linux/drivers/w1/w1.c
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   1/*
   2 *      w1.c
   3 *
   4 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
   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 <linux/delay.h>
  23#include <linux/kernel.h>
  24#include <linux/module.h>
  25#include <linux/moduleparam.h>
  26#include <linux/list.h>
  27#include <linux/interrupt.h>
  28#include <linux/spinlock.h>
  29#include <linux/timer.h>
  30#include <linux/device.h>
  31#include <linux/slab.h>
  32#include <linux/sched.h>
  33#include <linux/kthread.h>
  34#include <linux/freezer.h>
  35
  36#include <linux/atomic.h>
  37
  38#include "w1.h"
  39#include "w1_log.h"
  40#include "w1_int.h"
  41#include "w1_family.h"
  42#include "w1_netlink.h"
  43
  44MODULE_LICENSE("GPL");
  45MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
  46MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol.");
  47
  48static int w1_timeout = 10;
  49int w1_max_slave_count = 10;
  50int w1_max_slave_ttl = 10;
  51
  52module_param_named(timeout, w1_timeout, int, 0);
  53module_param_named(max_slave_count, w1_max_slave_count, int, 0);
  54module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
  55
  56DEFINE_MUTEX(w1_mlock);
  57LIST_HEAD(w1_masters);
  58
  59static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
  60
  61static int w1_master_match(struct device *dev, struct device_driver *drv)
  62{
  63        return 1;
  64}
  65
  66static int w1_master_probe(struct device *dev)
  67{
  68        return -ENODEV;
  69}
  70
  71static void w1_master_release(struct device *dev)
  72{
  73        struct w1_master *md = dev_to_w1_master(dev);
  74
  75        dev_dbg(dev, "%s: Releasing %s.\n", __func__, md->name);
  76        memset(md, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  77        kfree(md);
  78}
  79
  80static void w1_slave_release(struct device *dev)
  81{
  82        struct w1_slave *sl = dev_to_w1_slave(dev);
  83
  84        dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
  85
  86        while (atomic_read(&sl->refcnt)) {
  87                dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
  88                                sl->name, atomic_read(&sl->refcnt));
  89                if (msleep_interruptible(1000))
  90                        flush_signals(current);
  91        }
  92
  93        w1_family_put(sl->family);
  94        sl->master->slave_count--;
  95
  96        complete(&sl->released);
  97}
  98
  99static ssize_t w1_slave_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 100{
 101        struct w1_slave *sl = dev_to_w1_slave(dev);
 102
 103        return sprintf(buf, "%s\n", sl->name);
 104}
 105
 106static ssize_t w1_slave_read_id(struct device *dev,
 107        struct device_attribute *attr, char *buf)
 108{
 109        struct w1_slave *sl = dev_to_w1_slave(dev);
 110        ssize_t count = sizeof(sl->reg_num);
 111
 112        memcpy(buf, (u8 *)&sl->reg_num, count);
 113        return count;
 114}
 115
 116static struct device_attribute w1_slave_attr_name =
 117        __ATTR(name, S_IRUGO, w1_slave_read_name, NULL);
 118static struct device_attribute w1_slave_attr_id =
 119        __ATTR(id, S_IRUGO, w1_slave_read_id, NULL);
 120
 121/* Default family */
 122
 123static ssize_t w1_default_write(struct file *filp, struct kobject *kobj,
 124                                struct bin_attribute *bin_attr,
 125                                char *buf, loff_t off, size_t count)
 126{
 127        struct w1_slave *sl = kobj_to_w1_slave(kobj);
 128
 129        mutex_lock(&sl->master->mutex);
 130        if (w1_reset_select_slave(sl)) {
 131                count = 0;
 132                goto out_up;
 133        }
 134
 135        w1_write_block(sl->master, buf, count);
 136
 137out_up:
 138        mutex_unlock(&sl->master->mutex);
 139        return count;
 140}
 141
 142static ssize_t w1_default_read(struct file *filp, struct kobject *kobj,
 143                               struct bin_attribute *bin_attr,
 144                               char *buf, loff_t off, size_t count)
 145{
 146        struct w1_slave *sl = kobj_to_w1_slave(kobj);
 147
 148        mutex_lock(&sl->master->mutex);
 149        w1_read_block(sl->master, buf, count);
 150        mutex_unlock(&sl->master->mutex);
