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