/*
* Intel SpeedStep SMI driver.
*
* (C) 2003 Hiroshi Miura <miura@da-cha.org>
*
* Licensed under the terms of the GNU GPL License version 2.
*
*/
/*********************************************************************
* SPEEDSTEP - DEFINITIONS *
*********************************************************************/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <asm/ist.h>
#include "speedstep-lib.h"
/* speedstep system management interface port/command.
*
* These parameters are got from IST-SMI BIOS call.
* If user gives it, these are used.
*
*/
static int smi_port = 0;
static int smi_cmd = 0;
static unsigned int smi_sig = 0;
/* info about the processor */
static unsigned int speedstep_processor = 0;
/*
* There are only two frequency states for each processor. Values
* are in kHz for the time being.
*/
static struct cpufreq_frequency_table speedstep_freqs[] = {
{SPEEDSTEP_HIGH, 0},
{SPEEDSTEP_LOW, 0},
{0, CPUFREQ_TABLE_END},
};
#define GET_SPEEDSTEP_OWNER 0
#define GET_SPEEDSTEP_STATE 1
#define SET_SPEEDSTEP_STATE 2
#define GET_SPEEDSTEP_FREQS 4
/* how often shall the SMI call be tried if it failed, e.g. because
* of DMA activity going on? */
#define SMI_TRIES 5
#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-smi", msg)
/**
* speedstep_smi_ownership
*/
static int speedstep_smi_ownership (void)
{
u32 command, result, magic;
u32 function = GET_SPEEDSTEP_OWNER;
unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
magic = virt_to_phys(magic_data);
dprintk("trying to obtain ownership with command %x at port %x\n", command, smi_port);
__asm__ __volatile__(
"out %%al, (%%dx)\n"
: "=D" (result)
: "a" (command), "b" (function), "c" (0), "d" (smi_port), "D" (0), "S" (magic)
);
dprintk("result is %x\n", result);
return result;
}
/**
* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
* @low: the low frequency value is placed here
* @high: the high frequency value is placed here
*
* Only available on later SpeedStep-enabled systems, returns false results or
* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
* shows that the latter occurs if !(ist_info.event & 0xFFFF).
*/
static int speedstep_smi_get_freqs (unsigned int *low, unsigned int *high)
{
u32 command, result = 0, edi, high_mhz, low_mhz;
u32 state=0;
u32 function = GET_SPEEDSTEP_FREQS;
if (!(ist_info.event & 0xFFFF)) {
dprintk("bug #1422 -- can't read freqs from BIOS\n");
return -ENODEV;
}
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
dprintk("trying to determine frequencies with command %x at port %x\n", command, smi_port);
__asm__ __volatile__("movl $0, %%edi\n"
"out %%al, (%%dx)\n"
: "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi)
: "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
);
dprintk("result %x, low_freq %u, high_freq %u\n", result, low_mhz, high_mhz);
/* abort if results are obviously incorrect... */
if ((high_mhz + low_mhz) < 600)
return -EINVAL;
*high = high_mhz * 1000;
*low = low_mhz * 1000;
return result;
}
/**
* speedstep_get_state - set the SpeedStep state
* @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
*
*/
static int speedstep_get_state (void)
{
u32 function=GET_SPEEDSTEP_STATE;
u32 result, state, edi, command;
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
dprintk("trying to determine current setting with command %x at port %x\n", command, smi_port);
__asm__ __volatile__("movl $0, %%edi\n"
"out %%al, (%%dx)\n"
: "=a" (result), "=b" (state), "=D" (edi)
: "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0)
);
dprintk("state is %x, result is %x\n", state, result);
return (state & 1);
}
/**
* speedstep_set_state - set the SpeedStep state
* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
*
*/
static void speedstep_set_state (unsigned int state)
{
unsigned int result = 0, command, new_state;
unsigned long flags;
unsigned int function=SET_SPEEDSTEP_STATE;
unsigned int retry = 0;
if (state > 0x1)
return;
/* Disable IRQs */
local_irq_save(flags);
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
dprintk("trying to set frequency to state %u with command %x at port %x\n", state, command, smi_port);
do {
if (retry) {
dprintk("retry %u, previous result %u, waiting...\n", retry, result);
mdelay(retry * 50);
}
retry++;
__asm__ __volatile__(
"movl $0, %%edi\n"
"out %%al, (%%dx)\n"
: "=b" (new_state), "=D" (result)
: "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
);
} while ((new_state != state) && (retry <= SMI_TRIES));
/* enable IRQs */
local_irq_restore(flags);
if (new_state == state) {
dprintk("change to %u MHz succeeded after %u tries with result %u\n", (speedstep_freqs[new_state].frequency / 1000), retry, result);
} else {
printk(KERN_ERR "cpufreq: change failed with new_state %u and result %u\n", new_state, result);
}
return;
}
/**
* speedstep_target - set a new CPUFreq policy
* @policy: new policy
* @target_freq: new freq
* @relation:
*
* Sets a new CPUFreq policy/freq.
