
>> - unsigned long in_purr;
>> -
>> - idle_loop_prolog(&in_purr);
>> - get_lppaca()->donate_dedicated_cpu = 1;
>> -
>> - ppc64_runlatch_off();
>> - HMT_medium();
>> - check_and_cede_processor();
>> -
>> - get_lppaca()->donate_dedicated_cpu = 0;
>> -
>> - idle_loop_epilog(in_purr);
>> -
>> - return index;
>> -}
>> -
>> -static int shared_cede_loop(struct cpuidle_device *dev,
>> - struct cpuidle_driver *drv,
>> - int index)
>> -{
>> - unsigned long in_purr;
>> -
>> - idle_loop_prolog(&in_purr);
>> -
>> - /*
>> - * Yield the processor to the hypervisor. We return if
>> - * an external interrupt occurs (which are driven prior
>> - * to returning here) or if a prod occurs from another
>> - * processor. When returning here, external interrupts
>> - * are enabled.
>> - */
>> - check_and_cede_processor();
>> -
>> - idle_loop_epilog(in_purr);
>> -
>> - return index;
>> -}
>> -
>> -/*
>> - * States for dedicated partition case.
>> - */
>> -static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = {
>> - { /* Snooze */
>> - .name = "snooze",
>> - .desc = "snooze",
>> - .flags = CPUIDLE_FLAG_TIME_VALID,
>> - .exit_latency = 0,
>> - .target_residency = 0,
>> - .enter = &snooze_loop },
>> - { /* CEDE */
>> - .name = "CEDE",
>> - .desc = "CEDE",
>> - .flags = CPUIDLE_FLAG_TIME_VALID,
>> - .exit_latency = 10,
>> - .target_residency = 100,
>> - .enter = &dedicated_cede_loop },
>> -};
>> -
>> -/*
>> - * States for shared partition case.
>> - */
>> -static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
>> - { /* Shared Cede */
>> - .name = "Shared Cede",
>> - .desc = "Shared Cede",
>> - .flags = CPUIDLE_FLAG_TIME_VALID,
>> - .exit_latency = 0,
>> - .target_residency = 0,
>> - .enter = &shared_cede_loop },
>> -};
>> -
>> -void update_smt_snooze_delay(int cpu, int residency)
>> -{
>> - struct cpuidle_driver *drv = cpuidle_get_driver();
>> - struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
>> -
>> - if (cpuidle_state_table != dedicated_states)
>> - return;
>> -
>> - if (residency < 0) {
>> - /* Disable the Nap state on that cpu */
>> - if (dev)
>> - dev->states_usage[1].disable = 1;
>> - } else
>> - if (drv)
>> - drv->states[1].target_residency = residency;
>> -}
>> -
>> -static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
>> - unsigned long action, void *hcpu)
>> -{
>> - int hotcpu = (unsigned long)hcpu;
>> - struct cpuidle_device *dev =
>> - per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
>> -
>> - if (dev && cpuidle_get_driver()) {
>> - switch (action) {
>> - case CPU_ONLINE:
>> - case CPU_ONLINE_FROZEN:
>> - cpuidle_pause_and_lock();
>> - cpuidle_enable_device(dev);
>> - cpuidle_resume_and_unlock();
>> - break;
>> -
>> - case CPU_DEAD:
>> - case CPU_DEAD_FROZEN:
>> - cpuidle_pause_and_lock();
>> - cpuidle_disable_device(dev);
>> - cpuidle_resume_and_unlock();
>> - break;
>> -
>> - default:
>> - return NOTIFY_DONE;
>> - }
>> - }
>> - return NOTIFY_OK;
>> -}
>> -
>> -static struct notifier_block setup_hotplug_notifier = {
>> - .notifier_call = pseries_cpuidle_add_cpu_notifier,
>> -};
>> -
>> -/*
>> - * pseries_cpuidle_driver_init()
>> - */
>> -static int pseries_cpuidle_driver_init(void)
>> -{
>> - int idle_state;
>> - struct cpuidle_driver *drv = &pseries_idle_driver;
>> -
>> - drv->state_count = 0;
>> -
>> - for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) {
>> -
>> - if (idle_state > max_idle_state)
>> - break;
>> -
>> - /* is the state not enabled? */
