2 * (C) 2001 Dave Jones, Arjan van de ven.
3 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
5 * Licensed under the terms of the GNU GPL License version 2.
6 * Based upon reverse engineered information, and on Intel documentation
7 * for chipsets ICH2-M and ICH3-M.
9 * Many thanks to Ducrot Bruno for finding and fixing the last
10 * "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
11 * for extensive testing.
13 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
17 /*********************************************************************
18 * SPEEDSTEP - DEFINITIONS *
19 *********************************************************************/
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/cpufreq.h>
25 #include <linux/pci.h>
26 #include <linux/slab.h>
27 #include <linux/sched.h>
29 #include "speedstep-lib.h"
33 * It is necessary to know which chipset is used. As accesses to
34 * this device occur at various places in this module, we need a
35 * static struct pci_dev * pointing to that device.
37 static struct pci_dev *speedstep_chipset_dev;
40 /* speedstep_processor
42 static enum speedstep_processor speedstep_processor;
47 * There are only two frequency states for each processor. Values
48 * are in kHz for the time being.
50 static struct cpufreq_frequency_table speedstep_freqs[] = {
53 {0, CPUFREQ_TABLE_END},
57 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
62 * speedstep_find_register - read the PMBASE address
64 * Returns: -ENODEV if no register could be found
66 static int speedstep_find_register(void)
68 if (!speedstep_chipset_dev)
72 pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
73 if (!(pmbase & 0x01)) {
74 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
80 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
84 dprintk("pmbase is 0x%x\n", pmbase);
89 * speedstep_set_state - set the SpeedStep state
90 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
92 * Tries to change the SpeedStep state. Can be called from
93 * smp_call_function_single.
95 static void speedstep_set_state(unsigned int state)
105 local_irq_save(flags);
108 value = inb(pmbase + 0x50);
110 dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
112 /* write new state */
116 dprintk("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
118 /* Disable bus master arbitration */
119 pm2_blk = inb(pmbase + 0x20);
121 outb(pm2_blk, (pmbase + 0x20));
123 /* Actual transition */
124 outb(value, (pmbase + 0x50));
126 /* Restore bus master arbitration */
128 outb(pm2_blk, (pmbase + 0x20));
130 /* check if transition was successful */
131 value = inb(pmbase + 0x50);
134 local_irq_restore(flags);
136 dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
138 if (state == (value & 0x1))
139 dprintk("change to %u MHz succeeded\n",
140 speedstep_get_frequency(speedstep_processor) / 1000);
142 printk(KERN_ERR "cpufreq: change failed - I/O error\n");
147 /* Wrapper for smp_call_function_single. */
148 static void _speedstep_set_state(void *_state)
150 speedstep_set_state(*(unsigned int *)_state);
154 * speedstep_activate - activate SpeedStep control in the chipset
156 * Tries to activate the SpeedStep status and control registers.
157 * Returns -EINVAL on an unsupported chipset, and zero on success.
159 static int speedstep_activate(void)
163 if (!speedstep_chipset_dev)
166 pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
167 if (!(value & 0x08)) {
169 dprintk("activating SpeedStep (TM) registers\n");
170 pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
178 * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
180 * Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
181 * the LPC bridge / PM module which contains all power-management
182 * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
183 * chipset, or zero on failure.
185 static unsigned int speedstep_detect_chipset(void)
187 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
188 PCI_DEVICE_ID_INTEL_82801DB_12,
189 PCI_ANY_ID, PCI_ANY_ID,
191 if (speedstep_chipset_dev)
194 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
195 PCI_DEVICE_ID_INTEL_82801CA_12,
196 PCI_ANY_ID, PCI_ANY_ID,
198 if (speedstep_chipset_dev)
202 speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
203 PCI_DEVICE_ID_INTEL_82801BA_10,
204 PCI_ANY_ID, PCI_ANY_ID,
206 if (speedstep_chipset_dev) {
207 /* speedstep.c causes lockups on Dell Inspirons 8000 and
208 * 8100 which use a pretty old revision of the 82815
209 * host brige. Abort on these systems.
