11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * w1_int.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * This program is free software; you can redistribute it and/or modify 81da177e4SLinus Torvalds * it under the terms of the GNU General Public License as published by 91da177e4SLinus Torvalds * the Free Software Foundation; either version 2 of the License, or 101da177e4SLinus Torvalds * (at your option) any later version. 111da177e4SLinus Torvalds * 121da177e4SLinus Torvalds * This program is distributed in the hope that it will be useful, 131da177e4SLinus Torvalds * but WITHOUT ANY WARRANTY; without even the implied warranty of 141da177e4SLinus Torvalds * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 151da177e4SLinus Torvalds * GNU General Public License for more details. 161da177e4SLinus Torvalds * 171da177e4SLinus Torvalds * You should have received a copy of the GNU General Public License 181da177e4SLinus Torvalds * along with this program; if not, write to the Free Software 191da177e4SLinus Torvalds * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 201da177e4SLinus Torvalds */ 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds #include <linux/kernel.h> 231da177e4SLinus Torvalds #include <linux/list.h> 241da177e4SLinus Torvalds #include <linux/delay.h> 25674a396cSEvgeniy Polyakov #include <linux/kthread.h> 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds #include "w1.h" 281da177e4SLinus Torvalds #include "w1_log.h" 291da177e4SLinus Torvalds #include "w1_netlink.h" 3070d484bfSEvgeniy Polyakov #include "w1_int.h" 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds static u32 w1_ids = 1; 331da177e4SLinus Torvalds 346a158c0dSDavid Fries static int w1_enable_pullup = 1; 356a158c0dSDavid Fries module_param_named(enable_pullup, w1_enable_pullup, int, 0); 366a158c0dSDavid Fries 377785925dSEvgeniy Polyakov static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl, 387785925dSEvgeniy Polyakov struct device_driver *driver, 397785925dSEvgeniy Polyakov struct device *device) 401da177e4SLinus Torvalds { 411da177e4SLinus Torvalds struct w1_master *dev; 421da177e4SLinus Torvalds int err; 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds /* 451da177e4SLinus Torvalds * We are in process context(kernel thread), so can sleep. 461da177e4SLinus Torvalds */ 47dd00cc48SYoann Padioleau dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); 481da177e4SLinus Torvalds if (!dev) { 491da177e4SLinus Torvalds printk(KERN_ERR 501da177e4SLinus Torvalds "Failed to allocate %zd bytes for new w1 device.\n", 511da177e4SLinus Torvalds sizeof(struct w1_master)); 521da177e4SLinus Torvalds return NULL; 531da177e4SLinus Torvalds } 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds 561da177e4SLinus Torvalds dev->bus_master = (struct w1_bus_master *)(dev + 1); 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds dev->owner = THIS_MODULE; 591da177e4SLinus Torvalds dev->max_slave_count = slave_count; 601da177e4SLinus Torvalds dev->slave_count = 0; 611da177e4SLinus Torvalds dev->attempts = 0; 621da177e4SLinus Torvalds dev->initialized = 0; 631da177e4SLinus Torvalds dev->id = id; 641da177e4SLinus Torvalds dev->slave_ttl = slave_ttl; 656a158c0dSDavid Fries dev->enable_pullup = w1_enable_pullup; 662a9d0c17SEvgeniy Polyakov dev->search_count = -1; /* continual scan */ 671da177e4SLinus Torvalds 6801e14d6dSDavid Fries /* 1 for w1_process to decrement 6901e14d6dSDavid Fries * 1 for __w1_remove_master_device to decrement 7001e14d6dSDavid Fries */ 711da177e4SLinus Torvalds atomic_set(&dev->refcnt, 2); 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds INIT_LIST_HEAD(&dev->slist); 74abd52a13SEvgeniy Polyakov mutex_init(&dev->mutex); 751da177e4SLinus Torvalds 761da177e4SLinus