 151        return count;
 152}
 153
 154static struct bin_attribute w1_default_attr = {
 155      .attr = {
 156              .name = "rw",
 157              .mode = S_IRUGO | S_IWUSR,
 158      },
 159      .size = PAGE_SIZE,
 160      .read = w1_default_read,
 161      .write = w1_default_write,
 162};
 163
 164static int w1_default_add_slave(struct w1_slave *sl)
 165{
 166        return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
 167}
 168
 169static void w1_default_remove_slave(struct w1_slave *sl)
 170{
 171        sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
 172}
 173
 174static struct w1_family_ops w1_default_fops = {
 175        .add_slave      = w1_default_add_slave,
 176        .remove_slave   = w1_default_remove_slave,
 177};
 178
 179static struct w1_family w1_default_family = {
 180        .fops = &w1_default_fops,
 181};
 182
 183static int w1_uevent(struct device *dev, struct kobj_uevent_env *env);
 184
 185static struct bus_type w1_bus_type = {
 186        .name = "w1",
 187        .match = w1_master_match,
 188        .uevent = w1_uevent,
 189};
 190
 191struct device_driver w1_master_driver = {
 192        .name = "w1_master_driver",
 193        .bus = &w1_bus_type,
 194        .probe = w1_master_probe,
 195};
 196
 197struct device w1_master_device = {
 198        .parent = NULL,
 199        .bus = &w1_bus_type,
 200        .init_name = "w1 bus master",
 201        .driver = &w1_master_driver,
 202        .release = &w1_master_release
 203};
 204
 205static struct device_driver w1_slave_driver = {
 206        .name = "w1_slave_driver",
 207        .bus = &w1_bus_type,
 208};
 209
 210#if 0
 211struct device w1_slave_device = {
 212        .parent = NULL,
 213        .bus = &w1_bus_type,
 214        .init_name = "w1 bus slave",
 215        .driver = &w1_slave_driver,
 216        .release = &w1_slave_release
 217};
 218#endif  /*  0  */
 219
 220static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
 221{
 222        struct w1_master *md = dev_to_w1_master(dev);
 223        ssize_t count;
 224
 225        mutex_lock(&md->mutex);
 226        count = sprintf(buf, "%s\n", md->name);
 227        mutex_unlock(&md->mutex);
 228
 229        return count;
 230}
 231
 232static ssize_t w1_master_attribute_store_search(struct device * dev,
 233                                                struct device_attribute *attr,
 234                                                const char * buf, size_t count)
 235{
 236        long tmp;
 237        struct w1_master *md = dev_to_w1_master(dev);
 238
 239        if (strict_strtol(buf, 0, &tmp) == -EINVAL)
 240                return -EINVAL;
 241
 242        mutex_lock(&md->mutex);
 243        md->search_count = tmp;
 244        mutex_unlock(&md->mutex);
 245        wake_up_process(md->thread);
 246
 247        return count;
 248}
 249
 250static ssize_t w1_master_attribute_show_search(struct device *dev,
 251                                               struct device_attribute *attr,
 252                                               char *buf)
 253{
 254        struct w1_master *md = dev_to_w1_master(dev);
 255        ssize_t count;
 256
 257        mutex_lock(&md->mutex);
 258        count = sprintf(buf, "%d\n", md->search_count);
 259        mutex_unlock(&md->mutex);
 260
 261        return count;
 262}
 263
 264static ssize_t w1_master_attribute_store_pullup(struct device *dev,
 265                                                struct device_attribute *attr,
 266                                                const char *buf, size_t count)
 267{
 268        long tmp;
 269        struct w1_master *md = dev_to_w1_master(dev);
 270
 271        if (strict_strtol(buf, 0, &tmp) == -EINVAL)
 272                return -EINVAL;
 273
 274        mutex_lock(&md->mutex);
 275        md->enable_pullup = tmp;
 276        mutex_unlock(&md->mutex);
 277        wake_up_process(md->thread);
 278
 279        return count;
 280}
 281
 282static ssize_t w1_master_attribute_show_pullup(struct device *dev,
 283                                               struct device_attribute *attr,
 284                                               char *buf)
 285{
 286        struct w1_master *md = dev_to_w1_master(dev);
 287        ssize_t count;
 288
 289        mutex_lock(&md->mutex);
