arch/i386/kernel/cpu/cpufreq/speedstep-smi.c

   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
  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>
  23 #include <asm/ist.h>
  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.
  31  *
  32  */
  33 static int smi_port = 0;
  34 static int smi_cmd = 0;
  35 static unsigned int smi_sig = 0;
  36
  37 /* info about the processor */
  38 static unsigned int speedstep_processor = 0;
  39
  40 /*
  41  * There are only two frequency states for each processor. Values
  42  * are in kHz for the time being.
  43  */
  44 static struct cpufreq_frequency_table speedstep_freqs[] = {
  45         {SPEEDSTEP_HIGH,        0},
  46         {SPEEDSTEP_LOW,         0},
  47         {0,                     CPUFREQ_TABLE_END},
  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
  59 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-smi", msg)
  60
  61 /**
  62  * speedstep_smi_ownership
  63  */
  64 static int speedstep_smi_ownership (void)
  65 {
  66         u32 command, result, magic;
  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
  73         dprintk("trying to obtain ownership with command %x at port %x\n", command, smi_port);
  74
  75         __asm__ __volatile__(
  76                 "out %%al, (%%dx)\n"
  77                 : "=D" (result)
  78                 : "a" (command), "b" (function), "c" (0), "d" (smi_port),
  79                         "D" (0), "S" (magic)
  80                 : "memory"
  81         );
  82
  83         dprintk("result is %x\n", result);
  84
  85         return result;
  86 }
  87
  88 /**
  89  * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
  90  * @low: the low frequency value is placed here
  91  * @high: the high frequency value is placed here
  92  *
  93  * Only available on later SpeedStep-enabled systems, returns false results or
  94  * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
  95  * shows that the latter occurs if !(ist_info.event & 0xFFFF).
  96  */
  97 static int speedstep_smi_get_freqs (unsigned int *low, unsigned int *high)
  98 {
  99         u32 command, result = 0, edi, high_mhz, low_mhz;
 100         u32 state=0;
 101         u32 function = GET_SPEEDSTEP_FREQS;
 102
 103         if (!(ist_info.event & 0xFFFF)) {
 104                 dprintk("bug #1422 -- can't read freqs from BIOS\n");
 105                 return -ENODEV;
 106         }
 107
 108         command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
 109
 110         dprintk("trying to determine frequencies with command %x at port %x\n", command, smi_port);
 111
 112         __asm__ __volatile__("movl $0, %%edi\n"
 113                 "out %%al, (%%dx)\n"
 114                 : "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi)
 115                 : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
 116         );
 117
 118         dprintk("result %x, low_freq %u, high_freq %u\n", result, low_mhz, high_mhz);
 119
 120         /* abort if results are obviously incorrect... */
 121         if ((high_mhz + low_mhz) < 600)
 122                 return -EINVAL;
 123
 124         *high = high_mhz * 1000;
 125         *low  = low_mhz  * 1000;
 126
 127         return result;
 128 }
 129
 130 /**
 131  * speedstep_get_state - set the SpeedStep state
 132  * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
 133  *
 134  */
 135 static int speedstep_get_state (void)
 136 {
 137         u32 function=GET_SPEEDSTEP_STATE;
 138         u32 result, state, edi, command;
 139
 140         command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
 141
 142         dprintk("trying to determine current setting with command %x at port %x\n", command, smi_port);
 143
 144         __asm__ __volatile__("movl $0, %%edi\n"
 145                 "out %%al, (%%dx)\n"
 146                 : "=a" (result), "=b" (state), "=D" (edi)
 147                 : "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0)
 148         );
 149
 150         dprintk("state is %x, result is %x\n", state, result);
 151
 152         return (state & 1);
 153 }
 154
 155
 156 /**
 157  * speedstep_set_state - set the SpeedStep state
 158  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
 159  *
 160  */
 161 static void speedstep_set_state (unsigned int state)
 162 {
 163         unsigned int result = 0, command, new_state;
 164         unsigned long flags;
 165         unsigned int function=SET_SPEEDSTEP_STATE;
 166         unsigned int retry = 0;
 167
 168         if (state > 0x1)
 169                 return;
