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Thomas Gleixner4f190482019-05-27 08:55:14 +02001// SPDX-License-Identifier: GPL-2.0-only
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * Intel SpeedStep SMI driver.
4 *
5 * (C) 2003 Hiroshi Miura <miura@da-cha.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 */
7
8
9/*********************************************************************
10 * SPEEDSTEP - DEFINITIONS *
11 *********************************************************************/
12
Joe Perches1c5864e2016-04-05 13:28:25 -070013#define pr_fmt(fmt) "cpufreq: " fmt
14
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/kernel.h>
Dave Jones32ee8c32006-02-28 00:43:23 -050016#include <linux/module.h>
17#include <linux/moduleparam.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/init.h>
19#include <linux/cpufreq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/delay.h>
Dave Jonesbbfebd62009-01-17 23:55:22 -050021#include <linux/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <asm/ist.h>
Andi Kleenfa8031a2012-01-26 00:09:12 +010023#include <asm/cpu_device_id.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
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.
Dave Jones32ee8c32006-02-28 00:43:23 -050031 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 */
Dave Jonesbbfebd62009-01-17 23:55:22 -050033static int smi_port;
34static int smi_cmd;
35static unsigned int smi_sig;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
37/* info about the processor */
Rusty Russell1cce76c2009-11-17 14:39:53 -080038static enum speedstep_processor speedstep_processor;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Dave Jones32ee8c32006-02-28 00:43:23 -050040/*
41 * There are only two frequency states for each processor. Values
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 * are in kHz for the time being.
43 */
44static struct cpufreq_frequency_table speedstep_freqs[] = {
Viresh Kumar7f4b0462014-03-28 19:11:47 +053045 {0, SPEEDSTEP_HIGH, 0},
46 {0, SPEEDSTEP_LOW, 0},
47 {0, 0, CPUFREQ_TABLE_END},
Linus Torvalds1da177e2005-04-16 15:20:36 -070048};
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070059/**
60 * speedstep_smi_ownership
61 */
Dave Jonesbbfebd62009-01-17 23:55:22 -050062static int speedstep_smi_ownership(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070063{
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +010064 u32 command, result, magic, dummy;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 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
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +020071 pr_debug("trying to obtain ownership with command %x at port %x\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -050072 command, smi_port);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74 __asm__ __volatile__(
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +010075 "push %%ebp\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 "out %%al, (%%dx)\n"
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +010077 "pop %%ebp\n"
Dave Jonesbbfebd62009-01-17 23:55:22 -050078 : "=D" (result),
79 "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
80 "=S" (dummy)
Andrew Mortonf081a522006-03-25 01:51:51 -080081 : "a" (command), "b" (function), "c" (0), "d" (smi_port),
Dave Jonesbbfebd62009-01-17 23:55:22 -050082 "D" (0), "S" (magic)
Andrew Mortonf081a522006-03-25 01:51:51 -080083 : "memory"
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 );
85
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +020086 pr_debug("result is %x\n", result);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
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 */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500100static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101{
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +0100102 u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
Dave Jonesbbfebd62009-01-17 23:55:22 -0500103 u32 state = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 u32 function = GET_SPEEDSTEP_FREQS;
105
106 if (!(ist_info.event & 0xFFFF)) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200107 pr_debug("bug #1422 -- can't read freqs from BIOS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 return -ENODEV;
109 }
110
111 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
112
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200113 pr_debug("trying to determine frequencies with command %x at port %x\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -0500114 command, smi_port);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +0100116 __asm__ __volatile__(
117 "push %%ebp\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 "out %%al, (%%dx)\n"
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +0100119 "pop %%ebp"
Dave Jonesbbfebd62009-01-17 23:55:22 -0500120 : "=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)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 );
129
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200130 pr_debug("result %x, low_freq %u, high_freq %u\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -0500131 result, low_mhz, high_mhz);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
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;
Dave Jones32ee8c32006-02-28 00:43:23 -0500141}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