 290        count = sprintf(buf, "%d\n", md->enable_pullup);
 291        mutex_unlock(&md->mutex);
 292
 293        return count;
 294}
 295
 296static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 297{
 298        struct w1_master *md = dev_to_w1_master(dev);
 299        ssize_t count;
 300
 301        mutex_lock(&md->mutex);
 302        count = sprintf(buf, "0x%p\n", md->bus_master);
 303        mutex_unlock(&md->mutex);
 304        return count;
 305}
 306
 307static ssize_t w1_master_attribute_show_timeout(struct device *dev, struct device_attribute *attr, char *buf)
 308{
 309        ssize_t count;
 310        count = sprintf(buf, "%d\n", w1_timeout);
 311        return count;
 312}
 313
 314static ssize_t w1_master_attribute_show_max_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 315{
 316        struct w1_master *md = dev_to_w1_master(dev);
 317        ssize_t count;
 318
 319        mutex_lock(&md->mutex);
 320        count = sprintf(buf, "%d\n", md->max_slave_count);
 321        mutex_unlock(&md->mutex);
 322        return count;
 323}
 324
 325static ssize_t w1_master_attribute_show_attempts(struct device *dev, struct device_attribute *attr, char *buf)
 326{
 327        struct w1_master *md = dev_to_w1_master(dev);
 328        ssize_t count;
 329
 330        mutex_lock(&md->mutex);
 331        count = sprintf(buf, "%lu\n", md->attempts);
 332        mutex_unlock(&md->mutex);
 333        return count;
 334}
 335
 336static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
 337{
 338        struct w1_master *md = dev_to_w1_master(dev);
 339        ssize_t count;
 340
 341        mutex_lock(&md->mutex);
 342        count = sprintf(buf, "%d\n", md->slave_count);
 343        mutex_unlock(&md->mutex);
 344        return count;
 345}
 346
 347static ssize_t w1_master_attribute_show_slaves(struct device *dev,
 348        struct device_attribute *attr, char *buf)
 349{
 350        struct w1_master *md = dev_to_w1_master(dev);
 351        int c = PAGE_SIZE;
 352
 353        mutex_lock(&md->mutex);
 354
 355        if (md->slave_count == 0)
 356                c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
 357        else {
 358                struct list_head *ent, *n;
 359                struct w1_slave *sl;
 360
 361                list_for_each_safe(ent, n, &md->slist) {
 362                        sl = list_entry(ent, struct w1_slave, w1_slave_entry);
 363
 364                        c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
 365                }
 366        }
 367
 368        mutex_unlock(&md->mutex);
 369
 370        return PAGE_SIZE - c;
 371}
 372
 373static ssize_t w1_master_attribute_show_add(struct device *dev,
 374        struct device_attribute *attr, char *buf)
 375{
 376        int c = PAGE_SIZE;
 377        c -= snprintf(buf+PAGE_SIZE - c, c,
 378                "write device id xx-xxxxxxxxxxxx to add slave\n");
 379        return PAGE_SIZE - c;
 380}
 381
 382static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
 383        struct w1_reg_num *rn)
 384{
 385        unsigned int family;
 386        unsigned long long id;
 387        int i;
 388        u64 rn64_le;
 389
 390        /* The CRC value isn't read from the user because the sysfs directory
 391         * doesn't include it and most messages from the bus search don't
 392         * print it either.  It would be unreasonable for the user to then
 393         * provide it.
 394         */
 395        const char *error_msg = "bad slave string format, expecting "
 396                "ff-dddddddddddd\n";
 397
 398        if (buf[2] != '-') {
 399                dev_err(dev, "%s", error_msg);
 400                return -EINVAL;
 401        }
 402        i = sscanf(buf, "%02x-%012llx", &family, &id);
 403        if (i != 2) {
 404                dev_err(dev, "%s", error_msg);
 405                return -EINVAL;
 406        }
 407        rn->family = family;
 408        rn->id = id;
 409
 410        rn64_le = cpu_to_le64(*(u64 *)rn);
 411        rn->crc = w1_calc_crc8((u8 *)&rn64_le, 7);
 412
 413#if 0
 414        dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
 415                  rn->family, (unsigned long long)rn->id, rn->crc);
 416#endif
 417
 418        return 0;
 419}
 420
 421/* Searches the slaves in the w1_master and returns a pointer or NULL.
