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