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/*
* acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
* Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#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 <linux/compiler.h>
#include <linux/sched.h> /* current */
#include <asm/io.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
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 acpi_processor_performance *acpi_perf_data[NR_CPUS];
static struct cpufreq_driver acpi_cpufreq_driver;
static unsigned int acpi_pstate_strict;
static int
acpi_processor_write_port(
u16 port,
u8 bit_width,
u32 value)
{
if (bit_width <= 8) {
outb(value, port);
} else if (bit_width <= 16) {
outw(value, port);
} else if (bit_width <= 32) {
outl(value, port);
} else {
return -ENODEV;
}
return 0;
}
static int
acpi_processor_read_port(
u16 port,
u8 bit_width,
u32 *ret)
{
*ret = 0;
if (bit_width <= 8) {
*ret = inb(port);
} else if (bit_width <= 16) {
*ret = inw(port);
} else if (bit_width <= 32) {
*ret = inl(port);
} else {
return -ENODEV;
}
return 0;
}
static int
acpi_processor_set_performance (
struct cpufreq_acpi_io *data,
unsigned int cpu,
int state)
{
u16 port = 0;
u8 bit_width = 0;
int i = 0;
int ret = 0;
u32 value = 0;
int retval;
struct acpi_processor_performance *perf;
dprintk("acpi_processor_set_performance\n");
retval = 0;
perf = data->acpi_data;
if (state == perf->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);
return (retval);
}
}
dprintk("Transitioning from P%d to P%d\n", perf->state, state);
/*
* First we write the target state's 'control' value to the
* control_register.
*/
port = perf->control_register.address;
bit_width = perf->control_register.bit_width;
value = (u32) perf->states[state].control;
dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
ret = acpi_processor_write_port(port, bit_width, value);
if (ret) {
dprintk("Invalid port width 0x%04x\n", bit_width);
return (ret);
}
/*
* Assume the write went through when acpi_pstate_strict is not used.
* As read status_register is an expensive operation and there
* are no specific error cases where an IO port write will fail.
*/
if (acpi_pstate_strict) {
/* Then we read the 'status_register' and compare the value
* with the target state's 'status' to make sure the
* transition was successful.
* Note that we'll poll for up to 1ms (100 cycles of 10us)
* before giving up.
*/
port = perf->status_register.address;
bit_width = perf->status_register.bit_width;
dprintk("Looking for 0x%08x from port 0x%04x\n",
(u32) perf->states[state].status, port);
for (i = 0; i < 100; i++) {
ret = acpi_processor_read_port(port, bit_width, &value);
if (ret) {
dprintk("Invalid port width 0x%04x\n", bit_width);
return (ret);
}
if (value == (u32) perf->states[state].status)
break;
udelay(10);
}
} else {
value = (u32) perf->states[state].status;
}
if (unlikely(value != (u32) perf->states[state].status)) {
printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
retval = -ENODEV;
return (retval);
}
dprintk("Transition successful after %d microseconds\n", i * 10);
perf->state = state;
return (retval);
}
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];
struct acpi_processor_performance *perf;
struct cpufreq_freqs freqs;
cpumask_t online_policy_cpus;
cpumask_t saved_mask;
cpumask_t set_mask;
cpumask_t covered_cpus;
unsigned int cur_state = 0;
unsigned int next_state = 0;
unsigned int result = 0;
unsigned int j;
unsigned int tmp;
dprintk("acpi_cpufreq_setpolicy\n");
result = cpufreq_frequency_table_target(policy,
data->freq_table,
target_freq,
relation,
&next_state);
if (unlikely(result))
return (result);
perf = data->acpi_data;
cur_state = perf->state;
freqs.old = data->freq_table[cur_state].frequency;
freqs.new = data->freq_table[next_state].frequency;
#ifdef CONFIG_HOTPLUG_CPU
/* cpufreq holds the hotplug lock, so we are safe from here on */
cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
#else
online_policy_cpus = policy->cpus;
#endif
for_each_cpu_mask(j, online_policy_cpus) {
freqs.cpu = j;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
/*
* We need to call driver->target() on all or any CPU in
* policy->cpus, depending on policy->shared_type.
*/
saved_mask = current->cpus_allowed;
cpus_clear(covered_cpus);
for_each_cpu_mask(j, online_policy_cpus) {
/*
* Support for SMP systems.
* Make sure we are running on CPU that wants to change freq
*/
cpus_clear(set_mask);
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
cpus_or(set_mask, set_mask, online_policy_cpus);
else
cpu_set(j, set_mask);
set_cpus_allowed(current, set_mask);
if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
dprintk("couldn't limit to CPUs in this domain\n");
result = -EAGAIN;
break;
}
result = acpi_processor_set_performance (data, j, next_state);
if (result) {
result = -EAGAIN;
break;
}
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
break;
cpu_set(j, covered_cpus);
}
for_each_cpu_mask(j, online_policy_cpus) {
freqs.cpu = j;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
if (unlikely(result)) {
/*
* We have failed halfway through the frequency change.
* We have sent callbacks to online_policy_cpus and
* acpi_processor_set_performance() has been called on
* coverd_cpus. Best effort undo..