211 static struct pci_dev *hostbridge;
213 hostbridge = pci_get_subsys(PCI_VENDOR_ID_INTEL,
214 PCI_DEVICE_ID_INTEL_82815_MC,
215 PCI_ANY_ID, PCI_ANY_ID,
221 if (hostbridge->revision < 5) {
222 dprintk("hostbridge does not support speedstep\n");
223 speedstep_chipset_dev = NULL;
224 pci_dev_put(hostbridge);
228 pci_dev_put(hostbridge);
235 static void get_freq_data(void *_speed)
237 unsigned int *speed = _speed;
239 *speed = speedstep_get_frequency(speedstep_processor);
242 static unsigned int speedstep_get(unsigned int cpu)
246 /* You're supposed to ensure CPU is online. */
247 if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
250 dprintk("detected %u kHz as current frequency\n", speed);
255 * speedstep_target - set a new CPUFreq policy
256 * @policy: new policy
257 * @target_freq: the target frequency
258 * @relation: how that frequency relates to achieved frequency
259 * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
261 * Sets a new CPUFreq policy.
263 static int speedstep_target(struct cpufreq_policy *policy,
264 unsigned int target_freq,
265 unsigned int relation)
267 unsigned int newstate = 0, policy_cpu;
268 struct cpufreq_freqs freqs;
271 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
272 target_freq, relation, &newstate))
275 policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
276 freqs.old = speedstep_get(policy_cpu);
277 freqs.new = speedstep_freqs[newstate].frequency;
278 freqs.cpu = policy->cpu;
280 dprintk("transiting from %u to %u kHz\n", freqs.old, freqs.new);
282 /* no transition necessary */
283 if (freqs.old == freqs.new)
286 for_each_cpu(i, policy->cpus) {
288 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
291 smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
294 for_each_cpu(i, policy->cpus) {
296 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
304 * speedstep_verify - verifies a new CPUFreq policy
305 * @policy: new policy
307 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
308 * at least one border included.
310 static int speedstep_verify(struct cpufreq_policy *policy)
312 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
316 struct cpufreq_policy *policy;
320 static void get_freqs_on_cpu(void *_get_freqs)
322 struct get_freqs *get_freqs = _get_freqs;
325 speedstep_get_freqs(speedstep_processor,
326 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
327 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
328 &get_freqs->policy->cpuinfo.transition_latency,
329 &speedstep_set_state);
332 static int speedstep_cpu_init(struct cpufreq_policy *policy)
335 unsigned int policy_cpu, speed;
338 /* only run on CPU to be set, or on its sibling */
340 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
342 policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
344 /* detect low and high frequency and transition latency */
346 smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
350 /* get current speed setting */
351 speed = speedstep_get(policy_cpu);
355 dprintk("currently at %s speed setting - %i MHz\n",
356 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
360 /* cpuinfo and default policy values */
363 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
367 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
373 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
375 cpufreq_frequency_table_put_attr(policy->cpu);
379 static struct freq_attr *speedstep_attr[] = {
380 &cpufreq_freq_attr_scaling_available_freqs,
385 static struct cpufreq_driver speedstep_driver = {
386 .name = "speedstep-ich",
387 .verify = speedstep_verify,
388 .target = speedstep_target,
389 .init = speedstep_cpu_init,
390 .exit = speedstep_cpu_exit,
391 .get = speedstep_get,
392 .owner = THIS_MODULE,
393 .attr = speedstep_attr,
398 * speedstep_init - initializes the SpeedStep CPUFreq driver
400 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
401 * devices, -EINVAL on problems during initiatization, and zero on
404 static int __init speedstep_init(void)
406 /* detect processor */
407 speedstep_processor = speedstep_detect_processor();
408 if (!speedstep_processor) {
409 dprintk("Intel(R) SpeedStep(TM) capable processor "
415 if (!speedstep_detect_chipset()) {
416 dprintk("Intel(R) SpeedStep(TM) for this chipset not "
417 "(yet) available.\n");
421 /* activate speedstep support */
422 if (speedstep_activate()) {
423 pci_dev_put(speedstep_chipset_dev);
427 if (speedstep_find_register())
430 return cpufreq_register_driver(&speedstep_driver);
435 * speedstep_exit - unregisters SpeedStep support
437 * Unregisters SpeedStep support.
439 static void __exit speedstep_exit(void)
441 pci_dev_put(speedstep_chipset_dev);
442 cpufreq_unregister_driver(&speedstep_driver);
446 MODULE_AUTHOR("Dave Jones <davej@redhat.com>, "
447 "Dominik Brodowski <linux@brodo.de>");
448 MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
449 "with ICH-M southbridges.");
450 MODULE_LICENSE("GPL");
452 module_init(speedstep_init);
453 module_exit(speedstep_exit);