 170
 171         /* Disable IRQs */
 172         local_irq_save(flags);
 173
 174         command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
 175
 176         dprintk("trying to set frequency to state %u with command %x at port %x\n", state, command, smi_port);
 177
 178         do {
 179                 if (retry) {
 180                         dprintk("retry %u, previous result %u, waiting...\n", retry, result);
 181                         mdelay(retry * 50);
 182                 }
 183                 retry++;
 184                 __asm__ __volatile__(
 185                         "movl $0, %%edi\n"
 186                         "out %%al, (%%dx)\n"
 187                         : "=b" (new_state), "=D" (result)
 188                         : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
 189                         );
 190         } while ((new_state != state) && (retry <= SMI_TRIES));
 191
 192         /* enable IRQs */
 193         local_irq_restore(flags);
 194
 195         if (new_state == state) {
 196                 dprintk("change to %u MHz succeeded after %u tries with result %u\n", (speedstep_freqs[new_state].frequency / 1000), retry, result);
 197         } else {
 198                 printk(KERN_ERR "cpufreq: change failed with new_state %u and result %u\n", new_state, result);
 199         }
 200
 201         return;
 202 }
 203
 204
 205 /**
 206  * speedstep_target - set a new CPUFreq policy
 207  * @policy: new policy
 208  * @target_freq: new freq
 209  * @relation:
 210  *
 211  * Sets a new CPUFreq policy/freq.
 212  */
 213 static int speedstep_target (struct cpufreq_policy *policy,
 214                         unsigned int target_freq, unsigned int relation)
 215 {
 216         unsigned int newstate = 0;
 217         struct cpufreq_freqs freqs;
 218
 219         if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
 220                 return -EINVAL;
 221
 222         freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
 223         freqs.new = speedstep_freqs[newstate].frequency;
 224         freqs.cpu = 0; /* speedstep.c is UP only driver */
 225
 226         if (freqs.old == freqs.new)
 227                 return 0;
 228
 229         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 230         speedstep_set_state(newstate);
 231         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 232
 233         return 0;
 234 }
 235
 236
 237 /**
 238  * speedstep_verify - verifies a new CPUFreq policy
 239  * @policy: new policy
 240  *
 241  * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 242  * at least one border included.
 243  */
 244 static int speedstep_verify (struct cpufreq_policy *policy)
 245 {
 246         return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 247 }
 248
 249
 250 static int speedstep_cpu_init(struct cpufreq_policy *policy)
 251 {
 252         int result;
 253         unsigned int speed,state;
 254
 255         /* capability check */
 256         if (policy->cpu != 0)
 257                 return -ENODEV;
 258
 259         result = speedstep_smi_ownership();
 260         if (result) {
 261                 dprintk("fails in aquiring ownership of a SMI interface.\n");
 262                 return -EINVAL;
 263         }
 264
 265         /* detect low and high frequency */
 266         result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,
 267                                 &speedstep_freqs[SPEEDSTEP_HIGH].frequency);
 268         if (result) {
 269                 /* fall back to speedstep_lib.c dection mechanism: try both states out */
 270                 dprintk("could not detect low and high frequencies by SMI call.\n");
 271                 result = speedstep_get_freqs(speedstep_processor,
 272                                 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
 273                                 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
 274                                 NULL,
 275                                 &speedstep_set_state);
 276
 277                 if (result) {
 278                         dprintk("could not detect two different speeds -- aborting.\n");
 279                         return result;
 280                 } else
 281                         dprintk("workaround worked.\n");
 282         }
 283
 284         /* get current speed setting */
 285         state = speedstep_get_state();
 286         speed = speedstep_freqs[state].frequency;
 287
 288         dprintk("currently at %s speed setting - %i MHz\n",