 422 * Note: must hold the mutex
 423 */
 424static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
 425        struct w1_reg_num *rn)
 426{
 427        struct w1_slave *sl;
 428        list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 429                if (sl->reg_num.family == rn->family &&
 430                                sl->reg_num.id == rn->id &&
 431                                sl->reg_num.crc == rn->crc) {
 432                        return sl;
 433                }
 434        }
 435        return NULL;
 436}
 437
 438static ssize_t w1_master_attribute_store_add(struct device *dev,
 439                                                struct device_attribute *attr,
 440                                                const char *buf, size_t count)
 441{
 442        struct w1_master *md = dev_to_w1_master(dev);
 443        struct w1_reg_num rn;
 444        struct w1_slave *sl;
 445        ssize_t result = count;
 446
 447        if (w1_atoreg_num(dev, buf, count, &rn))
 448                return -EINVAL;
 449
 450        mutex_lock(&md->mutex);
 451        sl = w1_slave_search_device(md, &rn);
 452        /* It would be nice to do a targeted search one the one-wire bus
 453         * for the new device to see if it is out there or not.  But the
 454         * current search doesn't support that.
 455         */
 456        if (sl) {
 457                dev_info(dev, "Device %s already exists\n", sl->name);
 458                result = -EINVAL;
 459        } else {
 460                w1_attach_slave_device(md, &rn);
 461        }
 462        mutex_unlock(&md->mutex);
 463
 464        return result;
 465}
 466
 467static ssize_t w1_master_attribute_show_remove(struct device *dev,
 468        struct device_attribute *attr, char *buf)
 469{
 470        int c = PAGE_SIZE;
 471        c -= snprintf(buf+PAGE_SIZE - c, c,
 472                "write device id xx-xxxxxxxxxxxx to remove slave\n");
 473        return PAGE_SIZE - c;
 474}
 475
 476static ssize_t w1_master_attribute_store_remove(struct device *dev,
 477                                                struct device_attribute *attr,
 478                                                const char *buf, size_t count)
 479{
 480        struct w1_master *md = dev_to_w1_master(dev);
 481        struct w1_reg_num rn;
 482        struct w1_slave *sl;
 483        ssize_t result = count;
 484
 485        if (w1_atoreg_num(dev, buf, count, &rn))
 486                return -EINVAL;
 487
 488        mutex_lock(&md->mutex);
 489        sl = w1_slave_search_device(md, &rn);
 490        if (sl) {
 491                w1_slave_detach(sl);
 492        } else {
 493                dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
 494                        (unsigned long long)rn.id);
 495                result = -EINVAL;
 496        }
 497        mutex_unlock(&md->mutex);
 498
 499        return result;
 500}
 501
 502#define W1_MASTER_ATTR_RO(_name, _mode)                         \
 503        struct device_attribute w1_master_attribute_##_name =   \
 504                __ATTR(w1_master_##_name, _mode,                \
 505                       w1_master_attribute_show_##_name, NULL)
 506
 507#define W1_MASTER_ATTR_RW(_name, _mode)                         \
 508        struct device_attribute w1_master_attribute_##_name =   \
 509                __ATTR(w1_master_##_name, _mode,                \
 510                       w1_master_attribute_show_##_name,        \
 511                       w1_master_attribute_store_##_name)
 512
 513static W1_MASTER_ATTR_RO(name, S_IRUGO);
 514static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 515static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
 516static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 517static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 518static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 519static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 520static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUSR | S_IWGRP);
 521static W1_MASTER_ATTR_RW(pullup, S_IRUGO | S_IWUSR | S_IWGRP);
 522static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUSR | S_IWGRP);
 523static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUSR | S_IWGRP);
 524
 525static struct attribute *w1_master_default_attrs[] = {
 526        &w1_master_attribute_name.attr,
 527        &w1_master_attribute_slaves.attr,
 528        &w1_master_attribute_slave_count.attr,
 529        &w1_master_attribute_max_slave_count.attr,
 530        &w1_master_attribute_attempts.attr,
 531        &w1_master_attribute_timeout.attr,
 532        &w1_master_attribute_pointer.attr,
 533        &w1_master_attribute_search.attr,
 534        &w1_master_attribute_pullup.attr,
