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