 289                 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
 290                 (speed / 1000));
 291
 292         /* cpuinfo and default policy values */
 293         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 294         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 295         policy->cur = speed;
 296
 297         result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
 298         if (result)
 299                 return (result);
 300
 301         cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
 302
 303         return 0;
 304 }
 305
 306 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
 307 {
 308         cpufreq_frequency_table_put_attr(policy->cpu);
 309         return 0;
 310 }
 311
 312 static unsigned int speedstep_get(unsigned int cpu)
 313 {
 314         if (cpu)
 315                 return -ENODEV;
 316         return speedstep_get_processor_frequency(speedstep_processor);
 317 }
 318
 319
 320 static int speedstep_resume(struct cpufreq_policy *policy)
 321 {
 322         int result = speedstep_smi_ownership();
 323
 324         if (result)
 325                 dprintk("fails in re-aquiring ownership of a SMI interface.\n");
 326
 327         return result;
 328 }
 329
 330 static struct freq_attr* speedstep_attr[] = {
 331         &cpufreq_freq_attr_scaling_available_freqs,
 332         NULL,
 333 };
 334
 335 static struct cpufreq_driver speedstep_driver = {
 336         .name           = "speedstep-smi",
 337         .verify         = speedstep_verify,
 338         .target         = speedstep_target,
 339         .init           = speedstep_cpu_init,
 340         .exit           = speedstep_cpu_exit,
 341         .get            = speedstep_get,
 342         .resume         = speedstep_resume,
 343         .owner          = THIS_MODULE,
 344         .attr           = speedstep_attr,
 345 };
 346
 347 /**
 348  * speedstep_init - initializes the SpeedStep CPUFreq driver
 349  *
 350  *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 351  * BIOS, -EINVAL on problems during initiatization, and zero on
 352  * success.
 353  */
 354 static int __init speedstep_init(void)
 355 {
 356         speedstep_processor = speedstep_detect_processor();
 357
 358         switch (speedstep_processor) {
 359         case SPEEDSTEP_PROCESSOR_PIII_T:
 360         case SPEEDSTEP_PROCESSOR_PIII_C:
 361         case SPEEDSTEP_PROCESSOR_PIII_C_EARLY:
 362                 break;
 363         default:
 364                 speedstep_processor = 0;
 365         }
 366
 367         if (!speedstep_processor) {
 368                 dprintk ("No supported Intel CPU detected.\n");
 369                 return -ENODEV;
 370         }
 371
 372         dprintk("signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",
 373                 ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);
 374
 375         /* Error if no IST-SMI BIOS or no PARM
 376                  sig= 'ISGE' aka 'Intel Speedstep Gate E' */
 377         if ((ist_info.signature !=  0x47534943) && (
 378             (smi_port == 0) || (smi_cmd == 0)))
 379                 return -ENODEV;
 380
 381         if (smi_sig == 1)
 382                 smi_sig = 0x47534943;
 383         else
 384                 smi_sig = ist_info.signature;
 385
 386         /* setup smi_port from MODLULE_PARM or BIOS */
 387         if ((smi_port > 0xff) || (smi_port < 0))
 388                 return -EINVAL;
 389         else if (smi_port == 0)
 390                 smi_port = ist_info.command & 0xff;
 391
 392         if ((smi_cmd > 0xff) || (smi_cmd < 0))
 393                 return -EINVAL;
 394         else if (smi_cmd == 0)
 395                 smi_cmd = (ist_info.command >> 16) & 0xff;
 396
 397         return cpufreq_register_driver(&speedstep_driver);
 398 }
 399
 400
 401 /**
 402  * speedstep_exit - unregisters SpeedStep support
 403  *
 404  *   Unregisters SpeedStep support.
 405  */
 406 static void __exit speedstep_exit(void)
 407 {
 408         cpufreq_unregister_driver(&speedstep_driver);
 409 }
 410
 411 module_param(smi_port,  int, 0444);
 412 module_param(smi_cmd,   int, 0444);
 413 module_param(smi_sig,  uint, 0444);
 414
 415 MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");
 416 MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");
 417 MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");
 418
 419 MODULE_AUTHOR ("Hiroshi Miura");
 420 MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");
 421 MODULE_LICENSE ("GPL");
 422
 423 module_init(speedstep_init);
 424 module_exit(speedstep_exit);