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_SIG    0xffa3
  39 #define I8K_SMM_BIOS_VERSION    0x00a6
  40
  41 #define I8K_FAN_MULT            30
  42 #define I8K_MAX_TEMP            127
  43
  44 #define I8K_FN_NONE             0x00
  45 #define I8K_FN_UP               0x01
  46 #define I8K_FN_DOWN             0x02
  47 #define I8K_FN_MUTE             0x04
  48 #define I8K_FN_MASK             0x07
  49 #define I8K_FN_SHIFT            8
  50
  51 #define I8K_POWER_AC            0x05
  52 #define I8K_POWER_BATTERY       0x01
  53
  54 #define I8K_TEMPERATURE_BUG     1
  55
  56 static char bios_version[4];
  57
  58 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
  59 MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
  60 MODULE_LICENSE("GPL");
  61
  62 static int force;
  63 module_param(force, bool, 0);
  64 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
  65
  66 static int ignore_dmi;
  67 module_param(ignore_dmi, bool, 0);
  68 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
  69
  70 static int restricted;
  71 module_param(restricted, bool, 0);
  72 MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
  73
  74 static int power_status;
  75 module_param(power_status, bool, 0600);
  76 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
  77
  78 static int i8k_open_fs(struct inode *inode, struct file *file);
  79 static int i8k_ioctl(struct inode *, struct file *, unsigned int,
  80                      unsigned long);
  81
  82 static struct file_operations i8k_fops = {
  83         .open           = i8k_open_fs,
  84         .read           = seq_read,
  85         .llseek         = seq_lseek,
  86         .release        = single_release,
  87         .ioctl          = i8k_ioctl,
  88 };
  89
  90 struct smm_regs {
  91         unsigned int eax;
  92         unsigned int ebx __attribute__ ((packed));
  93         unsigned int ecx __attribute__ ((packed));
  94         unsigned int edx __attribute__ ((packed));
  95         unsigned int esi __attribute__ ((packed));
  96         unsigned int edi __attribute__ ((packed));
  97 };
  98
  99 static inline char *i8k_get_dmi_data(int field)
 100 {
 101         return dmi_get_system_info(field) ? : "N/A";
 102 }
 103
 104 /*
 105  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 106  */
 107 static int i8k_smm(struct smm_regs *regs)
 108 {
 109         int rc;
 110         int eax = regs->eax;
 111
 112         asm("pushl %%eax\n\t"
 113             "movl 0(%%eax),%%edx\n\t"
 114             "push %%edx\n\t"
 115             "movl 4(%%eax),%%ebx\n\t"
 116             "movl 8(%%eax),%%ecx\n\t"
 117             "movl 12(%%eax),%%edx\n\t"
 118             "movl 16(%%eax),%%esi\n\t"
 119             "movl 20(%%eax),%%edi\n\t"
 120             "popl %%eax\n\t"
 121             "out %%al,$0xb2\n\t"
 122             "out %%al,$0x84\n\t"
 123             "xchgl %%eax,(%%esp)\n\t"
 124             "movl %%ebx,4(%%eax)\n\t"
 125             "movl %%ecx,8(%%eax)\n\t"
 126             "movl %%edx,12(%%eax)\n\t"
 127             "movl %%esi,16(%%eax)\n\t"
 128             "movl %%edi,20(%%eax)\n\t"
 129             "popl %%edx\n\t"
 130             "movl %%edx,0(%%eax)\n\t"
 131             "lahf\n\t"
 132             "shrl $8,%%eax\n\t"
 133             "andl $1,%%eax\n":"=a"(rc)
 134             :    "a"(regs)
 135             :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 136
 137         if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
 138                 return -EINVAL;
 139
 140         return 0;
 141 }
 142
 143 /*
 144  * Read the bios version. Return the version as an integer corresponding
 145  * to the ascii value, for example "A17" is returned as 0x00413137.
