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 volatile("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 volatile("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"
 171             :"=a"(rc)
 172             :    "a"(regs)
 173             :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 174 #endif
 175         if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
 176                 return -EINVAL;
 177
 178         return 0;
 179 }
 180
 181 /*
 182  * Read the bios version. Return the version as an integer corresponding
 183  * to the ascii value, for example "A17" is returned as 0x00413137.
 184  */
 185 static int i8k_get_bios_version(void)
 186 {
 187         struct smm_regs regs = { .eax = I8K_SMM_BIOS_VERSION, };
 188
 189         return i8k_smm(&regs) ? : regs.eax;
 190 }
 191
 192 /*
 193  * Read the Fn key status.
 194  */
 195 static int i8k_get_fn_status(void)
 196 {
 197         struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
 198         int rc;
 199
 200         if ((rc = i8k_smm(&regs)) < 0)
 201                 return rc;
 202
 203         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 204         case I8K_FN_UP:
 205                 return I8K_VOL_UP;
 206         case I8K_FN_DOWN:
 207                 return I8K_VOL_DOWN;
 208         case I8K_FN_MUTE:
 209                 return I8K_VOL_MUTE;
 210         default:
 211                 return 0;
 212         }
 213 }
 214
 215 /*
 216  * Read the power status.
 217  */
 218 static int i8k_get_power_status(void)
 219 {
 220         struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
 221         int rc;
 222
 223         if ((rc = i8k_smm(&regs)) < 0)
 224                 return rc;
 225
 226         return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
 227 }
 228
 229 /*
 230  * Read the fan status.
 231  */
 232 static int i8k_get_fan_status(int fan)
 233 {
 234         struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
 235
 236         regs.ebx = fan & 0xff;
 237         return i8k_smm(&regs) ? : regs.eax & 0xff;
 238 }
 239
 240 /*
 241  * Read the fan speed in RPM.
 242  */
 243 static int i8k_get_fan_speed(int fan)
 244 {
 245         struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
 246
 247         regs.ebx = fan & 0xff;
 248         return i8k_smm(&regs) ? : (regs.eax & 0xffff) * fan_mult;
 249 }
 250
 251 /*
 252  * Set the fan speed (off, low, high). Returns the new fan status.
 253  */
 254 static int i8k_set_fan(int fan, int speed)
 255 {
 256         struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
 257
 258         speed = (speed < 0) ? 0 : ((speed > I8K_FAN_MAX) ? I8K_FAN_MAX : speed);
 259         regs.ebx = (fan & 0xff) | (speed << 8);
 260
 261         return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
 262 }
 263
 264 /*
 265  * Read the cpu temperature.
 266  */
 267 static int i8k_get_temp(int sensor)
 268 {
 269         struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP, };
 270         int rc;
 271         int temp;
 272
 273 #ifdef I8K_TEMPERATURE_BUG
 274         static int prev;
 275 #endif
 276         regs.ebx = sensor & 0xff;
 277         if ((rc = i8k_smm(&regs)) < 0)
 278                 return rc;
 279
 280         temp = regs.eax & 0xff;
 281
 282 #ifdef I8K_TEMPERATURE_BUG
 283         /*
 284          * Sometimes the temperature sensor returns 0x99, which is out of range.
