2 * Intel SpeedStep SMI driver.
4 * (C) 2003 Hiroshi Miura <miura@da-cha.org>
6 * Licensed under the terms of the GNU GPL License version 2.
11 /*********************************************************************
12 * SPEEDSTEP - DEFINITIONS *
13 *********************************************************************/
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/init.h>
19 #include <linux/cpufreq.h>
20 #include <linux/pci.h>
21 #include <linux/slab.h>
22 #include <linux/delay.h>
25 #include "speedstep-lib.h"
27 #define PFX "speedstep-smi: "
29 /* speedstep system management interface port/command.
31 * These parameters are got from IST-SMI BIOS call.
32 * If user gives it, these are used.
35 static int smi_port = 0;
36 static int smi_cmd = 0;
37 static unsigned int smi_sig = 0;
39 /* info about the processor */
40 static unsigned int speedstep_processor = 0;
43 * There are only two frequency states for each processor. Values
44 * are in kHz for the time being.
46 static struct cpufreq_frequency_table speedstep_freqs[] = {
49 {0, CPUFREQ_TABLE_END},
52 #define GET_SPEEDSTEP_OWNER 0
53 #define GET_SPEEDSTEP_STATE 1
54 #define SET_SPEEDSTEP_STATE 2
55 #define GET_SPEEDSTEP_FREQS 4
57 /* how often shall the SMI call be tried if it failed, e.g. because
58 * of DMA activity going on? */
62 * Define it if you want verbose debug output, e.g. for bug reporting
64 //#define SPEEDSTEP_DEBUG
66 #ifdef SPEEDSTEP_DEBUG
67 #define dprintk(msg...) printk(msg)
69 #define dprintk(msg...) do { } while(0)
73 * speedstep_smi_ownership
75 static int speedstep_smi_ownership (void)
77 u32 command, result, magic;
78 u32 function = GET_SPEEDSTEP_OWNER;
79 unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
81 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
82 magic = virt_to_phys(magic_data);
87 : "a" (command), "b" (function), "c" (0), "d" (smi_port), "D" (0), "S" (magic)
94 * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
95 * @low: the low frequency value is placed here
96 * @high: the high frequency value is placed here
98 * Only available on later SpeedStep-enabled systems, returns false results or
99 * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
100 * shows that the latter occurs if !(ist_info.event & 0xFFFF).
102 static int speedstep_smi_get_freqs (unsigned int *low, unsigned int *high)
104 u32 command, result, edi, high_mhz, low_mhz;
106 u32 function = GET_SPEEDSTEP_FREQS;
108 if (!(ist_info.event & 0xFFFF))
111 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
113 __asm__ __volatile__("movl $0, %%edi\n"
115 : "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi)
116 : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
119 /* abort if results are obviously incorrect... */
120 if ((high_mhz + low_mhz) < 600)
123 *high = high_mhz * 1000;
124 *low = low_mhz * 1000;
130 * speedstep_get_state - set the SpeedStep state
131 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
134 static int speedstep_get_state (void)
136 u32 function=GET_SPEEDSTEP_STATE;
137 u32 result, state, edi, command;
139 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
141 __asm__ __volatile__("movl $0, %%edi\n"
143 : "=a" (result), "=b" (state), "=D" (edi)
144 : "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0)
151 * speedstep_set_state - set the SpeedStep state
152 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
155 static void speedstep_set_state (unsigned int state)
157 unsigned int result = 0, command, new_state;
159 unsigned int function=SET_SPEEDSTEP_STATE;
160 unsigned int retry = 0;
166 local_irq_save(flags);
168 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
172 dprintk(KERN_INFO "cpufreq: retry %u, previous result %u\n", retry, result);
176 __asm__ __volatile__(
179 : "=b" (new_state), "=D" (result)
180 : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
182 } while ((new_state != state) && (retry <= SMI_TRIES));
185 local_irq_restore(flags);
187 if (new_state == state) {
188 dprintk(KERN_INFO "cpufreq: change to %u MHz succeeded after %u tries with result %u\n", (speedstep_freqs[new_state].frequency / 1000), retry, result);
190 printk(KERN_ERR "cpufreq: change failed with new_state %u and result %u\n", new_state, result);
198 * speedstep_target - set a new CPUFreq policy
199 * @policy: new policy
200 * @target_freq: new freq
203 * Sets a new CPUFreq policy/freq.