 535        &w1_master_attribute_add.attr,
 536        &w1_master_attribute_remove.attr,
 537        NULL
 538};
 539
 540static struct attribute_group w1_master_defattr_group = {
 541        .attrs = w1_master_default_attrs,
 542};
 543
 544int w1_create_master_attributes(struct w1_master *master)
 545{
 546        return sysfs_create_group(&master->dev.kobj, &w1_master_defattr_group);
 547}
 548
 549void w1_destroy_master_attributes(struct w1_master *master)
 550{
 551        sysfs_remove_group(&master->dev.kobj, &w1_master_defattr_group);
 552}
 553
 554static int w1_uevent(struct device *dev, struct kobj_uevent_env *env)
 555{
 556        struct w1_master *md = NULL;
 557        struct w1_slave *sl = NULL;
 558        char *event_owner, *name;
 559        int err = 0;
 560
 561        if (dev->driver == &w1_master_driver) {
 562                md = container_of(dev, struct w1_master, dev);
 563                event_owner = "master";
 564                name = md->name;
 565        } else if (dev->driver == &w1_slave_driver) {
 566                sl = container_of(dev, struct w1_slave, dev);
 567                event_owner = "slave";
 568                name = sl->name;
 569        } else {
 570                dev_dbg(dev, "Unknown event.\n");
 571                return -EINVAL;
 572        }
 573
 574        dev_dbg(dev, "Hotplug event for %s %s, bus_id=%s.\n",
 575                        event_owner, name, dev_name(dev));
 576
 577        if (dev->driver != &w1_slave_driver || !sl)
 578                goto end;
 579
 580        err = add_uevent_var(env, "W1_FID=%02X", sl->reg_num.family);
 581        if (err)
 582                goto end;
 583
 584        err = add_uevent_var(env, "W1_SLAVE_ID=%024LX",
 585                             (unsigned long long)sl->reg_num.id);
 586end:
 587        return err;
 588}
 589
 590static int __w1_attach_slave_device(struct w1_slave *sl)
 591{
 592        int err;
 593
 594        sl->dev.parent = &sl->master->dev;
 595        sl->dev.driver = &w1_slave_driver;
 596        sl->dev.bus = &w1_bus_type;
 597        sl->dev.release = &w1_slave_release;
 598
 599        dev_set_name(&sl->dev, "%02x-%012llx",
 600                 (unsigned int) sl->reg_num.family,
 601                 (unsigned long long) sl->reg_num.id);
 602        snprintf(&sl->name[0], sizeof(sl->name),
 603                 "%02x-%012llx",
 604                 (unsigned int) sl->reg_num.family,
 605                 (unsigned long long) sl->reg_num.id);
 606
 607        dev_dbg(&sl->dev, "%s: registering %s as %p.\n", __func__,
 608                dev_name(&sl->dev), sl);
 609
 610        err = device_register(&sl->dev);
 611        if (err < 0) {
 612                dev_err(&sl->dev,
 613                        "Device registration [%s] failed. err=%d\n",
 614                        dev_name(&sl->dev), err);
 615                return err;
 616        }
 617
 618        /* Create "name" entry */
 619        err = device_create_file(&sl->dev, &w1_slave_attr_name);
 620        if (err < 0) {
 621                dev_err(&sl->dev,
 622                        "sysfs file creation for [%s] failed. err=%d\n",
 623                        dev_name(&sl->dev), err);
 624                goto out_unreg;
 625        }
 626
 627        /* Create "id" entry */
 628        err = device_create_file(&sl->dev, &w1_slave_attr_id);
 629        if (err < 0) {
 630                dev_err(&sl->dev,
 631                        "sysfs file creation for [%s] failed. err=%d\n",
 632                        dev_name(&sl->dev), err);
 633                goto out_rem1;
 634        }
 635
 636        /* if the family driver needs to initialize something... */
 637        if (sl->family->fops && sl->family->fops->add_slave &&
 638            ((err = sl->family->fops->add_slave(sl)) < 0)) {
 639                dev_err(&sl->dev,
 640                        "sysfs file creation for [%s] failed. err=%d\n",
 641                        dev_name(&sl->dev), err);
 642                goto out_rem2;
 643        }
 644
 645        list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
 646
 647        return 0;
 648
 649out_rem2:
 650        device_remove_file(&sl->dev, &w1_slave_attr_id);
 651out_rem1:
 652        device_remove_file(&sl->dev, &w1_slave_attr_name);
 653out_unreg:
 654        device_unregister(&sl->dev);
 655        return err;
 656}
 657
 658static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 659{
 660        struct w1_slave *sl;
 661        struct w1_family *f;
 662        int err;
 663        struct w1_netlink_msg msg;
 664
 665        sl = kzalloc(sizeof(struct w1_slave), GFP_KERNEL);
 666        if (!sl) {
 667                dev_err(&dev->dev,
 668                         "%s: failed to allocate new slave device.\n",
