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 <linux/capability.h>
  26 #include <linux/mutex.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/io.h>
  29
  30 #include <linux/i8k.h>
  31
  32 #define I8K_VERSION             "1.14 21/02/2005"
  33
  34 #define I8K_SMM_FN_STATUS       0x0025
  35 #define I8K_SMM_POWER_STATUS    0x0069
  36 #define I8K_SMM_SET_FAN         0x01a3
  37 #define I8K_SMM_GET_FAN         0x00a3
  38 #define I8K_SMM_GET_SPEED       0x02a3
  39 #define I8K_SMM_GET_TEMP        0x10a3
  40 #define I8K_SMM_GET_DELL_SIG1   0xfea3
  41 #define I8K_SMM_GET_DELL_SIG2   0xffa3
  42 #define I8K_SMM_BIOS_VERSION    0x00a6
  43
  44 #define I8K_FAN_MULT            30
  45 #define I8K_MAX_TEMP            127
  46
  47 #define I8K_FN_NONE             0x00
  48 #define I8K_FN_UP               0x01
  49 #define I8K_FN_DOWN             0x02
  50 #define I8K_FN_MUTE             0x04
  51 #define I8K_FN_MASK             0x07
  52 #define I8K_FN_SHIFT            8
  53
  54 #define I8K_POWER_AC            0x05
  55 #define I8K_POWER_BATTERY       0x01
  56
  57 #define I8K_TEMPERATURE_BUG     1
  58
  59 static DEFINE_MUTEX(i8k_mutex);
  60 static char bios_version[4];
  61
  62 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
  63 MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
  64 MODULE_LICENSE("GPL");
  65
  66 static int force;
  67 module_param(force, bool, 0);
  68 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
  69
  70 static int ignore_dmi;
  71 module_param(ignore_dmi, bool, 0);
  72 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
  73
  74 static int restricted;
  75 module_param(restricted, bool, 0);
  76 MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
  77
  78 static int power_status;
  79 module_param(power_status, bool, 0600);
  80 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
  81
  82 static int fan_mult = I8K_FAN_MULT;
  83 module_param(fan_mult, int, 0);
  84 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with");
  85
  86 static int i8k_open_fs(struct inode *inode, struct file *file);
  87 static long i8k_ioctl(struct file *, unsigned int, unsigned long);
  88
  89 static const struct file_operations i8k_fops = {
  90         .owner          = THIS_MODULE,
  91         .open           = i8k_open_fs,
  92         .read           = seq_read,
  93         .llseek         = seq_lseek,
  94         .release        = single_release,
  95         .unlocked_ioctl = i8k_ioctl,
  96 };
  97
  98 struct smm_regs {
  99         unsigned int eax;
 100         unsigned int ebx __attribute__ ((packed));
 101         unsigned int ecx __attribute__ ((packed));
 102         unsigned int edx __attribute__ ((packed));
 103         unsigned int esi __attribute__ ((packed));
 104         unsigned int edi __attribute__ ((packed));
 105 };
 106
 107 static inline const char *i8k_get_dmi_data(int field)
 108 {
 109         const char *dmi_data = dmi_get_system_info(field);
 110
 111         return dmi_data && *dmi_data ? dmi_data : "?";
 112 }
 113
 114 /*
 115  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 116  */
 117 static int i8k_smm(struct smm_regs *regs)
 118 {
 119         int rc;
 120         int eax = regs->eax;
 121
 122 #if defined(CONFIG_X86_64)
 123         asm("pushq %%rax\n\t"
 124                 "movl 0(%%rax),%%edx\n\t"
 125                 "pushq %%rdx\n\t"
 126                 "movl 4(%%rax),%%ebx\n\t"
 127                 "movl 8(%%rax),%%ecx\n\t"
 128                 "movl 12(%%rax),%%edx\n\t"
 129                 "movl 16(%%rax),%%esi\n\t"
 130                 "movl 20(%%rax),%%edi\n\t"
 131                 "popq %%rax\n\t"
 132                 "out %%al,$0xb2\n\t"
 133                 "out %%al,$0x84\n\t"
 134                 "xchgq %%rax,(%%rsp)\n\t"
 135                 "movl %%ebx,4(%%rax)\n\t"
 136                 "movl %%ecx,8(%%rax)\n\t"
 137                 "movl %%edx,12(%%rax)\n\t"
 138                 "movl %%esi,16(%%rax)\n\t"
 139                 "movl %%edi,20(%%rax)\n\t"
 140                 "popq %%rdx\n\t"
 141                 "movl %%edx,0(%%rax)\n\t"
 142                 "lahf\n\t"
 143                 "shrl $8,%%eax\n\t"
 144                 "andl $1,%%eax\n"
