drivers/char/i8k.c

   1 /*
   2  * i8k.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
   3  *          See http://www.debian.org/~dz/i8k/ for more information
   4  *          and for latest version of this driver.
   5  *
   6  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2, or (at your option) any
  11  * later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/types.h>
  21 #include <linux/init.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/dmi.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/io.h>
  27
  28 #include <linux/i8k.h>
  29
  30 #define I8K_VERSION             "1.14 21/02/2005"
  31
  32 #define I8K_SMM_FN_STATUS       0x0025
  33 #define I8K_SMM_POWER_STATUS    0x0069
  34 #define I8K_SMM_SET_FAN         0x01a3
  35 #define I8K_SMM_GET_FAN         0x00a3
  36 #define I8K_SMM_GET_SPEED       0x02a3
  37 #define I8K_SMM_GET_TEMP        0x10a3
  38 #define I8K_SMM_GET_DELL_SIG    0xffa3
  39 #define I8K_SMM_BIOS_VERSION    0x00a6
  40
  41 #define I8K_FAN_MULT            30
  42 #define I8K_MAX_TEMP            127
  43
  44 #define I8K_FN_NONE             0x00
  45 #define I8K_FN_UP               0x01
  46 #define I8K_FN_DOWN             0x02
  47 #define I8K_FN_MUTE             0x04
  48 #define I8K_FN_MASK             0x07
  49 #define I8K_FN_SHIFT            8
  50
  51 #define I8K_POWER_AC            0x05
  52 #define I8K_POWER_BATTERY       0x01
  53
  54 #define I8K_TEMPERATURE_BUG     1
  55
  56 static char bios_version[4];
  57
  58 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
  59 MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
  60 MODULE_LICENSE("GPL");
  61
  62 static int force;
  63 module_param(force, bool, 0);
  64 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
  65
  66 static int ignore_dmi;
  67 module_param(ignore_dmi, bool, 0);
  68 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
  69
  70 static int restricted;
  71 module_param(restricted, bool, 0);
  72 MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
  73
  74 static int power_status;
  75 module_param(power_status, bool, 0600);
  76 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
  77
  78 static int i8k_open_fs(struct inode *inode, struct file *file);
  79 static int i8k_ioctl(struct inode *, struct file *, unsigned int,
  80                      unsigned long);
  81
  82 static struct file_operations i8k_fops = {
  83         .open           = i8k_open_fs,
  84         .read           = seq_read,
  85         .llseek         = seq_lseek,
  86         .release        = single_release,
  87         .ioctl          = i8k_ioctl,
  88 };
  89
  90 typedef struct {
  91         unsigned int eax;
  92         unsigned int ebx __attribute__ ((packed));
  93         unsigned int ecx __attribute__ ((packed));
  94         unsigned int edx __attribute__ ((packed));
  95         unsigned int esi __attribute__ ((packed));
  96         unsigned int edi __attribute__ ((packed));
  97 } SMMRegisters;
  98
  99 static inline char *i8k_get_dmi_data(int field)
 100 {
 101         return dmi_get_system_info(field) ? : "N/A";
 102 }
 103
 104 /*
 105  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 106  */
 107 static int i8k_smm(SMMRegisters * regs)
 108 {
 109         int rc;
 110         int eax = regs->eax;
 111
 112         asm("pushl %%eax\n\t"
 113             "movl 0(%%eax),%%edx\n\t"
 114             "push %%edx\n\t"
 115             "movl 4(%%eax),%%ebx\n\t"
 116             "movl 8(%%eax),%%ecx\n\t"
 117             "movl 12(%%eax),%%edx\n\t"
 118             "movl 16(%%eax),%%esi\n\t"
 119             "movl 20(%%eax),%%edi\n\t"
 120             "popl %%eax\n\t"
 121             "out %%al,$0xb2\n\t"
 122             "out %%al,$0x84\n\t"
 123             "xchgl %%eax,(%%esp)\n\t"
 124             "movl %%ebx,4(%%eax)\n\t"
 125             "movl %%ecx,8(%%eax)\n\t"
 126             "movl %%edx,12(%%eax)\n\t"
 127             "movl %%esi,16(%%eax)\n\t"
 128             "movl %%edi,20(%%eax)\n\t"
 129             "popl %%edx\n\t"
 130             "movl %%edx,0(%%eax)\n\t"
 131             "lahf\n\t"
 132             "shrl $8,%%eax\n\t"
 133             "andl $1,%%eax\n":"=a"(rc)
 134             :    "a"(regs)
 135             :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 136
 137         if ((rc != 0) || ((regs->eax & 0xffff) == 0xffff) || (regs->eax == eax)) {
 138                 return -EINVAL;
 139         }
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * Read the bios version. Return the version as an integer corresponding
 146  * to the ascii value, for example "A17" is returned as 0x00413137.