 669                         __func__);
 670                return -ENOMEM;
 671        }
 672
 673
 674        sl->owner = THIS_MODULE;
 675        sl->master = dev;
 676        set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 677
 678        memset(&msg, 0, sizeof(msg));
 679        memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 680        atomic_set(&sl->refcnt, 0);
 681        init_completion(&sl->released);
 682
 683        request_module("w1-family-0x%0x", rn->family);
 684
 685        spin_lock(&w1_flock);
 686        f = w1_family_registered(rn->family);
 687        if (!f) {
 688                f= &w1_default_family;
 689                dev_info(&dev->dev, "Family %x for %02x.%012llx.%02x is not registered.\n",
 690                          rn->family, rn->family,
 691                          (unsigned long long)rn->id, rn->crc);
 692        }
 693        __w1_family_get(f);
 694        spin_unlock(&w1_flock);
 695
 696        sl->family = f;
 697
 698
 699        err = __w1_attach_slave_device(sl);
 700        if (err < 0) {
 701                dev_err(&dev->dev, "%s: Attaching %s failed.\n", __func__,
 702                         sl->name);
 703                w1_family_put(sl->family);
 704                kfree(sl);
 705                return err;
 706        }
 707
 708        sl->ttl = dev->slave_ttl;
 709        dev->slave_count++;
 710
 711        memcpy(msg.id.id, rn, sizeof(msg.id));
 712        msg.type = W1_SLAVE_ADD;
 713        w1_netlink_send(dev, &msg);
 714
 715        return 0;
 716}
 717
 718void w1_slave_detach(struct w1_slave *sl)
 719{
 720        struct w1_netlink_msg msg;
 721
 722        dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
 723
 724        list_del(&sl->w1_slave_entry);
 725
 726        if (sl->family->fops && sl->family->fops->remove_slave)
 727                sl->family->fops->remove_slave(sl);
 728
 729        memset(&msg, 0, sizeof(msg));
 730        memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
 731        msg.type = W1_SLAVE_REMOVE;
 732        w1_netlink_send(sl->master, &msg);
 733
 734        device_remove_file(&sl->dev, &w1_slave_attr_id);
 735        device_remove_file(&sl->dev, &w1_slave_attr_name);
 736        device_unregister(&sl->dev);
 737
 738        wait_for_completion(&sl->released);
 739        kfree(sl);
 740}
 741
 742struct w1_master *w1_search_master_id(u32 id)
 743{
 744        struct w1_master *dev;
 745        int found = 0;
 746
 747        mutex_lock(&w1_mlock);
 748        list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 749                if (dev->id == id) {
 750                        found = 1;
 751                        atomic_inc(&dev->refcnt);
 752                        break;
 753                }
 754        }
 755        mutex_unlock(&w1_mlock);
 756
 757        return (found)?dev:NULL;
 758}
 759
 760struct w1_slave *w1_search_slave(struct w1_reg_num *id)
 761{
 762        struct w1_master *dev;
 763        struct w1_slave *sl = NULL;
 764        int found = 0;
 765
 766        mutex_lock(&w1_mlock);
 767        list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 768                mutex_lock(&dev->mutex);
 769                list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
 770                        if (sl->reg_num.family == id->family &&
 771                                        sl->reg_num.id == id->id &&
 772                                        sl->reg_num.crc == id->crc) {
 773                                found = 1;
 774                                atomic_inc(&dev->refcnt);
 775                                atomic_inc(&sl->refcnt);
 776                                break;
 777                        }
 778                }
 779                mutex_unlock(&dev->mutex);
 780
 781                if (found)
 782                        break;
 783        }
 784        mutex_unlock(&w1_mlock);
 785
 786        return (found)?sl:NULL;
 787}
 788
 789void w1_reconnect_slaves(struct w1_family *f, int attach)
 790{
 791        struct w1_slave *sl, *sln;
 792        struct w1_master *dev;
 793
 794        mutex_lock(&w1_mlock);
 795        list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 796                dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 797                        "for family %02x.\n", dev->name, f->fid);
 798                mutex_lock(&dev->mutex);
 799                list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 800                        /* If it is a new family, slaves with the default
 801                         * family driver and are that family will be
 802                         * connected.  If the family is going away, devices
 803                         * matching that family are reconneced.