>> - if (cpuidle_state_table[idle_state].enter == NULL)
>> - continue;
>> -
>> - drv->states[drv->state_count] = /* structure copy */
>> - cpuidle_state_table[idle_state];
>> -
>> - drv->state_count += 1;
>> - }
>> -
>> - return 0;
>> -}
>> -
>> -/* pseries_idle_devices_uninit(void)
>> - * unregister cpuidle devices and de-allocate memory
>> - */
>> -static void pseries_idle_devices_uninit(void)
>> -{
>> - int i;
>> - struct cpuidle_device *dev;
>> -
>> - for_each_possible_cpu(i) {
>> - dev = per_cpu_ptr(pseries_cpuidle_devices, i);
>> - cpuidle_unregister_device(dev);
>> - }
>> -
>> - free_percpu(pseries_cpuidle_devices);
>> - return;
>> -}
>> -
>> -/* pseries_idle_devices_init()
>> - * allocate, initialize and register cpuidle device
>> - */
>> -static int pseries_idle_devices_init(void)
>> -{
>> - int i;
>> - struct cpuidle_driver *drv = &pseries_idle_driver;
>> - struct cpuidle_device *dev;
>> -
>> - pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device);
>> - if (pseries_cpuidle_devices == NULL)
>> - return -ENOMEM;
>> -
>> - for_each_possible_cpu(i) {
>> - dev = per_cpu_ptr(pseries_cpuidle_devices, i);
>> - dev->state_count = drv->state_count;
>> - dev->cpu = i;
>> - if (cpuidle_register_device(dev)) {
>> - printk(KERN_DEBUG \
>> - "cpuidle_register_device %d failed!\n", i);
>> - return -EIO;
>> - }
>> - }
>> -
>> - return 0;
>> -}
>> -
>> -/*
>> - * pseries_idle_probe()
>> - * Choose state table for shared versus dedicated partition
>> - */
>> -static int pseries_idle_probe(void)
>> -{
>> -
>> - if (!firmware_has_feature(FW_FEATURE_SPLPAR))
>> - return -ENODEV;
>> -
>> - if (cpuidle_disable != IDLE_NO_OVERRIDE)
>> - return -ENODEV;
>> -
>> - if (max_idle_state == 0) {
>> - printk(KERN_DEBUG "pseries processor idle disabled.\n");
>> - return -EPERM;
>> - }
>> -
>> - if (get_lppaca()->shared_proc)
>> - cpuidle_state_table = shared_states;
>> - else
>> - cpuidle_state_table = dedicated_states;
>> -
>> - return 0;
>> -}
>> -
>> -static int __init pseries_processor_idle_init(void)
>> -{
>> - int retval;
>> -
>> - retval = pseries_idle_probe();
>> - if (retval)
>> - return retval;
>> -
>> - pseries_cpuidle_driver_init();
>> - retval = cpuidle_register_driver(&pseries_idle_driver);
>> - if (retval) {
>> - printk(KERN_DEBUG "Registration of pseries driver failed.\n");
>> - return retval;
>> - }
>> -
>> - retval = pseries_idle_devices_init();
>> - if (retval) {
>> - pseries_idle_devices_uninit();
>> - cpuidle_unregister_driver(&pseries_idle_driver);
>> - return retval;
>> - }
>> -
>> - register_cpu_notifier(&setup_hotplug_notifier);
>> - printk(KERN_DEBUG "pseries_idle_driver registered\n");
>> -
>> - return 0;
>> -}
>> -
>> -static void __exit pseries_processor_idle_exit(void)
>> -{
>> -
>> - unregister_cpu_notifier(&setup_hotplug_notifier);
>> - pseries_idle_devices_uninit();
>> - cpuidle_unregister_driver(&pseries_idle_driver);
>> -
>> - return;
>> -}
>> -
>> -module_init(pseries_processor_idle_init);
>> -module_exit(pseries_processor_idle_exit);
>> -
>> -MODULE_AUTHOR("Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>");
>> -MODULE_DESCRIPTION("Cpuidle driver for POWER");
>> -MODULE_LICENSE("GPL");
>> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
>> index 0e2cd5c..53ce03d 100644
>> --- a/drivers/cpuidle/Kconfig
>> +++ b/drivers/cpuidle/Kconfig
>> @@ -42,6 +42,13 @@ config CPU_IDLE_ZYNQ
>> help
>> Select this to enable cpuidle on Xilinx Zynq processors.