 147  */
 148 static int i8k_get_bios_version(void)
 149 {
 150         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 151         int rc;
 152
 153         regs.eax = I8K_SMM_BIOS_VERSION;
 154         if ((rc = i8k_smm(&regs)) < 0) {
 155                 return rc;
 156         }
 157
 158         return regs.eax;
 159 }
 160
 161 /*
 162  * Read the Fn key status.
 163  */
 164 static int i8k_get_fn_status(void)
 165 {
 166         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 167         int rc;
 168
 169         regs.eax = I8K_SMM_FN_STATUS;
 170         if ((rc = i8k_smm(&regs)) < 0) {
 171                 return rc;
 172         }
 173
 174         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 175         case I8K_FN_UP:
 176                 return I8K_VOL_UP;
 177         case I8K_FN_DOWN:
 178                 return I8K_VOL_DOWN;
 179         case I8K_FN_MUTE:
 180                 return I8K_VOL_MUTE;
 181         default:
 182                 return 0;
 183         }
 184 }
 185
 186 /*
 187  * Read the power status.
 188  */
 189 static int i8k_get_power_status(void)
 190 {
 191         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 192         int rc;
 193
 194         regs.eax = I8K_SMM_POWER_STATUS;
 195         if ((rc = i8k_smm(&regs)) < 0) {
 196                 return rc;
 197         }
 198
 199         switch (regs.eax & 0xff) {
 200         case I8K_POWER_AC:
 201                 return I8K_AC;
 202         default:
 203                 return I8K_BATTERY;
 204         }
 205 }
 206
 207 /*
 208  * Read the fan status.
 209  */
 210 static int i8k_get_fan_status(int fan)
 211 {
 212         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 213         int rc;
 214
 215         regs.eax = I8K_SMM_GET_FAN;
 216         regs.ebx = fan & 0xff;
 217         if ((rc = i8k_smm(&regs)) < 0) {
 218                 return rc;
 219         }
 220
 221         return (regs.eax & 0xff);
 222 }
 223
 224 /*
 225  * Read the fan speed in RPM.
 226  */
 227 static int i8k_get_fan_speed(int fan)
 228 {
 229         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 230         int rc;
 231
 232         regs.eax = I8K_SMM_GET_SPEED;
 233         regs.ebx = fan & 0xff;
 234         if ((rc = i8k_smm(&regs)) < 0) {
 235                 return rc;
 236         }
 237
 238         return (regs.eax & 0xffff) * I8K_FAN_MULT;
 239 }
 240
 241 /*
 242  * Set the fan speed (off, low, high). Returns the new fan status.
 243  */
 244 static int i8k_set_fan(int fan, int speed)
 245 {
 246         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 247         int rc;
 248
 249         speed = (speed < 0) ? 0 : ((speed > I8K_FAN_MAX) ? I8K_FAN_MAX : speed);
 250
 251         regs.eax = I8K_SMM_SET_FAN;
 252         regs.ebx = (fan & 0xff) | (speed << 8);
 253         if ((rc = i8k_smm(&regs)) < 0) {
 254                 return rc;
 255         }
 256
 257         return (i8k_get_fan_status(fan));
 258 }
 259
 260 /*
 261  * Read the cpu temperature.
 262  */
 263 static int i8k_get_cpu_temp(void)
 264 {
 265         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 266         int rc;
 267         int temp;
 268
 269 #ifdef I8K_TEMPERATURE_BUG
 270         static int prev = 0;
 271 #endif
 272
 273         regs.eax = I8K_SMM_GET_TEMP;
 274         if ((rc = i8k_smm(&regs)) < 0) {
 275                 return rc;
 276         }
 277         temp = regs.eax & 0xff;
 278
 279 #ifdef I8K_TEMPERATURE_BUG
 280         /*
 281          * Sometimes the temperature sensor returns 0x99, which is out of range.