 285          * In this case we return (once) the previous cached value. For example:
 286          # 1003655137 00000058 00005a4b
 287          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 288          # 1003655139 00000054 00005c52
 289          */
 290         if (temp > I8K_MAX_TEMP) {
 291                 temp = prev;
 292                 prev = I8K_MAX_TEMP;
 293         } else {
 294                 prev = temp;
 295         }
 296 #endif
 297
 298         return temp;
 299 }
 300
 301 static int i8k_get_dell_signature(int req_fn)
 302 {
 303         struct smm_regs regs = { .eax = req_fn, };
 304         int rc;
 305
 306         if ((rc = i8k_smm(&regs)) < 0)
 307                 return rc;
 308
 309         return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
 310 }
 311
 312 static int
 313 i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
 314 {
 315         int val = 0;
 316         int speed;
 317         unsigned char buff[16];
 318         int __user *argp = (int __user *)arg;
 319
 320         if (!argp)
 321                 return -EINVAL;
 322
 323         switch (cmd) {
 324         case I8K_BIOS_VERSION:
 325                 val = i8k_get_bios_version();
 326                 break;
 327
 328         case I8K_MACHINE_ID:
 329                 memset(buff, 0, 16);
 330                 strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL), sizeof(buff));
 331                 break;
 332
 333         case I8K_FN_STATUS:
 334                 val = i8k_get_fn_status();
 335                 break;
 336
 337         case I8K_POWER_STATUS:
 338                 val = i8k_get_power_status();
 339                 break;
 340
 341         case I8K_GET_TEMP:
 342                 val = i8k_get_temp(0);
 343                 break;
 344
 345         case I8K_GET_SPEED:
 346                 if (copy_from_user(&val, argp, sizeof(int)))
 347                         return -EFAULT;
 348
 349                 val = i8k_get_fan_speed(val);
 350                 break;
 351
 352         case I8K_GET_FAN:
 353                 if (copy_from_user(&val, argp, sizeof(int)))
 354                         return -EFAULT;
 355
 356                 val = i8k_get_fan_status(val);
 357                 break;
 358
 359         case I8K_SET_FAN:
 360                 if (restricted && !capable(CAP_SYS_ADMIN))
 361                         return -EPERM;
 362
 363                 if (copy_from_user(&val, argp, sizeof(int)))
 364                         return -EFAULT;
 365
 366                 if (copy_from_user(&speed, argp + 1, sizeof(int)))
 367                         return -EFAULT;
 368
 369                 val = i8k_set_fan(val, speed);
 370                 break;
 371
 372         default:
 373                 return -EINVAL;
 374         }
 375
 376         if (val < 0)
 377                 return val;
 378
 379         switch (cmd) {
 380         case I8K_BIOS_VERSION:
 381                 if (copy_to_user(argp, &val, 4))
 382                         return -EFAULT;
 383
 384                 break;
 385         case I8K_MACHINE_ID:
 386                 if (copy_to_user(argp, buff, 16))
 387                         return -EFAULT;
 388
 389                 break;
 390         default:
 391                 if (copy_to_user(argp, &val, sizeof(int)))
 392                         return -EFAULT;
 393
 394                 break;
 395         }
 396
 397         return 0;
 398 }
 399
 400 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
 401 {
 402         long ret;
 403
 404         mutex_lock(&i8k_mutex);
 405         ret = i8k_ioctl_unlocked(fp, cmd, arg);
 406         mutex_unlock(&i8k_mutex);
 407
 408         return ret;
 409 }
 410
 411 /*
 412  * Print the information for /proc/i8k.
 413  */
 414 static int i8k_proc_show(struct seq_file *seq, void *offset)
 415 {
 416         int fn_key, cpu_temp, ac_power;
 417         int left_fan, right_fan, left_speed, right_speed;
 418
 419         cpu_temp        = i8k_get_temp(0);                      /* 11100 µs */
 420         left_fan        = i8k_get_fan_status(I8K_FAN_LEFT);     /*   580 µs */
 421         right_fan       = i8k_get_fan_status(I8K_FAN_RIGHT);    /*   580 µs */
 422         left_speed      = i8k_get_fan_speed(I8K_FAN_LEFT);      /*   580 µs */
 423         right_speed     = i8k_get_fan_speed(I8K_FAN_RIGHT);     /*   580 µs */
 424         fn_key          = i8k_get_fn_status();                  /*   750 µs */
 425         if (power_status)
 426                 ac_power = i8k_get_power_status();              /* 14700 µs */
 427         else
 428                 ac_power = -1;
 429
 430         /*
 431          * Info:
 432          *
 433          * 1)  Format version (this will change if format changes)
 434          * 2)  BIOS version
 435          * 3)  BIOS machine ID
 436          * 4)  Cpu temperature
 437          * 5)  Left fan status
 438          * 6)  Right fan status
 439          * 7)  Left fan speed
 440          * 8)  Right fan speed
 441          * 9)  AC power
 442          * 10) Fn Key status
 443          */
 444         return seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
 445                           I8K_PROC_FMT,
 446                           bios_version,
 447                           i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
 448                           cpu_temp,
 449                           left_fan, right_fan, left_speed, right_speed,
 450                           ac_power, fn_key);
 451 }
 452
 453 static int i8k_open_fs(struct inode *inode, struct file *file)
 454 {
