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