 146  */
 147 static int i8k_get_bios_version(void)
 148 {
 149         struct smm_regs regs = { .eax = I8K_SMM_BIOS_VERSION, };
 150
 151         return i8k_smm(&regs) ? : regs.eax;
 152 }
 153
 154 /*
 155  * Read the Fn key status.
 156  */
 157 static int i8k_get_fn_status(void)
 158 {
 159         struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
 160         int rc;
 161
 162         if ((rc = i8k_smm(&regs)) < 0)
 163                 return rc;
 164
 165         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 166         case I8K_FN_UP:
 167                 return I8K_VOL_UP;
 168         case I8K_FN_DOWN:
 169                 return I8K_VOL_DOWN;
 170         case I8K_FN_MUTE:
 171                 return I8K_VOL_MUTE;
 172         default:
 173                 return 0;
 174         }
 175 }
 176
 177 /*
 178  * Read the power status.
 179  */
 180 static int i8k_get_power_status(void)
 181 {
 182         struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
 183         int rc;
 184
 185         if ((rc = i8k_smm(&regs)) < 0)
 186                 return rc;
 187
 188         return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
 189 }
 190
 191 /*
 192  * Read the fan status.
 193  */
 194 static int i8k_get_fan_status(int fan)
 195 {
 196         struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
 197
 198         regs.ebx = fan & 0xff;
 199         return i8k_smm(&regs) ? : regs.eax & 0xff;
 200 }
 201
 202 /*
 203  * Read the fan speed in RPM.
 204  */
 205 static int i8k_get_fan_speed(int fan)
 206 {
 207         struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
 208
 209         regs.ebx = fan & 0xff;
 210         return i8k_smm(&regs) ? : (regs.eax & 0xffff) * I8K_FAN_MULT;
 211 }
 212
 213 /*
 214  * Set the fan speed (off, low, high). Returns the new fan status.
 215  */
 216 static int i8k_set_fan(int fan, int speed)
 217 {
 218         struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
 219
 220         speed = (speed < 0) ? 0 : ((speed > I8K_FAN_MAX) ? I8K_FAN_MAX : speed);
 221         regs.ebx = (fan & 0xff) | (speed << 8);
 222
 223         return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
 224 }
 225
 226 /*
 227  * Read the cpu temperature.
 228  */
 229 static int i8k_get_cpu_temp(void)
 230 {
 231         struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP, };
 232         int rc;
 233         int temp;
 234
 235 #ifdef I8K_TEMPERATURE_BUG
 236         static int prev;
 237 #endif
 238
 239         if ((rc = i8k_smm(&regs)) < 0)
 240                 return rc;
 241
 242         temp = regs.eax & 0xff;
 243
 244 #ifdef I8K_TEMPERATURE_BUG
 245         /*
 246          * Sometimes the temperature sensor returns 0x99, which is out of range.
