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Commit 4db8699b authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Tony Luck
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[IA64] Add ACPI based P-state support 

Patch to support P-state transitions on ia64. This driver is based on ACPI,
and uses the ACPI processor driver interface to find out the P-state support
information for the processor. This driver plugs into generic cpufreq
infrastructure.

Once this driver is loaded successfully, ondemand/userspace governor can be
used to change the CPU frequency dynamically based on load or on request from
userspace process.

Refer :
ACPI specification -
      http://www.acpi.info
P-state related PAL calls -
      http://developer.intel.com/design/itanium/downloads/24869909.pdf



Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent fd589e0b

arch/ia64/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -383,6 +383,12 @@ source "drivers/acpi/Kconfig" 


endif



if PM



source "arch/ia64/kernel/cpufreq/Kconfig"



endif



endmenu



if !IA64_HP_SIM

arch/ia64/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o domain.o 
obj-$(CONFIG_NUMA)		+= numa.o

obj-$(CONFIG_PERFMON)		+= perfmon_default_smpl.o

obj-$(CONFIG_IA64_CYCLONE)	+= cyclone.o

obj-$(CONFIG_CPU_FREQ)		+= cpufreq/

obj-$(CONFIG_IA64_MCA_RECOVERY)	+= mca_recovery.o

obj-$(CONFIG_KPROBES)		+= kprobes.o jprobes.o

obj-$(CONFIG_IA64_UNCACHED_ALLOCATOR)	+= uncached.o

arch/ia64/kernel/cpufreq/Kconfig

0 → 100644
+29 −0
Original line number Diff line number Diff line 


#

# CPU Frequency scaling

#



menu "CPU Frequency scaling"



source "drivers/cpufreq/Kconfig"



if CPU_FREQ



comment "CPUFreq processor drivers"



config IA64_ACPI_CPUFREQ

	tristate "ACPI Processor P-States driver"

	select CPU_FREQ_TABLE

	depends on ACPI_PROCESSOR

	help

	This driver adds a CPUFreq driver which utilizes the ACPI

	Processor Performance States.



	For details, take a look at <file:Documentation/cpu-freq/>.



	If in doubt, say N.



endif   # CPU_FREQ



endmenu

arch/ia64/kernel/cpufreq/Makefile

0 → 100644
+1 −0
Original line number Diff line number Diff line 
obj-$(CONFIG_IA64_ACPI_CPUFREQ)		+= acpi-cpufreq.o

arch/ia64/kernel/cpufreq/acpi-cpufreq.c

0 → 100644
+499 −0
Original line number Diff line number Diff line 
/*

 * arch/ia64/kernel/cpufreq/acpi-cpufreq.c

 * This file provides the ACPI based P-state support. This

 * module works with generic cpufreq infrastructure. Most of

 * the code is based on i386 version

 * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)

 *

 * Copyright (C) 2005 Intel Corp

 *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>

 */



#include <linux/config.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/cpufreq.h>

#include <linux/proc_fs.h>

#include <linux/seq_file.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/pal.h>



#include <linux/acpi.h>

#include <acpi/processor.h>



#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)



MODULE_AUTHOR("Venkatesh Pallipadi");

MODULE_DESCRIPTION("ACPI Processor P-States Driver");

MODULE_LICENSE("GPL");





struct cpufreq_acpi_io {

	struct acpi_processor_performance	acpi_data;

	struct cpufreq_frequency_table		*freq_table;

	unsigned int				resume;

};



static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];



static struct cpufreq_driver acpi_cpufreq_driver;





static int

processor_set_pstate (

	u32	value)

{

	s64 retval;



	dprintk("processor_set_pstate\n");



	retval = ia64_pal_set_pstate((u64)value);



	if (retval) {

		dprintk("Failed to set freq to 0x%x, with error 0x%x\n",

		        value, retval);

		return -ENODEV;

	}

	return (int)retval;

}





static int

processor_get_pstate (

	u32	*value)

{

	u64	pstate_index = 0;

	s64 	retval;



	dprintk("processor_get_pstate\n");



	retval = ia64_pal_get_pstate(&pstate_index);

	*value = (u32) pstate_index;



	if (retval)

		dprintk("Failed to get current freq with "

		        "error 0x%x, idx 0x%x\n", retval, *value);



	return (int)retval;

}





/* To be used only after data->acpi_data is initialized */

static unsigned

extract_clock (

	struct cpufreq_acpi_io *data,

	unsigned value,

	unsigned int cpu)

{

	unsigned long i;



	dprintk("extract_clock\n");



	for (i = 0; i < data->acpi_data.state_count; i++) {

		if (value >= data->acpi_data.states[i].control)

			return data->acpi_data.states[i].core_frequency;

	}

	return data->acpi_data.states[i-1].core_frequency;

}





static unsigned int

processor_get_freq (

	struct cpufreq_acpi_io	*data,

	unsigned int		cpu)

{

	int			ret = 0;

	u32			value = 0;

	cpumask_t		saved_mask;

	unsigned long 		clock_freq;



	dprintk("processor_get_freq\n");



	saved_mask = current->cpus_allowed;

	set_cpus_allowed(current, cpumask_of_cpu(cpu));

	if (smp_processor_id() != cpu) {

		ret = -EAGAIN;

		goto migrate_end;

	}



	/*

	 * processor_get_pstate gets the average frequency since the

	 * last get. So, do two PAL_get_freq()...

