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)
118 *high = high_mhz * 1000;
119 *low = low_mhz * 1000;
125 * speedstep_get_state - set the SpeedStep state
126 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
129 static int speedstep_get_state (void)
131 u32 function=GET_SPEEDSTEP_STATE;
132 u32 result, state, edi, command;
134 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
136 __asm__ __volatile__("movl $0, %%edi\n"
138 : "=a" (result), "=b" (state), "=D" (edi)
139 : "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0)
146 * speedstep_set_state - set the SpeedStep state
147 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
150 static void speedstep_set_state (unsigned int state)
152 unsigned int result = 0, command, new_state;
154 unsigned int function=SET_SPEEDSTEP_STATE;
155 unsigned int retry = 0;
161 local_irq_save(flags);
163 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
167 dprintk(KERN_INFO "cpufreq: retry %u, previous result %u\n", retry, result);
171 __asm__ __volatile__(
174 : "=b" (new_state), "=D" (result)
175 : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
177 } while ((new_state != state) && (retry <= SMI_TRIES));
180 local_irq_restore(flags);
182 if (new_state == state) {
183 dprintk(KERN_INFO "cpufreq: change to %u MHz succeeded after %u tries with result %u\n", (freqs.new / 1000), retry, result);
185 printk(KERN_ERR "cpufreq: change failed with new_state %u and result %u\n", new_state, result);
193 * speedstep_target - set a new CPUFreq policy
194 * @policy: new policy
195 * @target_freq: new freq
198 * Sets a new CPUFreq policy/freq.
200 static int speedstep_target (struct cpufreq_policy *policy,
201 unsigned int target_freq, unsigned int relation)
203 unsigned int newstate = 0;
204 struct cpufreq_freqs freqs;
206 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
209 freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
210 freqs.new = speedstep_freqs[newstate].frequency;
211 freqs.cpu = 0; /* speedstep.c is UP only driver */
213 if (freqs.old == freqs.new)
216 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
217 speedstep_set_state(newstate);
218 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
225 * speedstep_verify - verifies a new CPUFreq policy
226 * @policy: new policy
228 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
229 * at least one border included.
231 static int speedstep_verify (struct cpufreq_policy *policy)
233 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
237 static int speedstep_cpu_init(struct cpufreq_policy *policy)
240 unsigned int speed,state;
242 /* capability check */
243 if (policy->cpu != 0)
246 result = speedstep_smi_ownership();
248 dprintk(KERN_INFO "cpufreq: fails an aquiring ownership of a SMI interface.\n");
252 /* detect low and high frequency */
253 result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,
254 &speedstep_freqs[SPEEDSTEP_HIGH].frequency);
256 /* fall back to speedstep_lib.c dection mechanism: try both states out */
257 dprintk(KERN_INFO PFX "could not detect low and high frequencies by SMI call.\n");
258 if (!speedstep_processor)
259 speedstep_processor = speedstep_detect_processor();
261 if (!speedstep_processor)
264 result = speedstep_get_freqs(speedstep_processor,
265 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
266 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
267 &speedstep_set_state);
270 dprintk(KERN_INFO PFX "could not detect two different speeds -- aborting.\n");
273 dprintk(KERN_INFO PFX "workaround worked.\n");
276 /* get current speed setting */
277 state = speedstep_get_state();
278 speed = speedstep_freqs[state].frequency;
280 dprintk(KERN_INFO "cpufreq: currently at %s speed setting - %i MHz\n",
281 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
284 /* cpuinfo and default policy values */
285 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
286 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
289 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
293 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
298 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
300 cpufreq_frequency_table_put_attr(policy->cpu);
304 static unsigned int speedstep_get(unsigned int cpu)
308 if (!speedstep_processor)
309 speedstep_processor = speedstep_detect_processor();
310 if (!speedstep_processor)
312 return speedstep_get_processor_frequency(speedstep_processor);
316 static int speedstep_resume(struct cpufreq_policy *policy)
318 int result = speedstep_smi_ownership();
321 dprintk(KERN_INFO "cpufreq: fails an aquiring ownership of a SMI interface.\n");
326 static struct freq_attr* speedstep_attr[] = {
327 &cpufreq_freq_attr_scaling_available_freqs,
331 static struct cpufreq_driver speedstep_driver = {
332 .name = "speedstep-smi",
333 .verify = speedstep_verify,
334 .target = speedstep_target,
335 .init = speedstep_cpu_init,
336 .exit = speedstep_cpu_exit,
337 .get = speedstep_get,
338 .resume = speedstep_resume,
339 .owner = THIS_MODULE,
340 .attr = speedstep_attr,
344 * speedstep_init - initializes the SpeedStep CPUFreq driver
346 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
347 * BIOS, -EINVAL on problems during initiatization, and zero on
350 static int __init speedstep_init(void)
352 struct cpuinfo_x86 *c = cpu_data;
354 if (c->x86_vendor != X86_VENDOR_INTEL) {
355 printk (KERN_INFO PFX "No Intel CPU detected.\n");
359 dprintk(KERN_DEBUG PFX "signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",
360 ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);
363 /* Error if no IST-SMI BIOS or no PARM
364 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
365 if ((ist_info.signature != 0x47534943) && (
366 (smi_port == 0) || (smi_cmd == 0)))
370 smi_sig = 0x47534943;
372 smi_sig = ist_info.signature;
374 /* setup smi_port from MODLULE_PARM or BIOS */
375 if ((smi_port > 0xff) || (smi_port < 0)) {
377 } else if (smi_port == 0) {
378 smi_port = ist_info.command & 0xff;
381 if ((smi_cmd > 0xff) || (smi_cmd < 0)) {
383 } else if (smi_cmd == 0) {
384 smi_cmd = (ist_info.command >> 16) & 0xff;
387 return cpufreq_register_driver(&speedstep_driver);
392 * speedstep_exit - unregisters SpeedStep support
394 * Unregisters SpeedStep support.
396 static void __exit speedstep_exit(void)
398 cpufreq_unregister_driver(&speedstep_driver);
401 module_param(smi_port, int, 0444);
402 module_param(smi_cmd, int, 0444);
403 module_param(smi_sig, uint, 0444);
405 MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");
406 MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");
407 MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");
409 MODULE_AUTHOR ("Hiroshi Miura");
410 MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");
411 MODULE_LICENSE ("GPL");
413 module_init(speedstep_init);
414 module_exit(speedstep_exit);