Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Intel SpeedStep SMI driver. | |
3 | * | |
4 | * (C) 2003 Hiroshi Miura <miura@da-cha.org> | |
5 | * | |
6 | * Licensed under the terms of the GNU GPL License version 2. | |
7 | * | |
8 | */ | |
9 | ||
10 | ||
11 | /********************************************************************* | |
12 | * SPEEDSTEP - DEFINITIONS * | |
13 | *********************************************************************/ | |
14 | ||
1c5864e2 JP |
15 | #define pr_fmt(fmt) "cpufreq: " fmt |
16 | ||
1da177e4 | 17 | #include <linux/kernel.h> |
32ee8c3e DJ |
18 | #include <linux/module.h> |
19 | #include <linux/moduleparam.h> | |
1da177e4 LT |
20 | #include <linux/init.h> |
21 | #include <linux/cpufreq.h> | |
1da177e4 | 22 | #include <linux/delay.h> |
bbfebd66 | 23 | #include <linux/io.h> |
1da177e4 | 24 | #include <asm/ist.h> |
fa8031ae | 25 | #include <asm/cpu_device_id.h> |
1da177e4 LT |
26 | |
27 | #include "speedstep-lib.h" | |
28 | ||
29 | /* speedstep system management interface port/command. | |
30 | * | |
31 | * These parameters are got from IST-SMI BIOS call. | |
32 | * If user gives it, these are used. | |
32ee8c3e | 33 | * |
1da177e4 | 34 | */ |
bbfebd66 DJ |
35 | static int smi_port; |
36 | static int smi_cmd; | |
37 | static unsigned int smi_sig; | |
1da177e4 LT |
38 | |
39 | /* info about the processor */ | |
1cce76c2 | 40 | static enum speedstep_processor speedstep_processor; |
1da177e4 | 41 | |
32ee8c3e DJ |
42 | /* |
43 | * There are only two frequency states for each processor. Values | |
1da177e4 LT |
44 | * are in kHz for the time being. |
45 | */ | |
46 | static struct cpufreq_frequency_table speedstep_freqs[] = { | |
7f4b0461 VK |
47 | {0, SPEEDSTEP_HIGH, 0}, |
48 | {0, SPEEDSTEP_LOW, 0}, | |
49 | {0, 0, CPUFREQ_TABLE_END}, | |
1da177e4 LT |
50 | }; |
51 | ||
52 | #define GET_SPEEDSTEP_OWNER 0 | |
53 | #define GET_SPEEDSTEP_STATE 1 | |
54 | #define SET_SPEEDSTEP_STATE 2 | |
55 | #define GET_SPEEDSTEP_FREQS 4 | |
56 | ||
57 | /* how often shall the SMI call be tried if it failed, e.g. because | |
58 | * of DMA activity going on? */ | |
59 | #define SMI_TRIES 5 | |
60 | ||
1da177e4 LT |
61 | /** |
62 | * speedstep_smi_ownership | |
63 | */ | |
bbfebd66 | 64 | static int speedstep_smi_ownership(void) |
1da177e4 | 65 | { |
c6e8256a | 66 | u32 command, result, magic, dummy; |
1da177e4 LT |
67 | u32 function = GET_SPEEDSTEP_OWNER; |
68 | unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation"; | |
69 | ||
70 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); | |
71 | magic = virt_to_phys(magic_data); | |
72 | ||
2d06d8c4 | 73 | pr_debug("trying to obtain ownership with command %x at port %x\n", |
bbfebd66 | 74 | command, smi_port); |
1da177e4 LT |
75 | |
76 | __asm__ __volatile__( | |
c6e8256a | 77 | "push %%ebp\n" |
1da177e4 | 78 | "out %%al, (%%dx)\n" |
c6e8256a | 79 | "pop %%ebp\n" |
bbfebd66 DJ |
80 | : "=D" (result), |
81 | "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy), | |
82 | "=S" (dummy) | |
f081a529 | 83 | : "a" (command), "b" (function), "c" (0), "d" (smi_port), |
bbfebd66 | 84 | "D" (0), "S" (magic) |
f081a529 | 85 | : "memory" |
1da177e4 LT |
86 | ); |
87 | ||
2d06d8c4 | 88 | pr_debug("result is %x\n", result); |
1da177e4 LT |
89 | |
90 | return result; | |
91 | } | |
92 | ||
93 | /** | |
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 | |
97 | * | |
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). | |
101 | */ | |
bbfebd66 | 102 | static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high) |
1da177e4 | 103 | { |
