Commit | Line | Data |
---|---|---|
4f19048f | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * Intel SpeedStep SMI driver. | |
4 | * | |
5 | * (C) 2003 Hiroshi Miura <miura@da-cha.org> | |
1da177e4 LT |
6 | */ |
7 | ||
8 | ||
9 | /********************************************************************* | |
10 | * SPEEDSTEP - DEFINITIONS * | |
11 | *********************************************************************/ | |
12 | ||
1c5864e2 JP |
13 | #define pr_fmt(fmt) "cpufreq: " fmt |
14 | ||
1da177e4 | 15 | #include <linux/kernel.h> |
32ee8c3e DJ |
16 | #include <linux/module.h> |
17 | #include <linux/moduleparam.h> | |
1da177e4 LT |
18 | #include <linux/init.h> |
19 | #include <linux/cpufreq.h> | |
1da177e4 | 20 | #include <linux/delay.h> |
bbfebd66 | 21 | #include <linux/io.h> |
1da177e4 | 22 | #include <asm/ist.h> |
fa8031ae | 23 | #include <asm/cpu_device_id.h> |
1da177e4 LT |
24 | |
25 | #include "speedstep-lib.h" | |
26 | ||
27 | /* speedstep system management interface port/command. | |
28 | * | |
29 | * These parameters are got from IST-SMI BIOS call. | |
30 | * If user gives it, these are used. | |
32ee8c3e | 31 | * |
1da177e4 | 32 | */ |
bbfebd66 DJ |
33 | static int smi_port; |
34 | static int smi_cmd; | |
35 | static unsigned int smi_sig; | |
1da177e4 LT |
36 | |
37 | /* info about the processor */ | |
1cce76c2 | 38 | static enum speedstep_processor speedstep_processor; |
1da177e4 | 39 | |
32ee8c3e DJ |
40 | /* |
41 | * There are only two frequency states for each processor. Values | |
1da177e4 LT |
42 | * are in kHz for the time being. |
43 | */ | |
44 | static struct cpufreq_frequency_table speedstep_freqs[] = { | |
7f4b0461 VK |
45 | {0, SPEEDSTEP_HIGH, 0}, |
46 | {0, SPEEDSTEP_LOW, 0}, | |
47 | {0, 0, CPUFREQ_TABLE_END}, | |
1da177e4 LT |
48 | }; |
49 | ||
50 | #define GET_SPEEDSTEP_OWNER 0 | |
51 | #define GET_SPEEDSTEP_STATE 1 | |
52 | #define SET_SPEEDSTEP_STATE 2 | |
53 | #define GET_SPEEDSTEP_FREQS 4 | |
54 | ||
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 | |
58 | ||
1da177e4 LT |
59 | /** |
60 | * speedstep_smi_ownership | |
61 | */ | |
bbfebd66 | 62 | static int speedstep_smi_ownership(void) |
1da177e4 | 63 | { |
c6e8256a | 64 | u32 command, result, magic, dummy; |
1da177e4 LT |
65 | u32 function = GET_SPEEDSTEP_OWNER; |
66 | unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation"; | |
67 | ||
68 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); | |
69 | magic = virt_to_phys(magic_data); | |
70 | ||
2d06d8c4 | 71 | pr_debug("trying to obtain ownership with command %x at port %x\n", |
bbfebd66 | 72 | command, smi_port); |
1da177e4 LT |
73 | |
74 | __asm__ __volatile__( | |
c6e8256a | 75 | "push %%ebp\n" |
1da177e4 | 76 | "out %%al, (%%dx)\n" |
c6e8256a | 77 | "pop %%ebp\n" |
bbfebd66 DJ |
78 | : "=D" (result), |
79 | "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy), | |
80 | "=S" (dummy) | |
f081a529 | 81 | : "a" (command), "b" (function), "c" (0), "d" (smi_port), |
bbfebd66 | 82 | "D" (0), "S" (magic) |
f081a529 | 83 | : "memory" |
1da177e4 LT |
84 | ); |
85 | ||
2d06d8c4 | 86 | pr_debug("result is %x\n", result); |
1da177e4 LT |
87 | |
88 | return result; | |
89 | } | |
90 | ||
91 | /** | |
92 | * speedstep_smi_get_freqs - get SpeedStep preferred & current freq. | |
93 | * @low: the low frequency value is placed here | |
94 | * @high: the high frequency value is placed here | |
95 | * | |
96 | * Only available on later SpeedStep-enabled systems, returns false results or | |
97 | * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing | |
98 | * shows that the latter occurs if !(ist_info.event & 0xFFFF). | |
99 | */ | |
bbfebd66 | 100 | static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high) |
1da177e4 | 101 | { |
c6e8256a | 102 | u32 command, result = 0, edi, high_mhz, low_mhz, dummy; |
bbfebd66 | 103 | u32 state = 0; |
1da177e4 LT |
104 | u32 function = GET_SPEEDSTEP_FREQS; |
105 | ||
106 | if (!(ist_info.event & 0xFFFF)) { | |
2d06d8c4 | 107 | pr_debug("bug #1422 -- can't read freqs from BIOS\n"); |
1da177e4 LT |
108 | return -ENODEV; |
109 | } | |
110 | ||
111 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); | |
112 | ||
2d06d8c4 | 113 | pr_debug("trying to determine frequencies with command %x at port %x\n", |
bbfebd66 | 114 | command, smi_port); |
1da177e4 | 115 | |
c6e8256a SD |
116 | __asm__ __volatile__( |
117 | "push %%ebp\n" | |
1da177e4 | 118 | "out %%al, (%%dx)\n" |
c6e8256a | 119 | "pop %%ebp" |
bbfebd66 DJ |
120 | : "=a" (result), |
121 | "=b" (high_mhz), | |
122 | "=c" (low_mhz), | |
123 | "=d" (state), "=D" (edi), "=S" (dummy) | |
124 | : "a" (command), | |
125 | "b" (function), | |
126 | "c" (state), | |
127 | "d" (smi_port), "S" (0), "D" (0) | |
1da177e4 LT |
128 | ); |
129 | ||
2d06d8c4 | 130 | pr_debug("result %x, low_freq %u, high_freq %u\n", |
bbfebd66 | 131 | result, low_mhz, high_mhz); |
1da177e4 LT |
132 | |
133 | /* abort if results are obviously incorrect... */ | |
134 | if ((high_mhz + low_mhz) < 600) | |
135 | return -EINVAL; | |
136 | ||
137 | *high = high_mhz * 1000; | |
138 | *low = low_mhz * 1000; | |
139 | ||
140 | return result; | |
32ee8c3e | 141 | } |
1da177e4 | 142 | |
1da177e4 LT |
143 | /** |
144 | * speedstep_set_state - set the SpeedStep state | |
145 | * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH) | |
146 | * | |
147 | */ | |
bbfebd66 | 148 | static void speedstep_set_state(unsigned int state) |
1da177e4 | 149 | { |
c6e8256a | 150 | unsigned int result = 0, command, new_state, dummy; |
1da177e4 | 151 | unsigned long flags; |
bbfebd66 | 152 | unsigned int function = SET_SPEEDSTEP_STATE; |
1da177e4 LT |
153 | unsigned int retry = 0; |
154 | ||
155 | if (state > 0x1) | |
156 | return; | |
157 | ||
158 | /* Disable IRQs */ | |
d4d4eda2 | 159 | preempt_disable(); |
1da177e4 LT |
160 | local_irq_save(flags); |
161 | ||
162 | command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); | |
163 | ||
2d06d8c4 | 164 | pr_debug("trying to set frequency to state %u " |
bbfebd66 DJ |
165 | "with command %x at port %x\n", |
166 | state, command, smi_port); | |
1da177e4 LT |
167 | |
168 | do { | |
169 | if (retry) { | |
d4d4eda2 MP |
170 | /* |
171 | * We need to enable interrupts, otherwise the blockage | |
172 | * won't resolve. | |
173 | * | |
174 | * We disable preemption so that other processes don't | |
175 | * run. If other processes were running, they could | |
176 | * submit more DMA requests, making the blockage worse. | |
177 | */ | |
2d06d8c4 | 178 | pr_debug("retry %u, previous result %u, waiting...\n", |
bbfebd66 | 179 | retry, result); |
d4d4eda2 | 180 | local_irq_enable(); |
1da177e4 | 181 | mdelay(retry * 50); |
d4d4eda2 | 182 | local_irq_disable(); |
1da177e4 LT |
183 | } |
184 | retry++; | |
185 | __asm__ __volatile__( | |
c6e8256a | 186 | "push %%ebp\n" |
1da177e4 | 187 | "out %%al, (%%dx)\n" |
c6e8256a | 188 | "pop %%ebp" |
bbfebd66 DJ |
189 | : "=b" (new_state), "=D" (result), |
190 | "=c" (dummy), "=a" (dummy), | |
191 | "=d" (dummy), "=S" (dummy) | |
192 | : "a" (command), "b" (function), "c" (state), | |
193 | "d" (smi_port), "S" (0), "D" (0) | |