205 static int speedstep_target (struct cpufreq_policy *policy,
206 unsigned int target_freq, unsigned int relation)
208 unsigned int newstate = 0;
209 struct cpufreq_freqs freqs;
211 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
214 freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
215 freqs.new = speedstep_freqs[newstate].frequency;
216 freqs.cpu = 0; /* speedstep.c is UP only driver */
218 if (freqs.old == freqs.new)
221 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
222 speedstep_set_state(newstate);
223 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
230 * speedstep_verify - verifies a new CPUFreq policy
231 * @policy: new policy
233 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
234 * at least one border included.
236 static int speedstep_verify (struct cpufreq_policy *policy)
238 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
242 static int speedstep_cpu_init(struct cpufreq_policy *policy)
245 unsigned int speed,state;
247 /* capability check */
248 if (policy->cpu != 0)
251 result = speedstep_smi_ownership();
253 dprintk(KERN_INFO "cpufreq: fails an aquiring ownership of a SMI interface.\n");
257 /* detect low and high frequency */
258 result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,
259 &speedstep_freqs[SPEEDSTEP_HIGH].frequency);
261 /* fall back to speedstep_lib.c dection mechanism: try both states out */
262 dprintk(KERN_INFO PFX "could not detect low and high frequencies by SMI call.\n");
263 if (!speedstep_processor)
264 speedstep_processor = speedstep_detect_processor();
266 if (!speedstep_processor)
269 result = speedstep_get_freqs(speedstep_processor,
270 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
271 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
272 &speedstep_set_state);
275 dprintk(KERN_INFO PFX "could not detect two different speeds -- aborting.\n");
278 dprintk(KERN_INFO PFX "workaround worked.\n");
281 /* get current speed setting */
282 state = speedstep_get_state();
283 speed = speedstep_freqs[state].frequency;
285 dprintk(KERN_INFO "cpufreq: currently at %s speed setting - %i MHz\n",
286 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
289 /* cpuinfo and default policy values */
290 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
291 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
294 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
298 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
303 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
305 cpufreq_frequency_table_put_attr(policy->cpu);
309 static unsigned int speedstep_get(unsigned int cpu)
313 if (!speedstep_processor)
314 speedstep_processor = speedstep_detect_processor();
315 if (!speedstep_processor)
317 return speedstep_get_processor_frequency(speedstep_processor);
321 static int speedstep_resume(struct cpufreq_policy *policy)
323 int result = speedstep_smi_ownership();
326 dprintk(KERN_INFO "cpufreq: fails an aquiring ownership of a SMI interface.\n");
331 static struct freq_attr* speedstep_attr[] = {
332 &cpufreq_freq_attr_scaling_available_freqs,
336 static struct cpufreq_driver speedstep_driver = {
337 .name = "speedstep-smi",
338 .verify = speedstep_verify,
339 .target = speedstep_target,
340 .init = speedstep_cpu_init,
341 .exit = speedstep_cpu_exit,
342 .get = speedstep_get,
343 .resume = speedstep_resume,
344 .owner = THIS_MODULE,
345 .attr = speedstep_attr,
349 * speedstep_init - initializes the SpeedStep CPUFreq driver
351 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
352 * BIOS, -EINVAL on problems during initiatization, and zero on
355 static int __init speedstep_init(void)
357 struct cpuinfo_x86 *c = cpu_data;
359 if (c->x86_vendor != X86_VENDOR_INTEL) {
360 printk (KERN_INFO PFX "No Intel CPU detected.\n");
364 dprintk(KERN_DEBUG PFX "signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",
365 ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);
368 /* Error if no IST-SMI BIOS or no PARM
369 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
370 if ((ist_info.signature != 0x47534943) && (
371 (smi_port == 0) || (smi_cmd == 0)))
375 smi_sig = 0x47534943;
377 smi_sig = ist_info.signature;
379 /* setup smi_port from MODLULE_PARM or BIOS */
380 if ((smi_port > 0xff) || (smi_port < 0)) {
382 } else if (smi_port == 0) {
383 smi_port = ist_info.command & 0xff;
386 if ((smi_cmd > 0xff) || (smi_cmd < 0)) {
388 } else if (smi_cmd == 0) {
389 smi_cmd = (ist_info.command >> 16) & 0xff;
392 return cpufreq_register_driver(&speedstep_driver);
397 * speedstep_exit - unregisters SpeedStep support
399 * Unregisters SpeedStep support.
401 static void __exit speedstep_exit(void)
403 cpufreq_unregister_driver(&speedstep_driver);
406 module_param(smi_port, int, 0444);
407 module_param(smi_cmd, int, 0444);
408 module_param(smi_sig, uint, 0444);
410 MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");
411 MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");
412 MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");
414 MODULE_AUTHOR ("Hiroshi Miura");
415 MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");
416 MODULE_LICENSE ("GPL");
418 module_init(speedstep_init);
419 module_exit(speedstep_exit);