Torvalds memcpy(&dev->dev, device, sizeof(struct device)); 771da177e4SLinus Torvalds snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id), 781da177e4SLinus Torvalds "w1_bus_master%u", dev->id); 791da177e4SLinus Torvalds snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds dev->driver = driver; 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds dev->seq = 1; 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds err = device_register(&dev->dev); 861da177e4SLinus Torvalds if (err) { 871da177e4SLinus Torvalds printk(KERN_ERR "Failed to register master device. err=%d\n", err); 881da177e4SLinus Torvalds memset(dev, 0, sizeof(struct w1_master)); 891da177e4SLinus Torvalds kfree(dev); 901da177e4SLinus Torvalds dev = NULL; 911da177e4SLinus Torvalds } 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds return dev; 941da177e4SLinus Torvalds } 951da177e4SLinus Torvalds 962c5bfdacSEvgeniy Polyakov static void w1_free_dev(struct w1_master *dev) 971da177e4SLinus Torvalds { 981da177e4SLinus Torvalds device_unregister(&dev->dev); 991da177e4SLinus Torvalds } 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds int w1_add_master_device(struct w1_bus_master *master) 1021da177e4SLinus Torvalds { 1031da177e4SLinus Torvalds struct w1_master *dev; 1041da177e4SLinus Torvalds int retval = 0; 1051da177e4SLinus Torvalds struct w1_netlink_msg msg; 1061da177e4SLinus Torvalds 107be57ce26SEvgeniy Polyakov /* validate minimum functionality */ 108be57ce26SEvgeniy Polyakov if (!(master->touch_bit && master->reset_bus) && 109c1f858b7SEvgeniy Polyakov !(master->write_bit && master->read_bit) && 110c1f858b7SEvgeniy Polyakov !(master->write_byte && master->read_byte && master->reset_bus)) { 111be57ce26SEvgeniy Polyakov printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 112be57ce26SEvgeniy Polyakov return(-EINVAL); 113be57ce26SEvgeniy Polyakov } 1146a158c0dSDavid Fries /* While it would be electrically possible to make a device that 1156a158c0dSDavid Fries * generated a strong pullup in bit bang mode, only hardare that 1166a158c0dSDavid Fries * controls 1-wire time frames are even expected to support a strong 1176a158c0dSDavid Fries * pullup. w1_io.c would need to support calling set_pullup before 1186a158c0dSDavid Fries * the last write_bit operation of a w1_write_8 which it currently 1196a158c0dSDavid Fries * doesn't. 1206a158c0dSDavid Fries */ 1216a158c0dSDavid Fries if (!master->write_byte && !master->touch_bit && master->set_pullup) { 1226a158c0dSDavid Fries printk(KERN_ERR "w1_add_master_device: set_pullup requires " 1236a158c0dSDavid Fries "write_byte or touch_bit, disabling\n"); 1246a158c0dSDavid Fries master->set_pullup = NULL; 1256a158c0dSDavid Fries } 126be57ce26SEvgeniy Polyakov 1277f772ed8SEvgeniy Polyakov dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device); 1281da177e4SLinus Torvalds if (!dev) 1291da177e4SLinus Torvalds return -ENOMEM; 1301da177e4SLinus Torvalds 13101e14d6dSDavid Fries retval = w1_create_master_attributes(dev); 13201e14d6dSDavid Fries if (retval) 13301e14d6dSDavid Fries goto err_out_free_dev; 13401e14d6dSDavid Fries 13501e14d6dSDavid Fries memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 13601e14d6dSDavid Fries 13701e14d6dSDavid Fries dev->initialized = 1; 13801e14d6dSDavid Fries 139674a396cSEvgeniy Polyakov dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 140674a396cSEvgeniy Polyakov if (IS_ERR(dev->thread)) { 141674a396cSEvgeniy Polyakov retval = PTR_ERR(dev->thread); 1421da177e4SLinus Torvalds dev_err(&dev->dev, 1431da177e4SLinus Torvalds "Failed to create new kernel thread. err=%d\n", 144674a396cSEvgeniy Polyakov retval); 14501e14d6dSDavid Fries goto err_out_rm_attr; 1461da177e4SLinus Torvalds } 1471da177e4SLinus Torvalds 148abd52a13SEvgeniy