1 /* 2 * w1_int.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/kernel.h> 23 #include <linux/list.h> 24 #include <linux/delay.h> 25 #include <linux/kthread.h> 26 #include <linux/slab.h> 27 #include <linux/export.h> 28 #include <linux/moduleparam.h> 29 30 #include "w1.h" 31 #include "w1_log.h" 32 #include "w1_netlink.h" 33 #include "w1_int.h" 34 35 static int w1_search_count = -1; /* Default is continual scan */ 36 module_param_named(search_count, w1_search_count, int, 0); 37 38 static int w1_enable_pullup = 1; 39 module_param_named(enable_pullup, w1_enable_pullup, int, 0); 40 41 static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl, 42 struct device_driver *driver, 43 struct device *device) 44 { 45 struct w1_master *dev; 46 int err; 47 48 /* 49 * We are in process context(kernel thread), so can sleep. 50 */ 51 dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); 52 if (!dev) { 53 pr_err("Failed to allocate %zd bytes for new w1 device.\n", 54 sizeof(struct w1_master)); 55 return NULL; 56 } 57 58 59 dev->bus_master = (struct w1_bus_master *)(dev + 1); 60 61 dev->owner = THIS_MODULE; 62 dev->max_slave_count = slave_count; 63 dev->slave_count = 0; 64 dev->attempts = 0; 65 dev->initialized = 0; 66 dev->id = id; 67 dev->slave_ttl = slave_ttl; 68 dev->search_count = w1_search_count; 69 dev->enable_pullup = w1_enable_pullup; 70 71 /* 1 for w1_process to decrement 72 * 1 for __w1_remove_master_device to decrement 73 */ 74 atomic_set(&dev->refcnt, 2); 75 76 INIT_LIST_HEAD(&dev->slist); 77 INIT_LIST_HEAD(&dev->async_list); 78 mutex_init(&dev->mutex); 79 mutex_init(&dev->bus_mutex); 80 mutex_init(&dev->list_mutex); 81 82 memcpy(&dev->dev, device, sizeof(struct device)); 83 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); 84 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 85 dev->dev.init_name = dev->name; 86 87 dev->driver = driver; 88 89 dev->seq = 1; 90 91 err = device_register(&dev->dev); 92 if (err) { 93 pr_err("Failed to register master device. err=%d\n", err); 94 memset(dev, 0, sizeof(struct w1_master)); 95 kfree(dev); 96 dev = NULL; 97 } 98 99 return dev; 100 } 101 102 static void w1_free_dev(struct w1_master *dev) 103 { 104 device_unregister(&dev->dev); 105 } 106 107 /** 108 * w1_add_master_device() - registers a new master device 109 * @master: master bus device to register 110 */ 111 int w1_add_master_device(struct w1_bus_master *master) 112 { 113 struct w1_master *dev, *entry; 114 int retval = 0; 115 struct w1_netlink_msg msg; 116 int id, found; 117 118 /* validate minimum functionality */ 119 if (!(master->touch_bit && master->reset_bus) && 120 !(master->write_bit && master->read_bit) && 121 !(master->write_byte && master->read_byte && master->reset_bus)) { 122 pr_err("w1_add_master_device: invalid function set\n"); 123 return(-EINVAL); 124 } 125 126 /* Lock until the device is added (or not) to w1_masters. */ 127 mutex_lock(&w1_mlock); 128 /* Search for the first available id (starting at 1). */ 129 id = 0; 130 do { 131 ++id; 132 found = 0; 133 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 134 if (entry->id == id) { 135 found = 1; 136 break; 137 } 138 } 139 } while (found); 140 141 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 142 &w1_master_driver, &w1_master_device); 143 if (!dev) { 144 mutex_unlock(&w1_mlock); 145 return -ENOMEM; 146 } 147 148 retval = w1_create_master_attributes(dev); 149 if (retval) { 150 mutex_unlock(&w1_mlock); 151 goto err_out_free_dev; 152 } 153 154 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 155 156 dev->initialized = 1; 157 158 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 159 if (IS_ERR(dev->thread)) { 160 retval = PTR_ERR(dev->thread); 161 dev_err(&dev->dev, 162 "Failed to create new kernel thread. err=%d\n", 163 retval); 164 mutex_unlock(&w1_mlock); 165 goto err_out_rm_attr; 166 } 167 168 list_add(&dev->w1_master_entry, &w1_masters); 169 mutex_unlock(&w1_mlock); 170 171 memset(&msg, 0, sizeof(msg)); 172 msg.id.mst.id = dev->id; 173 msg.type = W1_MASTER_ADD; 174 w1_netlink_send(dev, &msg); 175 176 return 0; 177 178 #if 0 /* Thread cleanup code, not required currently. */ 179 err_out_kill_thread: 180 set_bit(W1_ABORT_SEARCH, &dev->flags); 181 kthread_stop(dev->thread); 182 #endif 183 err_out_rm_attr: 184 w1_destroy_master_attributes(dev); 185 err_out_free_dev: 186 w1_free_dev(dev); 187 188 return retval; 189 } 190 191 void __w1_remove_master_device(struct w1_master *dev) 192 { 193 struct w1_netlink_msg msg; 194 struct w1_slave *sl, *sln; 195 196 mutex_lock(&w1_mlock); 197 list_del(&dev->w1_master_entry); 198 mutex_unlock(&w1_mlock); 199 200 set_bit(W1_ABORT_SEARCH, &dev->flags); 201 kthread_stop(dev->thread); 202 203 mutex_lock(&dev->mutex); 204 mutex_lock(&dev->list_mutex); 205 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 206 mutex_unlock(&dev->list_mutex); 207 w1_slave_detach(sl); 208 mutex_lock(&dev->list_mutex); 209 } 210 w1_destroy_master_attributes(dev); 211 mutex_unlock(&dev->list_mutex); 212 mutex_unlock(&dev->mutex); 213 atomic_dec(&dev->refcnt); 214 215 while (atomic_read(&dev->refcnt)) { 216 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 217 dev->name, atomic_read(&dev->refcnt)); 218 219 if (msleep_interruptible(1000)) 220 flush_signals(current); 221 mutex_lock(&dev->list_mutex); 222 w1_process_callbacks(dev); 223 mutex_unlock(&dev->list_mutex); 224 } 225 mutex_lock(&dev->list_mutex); 226 w1_process_callbacks(dev); 227 mutex_unlock(&dev->list_mutex); 228 229 memset(&msg, 0, sizeof(msg)); 230 msg.id.mst.id = dev->id; 231 msg.type = W1_MASTER_REMOVE; 232 w1_netlink_send(dev, &msg); 233 234 w1_free_dev(dev); 235 } 236 237 /** 238 * w1_remove_master_device() - unregister a master device 239 * @bm: master bus device to remove 240 */ 241 void w1_remove_master_device(struct w1_bus_master *bm) 242 { 243 struct w1_master *dev, *found = NULL; 244 245 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 246 if (!dev->initialized) 247 continue; 248 249 if (dev->bus_master->data == bm->data) { 250 found = dev; 251 break; 252 } 253 } 254 255 if (!found) { 256 pr_err("Device doesn't exist.\n"); 257 return; 258 } 259 260 __w1_remove_master_device(found); 261 } 262 263 EXPORT_SYMBOL(w1_add_master_device); 264 EXPORT_SYMBOL(w1_remove_master_device); 265