drivers/w1/w1.c

   1 /*
   2  *      w1.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <asm/atomic.h>
  23 #include <asm/delay.h>
  24
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/list.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/timer.h>
  32 #include <linux/device.h>
  33 #include <linux/slab.h>
  34 #include <linux/sched.h>
  35 #include <linux/suspend.h>
  36
  37 #include "w1.h"
  38 #include "w1_io.h"
  39 #include "w1_log.h"
  40 #include "w1_int.h"
  41 #include "w1_family.h"
  42 #include "w1_netlink.h"
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  46 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  47
  48 static int w1_timeout = 5 * HZ;
  49 int w1_max_slave_count = 10;
  50
  51 module_param_named(timeout, w1_timeout, int, 0);
  52 module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  53
  54 spinlock_t w1_mlock = SPIN_LOCK_UNLOCKED;
  55 LIST_HEAD(w1_masters);
  56
  57 static pid_t control_thread;
  58 static int control_needs_exit;
  59 static DECLARE_COMPLETION(w1_control_complete);
  60 static DECLARE_WAIT_QUEUE_HEAD(w1_control_wait);
  61
  62 static int w1_master_match(struct device *dev, struct device_driver *drv)
  63 {
  64         return 1;
  65 }
  66
  67 static int w1_master_probe(struct device *dev)
  68 {
  69         return -ENODEV;
  70 }
  71
  72 static int w1_master_remove(struct device *dev)
  73 {
  74         return 0;
  75 }
  76
  77 static void w1_master_release(struct device *dev)
  78 {
  79         struct w1_master *md = container_of(dev, struct w1_master, dev);
  80
  81         complete(&md->dev_released);
  82 }
  83
  84 static void w1_slave_release(struct device *dev)
  85 {
  86         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  87
  88         complete(&sl->dev_released);
  89 }
  90
  91 static ssize_t w1_default_read_name(struct device *dev, char *buf)
  92 {
  93         return sprintf(buf, "No family registered.\n");
  94 }
  95
  96 static ssize_t w1_default_read_bin(struct kobject *kobj, char *buf, loff_t off,
  97                      size_t count)
  98 {
  99         return sprintf(buf, "No family registered.\n");
 100 }
 101
 102 struct bus_type w1_bus_type = {
 103         .name = "w1",
 104         .match = w1_master_match,
 105 };
 106
 107 struct device_driver w1_driver = {
 108         .name = "w1_driver",
 109         .bus = &w1_bus_type,
 110         .probe = w1_master_probe,
 111         .remove = w1_master_remove,
 112 };
 113
 114 struct device w1_device = {
 115         .parent = NULL,
 116         .bus = &w1_bus_type,
 117         .bus_id = "w1 bus master",
 118         .driver = &w1_driver,
 119         .release = &w1_master_release
 120 };
 121
 122 static struct device_attribute w1_slave_attribute = {
 123         .attr = {
 124                         .name = "name",
 125                         .mode = S_IRUGO,
 126                         .owner = THIS_MODULE
 127         },
 128         .show = &w1_default_read_name,
 129 };
 130
 131 static struct device_attribute w1_slave_attribute_val = {
 132         .attr = {
 133                         .name = "value",
 134                         .mode = S_IRUGO,
 135                         .owner = THIS_MODULE
 136         },
 137         .show = &w1_default_read_name,
 138 };
 139
 140 static ssize_t w1_master_attribute_show(struct device *dev, char *buf)
 141 {
 142         return sprintf(buf, "please fix me\n");
 143 #if 0
 144         struct w1_master *md = container_of(dev, struct w1_master, dev);
 145         int c = PAGE_SIZE;
 146
 147         if (down_interruptible(&md->mutex))
 148                 return -EBUSY;
 149
 150         c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", md->name);
 151         c -= snprintf(buf + PAGE_SIZE - c, c,
 152                        "bus_master=0x%p, timeout=%d, max_slave_count=%d, attempts=%lu\n",
 153                        md->bus_master, w1_timeout, md->max_slave_count,
 154                        md->attempts);
 155         c -= snprintf(buf + PAGE_SIZE - c, c, "%d slaves: ",
