Merge branch 'mini2440-dev-unlikely' into mini2440-dev
[linux-2.6/mini2440.git] / arch / x86 / kernel / cpu / cpufreq / speedstep-smi.c
blobbefea088e4f58b472259f955a8304e5c834e083f
1 /*
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.
8 */
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/slab.h>
21 #include <linux/delay.h>
22 #include <linux/io.h>
23 #include <asm/ist.h>
25 #include "speedstep-lib.h"
27 /* speedstep system management interface port/command.
29 * These parameters are got from IST-SMI BIOS call.
30 * If user gives it, these are used.
33 static int smi_port;
34 static int smi_cmd;
35 static unsigned int smi_sig;
37 /* info about the processor */
38 static unsigned int speedstep_processor;
41 * There are only two frequency states for each processor. Values
42 * are in kHz for the time being.
44 static struct cpufreq_frequency_table speedstep_freqs[] = {
45 {SPEEDSTEP_HIGH, 0},
46 {SPEEDSTEP_LOW, 0},
47 {0, CPUFREQ_TABLE_END},
50 #define GET_SPEEDSTEP_OWNER 0
51 #define GET_SPEEDSTEP_STATE 1
52 #define SET_SPEEDSTEP_STATE 2
53 #define GET_SPEEDSTEP_FREQS 4
55 /* how often shall the SMI call be tried if it failed, e.g. because
56 * of DMA activity going on? */
57 #define SMI_TRIES 5
59 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
60 "speedstep-smi", msg)
62 /**
63 * speedstep_smi_ownership
65 static int speedstep_smi_ownership(void)
67 u32 command, result, magic, dummy;
68 u32 function = GET_SPEEDSTEP_OWNER;
69 unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
71 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
72 magic = virt_to_phys(magic_data);
74 dprintk("trying to obtain ownership with command %x at port %x\n",
75 command, smi_port);
77 __asm__ __volatile__(
78 "push %%ebp\n"
79 "out %%al, (%%dx)\n"
80 "pop %%ebp\n"
81 : "=D" (result),
82 "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
83 "=S" (dummy)
84 : "a" (command), "b" (function), "c" (0), "d" (smi_port),
85 "D" (0), "S" (magic)
86 : "memory"
89 dprintk("result is %x\n", result);
91 return result;
94 /**
95 * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
96 * @low: the low frequency value is placed here
97 * @high: the high frequency value is placed here
99 * Only available on later SpeedStep-enabled systems, returns false results or
100 * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
101 * shows that the latter occurs if !(ist_info.event & 0xFFFF).
103 static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high)
105 u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
106 u32 state = 0;
107 u32 function = GET_SPEEDSTEP_FREQS;
109 if (!(ist_info.event & 0xFFFF)) {
110 dprintk("bug #1422 -- can't read freqs from BIOS\n");
111 return -ENODEV;
114 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
116 dprintk("trying to determine frequencies with command %x at port %x\n",
117 command, smi_port);
119 __asm__ __volatile__(
120 "push %%ebp\n"
121 "out %%al, (%%dx)\n"
122 "pop %%ebp"
123 : "=a" (result),
124 "=b" (high_mhz),
125 "=c" (low_mhz),
126 "=d" (state), "=D" (edi), "=S" (dummy)
127 : "a" (command),
128 "b" (function),
129 "c" (state),
130 "d" (smi_port), "S" (0), "D" (0)
133 dprintk("result %x, low_freq %u, high_freq %u\n",
134 result, low_mhz, high_mhz);
136 /* abort if results are obviously incorrect... */
