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/dmi.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/io.h>
  26
  27 #include <linux/i8k.h>
  28
  29 #define I8K_VERSION             "1.13 14/05/2002"
  30
  31 #define I8K_SMM_FN_STATUS       0x0025
  32 #define I8K_SMM_POWER_STATUS    0x0069
  33 #define I8K_SMM_SET_FAN         0x01a3
  34 #define I8K_SMM_GET_FAN         0x00a3
  35 #define I8K_SMM_GET_SPEED       0x02a3
  36 #define I8K_SMM_GET_TEMP        0x10a3
  37 #define I8K_SMM_GET_DELL_SIG    0xffa3
  38 #define I8K_SMM_BIOS_VERSION    0x00a6
  39
  40 #define I8K_FAN_MULT            30
  41 #define I8K_MAX_TEMP            127
  42
  43 #define I8K_FN_NONE             0x00
  44 #define I8K_FN_UP               0x01
  45 #define I8K_FN_DOWN             0x02
  46 #define I8K_FN_MUTE             0x04
  47 #define I8K_FN_MASK             0x07
  48 #define I8K_FN_SHIFT            8
  49
  50 #define I8K_POWER_AC            0x05
  51 #define I8K_POWER_BATTERY       0x01
  52
  53 #define I8K_TEMPERATURE_BUG     1
  54
  55 static char bios_version[4];
  56
  57 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
  58 MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
  59 MODULE_LICENSE("GPL");
  60
  61 static int force;
  62 module_param(force, bool, 0);
  63 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
  64
  65 static int ignore_dmi;
  66 module_param(ignore_dmi, bool, 0);
  67 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
  68
  69 static int restricted;
  70 module_param(restricted, bool, 0);
  71 MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
  72
  73 static int power_status;
  74 module_param(power_status, bool, 0600);
  75 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
  76
  77 static ssize_t i8k_read(struct file *, char __user *, size_t, loff_t *);
  78 static int i8k_ioctl(struct inode *, struct file *, unsigned int,
  79                      unsigned long);
  80
  81 static struct file_operations i8k_fops = {
  82         .read = i8k_read,
  83         .ioctl = i8k_ioctl,
  84 };
  85
  86 typedef struct {
  87         unsigned int eax;
  88         unsigned int ebx __attribute__ ((packed));
  89         unsigned int ecx __attribute__ ((packed));
  90         unsigned int edx __attribute__ ((packed));
  91         unsigned int esi __attribute__ ((packed));
  92         unsigned int edi __attribute__ ((packed));
  93 } SMMRegisters;
  94
  95 static inline char *i8k_get_dmi_data(int field)
  96 {
  97         return dmi_get_system_info(field) ? : "N/A";
  98 }
  99
 100 /*
 101  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 102  */
 103 static int i8k_smm(SMMRegisters * regs)
 104 {
 105         int rc;
 106         int eax = regs->eax;
 107
 108         asm("pushl %%eax\n\t"
 109             "movl 0(%%eax),%%edx\n\t"
 110             "push %%edx\n\t"
 111             "movl 4(%%eax),%%ebx\n\t"
 112             "movl 8(%%eax),%%ecx\n\t"
 113             "movl 12(%%eax),%%edx\n\t"
 114             "movl 16(%%eax),%%esi\n\t"
 115             "movl 20(%%eax),%%edi\n\t"
 116             "popl %%eax\n\t"
 117             "out %%al,$0xb2\n\t"
 118             "out %%al,$0x84\n\t"
 119             "xchgl %%eax,(%%esp)\n\t"
 120             "movl %%ebx,4(%%eax)\n\t"
 121             "movl %%ecx,8(%%eax)\n\t"
 122             "movl %%edx,12(%%eax)\n\t"
 123             "movl %%esi,16(%%eax)\n\t"
 124             "movl %%edi,20(%%eax)\n\t"
 125             "popl %%edx\n\t"
 126             "movl %%edx,0(%%eax)\n\t"
 127             "lahf\n\t"
 128             "shrl $8,%%eax\n\t"
 129             "andl $1,%%eax\n":"=a"(rc)
 130             :    "a"(regs)
 131             :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 132
 133         if ((rc != 0) || ((regs->eax & 0xffff) == 0xffff) || (regs->eax == eax)) {
 134                 return -EINVAL;
 135         }
 136
 137         return 0;
 138 }
 139
 140 /*
 141  * Read the bios version. Return the version as an integer corresponding
 142  * to the ascii value, for example "A17" is returned as 0x00413137.