c6e8256a | 104 | u32 command, result = 0, edi, high_mhz, low_mhz, dummy; |
bbfebd66 | 105 | u32 state = 0; |
1da177e4 LT |
106 | u32 function = GET_SPEEDSTEP_FREQS; |
107 | ||
108 | if (!(ist_info.event & 0xFFFF)) { | |
2d06d8c4 | 109 | pr_debug("bug #1422 -- can't read freqs from BIOS\n"); |
1da177e4 LT |
110 | return -ENODEV; |
111 | } | |
112 | ||
113 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); | |
114 | ||
2d06d8c4 | 115 | pr_debug("trying to determine frequencies with command %x at port %x\n", |
bbfebd66 | 116 | command, smi_port); |
1da177e4 | 117 | |
c6e8256a SD |
118 | __asm__ __volatile__( |
119 | "push %%ebp\n" | |
1da177e4 | 120 | "out %%al, (%%dx)\n" |
c6e8256a | 121 | "pop %%ebp" |
bbfebd66 DJ |
122 | : "=a" (result), |
123 | "=b" (high_mhz), | |
124 | "=c" (low_mhz), | |
125 | "=d" (state), "=D" (edi), "=S" (dummy) | |
126 | : "a" (command), | |
127 | "b" (function), | |
128 | "c" (state), | |
129 | "d" (smi_port), "S" (0), "D" (0) | |
1da177e4 LT |
130 | ); |
131 | ||
2d06d8c4 | 132 | pr_debug("result %x, low_freq %u, high_freq %u\n", |
bbfebd66 | 133 | result, low_mhz, high_mhz); |
1da177e4 LT |
134 | |
135 | /* abort if results are obviously incorrect... */ | |
136 | if ((high_mhz + low_mhz) < 600) | |
137 | return -EINVAL; | |
138 | ||
139 | *high = high_mhz * 1000; | |
140 | *low = low_mhz * 1000; | |
141 | ||
142 | return result; | |
32ee8c3e | 143 | } |
1da177e4 | 144 | |
1da177e4 LT |
145 | /** |
146 | * speedstep_set_state - set the SpeedStep state | |
147 | * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH) | |
148 | * | |
149 | */ | |
bbfebd66 | 150 | static void speedstep_set_state(unsigned int state) |
1da177e4 | 151 | { |
c6e8256a | 152 | unsigned int result = 0, command, new_state, dummy; |
1da177e4 | 153 | unsigned long flags; |
bbfebd66 | 154 | unsigned int function = SET_SPEEDSTEP_STATE; |
1da177e4 LT |
155 | unsigned int retry = 0; |
156 | ||
157 | if (state > 0x1) | |
158 | return; | |
159 | ||
160 | /* Disable IRQs */ | |
d4d4eda2 | 161 | preempt_disable(); |
1da177e4 LT |
162 | local_irq_save(flags); |
163 | ||
164 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); | |
165 | ||
2d06d8c4 | 166 | pr_debug("trying to set frequency to state %u " |
bbfebd66 DJ |
167 | "with command %x at port %x\n", |
168 | state, command, smi_port); | |
1da177e4 LT |
169 | |
170 | do { | |
171 | if (retry) { | |
d4d4eda2 MP |
172 | /* |
173 | * We need to enable interrupts, otherwise the blockage | |
174 | * won't resolve. | |
175 | * | |
176 | * We disable preemption so that other processes don't | |
177 | * run. If other processes were running, they could | |
178 | * submit more DMA requests, making the blockage worse. | |
179 | */ | |
2d06d8c4 | 180 | pr_debug("retry %u, previous result %u, waiting...\n", |
bbfebd66 | 181 | retry, result); |
d4d4eda2 | 182 | local_irq_enable(); |
1da177e4 | 183 | mdelay(retry * 50); |
d4d4eda2 | 184 | local_irq_disable(); |
1da177e4 LT |
185 | } |
186 | retry++; | |
187 | __asm__ __volatile__( | |
c6e8256a | 188 | "push %%ebp\n" |
1da177e4 | 189 | "out %%al, (%%dx)\n" |
c6e8256a | 190 | "pop %%ebp" |
bbfebd66 DJ |
191 | : "=b" (new_state), "=D" (result), |
192 | "=c" (dummy), "=a" (dummy), | |
193 | "=d" (dummy), "=S" (dummy) | |
194 | : "a" (command), "b" (function), "c" (state), | |
195 | "d" (smi_port), "S" (0), "D" (0) | |
1da177e4 LT |
196 | ); |
197 | } while ((new_state != state) && (retry <= SMI_TRIES)); | |
198 | ||
199 | /* enable IRQs */ | |
200 | local_irq_restore(flags); | |
d4d4eda2 | 201 | preempt_enable(); |
1da177e4 | 202 | |
bbfebd66 | 203 | if (new_state == state) |