 145                 :"=a"(rc)
 146                 :    "a"(regs)
 147                 :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 148 #else
 149         asm("pushl %%eax\n\t"
 150             "movl 0(%%eax),%%edx\n\t"
 151             "push %%edx\n\t"
 152             "movl 4(%%eax),%%ebx\n\t"
 153             "movl 8(%%eax),%%ecx\n\t"
 154             "movl 12(%%eax),%%edx\n\t"
 155             "movl 16(%%eax),%%esi\n\t"
 156             "movl 20(%%eax),%%edi\n\t"
 157             "popl %%eax\n\t"
 158             "out %%al,$0xb2\n\t"
 159             "out %%al,$0x84\n\t"
 160             "xchgl %%eax,(%%esp)\n\t"
 161             "movl %%ebx,4(%%eax)\n\t"
 162             "movl %%ecx,8(%%eax)\n\t"
 163             "movl %%edx,12(%%eax)\n\t"
 164             "movl %%esi,16(%%eax)\n\t"
 165             "movl %%edi,20(%%eax)\n\t"
 166             "popl %%edx\n\t"
 167             "movl %%edx,0(%%eax)\n\t"
 168             "lahf\n\t"
 169             "shrl $8,%%eax\n\t"
 170             "andl $1,%%eax\n":"=a"(rc)
 171             :    "a"(regs)
 172             :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 173 #endif
 174         if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
 175                 return -EINVAL;
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * Read the bios version. Return the version as an integer corresponding
 182  * to the ascii value, for example "A17" is returned as 0x00413137.
 183  */
 184 static int i8k_get_bios_version(void)
 185 {
 186         struct smm_regs regs = { .eax = I8K_SMM_BIOS_VERSION, };
 187
 188         return i8k_smm(&regs) ? : regs.eax;
 189 }
 190
 191 /*
 192  * Read the Fn key status.
 193  */
 194 static int i8k_get_fn_status(void)
 195 {
 196         struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
 197         int rc;
 198
 199         if ((rc = i8k_smm(&regs)) < 0)
 200                 return rc;
 201
 202         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 203         case I8K_FN_UP:
 204                 return I8K_VOL_UP;
 205         case I8K_FN_DOWN:
 206                 return I8K_VOL_DOWN;
 207         case I8K_FN_MUTE:
 208                 return I8K_VOL_MUTE;
 209         default:
 210                 return 0;
 211         }
 212 }
 213
 214 /*
 215  * Read the power status.
 216  */
 217 static int i8k_get_power_status(void)
 218 {
 219         struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
 220         int rc;
 221
 222         if ((rc = i8k_smm(&regs)) < 0)
 223                 return rc;
 224
 225         return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
 226 }
 227
 228 /*
 229  * Read the fan status.
 230  */
 231 static int i8k_get_fan_status(int fan)
 232 {
 233         struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
 234
 235         regs.ebx = fan & 0xff;
 236         return i8k_smm(&regs) ? : regs.eax & 0xff;
 237 }
 238
 239 /*
 240  * Read the fan speed in RPM.
 241  */
 242 static int i8k_get_fan_speed(int fan)
 243 {
 244         struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
 245
 246         regs.ebx = fan & 0xff;
 247         return i8k_smm(&regs) ? : (regs.eax & 0xffff) * fan_mult;
 248 }
 249
 250 /*
 251  * Set the fan speed (off, low, high). Returns the new fan status.
 252  */
 253 static int i8k_set_fan(int fan, int speed)
 254 {
 255         struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
 256
 257         speed = (speed < 0) ? 0 : ((speed > I8K_FAN_MAX) ? I8K_FAN_MAX : speed);
 258         regs.ebx = (fan & 0xff) | (speed << 8);
 259
 260         return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
 261 }
 262
 263 /*
 264  * Read the cpu temperature.
 265  */
 266 static int i8k_get_temp(int sensor)
 267 {
 268         struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP, };
 269         int rc;
 270         int temp;
 271
 272 #ifdef I8K_TEMPERATURE_BUG
 273         static int prev;
 274 #endif
 275         regs.ebx = sensor & 0xff;
 276         if ((rc = i8k_smm(&regs)) < 0)
 277                 return rc;
 278
 279         temp = regs.eax & 0xff;
 280
 281 #ifdef I8K_TEMPERATURE_BUG
 282         /*
 283          * Sometimes the temperature sensor returns 0x99, which is out of range.