 143  */
 144 static int i8k_get_bios_version(void)
 145 {
 146         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 147         int rc;
 148
 149         regs.eax = I8K_SMM_BIOS_VERSION;
 150         if ((rc = i8k_smm(&regs)) < 0) {
 151                 return rc;
 152         }
 153
 154         return regs.eax;
 155 }
 156
 157 /*
 158  * Read the Fn key status.
 159  */
 160 static int i8k_get_fn_status(void)
 161 {
 162         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 163         int rc;
 164
 165         regs.eax = I8K_SMM_FN_STATUS;
 166         if ((rc = i8k_smm(&regs)) < 0) {
 167                 return rc;
 168         }
 169
 170         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 171         case I8K_FN_UP:
 172                 return I8K_VOL_UP;
 173         case I8K_FN_DOWN:
 174                 return I8K_VOL_DOWN;
 175         case I8K_FN_MUTE:
 176                 return I8K_VOL_MUTE;
 177         default:
 178                 return 0;
 179         }
 180 }
 181
 182 /*
 183  * Read the power status.
 184  */
 185 static int i8k_get_power_status(void)
 186 {
 187         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 188         int rc;
 189
 190         regs.eax = I8K_SMM_POWER_STATUS;
 191         if ((rc = i8k_smm(&regs)) < 0) {
 192                 return rc;
 193         }
 194
 195         switch (regs.eax & 0xff) {
 196         case I8K_POWER_AC:
 197                 return I8K_AC;
 198         default:
 199                 return I8K_BATTERY;
 200         }
 201 }
 202
 203 /*
 204  * Read the fan status.
 205  */
 206 static int i8k_get_fan_status(int fan)
 207 {
 208         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 209         int rc;
 210
 211         regs.eax = I8K_SMM_GET_FAN;
 212         regs.ebx = fan & 0xff;
 213         if ((rc = i8k_smm(&regs)) < 0) {
 214                 return rc;
 215         }
 216
 217         return (regs.eax & 0xff);
 218 }
 219
 220 /*
 221  * Read the fan speed in RPM.
 222  */
 223 static int i8k_get_fan_speed(int fan)
 224 {
 225         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 226         int rc;
 227
 228         regs.eax = I8K_SMM_GET_SPEED;
 229         regs.ebx = fan & 0xff;
 230         if ((rc = i8k_smm(&regs)) < 0) {
 231                 return rc;
 232         }
 233
 234         return (regs.eax & 0xffff) * I8K_FAN_MULT;
 235 }
 236
 237 /*
 238  * Set the fan speed (off, low, high). Returns the new fan status.
 239  */
 240 static int i8k_set_fan(int fan, int speed)
 241 {
 242         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 243         int rc;
 244
 245         speed = (speed < 0) ? 0 : ((speed > I8K_FAN_MAX) ? I8K_FAN_MAX : speed);
 246
 247         regs.eax = I8K_SMM_SET_FAN;
 248         regs.ebx = (fan & 0xff) | (speed << 8);
 249         if ((rc = i8k_smm(&regs)) < 0) {
 250                 return rc;
 251         }
 252
 253         return (i8k_get_fan_status(fan));
 254 }
 255
 256 /*
 257  * Read the cpu temperature.