	 */

	ret = processor_get_pstate(&value);

	ret = processor_get_pstate(&value);



	if (ret) {

		set_cpus_allowed(current, saved_mask);

		printk(KERN_WARNING "get performance failed with error %d\n",

		       ret);

		ret = -EAGAIN;

		goto migrate_end;

	}

	clock_freq = extract_clock(data, value, cpu);

	ret = (clock_freq*1000);



migrate_end:

	set_cpus_allowed(current, saved_mask);

	return ret;

}





static int

processor_set_freq (

	struct cpufreq_acpi_io	*data,

	unsigned int		cpu,

	int			state)

{

	int			ret = 0;

	u32			value = 0;

	struct cpufreq_freqs    cpufreq_freqs;

	cpumask_t		saved_mask;

	int			retval;



	dprintk("processor_set_freq\n");



	saved_mask = current->cpus_allowed;

	set_cpus_allowed(current, cpumask_of_cpu(cpu));

	if (smp_processor_id() != cpu) {

		retval = -EAGAIN;

		goto migrate_end;

	}



	if (state == data->acpi_data.state) {

		if (unlikely(data->resume)) {

			dprintk("Called after resume, resetting to P%d\n", state);

			data->resume = 0;

		} else {

			dprintk("Already at target state (P%d)\n", state);

			retval = 0;

			goto migrate_end;

		}

	}



	dprintk("Transitioning from P%d to P%d\n",

		data->acpi_data.state, state);



	/* cpufreq frequency struct */

	cpufreq_freqs.cpu = cpu;

	cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;

	cpufreq_freqs.new = data->freq_table[state].frequency;



	/* notify cpufreq */

	cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);



	/*

	 * First we write the target state's 'control' value to the

	 * control_register.

	 */



	value = (u32) data->acpi_data.states[state].control;



	dprintk("Transitioning to state: 0x%08x\n", value);



	ret = processor_set_pstate(value);

	if (ret) {

		unsigned int tmp = cpufreq_freqs.new;

		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);

		cpufreq_freqs.new = cpufreq_freqs.old;

		cpufreq_freqs.old = tmp;

		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);

		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);

		printk(KERN_WARNING "Transition failed with error %d\n", ret);

		retval = -ENODEV;

		goto migrate_end;

	}



	cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);



	data->acpi_data.state = state;



	retval = 0;



migrate_end:

	set_cpus_allowed(current, saved_mask);

	return (retval);

}





static unsigned int

acpi_cpufreq_get (

	unsigned int		cpu)

{

	struct cpufreq_acpi_io *data = acpi_io_data[cpu];



	dprintk("acpi_cpufreq_get\n");



	return processor_get_freq(data, cpu);

}





static int

acpi_cpufreq_target (

	struct cpufreq_policy   *policy,

	unsigned int target_freq,

	unsigned int relation)

{

	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];

	unsigned int next_state = 0;

	unsigned int result = 0;



	dprintk("acpi_cpufreq_setpolicy\n");



	result = cpufreq_frequency_table_target(policy,

			data->freq_table, target_freq, relation, &next_state);

	if (result)

		return (result);



	result = processor_set_freq(data, policy->cpu, next_state);



	return (result);

}





static int

acpi_cpufreq_verify (

	struct cpufreq_policy   *policy)

{

	unsigned int result = 0;

	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];



	dprintk("acpi_cpufreq_verify\n");



	result = cpufreq_frequency_table_verify(policy,

			data->freq_table);



	return (result);

}





/*

 * processor_init_pdc - let BIOS know about the SMP capabilities

 * of this driver

 * @perf: processor-specific acpi_io_data struct

 * @cpu: CPU being initialized

 *

 * To avoid issues with legacy OSes, some BIOSes require to be informed of

 * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC

 * accordingly. Actual call to _PDC is done in driver/acpi/processor.c

 */

static void

processor_init_pdc (

		struct acpi_processor_performance *perf,

		unsigned int cpu,

		struct acpi_object_list *obj_list

		)

{

	union acpi_object *obj;

	u32 *buf;



	dprintk("processor_init_pdc\n");



	perf->pdc = NULL;

	/* Initialize pdc. It will be used later. */

	if (!obj_list)

		return;



	if (!(obj_list->count && obj_list->pointer))

		return;



	obj = obj_list->pointer;

	if ((obj->buffer.length == 12) && obj->buffer.pointer) {

		buf = (u32 *)obj->buffer.pointer;

       		buf[0] = ACPI_PDC_REVISION_ID;

       		buf[1] = 1;

       		buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;

		perf->pdc = obj_list;

	}

	return;

}





static int

acpi_cpufreq_cpu_init (

	struct cpufreq_policy   *policy)