 156                        md->slave_count);
 157         if (md->slave_count == 0)
 158                 c -= snprintf(buf + PAGE_SIZE - c, c, "no.\n");
 159         else {
 160                 struct list_head *ent, *n;
 161                 struct w1_slave *sl;
 162
 163                 list_for_each_safe(ent, n, &md->slist) {
 164                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 165
 166                         c -= snprintf(buf + PAGE_SIZE - c, c, "%s[%p] ",
 167                                        sl->name, sl);
 168                 }
 169                 c -= snprintf(buf + PAGE_SIZE - c, c, "\n");
 170         }
 171
 172         up(&md->mutex);
 173
 174         return PAGE_SIZE - c;
 175 #endif
 176 }
 177
 178 struct device_attribute w1_master_attribute = {
 179         .attr = {
 180                         .name = "w1_master_stats",
 181                         .mode = S_IRUGO,
 182                         .owner = THIS_MODULE,
 183         },
 184         .show = &w1_master_attribute_show,
 185 };
 186
 187 static struct bin_attribute w1_slave_bin_attribute = {
 188         .attr = {
 189                         .name = "w1_slave",
 190                         .mode = S_IRUGO,
 191                         .owner = THIS_MODULE,
 192         },
 193         .size = W1_SLAVE_DATA_SIZE,
 194         .read = &w1_default_read_bin,
 195 };
 196
 197 static int __w1_attach_slave_device(struct w1_slave *sl)
 198 {
 199         int err;
 200
 201         sl->dev.parent = &sl->master->dev;
 202         sl->dev.driver = sl->master->driver;
 203         sl->dev.bus = &w1_bus_type;
 204         sl->dev.release = &w1_slave_release;
 205
 206         snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
 207                   "%x-%llx",
 208                   (unsigned int) sl->reg_num.family,
 209                   (unsigned long long) sl->reg_num.id);
 210         snprintf (&sl->name[0], sizeof(sl->name),
 211                   "%x-%llx",
 212                   (unsigned int) sl->reg_num.family,
 213                   (unsigned long long) sl->reg_num.id);
 214
 215         dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
 216                 &sl->dev.bus_id[0]);
 217
 218         err = device_register(&sl->dev);
 219         if (err < 0) {
 220                 dev_err(&sl->dev,
 221                          "Device registration [%s] failed. err=%d\n",
 222                          sl->dev.bus_id, err);
 223                 return err;
 224         }
 225
 226         w1_slave_bin_attribute.read = sl->family->fops->rbin;
 227         w1_slave_attribute.show = sl->family->fops->rname;
 228         w1_slave_attribute_val.show = sl->family->fops->rval;
 229         w1_slave_attribute_val.attr.name = sl->family->fops->rvalname;
 230
 231         err = device_create_file(&sl->dev, &w1_slave_attribute);
 232         if (err < 0) {
 233                 dev_err(&sl->dev,
 234                          "sysfs file creation for [%s] failed. err=%d\n",
 235                          sl->dev.bus_id, err);
 236                 device_unregister(&sl->dev);
 237                 return err;
 238         }
 239
 240         err = device_create_file(&sl->dev, &w1_slave_attribute_val);
 241         if (err < 0) {
 242                 dev_err(&sl->dev,
 243                          "sysfs file creation for [%s] failed. err=%d\n",
 244                          sl->dev.bus_id, err);
 245                 device_remove_file(&sl->dev, &w1_slave_attribute);
 246                 device_unregister(&sl->dev);
 247                 return err;
 248         }
 249
 250         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_slave_bin_attribute);
 251         if (err < 0) {
 252                 dev_err(&sl->dev,
 253                          "sysfs file creation for [%s] failed. err=%d\n",
 254                          sl->dev.bus_id, err);
 255                 device_remove_file(&sl->dev, &w1_slave_attribute);
 256                 device_remove_file(&sl->dev, &w1_slave_attribute_val);