143/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 * speedstep_set_state - set the SpeedStep state
145 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
146 *
147 */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500148static void speedstep_set_state(unsigned int state)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +0100150 unsigned int result = 0, command, new_state, dummy;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 unsigned long flags;
Dave Jonesbbfebd62009-01-17 23:55:22 -0500152 unsigned int function = SET_SPEEDSTEP_STATE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 unsigned int retry = 0;
154
155 if (state > 0x1)
156 return;
157
158 /* Disable IRQs */
Mikulas Patockad4d4eda2015-02-09 13:38:17 -0500159 preempt_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 local_irq_save(flags);
161
162 command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
163
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200164 pr_debug("trying to set frequency to state %u "
Dave Jonesbbfebd62009-01-17 23:55:22 -0500165 "with command %x at port %x\n",
166 state, command, smi_port);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
168 do {
169 if (retry) {
Mikulas Patockad4d4eda2015-02-09 13:38:17 -0500170 /*
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 */
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200178 pr_debug("retry %u, previous result %u, waiting...\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -0500179 retry, result);
Mikulas Patockad4d4eda2015-02-09 13:38:17 -0500180 local_irq_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 mdelay(retry * 50);
Mikulas Patockad4d4eda2015-02-09 13:38:17 -0500182 local_irq_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 }
184 retry++;
185 __asm__ __volatile__(
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +0100186 "push %%ebp\n"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 "out %%al, (%%dx)\n"
Stephan Diestelhorstc6e82562008-03-10 16:05:41 +0100188 "pop %%ebp"
Dave Jonesbbfebd62009-01-17 23:55:22 -0500189 : "=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)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 );
195 } while ((new_state != state) && (retry <= SMI_TRIES));
196
197 /* enable IRQs */
198 local_irq_restore(flags);
Mikulas Patockad4d4eda2015-02-09 13:38:17 -0500199 preempt_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Dave Jonesbbfebd62009-01-17 23:55:22 -0500201 if (new_state == state)
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200202 pr_debug("change to %u MHz succeeded after %u tries "
Dave Jonesbbfebd62009-01-17 23:55:22 -0500203 "with result %u\n",
204 (speedstep_freqs[new_state].frequency / 1000),
205 retry, result);
206 else
Joe Perches1c5864e2016-04-05 13:28:25 -0700207 pr_err("change to state %u failed with new_state %u and result %u\n",
Joe Perchesb49c22a2016-04-05 13:28:24 -0700208 state, new_state, result);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
210 return;
211}
212
213
214/**
215 * speedstep_target - set a new CPUFreq policy
216 * @policy: new policy
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530217 * @index: index of new freq
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 *
219 * Sets a new CPUFreq policy/freq.
220 */
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530221static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222{
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530223 speedstep_set_state(index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
225 return 0;
226}
227
228
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229static int speedstep_cpu_init(struct cpufreq_policy *policy)
230{
231 int result;
Dave Jonesbbfebd62009-01-17 23:55:22 -0500232 unsigned int *low, *high;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
234 /* capability check */
235 if (policy->cpu != 0)
236 return -ENODEV;
237
238 result = speedstep_smi_ownership();
239 if (result) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200240 pr_debug("fails in acquiring ownership of a SMI interface.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 return -EINVAL;
242 }
243
244 /* detect low and high frequency */
Dave Jonesbbfebd62009-01-17 23:55:22 -0500245 low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
246 high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
247
248 result = speedstep_smi_get_freqs(low, high);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 if (result) {
Dave Jonesbbfebd62009-01-17 23:55:22 -0500250 /* fall back to speedstep_lib.c dection mechanism:
251 * try both states out */
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200252 pr_debug("could not detect low and high frequencies "
Dave Jonesbbfebd62009-01-17 23:55:22 -0500253 "by SMI call.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 result = speedstep_get_freqs(speedstep_processor,
Dave Jonesbbfebd62009-01-17 23:55:22 -0500255 low, high,
Mattia Dongili1a107602005-12-02 21:59:41 +0100256 NULL,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 &speedstep_set_state);
258
259 if (result) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200260 pr_debug("could not detect two different speeds"
Dave Jonesbbfebd62009-01-17 23:55:22 -0500261 " -- aborting.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 return result;
263 } else
