kernel/2.6.29.6-aldebaran-rt/arch/x86/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/slab.h>
  21 #include <linux/delay.h>
  22 #include <asm/ist.h>
  23 #include <asm/io.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, dummy;
  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                 "push %%ebp\n"
  77                 "out %%al, (%%dx)\n"
  78                 "pop %%ebp\n"
  79                 : "=D" (result), "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
  80                         "=S" (dummy)
  81                 : "a" (command), "b" (function), "c" (0), "d" (smi_port),
  82                         "D" (0), "S" (magic)
  83                 : "memory"
  84         );
  85
  86         dprintk("result is %x\n", result);
  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  */
 100 static int speedstep_smi_get_freqs (unsigned int *low, unsigned int *high)
 101 {
 102         u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
 103         u32 state=0;
 104         u32 function = GET_SPEEDSTEP_FREQS;
 105
 106         if (!(ist_info.event & 0xFFFF)) {
 107                 dprintk("bug #1422 -- can't read freqs from BIOS\n");
 108                 return -ENODEV;
 109         }
 110
 111         command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
 112
 113         dprintk("trying to determine frequencies with command %x at port %x\n", command, smi_port);
 114
 115         __asm__ __volatile__(
 116                 "push %%ebp\n"
 117                 "out %%al, (%%dx)\n"
 118                 "pop %%ebp"
 119                 : "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi), "=S" (dummy)
 120                 : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0), "D" (0)
 121         );
 122
 123         dprintk("result %x, low_freq %u, high_freq %u\n", result, low_mhz, high_mhz);
 124
 125         /* abort if results are obviously incorrect... */
 126         if ((high_mhz + low_mhz) < 600)
 127                 return -EINVAL;
 128
 129         *high = high_mhz * 1000;
 130         *low  = low_mhz  * 1000;
 131
 132         return result;
 133 }
 134
 135 /**
 136  * speedstep_get_state - set the SpeedStep state
 137  * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
 138  *
 139  */
 140 static int speedstep_get_state (void)
 141 {
 142         u32 function=GET_SPEEDSTEP_STATE;
 143         u32 result, state, edi, command, dummy;
 144
 145         command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
 146
 147         dprintk("trying to determine current setting with command %x at port %x\n", command, smi_port);
 148
 149         __asm__ __volatile__(
 150                 "push %%ebp\n"
 151                 "out %%al, (%%dx)\n"
 152                 "pop %%ebp\n"
 153                 : "=a" (result), "=b" (state), "=D" (edi), "=c" (dummy), "=d" (dummy), "=S" (dummy)
 154                 : "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0), "D" (0)
 155         );
 156
 157         dprintk("state is %x, result is %x\n", state, result);
 158
 159         return (state & 1);
 160 }
 161
 162
 163 /**
 164  * speedstep_set_state - set the SpeedStep state
 165  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
 166  *
 167  */
 168 static void speedstep_set_state (unsigned int state)
 169 {
 170         unsigned int result = 0, command, new_state, dummy;
 171         unsigned long flags;
 172         unsigned int function=SET_SPEEDSTEP_STATE;
 173         unsigned int retry = 0;
 174
 175         if (state > 0x1)
 176                 return;
 177
 178         /* Disable IRQs */
 179         local_irq_save(flags);
 180
 181         command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
 182
 183         dprintk("trying to set frequency to state %u with command %x at port %x\n", state, command, smi_port);
 184
 185         do {
 186                 if (retry) {
 187                         dprintk("retry %u, previous result %u, waiting...\n", retry, result);
 188                         mdelay(retry * 50);
 189                 }
 190                 retry++;
 191                 __asm__ __volatile__(
 192                         "push %%ebp\n"
 193                         "out %%al, (%%dx)\n"
 194                         "pop %%ebp"
 195                         : "=b" (new_state), "=D" (result), "=c" (dummy), "=a" (dummy),
 196                                 "=d" (dummy), "=S" (dummy)
 197                         : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0), "D" (0)
 198                         );
 199         } while ((new_state != state) && (retry <= SMI_TRIES));
 200
 201         /* enable IRQs */
 202         local_irq_restore(flags);
 203
 204         if (new_state == state) {
 205                 dprintk("change to %u MHz succeeded after %u tries with result %u\n", (speedstep_freqs[new_state].frequency / 1000), retry, result);
 206         } else {
 207                 printk(KERN_ERR "cpufreq: change to state %u failed with new_state %u and result %u\n", state, new_state, result);
 208         }
 209
 210         return;
 211 }
 212
 213
 214 /**
 215  * speedstep_target - set a new CPUFreq policy
 216  * @policy: new policy
 217  * @target_freq: new freq
 218  * @relation:
 219  *
 220  * Sets a new CPUFreq policy/freq.
 221  */
 222 static int speedstep_target (struct cpufreq_policy *policy,
 223                         unsigned int target_freq, unsigned int relation)
 224 {
 225         unsigned int newstate = 0;
 226         struct cpufreq_freqs freqs;
 227
 228         if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
 229                 return -EINVAL;
 230
 231         freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
 232         freqs.new = speedstep_freqs[newstate].frequency;
 233         freqs.cpu = 0; /* speedstep.c is UP only driver */
 234
 235         if (freqs.old == freqs.new)
 236                 return 0;
 237
 238         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 239         speedstep_set_state(newstate);
 240         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 241
 242         return 0;
 243 }
 244
 245
 246 /**
 247  * speedstep_verify - verifies a new CPUFreq policy
 248  * @policy: new policy
 249  *
 250  * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 251  * at least one border included.
