/*
* 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/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 <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 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 ret = 0;
u32 value = 0;
int i = 0;
struct cpufreq_freqs cpufreq_freqs;
cpumask_t saved_mask;
int retval;
dprintk("acpi_processor_set_performance\n");
/*
* TBD: Use something other than set_cpus_allowed.
* As set_cpus_allowed is a bit racy,
* with any other set_cpus_allowed for this process.
*/
saved_mask = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(cpu));
if (smp_processor_id() != cpu) {
return (-EAGAIN);
}
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.
*/
port = data->acpi_data.control_register.address;
bit_width = data->acpi_data.control_register.bit_width;
value = (u32) data->acpi_data.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);
retval = ret;
goto migrate_end;
}
/*
* 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 = data->acpi_data.status_register.address;
bit_width = data->acpi_data.status_register.bit_width;
dprintk("Looking for 0x%08x from port 0x%04x\n",
(u32) data->acpi_data.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);
retval = ret;
goto migrate_end;
}
if (value == (u32) data->acpi_data.states[state].status)
break;
udelay(10);
}
} else {
i = 0;
value = (u32) data->acpi_data.states[state].status;
}
/* notify cpufreq */
cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
if (unlikely(value != (u32) data->acpi_data.states[state].status)) {
unsigned int tmp = cpufreq_freqs.new;
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 "acpi-cpufreq: Transition failed\n");
retval = -ENODEV;
goto migrate_end;
}
dprintk("Transition successful after %d microseconds\n", i * 10);
data->acpi_data.state = state;
retval = 0;
migrate_end:
set_cpus_allowed(current, saved_mask);
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];
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 = acpi_processor_set_performance (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);
}
static unsigned long
acpi_cpufreq_guess_freq (
struct cpufreq_acpi_io *data,
unsigned int cpu)
{
if (cpu_khz) {
/* search the closest match to cpu_khz */
unsigned int i;
unsigned long freq;
unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
for (i=0; i < (data->acpi_data.state_count - 1); i++) {
freq = freqn;
freqn = data->acpi_data.states[i+1].core_frequency * 1000;
if ((2 * cpu_khz) > (freqn + freq)) {
data->acpi_data.state = i;
return (freq);
}
}
data->acpi_data.state = data->acpi_data.state_count - 1;
return (freqn);
} else
/* assume CPU is at P0... */
data->acpi_data.state = 0;
return data->acpi_data.states[0].core_frequency * 1000;
}
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];
dprintk("acpi_cpufreq_cpu_init\n");
data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
if (!data)
return (-ENOMEM);
acpi_io_data[cpu] = data;
result = acpi_processor_register_performance(&data->acpi_data, cpu);
if (result)
goto err_free;
if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
}
/* 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_SYSTEM_IO) ||
(data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
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;
/* 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<=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\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);
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 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,
};
static int __init
acpi_cpufreq_init (void)
{
int result = 0;
dprintk("acpi_cpufreq_init\n");
result = cpufreq_register_driver(&acpi_cpufreq_driver);
return (result);
}
static void __exit
acpi_cpufreq_exit (void)
{
dprintk("acpi_cpufreq_exit\n");
cpufreq_unregister_driver(&acpi_cpufreq_driver);
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");