 284          * In this case we return (once) the previous cached value. For example:
 285          # 1003655137 00000058 00005a4b
 286          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 287          # 1003655139 00000054 00005c52
 288          */
 289         if (temp > I8K_MAX_TEMP) {
 290                 temp = prev;
 291                 prev = I8K_MAX_TEMP;
 292         } else {
 293                 prev = temp;
 294         }
 295 #endif
 296
 297         return temp;
 298 }
 299
 300 static int i8k_get_dell_signature(int req_fn)
 301 {
 302         struct smm_regs regs = { .eax = req_fn, };
 303         int rc;
 304
 305         if ((rc = i8k_smm(&regs)) < 0)
 306                 return rc;
 307
 308         return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
 309 }
 310
 311 static int
 312 i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
 313 {
 314         int val = 0;
 315         int speed;
 316         unsigned char buff[16];
 317         int __user *argp = (int __user *)arg;
 318
 319         if (!argp)
 320                 return -EINVAL;
 321
 322         switch (cmd) {
 323         case I8K_BIOS_VERSION:
 324                 val = i8k_get_bios_version();
 325                 break;
 326
 327         case I8K_MACHINE_ID:
 328                 memset(buff, 0, 16);
 329                 strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL), sizeof(buff));
 330                 break;
 331
 332         case I8K_FN_STATUS:
 333                 val = i8k_get_fn_status();
 334                 break;
 335
 336         case I8K_POWER_STATUS:
 337                 val = i8k_get_power_status();
 338                 break;
 339
 340         case I8K_GET_TEMP:
 341                 val = i8k_get_temp(0);
 342                 break;
 343
 344         case I8K_GET_SPEED:
 345                 if (copy_from_user(&val, argp, sizeof(int)))
 346                         return -EFAULT;
 347
 348                 val = i8k_get_fan_speed(val);
 349                 break;
 350
 351         case I8K_GET_FAN:
 352                 if (copy_from_user(&val, argp, sizeof(int)))
 353                         return -EFAULT;
 354
 355                 val = i8k_get_fan_status(val);
 356                 break;
 357
 358         case I8K_SET_FAN:
 359                 if (restricted && !capable(CAP_SYS_ADMIN))
 360                         return -EPERM;
 361
 362                 if (copy_from_user(&val, argp, sizeof(int)))
 363                         return -EFAULT;
 364
 365                 if (copy_from_user(&speed, argp + 1, sizeof(int)))
 366                         return -EFAULT;
 367
 368                 val = i8k_set_fan(val, speed);
 369                 break;
 370
 371         default:
 372                 return -EINVAL;
 373         }
 374
 375         if (val < 0)
 376                 return val;
 377
 378         switch (cmd) {
 379         case I8K_BIOS_VERSION:
 380                 if (copy_to_user(argp, &val, 4))
 381                         return -EFAULT;
 382
 383                 break;
 384         case I8K_MACHINE_ID:
 385                 if (copy_to_user(argp, buff, 16))
 386                         return -EFAULT;
 387
 388                 break;
 389         default:
 390                 if (copy_to_user(argp, &val, sizeof(int)))
 391                         return -EFAULT;
 392
 393                 break;
 394         }
 395
 396         return 0;
 397 }
 398
 399 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
 400 {
 401         long ret;
 402
 403         mutex_lock(&i8k_mutex);
 404         ret = i8k_ioctl_unlocked(fp, cmd, arg);
 405         mutex_unlock(&i8k_mutex);
 406
 407         return ret;
 408 }
 409
 410 /*
 411  * Print the information for /proc/i8k.
 412  */
 413 static int i8k_proc_show(struct seq_file *seq, void *offset)
 414 {
 415         int fn_key, cpu_temp, ac_power;
 416         int left_fan, right_fan, left_speed, right_speed;
 417
 418         cpu_temp        = i8k_get_temp(0);                      /* 11100 µs */
 419         left_fan        = i8k_get_fan_status(I8K_FAN_LEFT);     /*   580 µs */
 420         right_fan       = i8k_get_fan_status(I8K_FAN_RIGHT);    /*   580 µs */
 421         left_speed      = i8k_get_fan_speed(I8K_FAN_LEFT);      /*   580 µs */
 422         right_speed     = i8k_get_fan_speed(I8K_FAN_RIGHT);     /*   580 µs */
 423         fn_key          = i8k_get_fn_status();                  /*   750 µs */
 424         if (power_status)
 425                 ac_power = i8k_get_power_status();              /* 14700 µs */
 426         else
 427                 ac_power = -1;
 428
 429         /*
 430          * Info:
 431          *
 432          * 1)  Format version (this will change if format changes)
 433          * 2)  BIOS version
 434          * 3)  BIOS machine ID
 435          * 4)  Cpu temperature
 436          * 5)  Left fan status
 437          * 6)  Right fan status
 438          * 7)  Left fan speed
 439          * 8)  Right fan speed
 440          * 9)  AC power
 441          * 10) Fn Key status
 442          */
 443         return seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
 444                           I8K_PROC_FMT,
 445                           bios_version,
 446                           i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
 447                           cpu_temp,
 448                           left_fan, right_fan, left_speed, right_speed,
 449                           ac_power, fn_key);
 450 }
 451
 452 static int i8k_open_fs(struct inode *inode, struct file *file)
 453 {
