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