 257                 device_unregister(&sl->dev);
 258                 return err;
 259         }
 260
 261         list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 262
 263         return 0;
 264 }
 265
 266 static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 267 {
 268         struct w1_slave *sl;
 269         struct w1_family *f;
 270         int err;
 271
 272         sl = kmalloc(sizeof(struct w1_slave), GFP_KERNEL);
 273         if (!sl) {
 274                 dev_err(&dev->dev,
 275                          "%s: failed to allocate new slave device.\n",
 276                          __func__);
 277                 return -ENOMEM;
 278         }
 279
 280         memset(sl, 0, sizeof(*sl));
 281
 282         sl->owner = THIS_MODULE;
 283         sl->master = dev;
 284
 285         memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 286         atomic_set(&sl->refcnt, 0);
 287         init_completion(&sl->dev_released);
 288
 289         spin_lock(&w1_flock);
 290         f = w1_family_registered(rn->family);
 291         if (!f) {
 292                 spin_unlock(&w1_flock);
 293                 dev_info(&dev->dev, "Family %x is not registered.\n",
 294                           rn->family);
 295                 kfree(sl);
 296                 return -ENODEV;
 297         }
 298         __w1_family_get(f);
 299         spin_unlock(&w1_flock);
 300
 301         sl->family = f;
 302
 303
 304         err = __w1_attach_slave_device(sl);
 305         if (err < 0) {
 306                 dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 307                          sl->name);
 308                 w1_family_put(sl->family);
 309                 kfree(sl);
 310                 return err;
 311         }
 312
 313         dev->slave_count++;
 314
 315         return 0;
 316 }
 317
 318 static void w1_slave_detach(struct w1_slave *sl)
 319 {
 320         dev_info(&sl->dev, "%s: detaching %s.\n", __func__, sl->name);
 321
 322         while (atomic_read(&sl->refcnt))
 323                 schedule_timeout(10);
 324
 325         sysfs_remove_bin_file(&sl->dev.kobj, &w1_slave_bin_attribute);
 326         device_remove_file(&sl->dev, &w1_slave_attribute);
 327         device_unregister(&sl->dev);
 328         w1_family_put(sl->family);
 329 }
 330
 331 static void w1_search(struct w1_master *dev)
 332 {
 333         u64 last, rn, tmp;
 334         int i, count = 0, slave_count;
 335         int last_family_desc, last_zero, last_device;
 336         int search_bit, id_bit, comp_bit, desc_bit;
 337         struct list_head *ent;
 338         struct w1_slave *sl;
 339         int family_found = 0;
 340         struct w1_netlink_msg msg;
 341
 342         dev->attempts++;
 343
 344         memset(&msg, 0, sizeof(msg));
 345
 346         search_bit = id_bit = comp_bit = 0;
 347         rn = tmp = last = 0;
 348         last_device = last_zero = last_family_desc = 0;
 349
 350         desc_bit = 64;
 351
 352         while (!(id_bit && comp_bit) && !last_device
 353                 && count++ < dev->max_slave_count) {
 354                 last = rn;
 355                 rn = 0;
 356
 357                 last_family_desc = 0;
 358
 359                 /*
 360                  * Reset bus and all 1-wire device state machines
 361                  * so they can respond to our requests.
 362                  *
 363                  * Return 0 - device(s) present, 1 - no devices present.
 364                  */
 365                 if (w1_reset_bus(dev)) {
 366                         dev_info(&dev->dev, "No devices present on the wire.\n");
 367                         break;
 368                 }
 369
 370 #if 1
 371                 memset(&msg, 0, sizeof(msg));
 372
 373                 w1_write_8(dev, W1_SEARCH);
 374                 for (i = 0; i < 64; ++i) {
 375                         /*
 376                          * Read 2 bits from bus.
 377                          * All who don't sleep must send ID bit and COMPLEMENT ID bit.