Polyakov mutex_lock(&w1_mlock); 1491da177e4SLinus Torvalds list_add(&dev->w1_master_entry, &w1_masters); 150abd52a13SEvgeniy Polyakov mutex_unlock(&w1_mlock); 1511da177e4SLinus Torvalds 15212003375SEvgeniy Polyakov memset(&msg, 0, sizeof(msg)); 1531da177e4SLinus Torvalds msg.id.mst.id = dev->id; 1541da177e4SLinus Torvalds msg.type = W1_MASTER_ADD; 1551da177e4SLinus Torvalds w1_netlink_send(dev, &msg); 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds return 0; 1581da177e4SLinus Torvalds 15901e14d6dSDavid Fries #if 0 /* Thread cleanup code, not required currently. */ 1601da177e4SLinus Torvalds err_out_kill_thread: 161674a396cSEvgeniy Polyakov kthread_stop(dev->thread); 16201e14d6dSDavid Fries #endif 16301e14d6dSDavid Fries err_out_rm_attr: 16401e14d6dSDavid Fries w1_destroy_master_attributes(dev); 1651da177e4SLinus Torvalds err_out_free_dev: 1661da177e4SLinus Torvalds w1_free_dev(dev); 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds return retval; 1691da177e4SLinus Torvalds } 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds void __w1_remove_master_device(struct w1_master *dev) 1721da177e4SLinus Torvalds { 1731da177e4SLinus Torvalds struct w1_netlink_msg msg; 174c30c9b15SDavid Fries struct w1_slave *sl, *sln; 1751da177e4SLinus Torvalds 176674a396cSEvgeniy Polyakov kthread_stop(dev->thread); 1771da177e4SLinus Torvalds 178c30c9b15SDavid Fries mutex_lock(&w1_mlock); 179c30c9b15SDavid Fries list_del(&dev->w1_master_entry); 180c30c9b15SDavid Fries mutex_unlock(&w1_mlock); 181c30c9b15SDavid Fries 182c30c9b15SDavid Fries mutex_lock(&dev->mutex); 183c30c9b15SDavid Fries list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) 184c30c9b15SDavid Fries w1_slave_detach(sl); 185c30c9b15SDavid Fries w1_destroy_master_attributes(dev); 186c30c9b15SDavid Fries mutex_unlock(&dev->mutex); 187c30c9b15SDavid Fries atomic_dec(&dev->refcnt); 188c30c9b15SDavid Fries 1891da177e4SLinus Torvalds while (atomic_read(&dev->refcnt)) { 190674a396cSEvgeniy Polyakov dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 1911da177e4SLinus Torvalds dev->name, atomic_read(&dev->refcnt)); 1921da177e4SLinus Torvalds 1931da177e4SLinus Torvalds if (msleep_interruptible(1000)) 1941da177e4SLinus Torvalds flush_signals(current); 1951da177e4SLinus Torvalds } 1961da177e4SLinus Torvalds 19712003375SEvgeniy Polyakov memset(&msg, 0, sizeof(msg)); 1981da177e4SLinus Torvalds msg.id.mst.id = dev->id; 1991da177e4SLinus Torvalds msg.type = W1_MASTER_REMOVE; 2001da177e4SLinus Torvalds w1_netlink_send(dev, &msg); 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds w1_free_dev(dev); 2031da177e4SLinus Torvalds } 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds void w1_remove_master_device(struct w1_bus_master *bm) 2061da177e4SLinus Torvalds { 20759d9445eSEvgeniy Polyakov struct w1_master *dev, *found = NULL; 2081da177e4SLinus Torvalds 2097785925dSEvgeniy Polyakov list_for_each_entry(dev, &w1_masters, w1_master_entry) { 2101da177e4SLinus Torvalds if (!dev->initialized) 2111da177e4SLinus Torvalds continue; 2121da177e4SLinus Torvalds 21359d9445eSEvgeniy Polyakov if (dev->bus_master->data == bm->data) { 21459d9445eSEvgeniy Polyakov found = dev; 2151da177e4SLinus Torvalds break; 2161da177e4SLinus Torvalds } 21759d9445eSEvgeniy Polyakov } 2181da177e4SLinus Torvalds 21959d9445eSEvgeniy Polyakov if (!found) { 2201da177e4SLinus Torvalds printk(KERN_ERR "Device doesn't exist.\n"); 2211da177e4SLinus Torvalds return; 2221da177e4SLinus Torvalds } 2231da177e4SLinus Torvalds 22459d9445eSEvgeniy Polyakov __w1_remove_master_device(found); 2251da177e4SLinus Torvalds } 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvalds EXPORT_SYMBOL(w1_add_master_device); 2281da177e4SLinus Torvalds EXPORT_SYMBOL(w1_remove_master_device); 229