>>
>> +config CPU_IDLE_POWERPC
>> + bool "CPU Idle driver for POWERPC platforms"
>> + depends on PPC_PSERIES || PPC_POWERNV
>> + default y
>> + help
>> + Select this option to enable processor idle state management
>> + for POWERPC platform.
>> endif
>>
>> config ARCH_NEEDS_CPU_IDLE_COUPLED
>> diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
>> index 8767a7b..d12e205 100644
>> --- a/drivers/cpuidle/Makefile
>> +++ b/drivers/cpuidle/Makefile
>> @@ -8,3 +8,5 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
>> obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o
>> obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o
>> obj-$(CONFIG_CPU_IDLE_ZYNQ) += cpuidle-zynq.o
>> +
>> +obj-$(CONFIG_CPU_IDLE_POWERPC) += cpuidle-powerpc.o
>> diff --git a/drivers/cpuidle/cpuidle-powerpc.c b/drivers/cpuidle/cpuidle-powerpc.c
>> new file mode 100644
>> index 0000000..3662aba
>> --- /dev/null
>> +++ b/drivers/cpuidle/cpuidle-powerpc.c
>> @@ -0,0 +1,304 @@
>> +/*
>> + * processor_idle - idle state cpuidle driver.
>> + * Adapted from drivers/idle/intel_idle.c and
>> + * drivers/acpi/processor_idle.c
>> + *
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/moduleparam.h>
>> +#include <linux/cpuidle.h>
>> +#include <linux/cpu.h>
>> +#include <linux/notifier.h>
>> +
>> +#include <asm/paca.h>
>> +#include <asm/reg.h>
>> +#include <asm/machdep.h>
>> +#include <asm/firmware.h>
>> +#include <asm/runlatch.h>
>> +#include <asm/plpar_wrappers.h>
>> +
>> +struct cpuidle_driver powerpc_idle_driver = {
>> + .name = "powerpc_idle",
>> + .owner = THIS_MODULE,
>> +};
>> +
>> +#define MAX_IDLE_STATE_COUNT 2
>> +
>> +static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
>> +static struct cpuidle_state *cpuidle_state_table;
>> +
>> +static inline void idle_loop_prolog(unsigned long *in_purr)
>> +{
>> + *in_purr = mfspr(SPRN_PURR);
>> + /*
>> + * Indicate to the HV that we are idle. Now would be
>> + * a good time to find other work to dispatch.
