/*
* (C) 2001 Dave Jones, Arjan van de ven.
* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
*
* Licensed under the terms of the GNU GPL License version 2.
* Based upon reverse engineered information, and on Intel documentation
* for chipsets ICH2-M and ICH3-M.
*
* Many thanks to Ducrot Bruno for finding and fixing the last
* "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
* for extensive testing.
*
* BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
*/
/*********************************************************************
* SPEEDSTEP - DEFINITIONS *
*********************************************************************/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include "speedstep-lib.h"
/* speedstep_chipset:
* It is necessary to know which chipset is used. As accesses to
* this device occur at various places in this module, we need a
* static struct pci_dev * pointing to that device.
*/
static struct pci_dev *speedstep_chipset_dev;
/* speedstep_processor
*/
static unsigned int speedstep_processor = 0;
static u32 pmbase;
/*
* 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 dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-ich", msg)
/**
* speedstep_find_register - read the PMBASE address
*
* Returns: -ENODEV if no register could be found
*/
static int speedstep_find_register (void)
{
if (!speedstep_chipset_dev)
return -ENODEV;
/* get PMBASE */
pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
if (!(pmbase & 0x01)) {
printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
return -ENODEV;
}
pmbase &= 0xFFFFFFFE;
if (!pmbase) {
printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
return -ENODEV;
}
dprintk("pmbase is 0x%x\n", pmbase);
return 0;
}
/**
* speedstep_set_state - set the SpeedStep state
* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
*
* Tries to change the SpeedStep state.
*/
static void speedstep_set_state (unsigned int state)
{
u8 pm2_blk;
u8 value;
unsigned long flags;
if (state > 0x1)
return;
/* Disable IRQs */
local_irq_save(flags);
/* read state */
value = inb(pmbase + 0x50);
dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
/* write new state */
value &= 0xFE;
value |= state;
dprintk("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
/* Disable bus master arbitration */
pm2_blk = inb(pmbase + 0x20);
pm2_blk |= 0x01;
outb(pm2_blk, (pmbase + 0x20));
/* Actual transition */
outb(value, (pmbase + 0x50));
/* Restore bus master arbitration */
pm2_blk &= 0xfe;
outb(pm2_blk, (pmbase + 0x20));
/* check if transition was successful */
value = inb(pmbase + 0x50);
/* Enable IRQs */
local_irq_restore(flags);
dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
if (state == (value & 0x1)) {
dprintk("change to %u MHz succeeded\n", (speedstep_get_processor_frequency(speedstep_processor) / 1000));
} else {
printk (KERN_ERR "cpufreq: change failed - I/O error\n");
}
return;
}
/**
* speedstep_activate - activate SpeedStep control in the chipset
*
* Tries to activate the SpeedStep status and control registers.
* Returns -EINVAL on an unsupported chipset, and zero on success.
*/
static int speedstep_activate (void)
{
u16 value = 0;
if (!speedstep_chipset_dev)
return -EINVAL;
pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
if (!(value & 0x08)) {
value |= 0x08;
dprintk("activating SpeedStep (TM) registers\n");
pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
}
return 0;
}
/**
* speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
*
* Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
* the LPC bridge / PM module which contains all power-management
* functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
* chipset, or zero on failure.
*/
static unsigned int speedstep_detect_chipset (void)
{
speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
PCI_DEVICE_ID_INTEL_82801DB_12,
PCI_ANY_ID,
PCI_ANY_ID,
NULL);
if (speedstep_chipset_dev)
return 4; /* 4-M */
speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
PCI_DEVICE_ID_INTEL_82801CA_12,
PCI_ANY_ID,
PCI_ANY_ID,
NULL);
if (speedstep_chipset_dev)
return 3; /* 3-M */
speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
PCI_DEVICE_ID_INTEL_82801BA_10,
PCI_ANY_ID,
PCI_ANY_ID,
NULL);
if (speedstep_chipset_dev) {
/* speedstep.c causes lockups on Dell Inspirons 8000 and
* 8100 which use a pretty old revision of the 82815
* host brige. Abort on these systems.