 258  */
 259 static int i8k_get_cpu_temp(void)
 260 {
 261         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 262         int rc;
 263         int temp;
 264
 265 #ifdef I8K_TEMPERATURE_BUG
 266         static int prev = 0;
 267 #endif
 268
 269         regs.eax = I8K_SMM_GET_TEMP;
 270         if ((rc = i8k_smm(&regs)) < 0) {
 271                 return rc;
 272         }
 273         temp = regs.eax & 0xff;
 274
 275 #ifdef I8K_TEMPERATURE_BUG
 276         /*
 277          * Sometimes the temperature sensor returns 0x99, which is out of range.
 278          * In this case we return (once) the previous cached value. For example:
 279          # 1003655137 00000058 00005a4b
 280          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 281          # 1003655139 00000054 00005c52
 282          */
 283         if (temp > I8K_MAX_TEMP) {
 284                 temp = prev;
 285                 prev = I8K_MAX_TEMP;
 286         } else {
 287                 prev = temp;
 288         }
 289 #endif
 290
 291         return temp;
 292 }
 293
 294 static int i8k_get_dell_signature(void)
 295 {
 296         SMMRegisters regs = { 0, 0, 0, 0, 0, 0 };
 297         int rc;
 298
 299         regs.eax = I8K_SMM_GET_DELL_SIG;
 300         if ((rc = i8k_smm(&regs)) < 0) {
 301                 return rc;
 302         }
 303
 304         if ((regs.eax == 1145651527) && (regs.edx == 1145392204)) {
 305                 return 0;
 306         } else {
 307                 return -1;
 308         }
 309 }
 310
 311 static int i8k_ioctl(struct inode *ip, struct file *fp, unsigned int cmd,
 312                      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_cpu_temp();
 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
 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 /*
 401  * Print the information for /proc/i8k.
 402  */
 403 static int i8k_get_info(char *buffer, char **start, off_t fpos, int length)
 404 {
 405         int n, fn_key, cpu_temp, ac_power;
 406         int left_fan, right_fan, left_speed, right_speed;
 407
 408         cpu_temp        = i8k_get_cpu_temp();                   /* 11100 µs */
 409         left_fan        = i8k_get_fan_status(I8K_FAN_LEFT);     /*   580 µs */
 410         right_fan       = i8k_get_fan_status(I8K_FAN_RIGHT);    /*   580 µs */
 411         left_speed      = i8k_get_fan_speed(I8K_FAN_LEFT);      /*   580 µs */
 412         right_speed     = i8k_get_fan_speed(I8K_FAN_RIGHT);     /*   580 µs */
 413         fn_key          = i8k_get_fn_status();                  /*   750 µs */
 414         if (power_status) {
 415                 ac_power = i8k_get_power_status();              /* 14700 µs */
 416         } else {
 417                 ac_power = -1;
 418         }
 419
 420         /*
 421          * Info:
 422          *
 423          * 1)  Format version (this will change if format changes)
 424          * 2)  BIOS version
 425          * 3)  BIOS machine ID
 426          * 4)  Cpu temperature
 427          * 5)  Left fan status
 428          * 6)  Right fan status
 429          * 7)  Left fan speed
 430          * 8)  Right fan speed
 431          * 9)  AC power
 432          * 10) Fn Key status
 433          */
 434         n = sprintf(buffer, "%s %s %s %d %d %d %d %d %d %d\n",
 435                     I8K_PROC_FMT,
 436                     bios_version,
 437                     dmi_get_system_info(DMI_PRODUCT_SERIAL) ? : "N/A",
 438                     cpu_temp,
 439                     left_fan, right_fan, left_speed, right_speed,
 440                     ac_power, fn_key);
 441
 442         return n;
 443 }
 444
 445 static ssize_t i8k_read(struct file *f, char __user * buffer, size_t len,
 446                         loff_t * fpos)
 447 {
 448         int n;
 449         char info[128];
 450
 451         n = i8k_get_info(info, NULL, 0, 128);
 452         if (n <= 0) {
 453                 return n;
 454         }
 455
 456         if (*fpos >= n) {
 457                 return 0;
 458         }
 459
 460         if ((*fpos + len) >= n) {
 461                 len = n - *fpos;
 462         }
 463
 464         if (copy_to_user(buffer, info, len) != 0) {
 465                 return -EFAULT;
 466         }
 467
 468         *fpos += len;
 469         return len;
 470 }
 471
 472 static struct dmi_system_id __initdata i8k_dmi_table[] = {
 473         {
 474                 .ident = "Dell Inspiron",
 475                 .matches = {
 476                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 477                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 478                 },
 479         },
 480         {
 481                 .ident = "Dell Latitude",
 482                 .matches = {
 483                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 484                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 485                 },
 486         },
 487         { }
 488 };
 489
 490 /*
 491  * Probe for the presence of a supported laptop.