137 if ((high_mhz + low_mhz) < 600)
138 return -EINVAL;
140 *high = high_mhz * 1000;
141 *low = low_mhz * 1000;
143 return result;
147 * speedstep_get_state - set the SpeedStep state
148 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
151 static int speedstep_get_state(void)
153 u32 function = GET_SPEEDSTEP_STATE;
154 u32 result, state, edi, command, dummy;
156 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
158 dprintk("trying to determine current setting with command %x "
159 "at port %x\n", command, smi_port);
161 __asm__ __volatile__(
162 "push %%ebp\n"
163 "out %%al, (%%dx)\n"
164 "pop %%ebp\n"
165 : "=a" (result),
166 "=b" (state), "=D" (edi),
167 "=c" (dummy), "=d" (dummy), "=S" (dummy)
168 : "a" (command), "b" (function), "c" (0),
169 "d" (smi_port), "S" (0), "D" (0)
172 dprintk("state is %x, result is %x\n", state, result);
174 return state & 1;
179 * speedstep_set_state - set the SpeedStep state
180 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
183 static void speedstep_set_state(unsigned int state)
185 unsigned int result = 0, command, new_state, dummy;
186 unsigned long flags;
187 unsigned int function = SET_SPEEDSTEP_STATE;
188 unsigned int retry = 0;
190 if (state > 0x1)
191 return;
193 /* Disable IRQs */
194 local_irq_save(flags);
196 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
198 dprintk("trying to set frequency to state %u "
199 "with command %x at port %x\n",
200 state, command, smi_port);
202 do {
203 if (retry) {
204 dprintk("retry %u, previous result %u, waiting...\n",
205 retry, result);
206 mdelay(retry * 50);
208 retry++;
209 __asm__ __volatile__(
210 "push %%ebp\n"
211 "out %%al, (%%dx)\n"
212 "pop %%ebp"
213 : "=b" (new_state), "=D" (result),
214 "=c" (dummy), "=a" (dummy),
215 "=d" (dummy), "=S" (dummy)
216 : "a" (command), "b" (function), "c" (state),
217 "d" (smi_port), "S" (0), "D" (0)
219 } while ((new_state != state) && (retry <= SMI_TRIES));
221 /* enable IRQs */
222 local_irq_restore(flags);
224 if (new_state == state)
225 dprintk("change to %u MHz succeeded after %u tries "
226 "with result %u\n",
227 (speedstep_freqs[new_state].frequency / 1000),
228 retry, result);
229 else
230 printk(KERN_ERR "cpufreq: change to state %u "
231 "failed with new_state %u and result %u\n",
232 state, new_state, result);
234 return;
239 * speedstep_target - set a new CPUFreq policy
240 * @policy: new policy
241 * @target_freq: new freq
242 * @relation:
244 * Sets a new CPUFreq policy/freq.
246 static int speedstep_target(struct cpufreq_policy *policy,
247 unsigned int target_freq, unsigned int relation)
249 unsigned int newstate = 0;
250 struct cpufreq_freqs freqs;
252 if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
253 target_freq, relation, &newstate))
254 return -EINVAL;
256 freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
257 freqs.new = speedstep_freqs[newstate].frequency;
258 freqs.cpu = 0; /* speedstep.c is UP only driver */
260 if (freqs.old == freqs.new)
261 return 0;
263 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
264 speedstep_set_state(newstate);
265 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
267 return 0;
272 * speedstep_verify - verifies a new CPUFreq policy
273 * @policy: new policy
275 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
276 * at least one border included.