 282          * In this case we return (once) the previous cached value. For example:
 283          # 1003655137 00000058 00005a4b
 284          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 285          # 1003655139 00000054 00005c52
 286          */
 287         if (temp > I8K_MAX_TEMP) {
 288                 temp = prev;
 289                 prev = I8K_MAX_TEMP;
 290         } else {
 291                 prev = temp;
 292         }
 293 #endif
 294
 295         return temp;
 296 }
 297
 298 static int i8k_get_dell_signature(void)
 299 {
 300         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 301         int rc;
 302
 303         regs.eax = I8K_SMM_GET_DELL_SIG;
 304         if ((rc = i8k_smm(&regs)) < 0) {
 305                 return rc;
 306         }
 307
 308         if ((regs.eax == 1145651527) && (regs.edx == 1145392204)) {
 309                 return 0;
 310         } else {
 311                 return -1;
 312         }
 313 }
 314
 315 static int i8k_ioctl(struct inode *ip, struct file *fp, unsigned int cmd,
 316                      unsigned long arg)
 317 {
 318         int val = 0;
 319         int speed;
 320         unsigned char buff[16];
 321         int __user *argp = (int __user *)arg;
 322
 323         if (!argp)
 324                 return -EINVAL;
 325
 326         switch (cmd) {
 327         case I8K_BIOS_VERSION:
 328                 val = i8k_get_bios_version();
 329                 break;
 330
 331         case I8K_MACHINE_ID:
 332                 memset(buff, 0, 16);
 333                 strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL), sizeof(buff));
 334                 break;
 335
 336         case I8K_FN_STATUS:
 337                 val = i8k_get_fn_status();
 338                 break;
 339
 340         case I8K_POWER_STATUS:
 341                 val = i8k_get_power_status();
 342                 break;
 343
 344         case I8K_GET_TEMP:
 345                 val = i8k_get_cpu_temp();
 346                 break;
 347
 348         case I8K_GET_SPEED:
 349                 if (copy_from_user(&val, argp, sizeof(int))) {
 350                         return -EFAULT;
 351                 }
 352                 val = i8k_get_fan_speed(val);
 353                 break;
 354
 355         case I8K_GET_FAN:
 356                 if (copy_from_user(&val, argp, sizeof(int))) {
 357                         return -EFAULT;
 358                 }
 359                 val = i8k_get_fan_status(val);
 360                 break;
 361
 362         case I8K_SET_FAN:
 363                 if (restricted && !capable(CAP_SYS_ADMIN)) {
 364                         return -EPERM;
 365                 }
 366                 if (copy_from_user(&val, argp, sizeof(int))) {
 367                         return -EFAULT;
 368                 }
 369                 if (copy_from_user(&speed, argp + 1, sizeof(int))) {
 370                         return -EFAULT;
 371                 }
 372                 val = i8k_set_fan(val, speed);
 373                 break;
 374
 375         default:
 376                 return -EINVAL;
 377         }
 378
 379         if (val < 0) {
 380                 return val;
 381         }
 382
 383         switch (cmd) {
 384         case I8K_BIOS_VERSION:
 385                 if (copy_to_user(argp, &val, 4)) {
 386                         return -EFAULT;
 387                 }
 388                 break;
 389         case I8K_MACHINE_ID:
 390                 if (copy_to_user(argp, buff, 16)) {
 391                         return -EFAULT;
 392                 }
 393                 break;
 394         default:
 395                 if (copy_to_user(argp, &val, sizeof(int))) {
 396                         return -EFAULT;
 397                 }
 398                 break;
 399         }
 400
 401         return 0;
 402 }
 403
 404 /*
 405  * Print the information for /proc/i8k.
 406  */
 407 static int i8k_proc_show(struct seq_file *seq, void *offset)
 408 {
 409         int fn_key, cpu_temp, ac_power;
 410         int left_fan, right_fan, left_speed, right_speed;
 411
 412         cpu_temp        = i8k_get_cpu_temp();                   /* 11100 µs */
 413         left_fan        = i8k_get_fan_status(I8K_FAN_LEFT);     /*   580 µs */
 414         right_fan       = i8k_get_fan_status(I8K_FAN_RIGHT);    /*   580 µs */
 415         left_speed      = i8k_get_fan_speed(I8K_FAN_LEFT);      /*   580 µs */
 416         right_speed     = i8k_get_fan_speed(I8K_FAN_RIGHT);     /*   580 µs */
 417         fn_key          = i8k_get_fn_status();                  /*   750 µs */
 418         if (power_status) {
 419                 ac_power = i8k_get_power_status();              /* 14700 µs */
 420         } else {
 421                 ac_power = -1;
 422         }
 423
 424         /*
 425          * Info:
 426          *
 427          * 1)  Format version (this will change if format changes)
 428          * 2)  BIOS version
 429          * 3)  BIOS machine ID
 430          * 4)  Cpu temperature
 431          * 5)  Left fan status
 432          * 6)  Right fan status
 433          * 7)  Left fan speed
 434          * 8)  Right fan speed
 435          * 9)  AC power
 436          * 10) Fn Key status
 437          */
 438         return seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
 439                           I8K_PROC_FMT,
 440                           bios_version,
 441                           dmi_get_system_info(DMI_PRODUCT_SERIAL) ? : "N/A",
 442                           cpu_temp,
 443                           left_fan, right_fan, left_speed, right_speed,
 444                           ac_power, fn_key);
 445 }
 446
 447 static int i8k_open_fs(struct inode *inode, struct file *file)
 448 {
 449         return single_open(file, i8k_proc_show, NULL);
 450 }
 451
 452 static struct dmi_system_id __initdata i8k_dmi_table[] = {
 453         {
 454                 .ident = "Dell Inspiron",
 455                 .matches = {
 456                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 457                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 458                 },
 459         },
 460         {
 461                 .ident = "Dell Latitude",
 462                 .matches = {
 463                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 464                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 465                 },
 466         },
 467         { }
 468 };
 469
 470 /*
 471  * Probe for the presence of a supported laptop.