 492  */
 493 static int __init i8k_probe(void)
 494 {
 495         char buff[4];
 496         int version;
 497
 498         /*
 499          * Get DMI information
 500          */
 501         if (!dmi_check_system(i8k_dmi_table)) {
 502                 if (!ignore_dmi && !force)
 503                         return -ENODEV;
 504
 505                 printk(KERN_INFO "i8k: not running on a supported Dell system.\n");
 506                 printk(KERN_INFO "i8k: vendor=%s, model=%s, version=%s\n",
 507                         i8k_get_dmi_data(DMI_SYS_VENDOR),
 508                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
 509                         i8k_get_dmi_data(DMI_BIOS_VERSION));
 510         }
 511
 512         strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION), sizeof(bios_version));
 513
 514         /*
 515          * Get SMM Dell signature
 516          */
 517         if (i8k_get_dell_signature() != 0) {
 518                 printk(KERN_ERR "i8k: unable to get SMM Dell signature\n");
 519                 if (!force)
 520                         return -ENODEV;
 521         }
 522
 523         /*
 524          * Get SMM BIOS version.
 525          */
 526         version = i8k_get_bios_version();
 527         if (version <= 0) {
 528                 printk(KERN_WARNING "i8k: unable to get SMM BIOS version\n");
 529         } else {
 530                 buff[0] = (version >> 16) & 0xff;
 531                 buff[1] = (version >> 8) & 0xff;
 532                 buff[2] = (version) & 0xff;
 533                 buff[3] = '\0';
 534                 /*
 535                  * If DMI BIOS version is unknown use SMM BIOS version.
 536                  */
 537                 if (!dmi_get_system_info(DMI_BIOS_VERSION))
 538                         strlcpy(bios_version, buff, sizeof(bios_version));
 539
 540                 /*
 541                  * Check if the two versions match.
 542                  */
 543                 if (strncmp(buff, bios_version, sizeof(bios_version)) != 0)
 544                         printk(KERN_WARNING "i8k: BIOS version mismatch: %s != %s\n",
 545                                 buff, bios_version);
 546         }
 547
 548         return 0;
 549 }
 550
 551 #ifdef MODULE
 552 static
 553 #endif
 554 int __init i8k_init(void)
 555 {
 556         struct proc_dir_entry *proc_i8k;
 557
 558         /* Are we running on an supported laptop? */
 559         if (i8k_probe())
 560                 return -ENODEV;
 561
 562         /* Register the proc entry */
 563         proc_i8k = create_proc_info_entry("i8k", 0, NULL, i8k_get_info);
 564         if (!proc_i8k) {
 565                 return -ENOENT;
 566         }
 567         proc_i8k->proc_fops = &i8k_fops;
 568         proc_i8k->owner = THIS_MODULE;
 569
 570         printk(KERN_INFO
 571                "Dell laptop SMM driver v%s Massimo Dal Zotto (dz@debian.org)\n",
 572                I8K_VERSION);
 573
 574         return 0;
 575 }
 576
 577 #ifdef MODULE
 578 int init_module(void)
 579 {
 580         return i8k_init();
 581 }
 582
 583 void cleanup_module(void)
 584 {
 585         /* Remove the proc entry */
 586         remove_proc_entry("i8k", NULL);
 587
 588         printk(KERN_INFO "i8k: module unloaded\n");
 589 }
 590 #endif
 591
 592 /* end of file */