[RFC PATCH V3 3/5] powerpc/cpuidle: Generic powerpc backend cpuidle driver.

[Wang Dongsheng-B40534]

I think we should move the states and handle function to arch/power/platform*
The states and handle function is belong to backend driver, not for this, different platform have different state.
Different platforms to make their own deal with these states.

I think we cannot put all the status of different platforms and handler in this driver.

> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
> index 0e2cd5c..99ee5d4 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 PPC64

Why not PPC?


> +	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..5756085
> --- /dev/null
> +++ b/drivers/cpuidle/cpuidle-powerpc.c
> @@ -0,0 +1,361 @@
> +/*
> + *  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;
If this is a generic driver, do not define MAX_IDLE_STATE_COUNT, because we don't know how many state on other platforms.

How about using ARRAY_SIZE to get the max idle state?

> +static struct cpuidle_device __percpu *powerpc_cpuidle_devices;
> +static struct cpuidle_state *cpuidle_state_table;
> +
Should be remove all about *device*.
If the notifier handle using device, you can use "cpuidle_devices"(include/linux/cpuidle.h).

> +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(powerpc_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,
> +};
> +
We should discuss this with Daniel.

> +/*
> + * 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;
> +
Did the state have dependent?
If yes, may be should break out the loop, not continue.

> +		drv->states[drv->state_count] =	/* structure copy */
> +			cpuidle_state_table[idle_state];
> +
> +		drv->state_count += 1;
> +	}
> +
> +	return 0;
> +}
> +
> +/* powerpc_idle_devices_uninit(void)
> + * unregister cpuidle devices and de-allocate memory
> + */
> +static void powerpc_idle_devices_uninit(void)
> +{
> +	int i;
> +	struct cpuidle_device *dev;
> +
> +	for_each_possible_cpu(i) {
> +		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
> +		cpuidle_unregister_device(dev);
> +	}
> +
> +	free_percpu(powerpc_cpuidle_devices);
> +	return;
> +}
> +
> +/* powerpc_idle_devices_init()
> + * allocate, initialize and register cpuidle device
> + */
> +static int powerpc_idle_devices_init(void)
> +{
> +	int i;
> +	struct cpuidle_driver *drv = &powerpc_idle_driver;
> +	struct cpuidle_device *dev;
> +
> +	powerpc_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> +	if (powerpc_cpuidle_devices == NULL)
> +		return -ENOMEM;
> +
> +	for_each_possible_cpu(i) {
> +		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
> +		dev->state_count = drv->state_count;
> +		dev->cpu = i;
> +		if (cpuidle_register_device(dev)) {

Please use cpuidle_register().

> +			printk(KERN_DEBUG \
> +				"cpuidle_register_device %d failed!\n", i);
> +			return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * powerpc_idle_probe()
> + * Choose state table for shared versus dedicated partition
> + */
> +static int powerpc_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 "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_driver(&powerpc_idle_driver);
> +	if (retval) {
> +		printk(KERN_DEBUG "Registration of powerpc driver failed.\n");
> +		return retval;
> +	}
> +
> +	retval = powerpc_idle_devices_init();
> +	if (retval) {
> +		powerpc_idle_devices_uninit();
> +		cpuidle_unregister_driver(&powerpc_idle_driver);
> +		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);
> +	powerpc_idle_devices_uninit();
> +	cpuidle_unregister_driver(&powerpc_idle_driver);
> +
> +	return;
> +}
> +
Did you test module mode? *Remove* the module cannot work.
>