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