 378                          * They actually are ANDed between all senders.
 379                          */
 380                         id_bit = w1_read_bit(dev);
 381                         comp_bit = w1_read_bit(dev);
 382
 383                         if (id_bit && comp_bit)
 384                                 break;
 385
 386                         if (id_bit == 0 && comp_bit == 0) {
 387                                 if (i == desc_bit)
 388                                         search_bit = 1;
 389                                 else if (i > desc_bit)
 390                                         search_bit = 0;
 391                                 else
 392                                         search_bit = ((last >> i) & 0x1);
 393
 394                                 if (search_bit == 0) {
 395                                         last_zero = i;
 396                                         if (last_zero < 9)
 397                                                 last_family_desc = last_zero;
 398                                 }
 399
 400                         }
 401                         else
 402                                 search_bit = id_bit;
 403
 404                         tmp = search_bit;
 405                         rn |= (tmp << i);
 406
 407                         /*
 408                          * Write 1 bit to bus
 409                          * and make all who don't have "search_bit" in "i"'th position
 410                          * in it's registration number sleep.
 411                          */
 412                         w1_write_bit(dev, search_bit);
 413
 414                 }
 415 #endif
 416                 msg.id.w1_id = rn;
 417                 msg.val = w1_calc_crc8((u8 *) & rn, 7);
 418                 w1_netlink_send(dev, &msg);
 419
 420                 if (desc_bit == last_zero)
 421                         last_device = 1;
 422
 423                 desc_bit = last_zero;
 424
 425                 slave_count = 0;
 426                 list_for_each(ent, &dev->slist) {
 427                         struct w1_reg_num *tmp;
 428
 429                         tmp = (struct w1_reg_num *) &rn;
 430
 431                         sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 432
 433                         if (sl->reg_num.family == tmp->family &&
 434                             sl->reg_num.id == tmp->id &&
 435                             sl->reg_num.crc == tmp->crc)
 436                                 break;
 437                         else if (sl->reg_num.family == tmp->family) {
 438                                 family_found = 1;
 439                                 break;
 440                         }
 441
 442                         slave_count++;
 443                 }
 444
 445                 if (slave_count == dev->slave_count &&
 446                     msg.val && (*((__u8 *) & msg.val) == msg.id.id.crc)) {
 447                         w1_attach_slave_device(dev, (struct w1_reg_num *) &rn);
 448                 }
 449         }
 450 }
 451
 452 int w1_control(void *data)
 453 {
 454         struct w1_slave *sl;
 455         struct w1_master *dev;
 456         struct list_head *ent, *ment, *n, *mn;
 457         int err, have_to_wait = 0, timeout;
 458
 459         daemonize("w1_control");
 460         allow_signal(SIGTERM);
 461
 462         while (!control_needs_exit || have_to_wait) {
 463                 have_to_wait = 0;
 464
 465                 timeout = w1_timeout;
 466                 do {
 467                         timeout = interruptible_sleep_on_timeout(&w1_control_wait, timeout);
 468                         if (current->flags & PF_FREEZE)
 469                                 refrigerator(PF_FREEZE);
 470                 } while (!signal_pending(current) && (timeout > 0));
 471
 472                 if (signal_pending(current))
 473                         flush_signals(current);
 474
 475                 list_for_each_safe(ment, mn, &w1_masters) {
 476                         dev = list_entry(ment, struct w1_master, w1_master_entry);
 477
 478                         if (!control_needs_exit && !dev->need_exit)
 479                                 continue;
 480                         /*
 481                          * Little race: we can create thread but not set the flag.
 482                          * Get a chance for external process to set flag up.