*/
if (!cpus_empty(covered_cpus)) {
for_each_cpu_mask(j, covered_cpus) {
policy->cpu = j;
acpi_processor_set_performance (data,
j,
cur_state);
}
}
tmp = freqs.new;
freqs.new = freqs.old;
freqs.old = tmp;
for_each_cpu_mask(j, online_policy_cpus) {
freqs.cpu = j;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
}
set_cpus_allowed(current, saved_mask);
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);
}
static unsigned long
acpi_cpufreq_guess_freq (
struct cpufreq_acpi_io *data,
unsigned int cpu)
{
struct acpi_processor_performance *perf = data->acpi_data;
if (cpu_khz) {
/* search the closest match to cpu_khz */
unsigned int i;
unsigned long freq;
unsigned long freqn = perf->states[0].core_frequency * 1000;
for (i = 0; i < (perf->state_count - 1); i++) {
freq = freqn;
freqn = perf->states[i+1].core_frequency * 1000;
if ((2 * cpu_khz) > (freqn + freq)) {
perf->state = i;
return (freq);
}
}
perf->state = perf->state_count - 1;
return (freqn);
} else {
/* assume CPU is at P0... */
perf->state = 0;
return perf->states[0].core_frequency * 1000;
}
}
/*
* acpi_cpufreq_early_init - initialize ACPI P-States library
*
* Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
* in order to determine correct frequency and voltage pairings. We can
* do _PDC and _PSD and find out the processor dependency for the
* actual init that will happen later...
*/
static int acpi_cpufreq_early_init_acpi(void)
{
struct acpi_processor_performance *data;
unsigned int i, j;
dprintk("acpi_cpufreq_early_init\n");
for_each_possible_cpu(i) {
data = kzalloc(sizeof(struct acpi_processor_performance),
GFP_KERNEL);
if (!data) {
for_each_possible_cpu(j) {
kfree(acpi_perf_data[j]);
acpi_perf_data[j] = NULL;
}
return (-ENOMEM);
}
acpi_perf_data[i] = data;
}
/* Do initialization in ACPI core */
return acpi_processor_preregister_performance(acpi_perf_data);
}
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;
struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
struct acpi_processor_performance *perf;
dprintk("acpi_cpufreq_cpu_init\n");
if (!acpi_perf_data[cpu])
return (-ENODEV);
data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
if (!data)
return (-ENOMEM);
data->acpi_data = acpi_perf_data[cpu];
acpi_io_data[cpu] = data;
result = acpi_processor_register_performance(data->acpi_data, cpu);
if (result)
goto err_free;
perf = data->acpi_data;
policy->shared_type = perf->shared_type;
/*
* Will let policy->cpus know about dependency only when software
* coordination is required.
*/
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
policy->cpus = perf->shared_cpu_map;
if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
}
/* capability check */
if (perf->state_count <= 1) {
dprintk("No P-States\n");
result = -ENODEV;
goto err_unreg;
}
if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
(perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
dprintk("Unsupported address space [%d, %d]\n",
(u32) (perf->control_register.space_id),
(u32) (perf->status_register.space_id));
result = -ENODEV;
goto err_unreg;
}
/* alloc freq_table */
data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->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<perf->state_count; i++) {
if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
}
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
/* The current speed is unknown and not detectable by ACPI... */
policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
/* table init */
for (i=0; i<=perf->state_count; i++)
{
data->freq_table[i].index = i;
if (i<perf->state_count)
data->freq_table[i].frequency = perf->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 < perf->state_count; i++)
dprintk(" %cP%d: %d MHz, %d mW, %d uS\n",
(i == perf->state?'*':' '), i,
(u32) perf->states[i].core_frequency,
(u32) perf->states[i].power,
(u32) perf->states[i].transition_latency);
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(perf, 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 int
acpi_cpufreq_resume (
struct cpufreq_policy *policy)
{
struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
dprintk("acpi_cpufreq_resume\n");
data->resume = 1;
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,
.init = acpi_cpufreq_cpu_init,
.exit = acpi_cpufreq_cpu_exit,
.resume = acpi_cpufreq_resume,
.name = "acpi-cpufreq",
.owner = THIS_MODULE,
.attr = acpi_cpufreq_attr,
.flags = CPUFREQ_STICKY,
};
static int __init
acpi_cpufreq_init (void)
{
dprintk("acpi_cpufreq_init\n");
acpi_cpufreq_early_init_acpi();
return cpufreq_register_driver(&acpi_cpufreq_driver);
}
static void __exit
acpi_cpufreq_exit (void)
{
unsigned int i;
dprintk("acpi_cpufreq_exit\n");
cpufreq_unregister_driver(&acpi_cpufreq_driver);
for_each_possible_cpu(i) {
kfree(acpi_perf_data[i]);
acpi_perf_data[i] = NULL;
}
return;
}
module_param(acpi_pstate_strict, uint, 0644);
MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
late_initcall(acpi_cpufreq_init);
module_exit(acpi_cpufreq_exit);
MODULE_ALIAS("acpi");