1da177e4 LT |
194 | ); |
195 | } while ((new_state != state) && (retry <= SMI_TRIES)); | |
196 | ||
197 | /* enable IRQs */ | |
198 | local_irq_restore(flags); | |
d4d4eda2 | 199 | preempt_enable(); |
1da177e4 | 200 | |
bbfebd66 | 201 | if (new_state == state) |
2d06d8c4 | 202 | pr_debug("change to %u MHz succeeded after %u tries " |
bbfebd66 DJ |
203 | "with result %u\n", |
204 | (speedstep_freqs[new_state].frequency / 1000), | |
205 | retry, result); | |
206 | else | |
1c5864e2 | 207 | pr_err("change to state %u failed with new_state %u and result %u\n", |
b49c22a6 | 208 | state, new_state, result); |
1da177e4 LT |
209 | |
210 | return; | |
211 | } | |
212 | ||
213 | ||
214 | /** | |
215 | * speedstep_target - set a new CPUFreq policy | |
216 | * @policy: new policy | |
9c0ebcf7 | 217 | * @index: index of new freq |
1da177e4 LT |
218 | * |
219 | * Sets a new CPUFreq policy/freq. | |
220 | */ | |
9c0ebcf7 | 221 | static int speedstep_target(struct cpufreq_policy *policy, unsigned int index) |
1da177e4 | 222 | { |
9c0ebcf7 | 223 | speedstep_set_state(index); |
1da177e4 LT |
224 | |
225 | return 0; | |
226 | } | |
227 | ||
228 | ||
1da177e4 LT |
229 | static int speedstep_cpu_init(struct cpufreq_policy *policy) |
230 | { | |
231 | int result; | |
bbfebd66 | 232 | unsigned int *low, *high; |
1da177e4 LT |
233 | |
234 | /* capability check */ | |
235 | if (policy->cpu != 0) | |
236 | return -ENODEV; | |
237 | ||
238 | result = speedstep_smi_ownership(); | |
239 | if (result) { | |
2d06d8c4 | 240 | pr_debug("fails in acquiring ownership of a SMI interface.\n"); |
1da177e4 LT |
241 | return -EINVAL; |
242 | } | |
243 | ||
244 | /* detect low and high frequency */ | |
bbfebd66 DJ |
245 | low = &speedstep_freqs[SPEEDSTEP_LOW].frequency; |
246 | high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency; | |
247 | ||
248 | result = speedstep_smi_get_freqs(low, high); | |
1da177e4 | 249 | if (result) { |
bbfebd66 DJ |
250 | /* fall back to speedstep_lib.c dection mechanism: |
251 | * try both states out */ | |
2d06d8c4 | 252 | pr_debug("could not detect low and high frequencies " |
bbfebd66 | 253 | "by SMI call.\n"); |
1da177e4 | 254 | result = speedstep_get_freqs(speedstep_processor, |
bbfebd66 | 255 | low, high, |
1a10760c | 256 | NULL, |
1da177e4 LT |
257 | &speedstep_set_state); |
258 | ||
259 | if (result) { | |
2d06d8c4 | 260 | pr_debug("could not detect two different speeds" |
bbfebd66 | 261 | " -- aborting.\n"); |
1da177e4 LT |
262 | return result; |
263 | } else | |
2d06d8c4 | 264 | pr_debug("workaround worked.\n"); |
1da177e4 LT |
265 | } |
266 | ||
2d28b036 VK |
267 | policy->freq_table = speedstep_freqs; |
268 | ||
269 | return 0; | |
1da177e4 LT |
270 | } |
271 | ||
1da177e4 LT |
272 | static unsigned int speedstep_get(unsigned int cpu) |
273 | { | |
274 | if (cpu) | |
275 | return -ENODEV; | |
bbfebd66 | 276 | return speedstep_get_frequency(speedstep_processor); |
1da177e4 LT |
277 | } |
278 | ||
279 | ||
280 | static int speedstep_resume(struct cpufreq_policy *policy) | |
281 | { | |
282 | int result = speedstep_smi_ownership(); | |
283 | ||
284 | if (result) | |
2d06d8c4 | 285 | pr_debug("fails in re-acquiring ownership of a SMI interface.\n"); |
1da177e4 LT |
286 | |
287 | return result; | |
288 | } | |
289 | ||
221dee28 | 290 | static struct cpufreq_driver speedstep_driver = { |
1da177e4 | 291 | .name = "speedstep-smi", |
fe829ed8 | 292 | .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, |
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 | 301 | static const struct x86_cpu_id ss_smi_ids[] = { |