 804                         */
 805                        if ((attach && sl->family->fid == W1_FAMILY_DEFAULT
 806                                && sl->reg_num.family == f->fid) ||
 807                                (!attach && sl->family->fid == f->fid)) {
 808                                struct w1_reg_num rn;
 809
 810                                memcpy(&rn, &sl->reg_num, sizeof(rn));
 811                                w1_slave_detach(sl);
 812
 813                                w1_attach_slave_device(dev, &rn);
 814                        }
 815                }
 816                dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
 817                        "has been finished.\n", dev->name);
 818                mutex_unlock(&dev->mutex);
 819        }
 820        mutex_unlock(&w1_mlock);
 821}
 822
 823void w1_slave_found(struct w1_master *dev, u64 rn)
 824{
 825        struct w1_slave *sl;
 826        struct w1_reg_num *tmp;
 827        u64 rn_le = cpu_to_le64(rn);
 828
 829        atomic_inc(&dev->refcnt);
 830
 831        tmp = (struct w1_reg_num *) &rn;
 832
 833        sl = w1_slave_search_device(dev, tmp);
 834        if (sl) {
 835                set_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 836        } else {
 837                if (rn && tmp->crc == w1_calc_crc8((u8 *)&rn_le, 7))
 838                        w1_attach_slave_device(dev, tmp);
 839        }
 840
 841        atomic_dec(&dev->refcnt);
 842}
 843
 844/**
 845 * Performs a ROM Search & registers any devices found.
 846 * The 1-wire search is a simple binary tree search.
 847 * For each bit of the address, we read two bits and write one bit.
 848 * The bit written will put to sleep all devies that don't match that bit.
 849 * When the two reads differ, the direction choice is obvious.
 850 * When both bits are 0, we must choose a path to take.
 851 * When we can scan all 64 bits without having to choose a path, we are done.
 852 *
 853 * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
 854 *
 855 * @dev        The master device to search
 856 * @cb         Function to call when a device is found
 857 */
 858void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb)
 859{
 860        u64 last_rn, rn, tmp64;
 861        int i, slave_count = 0;
 862        int last_zero, last_device;
 863        int search_bit, desc_bit;
 864        u8  triplet_ret = 0;
 865
 866        search_bit = 0;
 867        rn = last_rn = 0;
 868        last_device = 0;
 869        last_zero = -1;
 870
 871        desc_bit = 64;
 872
 873        while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
 874                last_rn = rn;
 875                rn = 0;
 876
 877                /*
 878                 * Reset bus and all 1-wire device state machines
 879                 * so they can respond to our requests.
 880                 *
 881                 * Return 0 - device(s) present, 1 - no devices present.
 882                 */
 883                mutex_lock(&dev->bus_mutex);
 884                if (w1_reset_bus(dev)) {
 885                        mutex_unlock(&dev->bus_mutex);
 886                        dev_dbg(&dev->dev, "No devices present on the wire.\n");
 887                        break;
 888                }
 889
 890                /* Do fast search on single slave bus */
 891                if (dev->max_slave_count == 1) {
 892                        int rv;
 893                        w1_write_8(dev, W1_READ_ROM);
 894                        rv = w1_read_block(dev, (u8 *)&rn, 8);
 895                        mutex_unlock(&dev->bus_mutex);
 896
 897                        if (rv == 8 && rn)
 898                                cb(dev, rn);
 899
 900                        break;
 901                }
 902
 903                /* Start the search */
 904                w1_write_8(dev, search_type);
 905                for (i = 0; i < 64; ++i) {
 906                        /* Determine the direction/search bit */
 907                        if (i == desc_bit)
 908                                search_bit = 1;   /* took the 0 path last time, so take the 1 path */
 909                        else if (i > desc_bit)
 910                                search_bit = 0;   /* take the 0 path on the next branch */
 911                        else
 912                                search_bit = ((last_rn >> i) & 0x1);
 913
 914                        /** Read two bits and write one bit */
 915                        triplet_ret = w1_triplet(dev, search_bit);
 916
 917                        /* quit if no device responded */
 918                        if ( (triplet_ret & 0x03) == 0x03 )
 919                                break;
 920
 921                        /* If both directions were valid, and we took the 0 path... */
 922                        if (triplet_ret == 0)
 923                                last_zero = i;
 924
 925                        /* extract the direction taken & update the device number */