 472  */
 473 static int __init i8k_probe(void)
 474 {
 475         char buff[4];
 476         int version;
 477
 478         /*
 479          * Get DMI information
 480          */
 481         if (!dmi_check_system(i8k_dmi_table)) {
 482                 if (!ignore_dmi && !force)
 483                         return -ENODEV;
 484
 485                 printk(KERN_INFO "i8k: not running on a supported Dell system.\n");
 486                 printk(KERN_INFO "i8k: vendor=%s, model=%s, version=%s\n",
 487                         i8k_get_dmi_data(DMI_SYS_VENDOR),
 488                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
 489                         i8k_get_dmi_data(DMI_BIOS_VERSION));
 490         }
 491
 492         strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION), sizeof(bios_version));
 493
 494         /*
 495          * Get SMM Dell signature
 496          */
 497         if (i8k_get_dell_signature() != 0) {
 498                 printk(KERN_ERR "i8k: unable to get SMM Dell signature\n");
 499                 if (!force)
 500                         return -ENODEV;
 501         }
 502
 503         /*
 504          * Get SMM BIOS version.
 505          */
 506         version = i8k_get_bios_version();
 507         if (version <= 0) {
 508                 printk(KERN_WARNING "i8k: unable to get SMM BIOS version\n");
 509         } else {
 510                 buff[0] = (version >> 16) & 0xff;
 511                 buff[1] = (version >> 8) & 0xff;
 512                 buff[2] = (version) & 0xff;
 513                 buff[3] = '\0';
 514                 /*
 515                  * If DMI BIOS version is unknown use SMM BIOS version.
 516                  */
 517                 if (!dmi_get_system_info(DMI_BIOS_VERSION))
 518                         strlcpy(bios_version, buff, sizeof(bios_version));
 519
 520                 /*
 521                  * Check if the two versions match.
 522                  */
 523                 if (strncmp(buff, bios_version, sizeof(bios_version)) != 0)
 524                         printk(KERN_WARNING "i8k: BIOS version mismatch: %s != %s\n",
 525                                 buff, bios_version);
 526         }
 527
 528         return 0;
 529 }
 530
 531 #ifdef MODULE
 532 static
 533 #endif
 534 int __init i8k_init(void)
 535 {
 536         struct proc_dir_entry *proc_i8k;
 537
 538         /* Are we running on an supported laptop? */
 539         if (i8k_probe())
 540                 return -ENODEV;
 541
 542         /* Register the proc entry */
 543         proc_i8k = create_proc_entry("i8k", 0, NULL);
 544         if (!proc_i8k)
 545                 return -ENOENT;
 546
 547         proc_i8k->proc_fops = &i8k_fops;
 548         proc_i8k->owner = THIS_MODULE;
 549
 550         printk(KERN_INFO
 551                "Dell laptop SMM driver v%s Massimo Dal Zotto (dz@debian.org)\n",
 552                I8K_VERSION);
 553
 554         return 0;
 555 }
 556
 557 #ifdef MODULE
 558 int init_module(void)
 559 {
 560         return i8k_init();
 561 }
 562
 563 void cleanup_module(void)
 564 {
 565         /* Remove the proc entry */
 566         remove_proc_entry("i8k", NULL);
 567
 568         printk(KERN_INFO "i8k: module unloaded\n");
 569 }
 570 #endif
 571
 572 /* end of file */