 454         return single_open(file, i8k_proc_show, NULL);
 455 }
 456
 457 static struct dmi_system_id __initdata i8k_dmi_table[] = {
 458         {
 459                 .ident = "Dell Inspiron",
 460                 .matches = {
 461                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 462                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 463                 },
 464         },
 465         {
 466                 .ident = "Dell Latitude",
 467                 .matches = {
 468                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 469                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 470                 },
 471         },
 472         {
 473                 .ident = "Dell Inspiron 2",
 474                 .matches = {
 475                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 476                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 477                 },
 478         },
 479         {
 480                 .ident = "Dell Latitude 2",
 481                 .matches = {
 482                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 483                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 484                 },
 485         },
 486         {       /* UK Inspiron 6400  */
 487                 .ident = "Dell Inspiron 3",
 488                 .matches = {
 489                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 490                         DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
 491                 },
 492         },
 493         {
 494                 .ident = "Dell Inspiron 3",
 495                 .matches = {
 496                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 497                         DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
 498                 },
 499         },
 500         {
 501                 .ident = "Dell Precision",
 502                 .matches = {
 503                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 504                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
 505                 },
 506         },
 507         {
 508                 .ident = "Dell Vostro",
 509                 .matches = {
 510                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 511                         DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
 512                 },
 513         },
 514         { }
 515 };
 516
 517 /*
 518  * Probe for the presence of a supported laptop.
 519  */
 520 static int __init i8k_probe(void)
 521 {
 522         char buff[4];
 523         int version;
 524
 525         /*
 526          * Get DMI information
 527          */
 528         if (!dmi_check_system(i8k_dmi_table)) {
 529                 if (!ignore_dmi && !force)
 530                         return -ENODEV;
 531
 532                 printk(KERN_INFO "i8k: not running on a supported Dell system.\n");
 533                 printk(KERN_INFO "i8k: vendor=%s, model=%s, version=%s\n",
 534                         i8k_get_dmi_data(DMI_SYS_VENDOR),
 535                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
 536                         i8k_get_dmi_data(DMI_BIOS_VERSION));
 537         }
 538
 539         strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION), sizeof(bios_version));
 540
 541         /*
 542          * Get SMM Dell signature
 543          */
 544         if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
 545             i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
 546                 printk(KERN_ERR "i8k: unable to get SMM Dell signature\n");
 547                 if (!force)
 548                         return -ENODEV;
 549         }
 550
 551         /*
 552          * Get SMM BIOS version.
 553          */
 554         version = i8k_get_bios_version();
 555         if (version <= 0) {
 556                 printk(KERN_WARNING "i8k: unable to get SMM BIOS version\n");
 557         } else {
 558                 buff[0] = (version >> 16) & 0xff;
 559                 buff[1] = (version >> 8) & 0xff;
 560                 buff[2] = (version) & 0xff;
 561                 buff[3] = '\0';
 562                 /*
 563                  * If DMI BIOS version is unknown use SMM BIOS version.
 564                  */
 565                 if (!dmi_get_system_info(DMI_BIOS_VERSION))
 566                         strlcpy(bios_version, buff, sizeof(bios_version));
 567
 568                 /*
 569                  * Check if the two versions match.
 570                  */
 571                 if (strncmp(buff, bios_version, sizeof(bios_version)) != 0)
 572                         printk(KERN_WARNING "i8k: BIOS version mismatch: %s != %s\n",
 573                                 buff, bios_version);
 574         }
 575
 576         return 0;
 577 }
 578
 579 static int __init i8k_init(void)
 580 {
 581         struct proc_dir_entry *proc_i8k;
 582
 583         /* Are we running on an supported laptop? */
 584         if (i8k_probe())
 585                 return -ENODEV;
 586
 587         /* Register the proc entry */
 588         proc_i8k = proc_create("i8k", 0, NULL, &i8k_fops);
 589         if (!proc_i8k)
 590                 return -ENOENT;
 591
 592         printk(KERN_INFO
 593                "Dell laptop SMM driver v%s Massimo Dal Zotto (dz@debian.org)\n",
 594                I8K_VERSION);
 595
 596         return 0;
 597 }
 598
 599 static void __exit i8k_exit(void)
 600 {
 601         remove_proc_entry("i8k", NULL);
 602 }
 603
 604 module_init(i8k_init);
 605 module_exit(i8k_exit);