 252  */
 253 static int speedstep_verify (struct cpufreq_policy *policy)
 254 {
 255         return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 256 }
 257
 258
 259 static int speedstep_cpu_init(struct cpufreq_policy *policy)
 260 {
 261         int result;
 262         unsigned int speed,state;
 263
 264         /* capability check */
 265         if (policy->cpu != 0)
 266                 return -ENODEV;
 267
 268         result = speedstep_smi_ownership();
 269         if (result) {
 270                 dprintk("fails in aquiring ownership of a SMI interface.\n");
 271                 return -EINVAL;
 272         }
 273
 274         /* detect low and high frequency */
 275         result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,
 276                                 &speedstep_freqs[SPEEDSTEP_HIGH].frequency);
 277         if (result) {
 278                 /* fall back to speedstep_lib.c dection mechanism: try both states out */
 279                 dprintk("could not detect low and high frequencies by SMI call.\n");
 280                 result = speedstep_get_freqs(speedstep_processor,
 281                                 &speedstep_freqs[SPEEDSTEP_LOW].frequency,
 282                                 &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
 283                                 NULL,
 284                                 &speedstep_set_state);
 285
 286                 if (result) {
 287                         dprintk("could not detect two different speeds -- aborting.\n");
 288                         return result;
 289                 } else
 290                         dprintk("workaround worked.\n");
 291         }
 292
 293         /* get current speed setting */
 294         state = speedstep_get_state();
 295         speed = speedstep_freqs[state].frequency;
 296
 297         dprintk("currently at %s speed setting - %i MHz\n",
 298                 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
 299                 (speed / 1000));
 300
 301         /* cpuinfo and default policy values */
 302         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 303         policy->cur = speed;
 304
 305         result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
 306         if (result)
 307                 return (result);
 308
 309         cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
 310
 311         return 0;
 312 }
 313
 314 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
 315 {
 316         cpufreq_frequency_table_put_attr(policy->cpu);
 317         return 0;
 318 }
 319
 320 static unsigned int speedstep_get(unsigned int cpu)
 321 {
 322         if (cpu)
 323                 return -ENODEV;
 324         return speedstep_get_processor_frequency(speedstep_processor);
 325 }
 326
 327
 328 static int speedstep_resume(struct cpufreq_policy *policy)
 329 {
 330         int result = speedstep_smi_ownership();
 331
 332         if (result)
 333                 dprintk("fails in re-aquiring ownership of a SMI interface.\n");
 334
 335         return result;
 336 }
 337
 338 static struct freq_attr* speedstep_attr[] = {
 339         &cpufreq_freq_attr_scaling_available_freqs,
 340         NULL,
 341 };
 342
 343 static struct cpufreq_driver speedstep_driver = {
 344         .name           = "speedstep-smi",
 345         .verify         = speedstep_verify,
 346         .target         = speedstep_target,
 347         .init           = speedstep_cpu_init,
 348         .exit           = speedstep_cpu_exit,
 349         .get            = speedstep_get,
 350         .resume         = speedstep_resume,
 351         .owner          = THIS_MODULE,
 352         .attr           = speedstep_attr,
 353 };
 354
 355 /**
 356  * speedstep_init - initializes the SpeedStep CPUFreq driver
 357  *
 358  *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 359  * BIOS, -EINVAL on problems during initiatization, and zero on
 360  * success.
 361  */
 362 static int __init speedstep_init(void)
 363 {
 364         speedstep_processor = speedstep_detect_processor();
 365
 366         switch (speedstep_processor) {
 367         case SPEEDSTEP_PROCESSOR_PIII_T:
 368         case SPEEDSTEP_PROCESSOR_PIII_C:
 369         case SPEEDSTEP_PROCESSOR_PIII_C_EARLY:
 370                 break;
 371         default:
 372                 speedstep_processor = 0;
 373         }
 374
 375         if (!speedstep_processor) {
 376                 dprintk ("No supported Intel CPU detected.\n");
 377                 return -ENODEV;
 378         }
 379
 380         dprintk("signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",
 381                 ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);
 382
 383         /* Error if no IST-SMI BIOS or no PARM
 384                  sig= 'ISGE' aka 'Intel Speedstep Gate E' */
 385         if ((ist_info.signature !=  0x47534943) && (
 386             (smi_port == 0) || (smi_cmd == 0)))
 387                 return -ENODEV;
 388
 389         if (smi_sig == 1)
 390                 smi_sig = 0x47534943;
 391         else
 392                 smi_sig = ist_info.signature;
 393
 394         /* setup smi_port from MODLULE_PARM or BIOS */
 395         if ((smi_port > 0xff) || (smi_port < 0))
 396                 return -EINVAL;
 397         else if (smi_port == 0)
 398                 smi_port = ist_info.command & 0xff;
 399
 400         if ((smi_cmd > 0xff) || (smi_cmd < 0))
 401                 return -EINVAL;
 402         else if (smi_cmd == 0)
 403                 smi_cmd = (ist_info.command >> 16) & 0xff;
 404
 405         return cpufreq_register_driver(&speedstep_driver);
 406 }
 407
 408
 409 /**
 410  * speedstep_exit - unregisters SpeedStep support
 411  *
 412  *   Unregisters SpeedStep support.
 413  */
 414 static void __exit speedstep_exit(void)
 415 {
 416         cpufreq_unregister_driver(&speedstep_driver);
 417 }
 418
 419 module_param(smi_port,  int, 0444);
 420 module_param(smi_cmd,   int, 0444);
 421 module_param(smi_sig,  uint, 0444);
 422
 423 MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");
 424 MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");
 425 MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");
 426
 427 MODULE_AUTHOR ("Hiroshi Miura");
 428 MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");
 429 MODULE_LICENSE ("GPL");
 430
 431 module_init(speedstep_init);
 432 module_exit(speedstep_exit);