*/
static struct pci_dev *hostbridge;
u8 rev = 0;
hostbridge = pci_get_subsys(PCI_VENDOR_ID_INTEL,
PCI_DEVICE_ID_INTEL_82815_MC,
PCI_ANY_ID,
PCI_ANY_ID,
NULL);
if (!hostbridge)
return 2; /* 2-M */
pci_read_config_byte(hostbridge, PCI_REVISION_ID, &rev);
if (rev < 5) {
dprintk("hostbridge does not support speedstep\n");
speedstep_chipset_dev = NULL;
pci_dev_put(hostbridge);
return 0;
}
pci_dev_put(hostbridge);
return 2; /* 2-M */
}
return 0;
}
static unsigned int _speedstep_get(cpumask_t cpus)
{
unsigned int speed;
cpumask_t cpus_allowed;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed(current, cpus);
speed = speedstep_get_processor_frequency(speedstep_processor);
set_cpus_allowed(current, cpus_allowed);
dprintk("detected %u kHz as current frequency\n", speed);
return speed;
}
static unsigned int speedstep_get(unsigned int cpu)
{
return _speedstep_get(cpumask_of_cpu(cpu));
}
/**
* speedstep_target - set a new CPUFreq policy
* @policy: new policy
* @target_freq: the target frequency
* @relation: how that frequency relates to achieved frequency (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
*
* Sets a new CPUFreq policy.
*/
static int speedstep_target (struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int newstate = 0;
struct cpufreq_freqs freqs;
cpumask_t cpus_allowed;
int i;
if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
return -EINVAL;
freqs.old = _speedstep_get(policy->cpus);
freqs.new = speedstep_freqs[newstate].frequency;
freqs.cpu = policy->cpu;
dprintk("transiting from %u to %u kHz\n", freqs.old, freqs.new);
/* no transition necessary */
if (freqs.old == freqs.new)
return 0;
cpus_allowed = current->cpus_allowed;
for_each_cpu_mask(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
/* switch to physical CPU where state is to be changed */
set_cpus_allowed(current, policy->cpus);
speedstep_set_state(newstate);
/* allow to be run on all CPUs */
set_cpus_allowed(current, cpus_allowed);
for_each_cpu_mask(i, policy->cpus) {
freqs.cpu = i;
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 = 0;
unsigned int speed;
cpumask_t cpus_allowed;
/* only run on CPU to be set, or on its sibling */
#ifdef CONFIG_SMP
policy->cpus = cpu_sibling_map[policy->cpu];
#endif
cpus_allowed = current->cpus_allowed;
set_cpus_allowed(current, policy->cpus);
/* detect low and high frequency and transition latency */
result = speedstep_get_freqs(speedstep_processor,
&speedstep_freqs[SPEEDSTEP_LOW].frequency,
&speedstep_freqs[SPEEDSTEP_HIGH].frequency,
&policy->cpuinfo.transition_latency,
&speedstep_set_state);
set_cpus_allowed(current, cpus_allowed);
if (result)
return result;
/* get current speed setting */
speed = _speedstep_get(policy->cpus);
if (!speed)
return -EIO;
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->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 struct freq_attr* speedstep_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver speedstep_driver = {
.name = "speedstep-ich",
.verify = speedstep_verify,
.target = speedstep_target,
.init = speedstep_cpu_init,
.exit = speedstep_cpu_exit,
.get = speedstep_get,
.owner = THIS_MODULE,
.attr = speedstep_attr,
};
/**
* speedstep_init - initializes the SpeedStep CPUFreq driver
*
* Initializes the SpeedStep support. Returns -ENODEV on unsupported
* devices, -EINVAL on problems during initiatization, and zero on
* success.
*/
static int __init speedstep_init(void)
{
/* detect processor */
speedstep_processor = speedstep_detect_processor();
if (!speedstep_processor) {
dprintk("Intel(R) SpeedStep(TM) capable processor not found\n");
return -ENODEV;
}
/* detect chipset */
if (!speedstep_detect_chipset()) {
dprintk("Intel(R) SpeedStep(TM) for this chipset not (yet) available.\n");
return -ENODEV;
}
/* activate speedstep support */
if (speedstep_activate()) {
pci_dev_put(speedstep_chipset_dev);
return -EINVAL;
}
if (speedstep_find_register())
return -ENODEV;
return cpufreq_register_driver(&speedstep_driver);
}
/**
* speedstep_exit - unregisters SpeedStep support
*
* Unregisters SpeedStep support.
*/
static void __exit speedstep_exit(void)
{
pci_dev_put(speedstep_chipset_dev);
cpufreq_unregister_driver(&speedstep_driver);
}
MODULE_AUTHOR ("Dave Jones <davej@codemonkey.org.uk>, Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION ("Speedstep driver for Intel mobile processors on chipsets with ICH-M southbridges.");
MODULE_LICENSE ("GPL");
module_init(speedstep_init);
module_exit(speedstep_exit);