 483                          */
 484                         if (!dev->initialized) {
 485                                 have_to_wait = 1;
 486                                 continue;
 487                         }
 488
 489                         spin_lock(&w1_mlock);
 490                         list_del(&dev->w1_master_entry);
 491                         spin_unlock(&w1_mlock);
 492
 493                         if (control_needs_exit) {
 494                                 dev->need_exit = 1;
 495
 496                                 err = kill_proc(dev->kpid, SIGTERM, 1);
 497                                 if (err)
 498                                         dev_err(&dev->dev,
 499                                                  "Failed to send signal to w1 kernel thread %d.\n",
 500                                                  dev->kpid);
 501                         }
 502
 503                         wait_for_completion(&dev->dev_exited);
 504
 505                         list_for_each_safe(ent, n, &dev->slist) {
 506                                 sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 507
 508                                 if (!sl)
 509                                         dev_warn(&dev->dev,
 510                                                   "%s: slave entry is NULL.\n",
 511                                                   __func__);
 512                                 else {
 513                                         list_del(&sl->w1_slave_entry);
 514
 515                                         w1_slave_detach(sl);
 516                                         kfree(sl);
 517                                 }
 518                         }
 519                         device_remove_file(&dev->dev, &w1_master_attribute);
 520                         atomic_dec(&dev->refcnt);
 521                 }
 522         }
 523
 524         complete_and_exit(&w1_control_complete, 0);
 525 }
 526
 527 int w1_process(void *data)
 528 {
 529         struct w1_master *dev = (struct w1_master *) data;
 530         unsigned long timeout;
 531
 532         daemonize("%s", dev->name);
 533         allow_signal(SIGTERM);
 534
 535         while (!dev->need_exit) {
 536                 timeout = w1_timeout;
 537                 do {
 538                         timeout = interruptible_sleep_on_timeout(&dev->kwait, timeout);
 539                         if (current->flags & PF_FREEZE)
 540                                 refrigerator(PF_FREEZE);
 541                 } while (!signal_pending(current) && (timeout > 0));
 542
 543                 if (signal_pending(current))
 544                         flush_signals(current);
 545
 546                 if (dev->need_exit)
 547                         break;
 548
 549                 if (!dev->initialized)
 550                         continue;
 551
 552                 if (down_interruptible(&dev->mutex))
 553                         continue;
 554                 w1_search(dev);
 555                 up(&dev->mutex);
 556         }
 557
 558         atomic_dec(&dev->refcnt);
 559         complete_and_exit(&dev->dev_exited, 0);
 560
 561         return 0;
 562 }
 563
 564 int w1_init(void)
 565 {
 566         int retval;
 567
 568         printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
 569
 570         retval = bus_register(&w1_bus_type);
 571         if (retval) {
 572                 printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
 573                 goto err_out_exit_init;
 574         }
 575
 576         retval = driver_register(&w1_driver);
 577         if (retval) {
 578                 printk(KERN_ERR
 579                         "Failed to register master driver. err=%d.\n",
 580                         retval);
 581                 goto err_out_bus_unregister;
 582         }
 583
 584         control_thread = kernel_thread(&w1_control, NULL, 0);
 585         if (control_thread < 0) {
 586                 printk(KERN_ERR "Failed to create control thread. err=%d\n",
 587                         control_thread);
 588                 retval = control_thread;
 589                 goto err_out_driver_unregister;
 590         }
 591
 592         return 0;
 593
 594 err_out_driver_unregister:
 595         driver_unregister(&w1_driver);
 596
 597 err_out_bus_unregister:
 598         bus_unregister(&w1_bus_type);
 599
 600 err_out_exit_init:
 601         return retval;
 602 }
 603
 604 void w1_fini(void)
 605 {
 606         struct w1_master *dev;
 607         struct list_head *ent, *n;
 608
 609         list_for_each_safe(ent, n, &w1_masters) {
 610                 dev = list_entry(ent, struct w1_master, w1_master_entry);
 611                 __w1_remove_master_device(dev);
 612         }
 613
 614         control_needs_exit = 1;
 615
 616         wait_for_completion(&w1_control_complete);
 617
 618         driver_unregister(&w1_driver);
 619         bus_unregister(&w1_bus_type);
 620 }
 621
 622 module_init(w1_init);
 623 module_exit(w1_fini);