b11d77fa TG |
302 | X86_MATCH_VENDOR_FAM_MODEL(INTEL, 6, 0x8, 0), |
303 | X86_MATCH_VENDOR_FAM_MODEL(INTEL, 6, 0xb, 0), | |
304 | X86_MATCH_VENDOR_FAM_MODEL(INTEL, 15, 0x2, 0), | |
fa8031ae AK |
305 | {} |
306 | }; | |
fa8031ae | 307 | |
1da177e4 LT |
308 | /** |
309 | * speedstep_init - initializes the SpeedStep CPUFreq driver | |
310 | * | |
311 | * Initializes the SpeedStep support. Returns -ENODEV on unsupported | |
312 | * BIOS, -EINVAL on problems during initiatization, and zero on | |
313 | * success. | |
314 | */ | |
315 | static int __init speedstep_init(void) | |
316 | { | |
fa8031ae AK |
317 | if (!x86_match_cpu(ss_smi_ids)) |
318 | return -ENODEV; | |
319 | ||
1da177e4 LT |
320 | speedstep_processor = speedstep_detect_processor(); |
321 | ||
322 | switch (speedstep_processor) { | |
bbfebd66 DJ |
323 | case SPEEDSTEP_CPU_PIII_T: |
324 | case SPEEDSTEP_CPU_PIII_C: | |
325 | case SPEEDSTEP_CPU_PIII_C_EARLY: | |
1da177e4 LT |
326 | break; |
327 | default: | |
328 | speedstep_processor = 0; | |
329 | } | |
330 | ||
331 | if (!speedstep_processor) { | |
2d06d8c4 | 332 | pr_debug("No supported Intel CPU detected.\n"); |
1da177e4 LT |
333 | return -ENODEV; |
334 | } | |
335 | ||
a5f30eba HW |
336 | pr_debug("signature:0x%.8x, command:0x%.8x, " |
337 | "event:0x%.8x, perf_level:0x%.8x.\n", | |
bbfebd66 DJ |
338 | ist_info.signature, ist_info.command, |
339 | ist_info.event, ist_info.perf_level); | |
1da177e4 | 340 | |
32ee8c3e | 341 | /* Error if no IST-SMI BIOS or no PARM |
1da177e4 | 342 | sig= 'ISGE' aka 'Intel Speedstep Gate E' */ |
32ee8c3e | 343 | if ((ist_info.signature != 0x47534943) && ( |
1da177e4 LT |
344 | (smi_port == 0) || (smi_cmd == 0))) |
345 | return -ENODEV; | |
346 | ||
347 | if (smi_sig == 1) | |
348 | smi_sig = 0x47534943; | |
349 | else | |
350 | smi_sig = ist_info.signature; | |
351 | ||
352 | /* setup smi_port from MODLULE_PARM or BIOS */ | |
32ee8c3e | 353 | if ((smi_port > 0xff) || (smi_port < 0)) |
1da177e4 | 354 | return -EINVAL; |
32ee8c3e | 355 | else if (smi_port == 0) |
1da177e4 | 356 | smi_port = ist_info.command & 0xff; |
1da177e4 | 357 | |
32ee8c3e | 358 | if ((smi_cmd > 0xff) || (smi_cmd < 0)) |
1da177e4 | 359 | return -EINVAL; |
32ee8c3e | 360 | else if (smi_cmd == 0) |
1da177e4 | 361 | smi_cmd = (ist_info.command >> 16) & 0xff; |
1da177e4 LT |
362 | |
363 | return cpufreq_register_driver(&speedstep_driver); | |
364 | } | |
365 | ||
366 | ||
367 | /** | |
368 | * speedstep_exit - unregisters SpeedStep support | |
369 | * | |
370 | * Unregisters SpeedStep support. | |
371 | */ | |
372 | static void __exit speedstep_exit(void) | |
373 | { | |
374 | cpufreq_unregister_driver(&speedstep_driver); | |
375 | } | |
376 | ||
40059ec6 | 377 | module_param_hw(smi_port, int, ioport, 0444); |
bbfebd66 DJ |
378 | module_param(smi_cmd, int, 0444); |
379 | module_param(smi_sig, uint, 0444); | |
1da177e4 | 380 | |
bbfebd66 DJ |
381 | MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value " |
382 | "-- Intel's default setting is 0xb2"); | |
383 | MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value " | |
384 | "-- Intel's default setting is 0x82"); | |
385 | MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the " | |
386 | "SMI interface."); | |
1da177e4 | 387 | |
bbfebd66 DJ |
388 | MODULE_AUTHOR("Hiroshi Miura"); |
389 | MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface."); | |
390 | MODULE_LICENSE("GPL"); | |
1da177e4 LT |
391 | |
392 | module_init(speedstep_init); | |
393 | module_exit(speedstep_exit); |