>> + */
>> + set_lppaca_idle(1);
>> +}
>> +
>> +static inline void idle_loop_epilog(unsigned long in_purr)
>> +{
>> + add_lppaca_wait_state(mfspr(SPRN_PURR) - in_purr);
>> + set_lppaca_idle(0);
>> +}
>> +
>> +static int snooze_loop(struct cpuidle_device *dev,
>> + struct cpuidle_driver *drv,
>> + int index)
>> +{
>> + unsigned long in_purr;
>> +
>> + idle_loop_prolog(&in_purr);
>> + local_irq_enable();
>> + set_thread_flag(TIF_POLLING_NRFLAG);
>> +
>> + while (!need_resched()) {
>> + ppc64_runlatch_off();
>> + HMT_low();
>> + HMT_very_low();
>> + }
>> +
>> + HMT_medium();
>> + clear_thread_flag(TIF_POLLING_NRFLAG);
>> + smp_mb();
>> +
>> + idle_loop_epilog(in_purr);
>> +
>> + return index;
>> +}
>> +
>> +static void check_and_cede_processor(void)
>> +{
>> + /*
>> + * Ensure our interrupt state is properly tracked,
>> + * also checks if no interrupt has occurred while we
>> + * were soft-disabled
>> + */
>> + if (prep_irq_for_idle()) {
>> + cede_processor();
>> +#ifdef CONFIG_TRACE_IRQFLAGS
>> + /* Ensure that H_CEDE returns with IRQs on */
>> + if (WARN_ON(!(mfmsr() & MSR_EE)))
>> + __hard_irq_enable();
>> +#endif
>> + }
>> +}
>> +
>> +static int dedicated_cede_loop(struct cpuidle_device *dev,
>> + struct cpuidle_driver *drv,
>> + int index)
>> +{
>> + unsigned long in_purr;
>> +
>> + idle_loop_prolog(&in_purr);
>> + set_lppaca_donate_dedicated_cpu(1);
>> +
>> + ppc64_runlatch_off();
>> + HMT_medium();
>> + check_and_cede_processor();
>> +
>> + set_lppaca_donate_dedicated_cpu(0);
>> + idle_loop_epilog(in_purr);
>> +
>> + return index;
>> +}
>> +
>> +static int shared_cede_loop(struct cpuidle_device *dev,
>> + struct cpuidle_driver *drv,
>> + int index)
>> +{
>> + unsigned long in_purr;
>> +
>> + idle_loop_prolog(&in_purr);
>> +
>> + /*
>> + * Yield the processor to the hypervisor. We return if
>> + * an external interrupt occurs (which are driven prior
>> + * to returning here) or if a prod occurs from another
>> + * processor. When returning here, external interrupts
>> + * are enabled.
>> + */
>> + check_and_cede_processor();
>> +
>> + idle_loop_epilog(in_purr);
>> +
>> + return index;
>> +}
>> +
>> +/*
>> + * States for dedicated partition case.
>> + */
>> +static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = {
>> + { /* Snooze */
>> + .name = "snooze",
>> + .desc = "snooze",
>> + .flags = CPUIDLE_FLAG_TIME_VALID,
>> + .exit_latency = 0,
>> + .target_residency = 0,
>> + .enter = &snooze_loop },
>> + { /* CEDE */
>> + .name = "CEDE",
>> + .desc = "CEDE",
>> + .flags = CPUIDLE_FLAG_TIME_VALID,
>> + .exit_latency = 10,
>> + .target_residency = 100,
>> + .enter = &dedicated_cede_loop },
>> +};
>> +
>> +/*
>> + * States for shared partition case.