 926                        tmp64 = (triplet_ret >> 2);
 927                        rn |= (tmp64 << i);
 928
 929                        /* ensure we're called from kthread and not by netlink callback */
 930                        if (!dev->priv && kthread_should_stop()) {
 931                                mutex_unlock(&dev->bus_mutex);
 932                                dev_dbg(&dev->dev, "Abort w1_search\n");
 933                                return;
 934                        }
 935                }
 936                mutex_unlock(&dev->bus_mutex);
 937
 938                if ( (triplet_ret & 0x03) != 0x03 ) {
 939                        if ( (desc_bit == last_zero) || (last_zero < 0))
 940                                last_device = 1;
 941                        desc_bit = last_zero;
 942                        cb(dev, rn);
 943                }
 944        }
 945}
 946
 947void w1_search_process_cb(struct w1_master *dev, u8 search_type,
 948        w1_slave_found_callback cb)
 949{
 950        struct w1_slave *sl, *sln;
 951
 952        list_for_each_entry(sl, &dev->slist, w1_slave_entry)
 953                clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 954
 955        w1_search_devices(dev, search_type, cb);
 956
 957        list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
 958                if (!test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags) && !--sl->ttl)
 959                        w1_slave_detach(sl);
 960                else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
 961                        sl->ttl = dev->slave_ttl;
 962        }
 963
 964        if (dev->search_count > 0)
 965                dev->search_count--;
 966}
 967
 968static void w1_search_process(struct w1_master *dev, u8 search_type)
 969{
 970        w1_search_process_cb(dev, search_type, w1_slave_found);
 971}
 972
 973int w1_process(void *data)
 974{
 975        struct w1_master *dev = (struct w1_master *) data;
 976        /* As long as w1_timeout is only set by a module parameter the sleep
 977         * time can be calculated in jiffies once.
 978         */
 979        const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
 980
 981        while (!kthread_should_stop()) {
 982                if (dev->search_count) {
 983                        mutex_lock(&dev->mutex);
 984                        w1_search_process(dev, W1_SEARCH);
 985                        mutex_unlock(&dev->mutex);
 986                }
 987
 988                try_to_freeze();
 989                __set_current_state(TASK_INTERRUPTIBLE);
 990
 991                if (kthread_should_stop())
 992                        break;
 993
 994                /* Only sleep when the search is active. */
 995                if (dev->search_count)
 996                        schedule_timeout(jtime);
 997                else
 998                        schedule();
 999        }
1000
1001        atomic_dec(&dev->refcnt);
1002
1003        return 0;
1004}
1005
1006static int __init w1_init(void)
1007{
1008        int retval;
1009
1010        printk(KERN_INFO "Driver for 1-wire Dallas network protocol.\n");
1011
1012        w1_init_netlink();
1013
1014        retval = bus_register(&w1_bus_type);
1015        if (retval) {
1016                printk(KERN_ERR "Failed to register bus. err=%d.\n", retval);
1017                goto err_out_exit_init;
1018        }
1019
1020        retval = driver_register(&w1_master_driver);
1021        if (retval) {
1022                printk(KERN_ERR
1023                        "Failed to register master driver. err=%d.\n",
1024                        retval);
1025                goto err_out_bus_unregister;
1026        }
1027
1028        retval = driver_register(&w1_slave_driver);
1029        if (retval) {
1030                printk(KERN_ERR
1031                        "Failed to register slave driver. err=%d.\n",
1032                        retval);
1033                goto err_out_master_unregister;
1034        }
1035
1036        return 0;
1037
1038#if 0
1039/* For undoing the slave register if there was a step after it. */
1040err_out_slave_unregister:
1041        driver_unregister(&w1_slave_driver);
1042#endif
1043
1044err_out_master_unregister:
1045        driver_unregister(&w1_master_driver);
1046
1047err_out_bus_unregister:
1048        bus_unregister(&w1_bus_type);
1049
1050err_out_exit_init:
1051        return retval;
1052}
1053
1054static void __exit w1_fini(void)
1055{
1056        struct w1_master *dev;
1057
1058        /* Set netlink removal messages and some cleanup */
1059        list_for_each_entry(dev, &w1_masters, w1_master_entry)
1060                __w1_remove_master_device(dev);
1061
1062        w1_fini_netlink();
1063
1064        driver_unregister(&w1_slave_driver);
1065        driver_unregister(&w1_master_driver);
1066        bus_unregister(&w1_bus_type);
1067}
1068
1069module_init(w1_init);
1070module_exit(w1_fini);
1071
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