 247          * In this case we return (once) the previous cached value. For example:
 248          # 1003655137 00000058 00005a4b
 249          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 250          # 1003655139 00000054 00005c52
 251          */
 252         if (temp > I8K_MAX_TEMP) {
 253                 temp = prev;
 254                 prev = I8K_MAX_TEMP;
 255         } else {
 256                 prev = temp;
 257         }
 258 #endif
 259
 260         return temp;
 261 }
 262
 263 static int i8k_get_dell_signature(void)
 264 {
 265         struct smm_regs regs = { .eax = I8K_SMM_GET_DELL_SIG, };
 266         int rc;
 267
 268         if ((rc = i8k_smm(&regs)) < 0)
 269                 return rc;
 270
 271         return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
 272 }
 273
 274 static int i8k_ioctl(struct inode *ip, struct file *fp, unsigned int cmd,
 275                      unsigned long arg)
 276 {
 277         int val = 0;
 278         int speed;
 279         unsigned char buff[16];
 280         int __user *argp = (int __user *)arg;
 281
 282         if (!argp)
 283                 return -EINVAL;
 284
 285         switch (cmd) {
 286         case I8K_BIOS_VERSION:
 287                 val = i8k_get_bios_version();
 288                 break;
 289
 290         case I8K_MACHINE_ID:
 291                 memset(buff, 0, 16);
 292                 strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL), sizeof(buff));
 293                 break;
 294
 295         case I8K_FN_STATUS:
 296                 val = i8k_get_fn_status();
 297                 break;
 298
 299         case I8K_POWER_STATUS:
 300                 val = i8k_get_power_status();
 301                 break;
 302
 303         case I8K_GET_TEMP:
 304                 val = i8k_get_cpu_temp();
 305                 break;
 306
 307         case I8K_GET_SPEED:
 308                 if (copy_from_user(&val, argp, sizeof(int)))
 309                         return -EFAULT;
 310
 311                 val = i8k_get_fan_speed(val);
 312                 break;
 313
 314         case I8K_GET_FAN:
 315                 if (copy_from_user(&val, argp, sizeof(int)))
 316                         return -EFAULT;
 317
 318                 val = i8k_get_fan_status(val);
 319                 break;
 320
 321         case I8K_SET_FAN:
 322                 if (restricted && !capable(CAP_SYS_ADMIN))
 323                         return -EPERM;
 324
 325                 if (copy_from_user(&val, argp, sizeof(int)))
 326                         return -EFAULT;
 327
 328                 if (copy_from_user(&speed, argp + 1, sizeof(int)))
 329                         return -EFAULT;
 330
 331                 val = i8k_set_fan(val, speed);
 332                 break;
 333
 334         default:
 335                 return -EINVAL;
 336         }
 337
 338         if (val < 0)
 339                 return val;
 340
 341         switch (cmd) {
 342         case I8K_BIOS_VERSION:
 343                 if (copy_to_user(argp, &val, 4))
 344                         return -EFAULT;
 345
 346                 break;
 347         case I8K_MACHINE_ID:
 348                 if (copy_to_user(argp, buff, 16))
 349                         return -EFAULT;
 350
 351                 break;
 352         default:
 353                 if (copy_to_user(argp, &val, sizeof(int)))
 354                         return -EFAULT;
 355
 356                 break;
 357         }
 358
 359         return 0;
 360 }
 361
 362 /*
 363  * Print the information for /proc/i8k.
 364  */
 365 static int i8k_proc_show(struct seq_file *seq, void *offset)
 366 {
 367         int fn_key, cpu_temp, ac_power;
 368         int left_fan, right_fan, left_speed, right_speed;
 369
 370         cpu_temp        = i8k_get_cpu_temp();                   /* 11100 µs */
 371         left_fan        = i8k_get_fan_status(I8K_FAN_LEFT);     /*   580 µs */
 372         right_fan       = i8k_get_fan_status(I8K_FAN_RIGHT);    /*   580 µs */
 373         left_speed      = i8k_get_fan_speed(I8K_FAN_LEFT);      /*   580 µs */
 374         right_speed     = i8k_get_fan_speed(I8K_FAN_RIGHT);     /*   580 µs */
 375         fn_key          = i8k_get_fn_status();                  /*   750 µs */
 376         if (power_status)
 377                 ac_power = i8k_get_power_status();              /* 14700 µs */
 378         else
 379                 ac_power = -1;
 380
 381         /*
 382          * Info:
 383          *
 384          * 1)  Format version (this will change if format changes)
 385          * 2)  BIOS version
 386          * 3)  BIOS machine ID
 387          * 4)  Cpu temperature
 388          * 5)  Left fan status
 389          * 6)  Right fan status
 390          * 7)  Left fan speed
 391          * 8)  Right fan speed
 392          * 9)  AC power
 393          * 10) Fn Key status
 394          */
 395         return seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
 396                           I8K_PROC_FMT,
 397                           bios_version,
 398                           dmi_get_system_info(DMI_PRODUCT_SERIAL) ? : "N/A",
 399                           cpu_temp,
 400                           left_fan, right_fan, left_speed, right_speed,
 401                           ac_power, fn_key);
 402 }
 403
 404 static int i8k_open_fs(struct inode *inode, struct file *file)
 405 {
 406         return single_open(file, i8k_proc_show, NULL);
 407 }
 408
 409 static struct dmi_system_id __initdata i8k_dmi_table[] = {
 410         {
 411                 .ident = "Dell Inspiron",
 412                 .matches = {
 413                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 414                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 415                 },
 416         },
 417         {
 418                 .ident = "Dell Latitude",
 419                 .matches = {
 420                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 421                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 422                 },
 423         },
 424         { }
 425 };
 426
 427 /*
 428  * Probe for the presence of a supported laptop.