*/
static int speedstep_target (struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
unsigned int newstate = 0;
struct cpufreq_freqs freqs;
if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
return -EINVAL;
freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
freqs.new = speedstep_freqs[newstate].frequency;
freqs.cpu = 0; /* speedstep.c is UP only driver */
if (freqs.old == freqs.new)
return 0;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
speedstep_set_state(newstate);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return 0;
}
/**
* speedstep_verify - verifies a new CPUFreq policy
* @policy: new policy
*
* Limit must be within speedstep_low_freq and speedstep_high_freq, with
* at least one border included.
*/
static int speedstep_verify (struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
}
static int speedstep_cpu_init(struct cpufreq_policy *policy)
{
int result;
unsigned int speed,state;
/* capability check */
if (policy->cpu != 0)
return -ENODEV;
result = speedstep_smi_ownership();
if (result) {
dprintk("fails in aquiring ownership of a SMI interface.\n");
return -EINVAL;
}
/* detect low and high frequency */
result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,
&speedstep_freqs[SPEEDSTEP_HIGH].frequency);
if (result) {
/* fall back to speedstep_lib.c dection mechanism: try both states out */
dprintk("could not detect low and high frequencies by SMI call.\n");
result = speedstep_get_freqs(speedstep_processor,
&speedstep_freqs[SPEEDSTEP_LOW].frequency,
&speedstep_freqs[SPEEDSTEP_HIGH].frequency,
NULL,
&speedstep_set_state);
if (result) {
dprintk("could not detect two different speeds -- aborting.\n");
return result;
} else
dprintk("workaround worked.\n");
}
/* get current speed setting */
state = speedstep_get_state();
speed = speedstep_freqs[state].frequency;
dprintk("currently at %s speed setting - %i MHz\n",
(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
(speed / 1000));
/* cpuinfo and default policy values */
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
policy->cur = speed;
result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
if (result)
return (result);
cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
return 0;
}
static int speedstep_cpu_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
return 0;
}
static unsigned int speedstep_get(unsigned int cpu)
{
if (cpu)
return -ENODEV;
return speedstep_get_processor_frequency(speedstep_processor);
}
static int speedstep_resume(struct cpufreq_policy *policy)
{
int result = speedstep_smi_ownership();
if (result)
dprintk("fails in re-aquiring ownership of a SMI interface.\n");
return result;
}
static struct freq_attr* speedstep_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver speedstep_driver = {
.name = "speedstep-smi",
.verify = speedstep_verify,
.target = speedstep_target,
.init = speedstep_cpu_init,
.exit = speedstep_cpu_exit,
.get = speedstep_get,
.resume = speedstep_resume,
.owner = THIS_MODULE,
.attr = speedstep_attr,
};
/**
* speedstep_init - initializes the SpeedStep CPUFreq driver
*
* Initializes the SpeedStep support. Returns -ENODEV on unsupported
* BIOS, -EINVAL on problems during initiatization, and zero on
* success.
*/
static int __init speedstep_init(void)
{
speedstep_processor = speedstep_detect_processor();
switch (speedstep_processor) {
case SPEEDSTEP_PROCESSOR_PIII_T:
case SPEEDSTEP_PROCESSOR_PIII_C:
case SPEEDSTEP_PROCESSOR_PIII_C_EARLY:
break;
case SPEEDSTEP_PROCESSOR_P4M:
printk(KERN_INFO "speedstep-smi: you're trying to use this cpufreq driver on a Pentium 4-based CPU. Most likely it will not work.\n");
break;
default:
speedstep_processor = 0;
}
if (!speedstep_processor) {
dprintk ("No supported Intel CPU detected.\n");
return -ENODEV;
}
dprintk("signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",
ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);
/* Error if no IST-SMI BIOS or no PARM
sig= 'ISGE' aka 'Intel Speedstep Gate E' */
if ((ist_info.signature != 0x47534943) && (
(smi_port == 0) || (smi_cmd == 0)))
return -ENODEV;
if (smi_sig == 1)
smi_sig = 0x47534943;
else
smi_sig = ist_info.signature;
/* setup smi_port from MODLULE_PARM or BIOS */
if ((smi_port > 0xff) || (smi_port < 0)) {
return -EINVAL;
} else if (smi_port == 0) {
smi_port = ist_info.command & 0xff;
}
if ((smi_cmd > 0xff) || (smi_cmd < 0)) {
return -EINVAL;
} else if (smi_cmd == 0) {
smi_cmd = (ist_info.command >> 16) & 0xff;
}
return cpufreq_register_driver(&speedstep_driver);
}
/**
* speedstep_exit - unregisters SpeedStep support
*
* Unregisters SpeedStep support.
*/
static void __exit speedstep_exit(void)
{
cpufreq_unregister_driver(&speedstep_driver);
}
module_param(smi_port, int, 0444);
module_param(smi_cmd, int, 0444);
module_param(smi_sig, uint, 0444);
MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");
MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");
MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");
MODULE_AUTHOR ("Hiroshi Miura");
MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");
MODULE_LICENSE ("GPL");
module_init(speedstep_init);
module_exit(speedstep_exit);