{

	unsigned int		i;

	unsigned int		cpu = policy->cpu;

	struct cpufreq_acpi_io	*data;

	unsigned int		result = 0;



	union acpi_object		arg0 = {ACPI_TYPE_BUFFER};

	u32				arg0_buf[3];

	struct acpi_object_list 	arg_list = {1, &arg0};



	dprintk("acpi_cpufreq_cpu_init\n");

	/* setup arg_list for _PDC settings */

        arg0.buffer.length = 12;

        arg0.buffer.pointer = (u8 *) arg0_buf;



	data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);

	if (!data)

		return (-ENOMEM);



	memset(data, 0, sizeof(struct cpufreq_acpi_io));



	acpi_io_data[cpu] = data;



	processor_init_pdc(&data->acpi_data, cpu, &arg_list);

	result = acpi_processor_register_performance(&data->acpi_data, cpu);

	data->acpi_data.pdc = NULL;



	if (result)

		goto err_free;



	/* capability check */

	if (data->acpi_data.state_count <= 1) {

		dprintk("No P-States\n");

		result = -ENODEV;

		goto err_unreg;

	}



	if ((data->acpi_data.control_register.space_id !=

					ACPI_ADR_SPACE_FIXED_HARDWARE) ||

	    (data->acpi_data.status_register.space_id !=

					ACPI_ADR_SPACE_FIXED_HARDWARE)) {

		dprintk("Unsupported address space [%d, %d]\n",

			(u32) (data->acpi_data.control_register.space_id),

			(u32) (data->acpi_data.status_register.space_id));

		result = -ENODEV;

		goto err_unreg;

	}



	/* alloc freq_table */

	data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *

	                           (data->acpi_data.state_count + 1),

	                           GFP_KERNEL);

	if (!data->freq_table) {

		result = -ENOMEM;

		goto err_unreg;

	}



	/* detect transition latency */

	policy->cpuinfo.transition_latency = 0;

	for (i=0; i<data->acpi_data.state_count; i++) {

		if ((data->acpi_data.states[i].transition_latency * 1000) >

		    policy->cpuinfo.transition_latency) {

			policy->cpuinfo.transition_latency =

			    data->acpi_data.states[i].transition_latency * 1000;

		}

	}

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;



	policy->cur = processor_get_freq(data, policy->cpu);



	/* table init */

	for (i = 0; i <= data->acpi_data.state_count; i++)

	{

		data->freq_table[i].index = i;

		if (i < data->acpi_data.state_count) {

			data->freq_table[i].frequency =

			      data->acpi_data.states[i].core_frequency * 1000;

		} else {

			data->freq_table[i].frequency = CPUFREQ_TABLE_END;

		}

	}



	result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);

	if (result) {

		goto err_freqfree;

	}



	/* notify BIOS that we exist */

	acpi_processor_notify_smm(THIS_MODULE);



	printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "

	       "activated.\n", cpu);



	for (i = 0; i < data->acpi_data.state_count; i++)

		dprintk("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",

			(i == data->acpi_data.state?'*':' '), i,

			(u32) data->acpi_data.states[i].core_frequency,

			(u32) data->acpi_data.states[i].power,

			(u32) data->acpi_data.states[i].transition_latency,

			(u32) data->acpi_data.states[i].bus_master_latency,

			(u32) data->acpi_data.states[i].status,

			(u32) data->acpi_data.states[i].control);



	cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);



	/* the first call to ->target() should result in us actually

	 * writing something to the appropriate registers. */

	data->resume = 1;



	return (result);



 err_freqfree:

	kfree(data->freq_table);

 err_unreg:

	acpi_processor_unregister_performance(&data->acpi_data, cpu);

 err_free:

	kfree(data);

	acpi_io_data[cpu] = NULL;



	return (result);

}





static int

acpi_cpufreq_cpu_exit (

	struct cpufreq_policy   *policy)

{

	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];



	dprintk("acpi_cpufreq_cpu_exit\n");



	if (data) {

		cpufreq_frequency_table_put_attr(policy->cpu);

		acpi_io_data[policy->cpu] = NULL;

		acpi_processor_unregister_performance(&data->acpi_data,

		                                      policy->cpu);

		kfree(data);

	}



	return (0);

}





static struct freq_attr* acpi_cpufreq_attr[] = {

	&cpufreq_freq_attr_scaling_available_freqs,

	NULL,

};





static struct cpufreq_driver acpi_cpufreq_driver = {

	.verify 	= acpi_cpufreq_verify,

	.target 	= acpi_cpufreq_target,

	.get 		= acpi_cpufreq_get,

	.init		= acpi_cpufreq_cpu_init,

	.exit		= acpi_cpufreq_cpu_exit,

	.name		= "acpi-cpufreq",

	.owner		= THIS_MODULE,

	.attr           = acpi_cpufreq_attr,

};





static int __init

acpi_cpufreq_init (void)

{

	dprintk("acpi_cpufreq_init\n");



 	return cpufreq_register_driver(&acpi_cpufreq_driver);

}





static void __exit

acpi_cpufreq_exit (void)

{

	dprintk("acpi_cpufreq_exit\n");



	cpufreq_unregister_driver(&acpi_cpufreq_driver);

	return;

}





late_initcall(acpi_cpufreq_init);

module_exit(acpi_cpufreq_exit);