 429  */
 430 static int __init i8k_probe(void)
 431 {
 432         char buff[4];
 433         int version;
 434
 435         /*
 436          * Get DMI information
 437          */
 438         if (!dmi_check_system(i8k_dmi_table)) {
 439                 if (!ignore_dmi && !force)
 440                         return -ENODEV;
 441
 442                 printk(KERN_INFO "i8k: not running on a supported Dell system.\n");
 443                 printk(KERN_INFO "i8k: vendor=%s, model=%s, version=%s\n",
 444                         i8k_get_dmi_data(DMI_SYS_VENDOR),
 445                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
 446                         i8k_get_dmi_data(DMI_BIOS_VERSION));
 447         }
 448
 449         strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION), sizeof(bios_version));
 450
 451         /*
 452          * Get SMM Dell signature
 453          */
 454         if (i8k_get_dell_signature() != 0) {
 455                 printk(KERN_ERR "i8k: unable to get SMM Dell signature\n");
 456                 if (!force)
 457                         return -ENODEV;
 458         }
 459
 460         /*
 461          * Get SMM BIOS version.
 462          */
 463         version = i8k_get_bios_version();
 464         if (version <= 0) {
 465                 printk(KERN_WARNING "i8k: unable to get SMM BIOS version\n");
 466         } else {
 467                 buff[0] = (version >> 16) & 0xff;
 468                 buff[1] = (version >> 8) & 0xff;
 469                 buff[2] = (version) & 0xff;
 470                 buff[3] = '\0';
 471                 /*
 472                  * If DMI BIOS version is unknown use SMM BIOS version.
 473                  */
 474                 if (!dmi_get_system_info(DMI_BIOS_VERSION))
 475                         strlcpy(bios_version, buff, sizeof(bios_version));
 476
 477                 /*
 478                  * Check if the two versions match.
 479                  */
 480                 if (strncmp(buff, bios_version, sizeof(bios_version)) != 0)
 481                         printk(KERN_WARNING "i8k: BIOS version mismatch: %s != %s\n",
 482                                 buff, bios_version);
 483         }
 484
 485         return 0;
 486 }
 487
 488 static int __init i8k_init(void)
 489 {
 490         struct proc_dir_entry *proc_i8k;
 491
 492         /* Are we running on an supported laptop? */
 493         if (i8k_probe())
 494                 return -ENODEV;
 495
 496         /* Register the proc entry */
 497         proc_i8k = create_proc_entry("i8k", 0, NULL);
 498         if (!proc_i8k)
 499                 return -ENOENT;
 500
 501         proc_i8k->proc_fops = &i8k_fops;
 502         proc_i8k->owner = THIS_MODULE;
 503
 504         printk(KERN_INFO
 505                "Dell laptop SMM driver v%s Massimo Dal Zotto (dz@debian.org)\n",
 506                I8K_VERSION);
 507
 508         return 0;
 509 }
 510
 511 static void __exit i8k_exit(void)
 512 {
 513         remove_proc_entry("i8k", NULL);
 514 }
 515
 516 module_init(i8k_init);
 517 module_exit(i8k_exit);