2d06d8c4 | 204 | pr_debug("change to %u MHz succeeded after %u tries " |
bbfebd66 DJ |
205 | "with result %u\n", |
206 | (speedstep_freqs[new_state].frequency / 1000), | |
207 | retry, result); | |
208 | else | |
1c5864e2 | 209 | pr_err("change to state %u failed with new_state %u and result %u\n", |
b49c22a6 | 210 | state, new_state, result); |
1da177e4 LT |
211 | |
212 | return; | |
213 | } | |
214 | ||
215 | ||
216 | /** | |
217 | * speedstep_target - set a new CPUFreq policy | |
218 | * @policy: new policy | |
9c0ebcf7 | 219 | * @index: index of new freq |
1da177e4 LT |
220 | * |
221 | * Sets a new CPUFreq policy/freq. | |
222 | */ | |
9c0ebcf7 | 223 | static int speedstep_target(struct cpufreq_policy *policy, unsigned int index) |
1da177e4 | 224 | { |
9c0ebcf7 | 225 | speedstep_set_state(index); |
1da177e4 LT |
226 | |
227 | return 0; | |
228 | } | |
229 | ||
230 | ||
1da177e4 LT |
231 | static int speedstep_cpu_init(struct cpufreq_policy *policy) |
232 | { | |
233 | int result; | |
bbfebd66 | 234 | unsigned int *low, *high; |
1da177e4 LT |
235 | |
236 | /* capability check */ | |
237 | if (policy->cpu != 0) | |
238 | return -ENODEV; | |
239 | ||
240 | result = speedstep_smi_ownership(); | |
241 | if (result) { | |
2d06d8c4 | 242 | pr_debug("fails in acquiring ownership of a SMI interface.\n"); |
1da177e4 LT |
243 | return -EINVAL; |
244 | } | |
245 | ||
246 | /* detect low and high frequency */ | |
bbfebd66 DJ |
247 | low = &speedstep_freqs[SPEEDSTEP_LOW].frequency; |
248 | high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency; | |
249 | ||
250 | result = speedstep_smi_get_freqs(low, high); | |
1da177e4 | 251 | if (result) { |
bbfebd66 DJ |
252 | /* fall back to speedstep_lib.c dection mechanism: |
253 | * try both states out */ | |
2d06d8c4 | 254 | pr_debug("could not detect low and high frequencies " |
bbfebd66 | 255 | "by SMI call.\n"); |
1da177e4 | 256 | result = speedstep_get_freqs(speedstep_processor, |
bbfebd66 | 257 | low, high, |
1a10760c | 258 | NULL, |
1da177e4 LT |
259 | &speedstep_set_state); |
260 | ||
261 | if (result) { | |
2d06d8c4 | 262 | pr_debug("could not detect two different speeds" |
bbfebd66 | 263 | " -- aborting.\n"); |
1da177e4 LT |
264 | return result; |
265 | } else | |
2d06d8c4 | 266 | pr_debug("workaround worked.\n"); |
1da177e4 LT |
267 | } |
268 | ||
1da177e4 | 269 | policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
5f3a2d39 | 270 | return cpufreq_table_validate_and_show(policy, speedstep_freqs); |
1da177e4 LT |
271 | } |
272 | ||
1da177e4 LT |
273 | static unsigned int speedstep_get(unsigned int cpu) |
274 | { | |
275 | if (cpu) | |
276 | return -ENODEV; | |
bbfebd66 | 277 | return speedstep_get_frequency(speedstep_processor); |
1da177e4 LT |
278 | } |
279 | ||
280 | ||
281 | static int speedstep_resume(struct cpufreq_policy *policy) | |
282 | { | |
283 | int result = speedstep_smi_ownership(); | |
284 | ||
285 | if (result) | |
2d06d8c4 | 286 | pr_debug("fails in re-acquiring ownership of a SMI interface.\n"); |
1da177e4 LT |
287 | |
288 | return result; | |
289 | } | |
290 | ||
221dee28 | 291 | static struct cpufreq_driver speedstep_driver = { |
1da177e4 | 292 | .name = "speedstep-smi", |
3be1394a | 293 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 294 | .target_index = speedstep_target, |
1da177e4 | 295 | .init = speedstep_cpu_init, |
1da177e4 LT |
296 | .get = speedstep_get, |
297 | .resume = speedstep_resume, | |
3be1394a | 298 | .attr = cpufreq_generic_attr, |
1da177e4 LT |
299 | }; |
300 | ||
fa8031ae AK |
301 | static const struct x86_cpu_id ss_smi_ids[] = { |