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200264 pr_debug("workaround worked.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 }
266
Viresh Kumar2d28b032018-02-26 10:39:08 +0530267 policy->freq_table = speedstep_freqs;
268
269 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270}
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272static unsigned int speedstep_get(unsigned int cpu)
273{
274 if (cpu)
275 return -ENODEV;
Dave Jonesbbfebd62009-01-17 23:55:22 -0500276 return speedstep_get_frequency(speedstep_processor);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277}
278
279
280static int speedstep_resume(struct cpufreq_policy *policy)
281{
282 int result = speedstep_smi_ownership();
283
284 if (result)
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200285 pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
287 return result;
288}
289
Linus Torvalds221dee22007-02-26 14:55:48 -0800290static struct cpufreq_driver speedstep_driver = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 .name = "speedstep-smi",
Viresh Kumarfe829ed2017-07-19 15:42:48 +0530292 .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
Viresh Kumar3be13942013-10-03 20:28:28 +0530293 .verify = cpufreq_generic_frequency_table_verify,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530294 .target_index = speedstep_target,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 .init = speedstep_cpu_init,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 .get = speedstep_get,
297 .resume = speedstep_resume,
Viresh Kumar3be13942013-10-03 20:28:28 +0530298 .attr = cpufreq_generic_attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299};
300
Andi Kleenfa8031a2012-01-26 00:09:12 +0100301static const struct x86_cpu_id ss_smi_ids[] = {
Thomas Gleixnerb11d77f2020-03-24 14:51:51 +0100302 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),
Andi Kleenfa8031a2012-01-26 00:09:12 +0100305 {}
306};
Andi Kleenfa8031a2012-01-26 00:09:12 +0100307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308/**
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 */
315static int __init speedstep_init(void)
316{
Andi Kleenfa8031a2012-01-26 00:09:12 +0100317 if (!x86_match_cpu(ss_smi_ids))
318 return -ENODEV;
319
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 speedstep_processor = speedstep_detect_processor();
321
322 switch (speedstep_processor) {
Dave Jonesbbfebd62009-01-17 23:55:22 -0500323 case SPEEDSTEP_CPU_PIII_T:
324 case SPEEDSTEP_CPU_PIII_C:
325 case SPEEDSTEP_CPU_PIII_C_EARLY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 default:
328 speedstep_processor = 0;
329 }
330
331 if (!speedstep_processor) {
Dominik Brodowski2d06d8c2011-03-27 15:04:46 +0200332 pr_debug("No supported Intel CPU detected.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 return -ENODEV;
334 }
335
Hans Wennborga5f30eb2014-08-06 22:52:23 -0700336 pr_debug("signature:0x%.8x, command:0x%.8x, "
337 "event:0x%.8x, perf_level:0x%.8x.\n",
Dave Jonesbbfebd62009-01-17 23:55:22 -0500338 ist_info.signature, ist_info.command,
339 ist_info.event, ist_info.perf_level);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
Dave Jones32ee8c32006-02-28 00:43:23 -0500341 /* Error if no IST-SMI BIOS or no PARM
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
Dave Jones32ee8c32006-02-28 00:43:23 -0500343 if ((ist_info.signature != 0x47534943) && (
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 (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 */
Dave Jones32ee8c32006-02-28 00:43:23 -0500353 if ((smi_port > 0xff) || (smi_port < 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 return -EINVAL;
Dave Jones32ee8c32006-02-28 00:43:23 -0500355 else if (smi_port == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 smi_port = ist_info.command & 0xff;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357
Dave Jones32ee8c32006-02-28 00:43:23 -0500358 if ((smi_cmd > 0xff) || (smi_cmd < 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 return -EINVAL;
Dave Jones32ee8c32006-02-28 00:43:23 -0500360 else if (smi_cmd == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 smi_cmd = (ist_info.command >> 16) & 0xff;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
363 return cpufreq_register_driver(&speedstep_driver);
364}
365
366
367/**
368 * speedstep_exit - unregisters SpeedStep support
369 *
370 * Unregisters SpeedStep support.
371 */
372static void __exit speedstep_exit(void)
373{
374 cpufreq_unregister_driver(&speedstep_driver);
375}
376
David Howells40059ec2017-04-04 16:54:22 +0100377module_param_hw(smi_port, int, ioport, 0444);
Dave Jonesbbfebd62009-01-17 23:55:22 -0500378module_param(smi_cmd, int, 0444);
379module_param(smi_sig, uint, 0444);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380
Dave Jonesbbfebd62009-01-17 23:55:22 -0500381MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
382 "-- Intel's default setting is 0xb2");
383MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
384 "-- Intel's default setting is 0x82");
385MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
386 "SMI interface.");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387
Dave Jonesbbfebd62009-01-17 23:55:22 -0500388MODULE_AUTHOR("Hiroshi Miura");
389MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
390MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391
392module_init(speedstep_init);
393module_exit(speedstep_exit);