 455         return single_open(file, i8k_proc_show, NULL);
 456 }
 457
 458 static struct dmi_system_id __initdata i8k_dmi_table[] = {
 459         {
 460                 .ident = "Dell Inspiron",
 461                 .matches = {
 462                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 463                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 464                 },
 465         },
 466         {
 467                 .ident = "Dell Latitude",
 468                 .matches = {
 469                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 470                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 471                 },
 472         },
 473         {
 474                 .ident = "Dell Inspiron 2",
 475                 .matches = {
 476                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 477                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 478                 },
 479         },
 480         {
 481                 .ident = "Dell Latitude 2",
 482                 .matches = {
 483                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 484                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 485                 },
 486         },
 487         {       /* UK Inspiron 6400  */
 488                 .ident = "Dell Inspiron 3",
 489                 .matches = {
 490                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 491                         DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
 492                 },
 493         },
 494         {
 495                 .ident = "Dell Inspiron 3",
 496                 .matches = {
 497                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 498                         DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
 499                 },
 500         },
 501         {
 502                 .ident = "Dell Precision",
 503                 .matches = {
 504                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 505                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
 506                 },
 507         },
 508         {
 509                 .ident = "Dell Vostro",
 510                 .matches = {
 511                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 512                         DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
 513                 },
 514         },
 515         { }
 516 };
 517
 518 /*
 519  * Probe for the presence of a supported laptop.
 520  */
 521 static int __init i8k_probe(void)
 522 {
 523         char buff[4];
 524         int version;
 525
 526         /*
 527          * Get DMI information
 528          */
 529         if (!dmi_check_system(i8k_dmi_table)) {
 530                 if (!ignore_dmi && !force)
 531                         return -ENODEV;
 532
 533                 printk(KERN_INFO "i8k: not running on a supported Dell system.\n");
 534                 printk(KERN_INFO "i8k: vendor=%s, model=%s, version=%s\n",
 535                         i8k_get_dmi_data(DMI_SYS_VENDOR),
 536                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
 537                         i8k_get_dmi_data(DMI_BIOS_VERSION));
 538         }
 539
 540         strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION), sizeof(bios_version));
 541
 542         /*
 543          * Get SMM Dell signature
 544          */
 545         if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
 546             i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
 547                 printk(KERN_ERR "i8k: unable to get SMM Dell signature\n");
 548                 if (!force)
 549                         return -ENODEV;
 550         }
 551
 552         /*
 553          * Get SMM BIOS version.
 554          */
 555         version = i8k_get_bios_version();
 556         if (version <= 0) {
 557                 printk(KERN_WARNING "i8k: unable to get SMM BIOS version\n");
 558         } else {
 559                 buff[0] = (version >> 16) & 0xff;
 560                 buff[1] = (version >> 8) & 0xff;
 561                 buff[2] = (version) & 0xff;
 562                 buff[3] = '\0';
 563                 /*
 564                  * If DMI BIOS version is unknown use SMM BIOS version.
 565                  */
 566                 if (!dmi_get_system_info(DMI_BIOS_VERSION))
 567                         strlcpy(bios_version, buff, sizeof(bios_version));
 568
 569                 /*
 570                  * Check if the two versions match.
 571                  */
 572                 if (strncmp(buff, bios_version, sizeof(bios_version)) != 0)
 573                         printk(KERN_WARNING "i8k: BIOS version mismatch: %s != %s\n",
 574                                 buff, bios_version);
 575         }
 576
 577         return 0;
 578 }
 579
 580 static int __init i8k_init(void)
 581 {
 582         struct proc_dir_entry *proc_i8k;
 583
 584         /* Are we running on an supported laptop? */
 585         if (i8k_probe())
 586                 return -ENODEV;
 587
 588         /* Register the proc entry */
 589         proc_i8k = proc_create("i8k", 0, NULL, &i8k_fops);
 590         if (!proc_i8k)
 591                 return -ENOENT;
 592
 593         printk(KERN_INFO
 594                "Dell laptop SMM driver v%s Massimo Dal Zotto (dz@debian.org)\n",
 595                I8K_VERSION);
 596
 597         return 0;
 598 }
 599
 600 static void __exit i8k_exit(void)
 601 {
 602         remove_proc_entry("i8k", NULL);
 603 }
 604
 605 module_init(i8k_init);
 606 module_exit(i8k_exit);