302 | { X86_VENDOR_INTEL, 6, 0xb, }, | |
303 | { X86_VENDOR_INTEL, 6, 0x8, }, | |
304 | { X86_VENDOR_INTEL, 15, 2 }, | |
305 | {} | |
306 | }; | |
307 | #if 0 | |
308 | /* Not auto loaded currently */ | |
309 | MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids); | |
310 | #endif | |
311 | ||
1da177e4 LT |
312 | /** |
313 | * speedstep_init - initializes the SpeedStep CPUFreq driver | |
314 | * | |
315 | * Initializes the SpeedStep support. Returns -ENODEV on unsupported | |
316 | * BIOS, -EINVAL on problems during initiatization, and zero on | |
317 | * success. | |
318 | */ | |
319 | static int __init speedstep_init(void) | |
320 | { | |
fa8031ae AK |
321 | if (!x86_match_cpu(ss_smi_ids)) |
322 | return -ENODEV; | |
323 | ||
1da177e4 LT |
324 | speedstep_processor = speedstep_detect_processor(); |
325 | ||
326 | switch (speedstep_processor) { | |
bbfebd66 DJ |
327 | case SPEEDSTEP_CPU_PIII_T: |
328 | case SPEEDSTEP_CPU_PIII_C: | |
329 | case SPEEDSTEP_CPU_PIII_C_EARLY: | |
1da177e4 LT |
330 | break; |
331 | default: | |
332 | speedstep_processor = 0; | |
333 | } | |
334 | ||
335 | if (!speedstep_processor) { | |
2d06d8c4 | 336 | pr_debug("No supported Intel CPU detected.\n"); |
1da177e4 LT |
337 | return -ENODEV; |
338 | } | |
339 | ||
a5f30eba HW |
340 | pr_debug("signature:0x%.8x, command:0x%.8x, " |
341 | "event:0x%.8x, perf_level:0x%.8x.\n", | |
bbfebd66 DJ |
342 | ist_info.signature, ist_info.command, |
343 | ist_info.event, ist_info.perf_level); | |
1da177e4 | 344 | |
32ee8c3e | 345 | /* Error if no IST-SMI BIOS or no PARM |
1da177e4 | 346 | sig= 'ISGE' aka 'Intel Speedstep Gate E' */ |
32ee8c3e | 347 | if ((ist_info.signature != 0x47534943) && ( |
1da177e4 LT |
348 | (smi_port == 0) || (smi_cmd == 0))) |
349 | return -ENODEV; | |
350 | ||
351 | if (smi_sig == 1) | |
352 | smi_sig = 0x47534943; | |
353 | else | |
354 | smi_sig = ist_info.signature; | |
355 | ||
356 | /* setup smi_port from MODLULE_PARM or BIOS */ | |
32ee8c3e | 357 | if ((smi_port > 0xff) || (smi_port < 0)) |
1da177e4 | 358 | return -EINVAL; |
32ee8c3e | 359 | else if (smi_port == 0) |
1da177e4 | 360 | smi_port = ist_info.command & 0xff; |
1da177e4 | 361 | |
32ee8c3e | 362 | if ((smi_cmd > 0xff) || (smi_cmd < 0)) |
1da177e4 | 363 | return -EINVAL; |
32ee8c3e | 364 | else if (smi_cmd == 0) |
1da177e4 | 365 | smi_cmd = (ist_info.command >> 16) & 0xff; |
1da177e4 LT |
366 | |
367 | return cpufreq_register_driver(&speedstep_driver); | |
368 | } | |
369 | ||
370 | ||
371 | /** | |
372 | * speedstep_exit - unregisters SpeedStep support | |
373 | * | |
374 | * Unregisters SpeedStep support. | |
375 | */ | |
376 | static void __exit speedstep_exit(void) | |
377 | { | |
378 | cpufreq_unregister_driver(&speedstep_driver); | |
379 | } | |
380 | ||
bbfebd66 DJ |
381 | module_param(smi_port, int, 0444); |
382 | module_param(smi_cmd, int, 0444); | |
383 | module_param(smi_sig, uint, 0444); | |
1da177e4 | 384 | |
bbfebd66 DJ |
385 | MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value " |
386 | "-- Intel's default setting is 0xb2"); | |
387 | MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value " | |
388 | "-- Intel's default setting is 0x82"); | |
389 | MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the " | |
390 | "SMI interface."); | |
1da177e4 | 391 | |
bbfebd66 DJ |
392 | MODULE_AUTHOR("Hiroshi Miura"); |
393 | MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface."); | |
394 | MODULE_LICENSE("GPL"); | |
1da177e4 LT |
395 | |
396 | module_init(speedstep_init); | |
397 | module_exit(speedstep_exit); |