>> + */
>> +static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
>> + { /* Shared Cede */
>> + .name = "Shared Cede",
>> + .desc = "Shared Cede",
>> + .flags = CPUIDLE_FLAG_TIME_VALID,
>> + .exit_latency = 0,
>> + .target_residency = 0,
>> + .enter = &shared_cede_loop },
>> +};
>> +
>> +void update_smt_snooze_delay(int cpu, int residency)
>> +{
>> + struct cpuidle_driver *drv = cpuidle_get_driver();
>> + struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
>> +
>> + if (cpuidle_state_table != dedicated_states)
>> + return;
>> +
>> + if (residency < 0) {
>> + /* Disable the Nap state on that cpu */
>> + if (dev)
>> + dev->states_usage[1].disable = 1;
>> + } else
>> + if (drv)
>> + drv->states[1].target_residency = residency;
>> +}
>> +
>> +static int powerpc_cpuidle_add_cpu_notifier(struct notifier_block *n,
>> + unsigned long action, void *hcpu)
>> +{
>> + int hotcpu = (unsigned long)hcpu;
>> + struct cpuidle_device *dev =
>> + per_cpu_ptr(cpuidle_devices, hotcpu);
>> +
>> + if (dev && cpuidle_get_driver()) {
>> + switch (action) {
>> + case CPU_ONLINE:
>> + case CPU_ONLINE_FROZEN:
>> + cpuidle_pause_and_lock();
>> + cpuidle_enable_device(dev);
>> + cpuidle_resume_and_unlock();
>> + break;
>> +
>> + case CPU_DEAD:
>> + case CPU_DEAD_FROZEN:
>> + cpuidle_pause_and_lock();
>> + cpuidle_disable_device(dev);
>> + cpuidle_resume_and_unlock();
>> + break;
>> +
>> + default:
>> + return NOTIFY_DONE;
>> + }
>> + }
>> + return NOTIFY_OK;
>> +}
>> +
>> +static struct notifier_block setup_hotplug_notifier = {
>> + .notifier_call = powerpc_cpuidle_add_cpu_notifier,
>> +};
>> +
>> +/*
>> + * powerpc_cpuidle_driver_init()
>> + */
>> +static int powerpc_cpuidle_driver_init(void)
>> +{
>> + int idle_state;
>> + struct cpuidle_driver *drv = &powerpc_idle_driver;
>> +
>> + drv->state_count = 0;
>> +
>> + for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) {
>> +
>> + if (idle_state > max_idle_state)
>> + break;
>> +
>> + /* is the state not enabled? */
>> + if (cpuidle_state_table[idle_state].enter == NULL)
>> + continue;
>> +
>> + drv->states[drv->state_count] = /* structure copy */
>> + cpuidle_state_table[idle_state];
>> +
>> + drv->state_count += 1;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * powerpc_idle_probe()
>> + * Choose state table for shared versus dedicated partition
>> + */
>> +static int powerpc_idle_probe(void)
>> +{
>> +
>> + if (cpuidle_disable != IDLE_NO_OVERRIDE)
>> + return -ENODEV;
>> +
>> + if (max_idle_state == 0) {
>> + printk(KERN_DEBUG "powerpc processor idle disabled.\n");
>> + return -EPERM;
>> + }
>> +
>> + if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
>> + if (get_lppaca_is_shared_proc() == 1)
>> + cpuidle_state_table = shared_states;
>> + else if (get_lppaca_is_shared_proc() == 0)
>> + cpuidle_state_table = dedicated_states;
>> + } else
>> + return -ENODEV;
>> +
>> + return 0;
>> +}
>> +
>> +static int __init powerpc_processor_idle_init(void)
>> +{
>> + int retval;
>> +
>> + retval = powerpc_idle_probe();
>> + if (retval)
>> + return retval;
>> +
>> + powerpc_cpuidle_driver_init();
>> + retval = cpuidle_register(&powerpc_idle_driver, NULL);
>> + if (retval) {
>> + printk(KERN_DEBUG "Registration of powerpc driver failed.\n");
>> + return retval;
>> + }
>> +
>> + register_cpu_notifier(&setup_hotplug_notifier);
>> + printk(KERN_DEBUG "powerpc_idle_driver registered\n");
>> +
>> + return 0;
>> +}
>> +
>> +static void __exit powerpc_processor_idle_exit(void)
>> +{
>> +
>> + unregister_cpu_notifier(&setup_hotplug_notifier);
>> + cpuidle_unregister(&powerpc_idle_driver);
>> + return;
>> +}
>> +
>> +module_init(powerpc_processor_idle_init);
>> +module_exit(powerpc_processor_idle_exit);
>> +
>> +MODULE_AUTHOR("Deepthi Dharwar <deepthi@...ux.vnet.ibm.com>");
>> +MODULE_DESCRIPTION("Cpuidle driver for powerpc");
>> +MODULE_LICENSE("GPL");
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@...ts.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
>
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