278 static int speedstep_verify(struct cpufreq_policy *policy)
280 return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
284 static int speedstep_cpu_init(struct cpufreq_policy *policy)
286 int result;
287 unsigned int speed, state;
288 unsigned int *low, *high;
290 /* capability check */
291 if (policy->cpu != 0)
292 return -ENODEV;
294 result = speedstep_smi_ownership();
295 if (result) {
296 dprintk("fails in aquiring ownership of a SMI interface.\n");
297 return -EINVAL;
300 /* detect low and high frequency */
301 low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
302 high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
304 result = speedstep_smi_get_freqs(low, high);
305 if (result) {
306 /* fall back to speedstep_lib.c dection mechanism:
307 * try both states out */
308 dprintk("could not detect low and high frequencies "
309 "by SMI call.\n");
310 result = speedstep_get_freqs(speedstep_processor,
311 low, high,
312 NULL,
313 &speedstep_set_state);
315 if (result) {
316 dprintk("could not detect two different speeds"
317 " -- aborting.\n");
318 return result;
319 } else
320 dprintk("workaround worked.\n");
323 /* get current speed setting */
324 state = speedstep_get_state();
325 speed = speedstep_freqs[state].frequency;
327 dprintk("currently at %s speed setting - %i MHz\n",
328 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
329 ? "low" : "high",
330 (speed / 1000));
332 /* cpuinfo and default policy values */
333 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
334 policy->cur = speed;
336 result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
337 if (result)
338 return result;
340 cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
342 return 0;
345 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
347 cpufreq_frequency_table_put_attr(policy->cpu);
348 return 0;
351 static unsigned int speedstep_get(unsigned int cpu)
353 if (cpu)
354 return -ENODEV;
355 return speedstep_get_frequency(speedstep_processor);
359 static int speedstep_resume(struct cpufreq_policy *policy)
361 int result = speedstep_smi_ownership();
363 if (result)
364 dprintk("fails in re-aquiring ownership of a SMI interface.\n");
366 return result;
369 static struct freq_attr *speedstep_attr[] = {
370 &cpufreq_freq_attr_scaling_available_freqs,
371 NULL,
374 static struct cpufreq_driver speedstep_driver = {
375 .name = "speedstep-smi",
376 .verify = speedstep_verify,
377 .target = speedstep_target,
378 .init = speedstep_cpu_init,
379 .exit = speedstep_cpu_exit,
380 .get = speedstep_get,
381 .resume = speedstep_resume,
382 .owner = THIS_MODULE,
383 .attr = speedstep_attr,
387 * speedstep_init - initializes the SpeedStep CPUFreq driver
389 * Initializes the SpeedStep support. Returns -ENODEV on unsupported
390 * BIOS, -EINVAL on problems during initiatization, and zero on
391 * success.
393 static int __init speedstep_init(void)
395 speedstep_processor = speedstep_detect_processor();
397 switch (speedstep_processor) {
398 case SPEEDSTEP_CPU_PIII_T:
399 case SPEEDSTEP_CPU_PIII_C:
400 case SPEEDSTEP_CPU_PIII_C_EARLY:
401 break;
402 default:
403 speedstep_processor = 0;
406 if (!speedstep_processor) {
407 dprintk("No supported Intel CPU detected.\n");
408 return -ENODEV;
411 dprintk("signature:0x%.8lx, command:0x%.8lx, "
412 "event:0x%.8lx, perf_level:0x%.8lx.\n",
413 ist_info.signature, ist_info.command,
414 ist_info.event, ist_info.perf_level);
416 /* Error if no IST-SMI BIOS or no PARM
417 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
418 if ((ist_info.signature != 0x47534943) && (
419 (smi_port == 0) || (smi_cmd == 0)))
420 return -ENODEV;
422 if (smi_sig == 1)
423 smi_sig = 0x47534943;
424 else
425 smi_sig = ist_info.signature;
427 /* setup smi_port from MODLULE_PARM or BIOS */
428 if ((smi_port > 0xff) || (smi_port < 0))
429 return -EINVAL;
430 else if (smi_port == 0)
431 smi_port = ist_info.command & 0xff;
433 if ((smi_cmd > 0xff) || (smi_cmd < 0))
434 return -EINVAL;
435 else if (smi_cmd == 0)
436 smi_cmd = (ist_info.command >> 16) & 0xff;
438 return cpufreq_register_driver(&speedstep_driver);
443 * speedstep_exit - unregisters SpeedStep support
445 * Unregisters SpeedStep support.
447 static void __exit speedstep_exit(void)
449 cpufreq_unregister_driver(&speedstep_driver);
452 module_param(smi_port, int, 0444);
453 module_param(smi_cmd, int, 0444);
454 module_param(smi_sig, uint, 0444);
456 MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
457 "-- Intel's default setting is 0xb2");
458 MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
459 "-- Intel's default setting is 0x82");
460 MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
461 "SMI interface.");
463 MODULE_AUTHOR("Hiroshi Miura");
464 MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
465 MODULE_LICENSE("GPL");
467 module_init(speedstep_init);
468 module_exit(speedstep_exit);