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 put_device(&dev->dev); 95 dev = NULL; 96 } 97 98 return dev; 99 } 100 101 static void w1_free_dev(struct w1_master *dev) 102 { 103 device_unregister(&dev->dev); 104 } 105 106 /** 107 * w1_add_master_device() - registers a new master device 108 * @master: master bus device to register 109 */ 110 int w1_add_master_device(struct w1_bus_master *master) 111 { 112 struct w1_master *dev, *entry; 113 int retval = 0; 114 struct w1_netlink_msg msg; 115 int id, found; 116 117 /* validate minimum functionality */ 118 if (!(master->touch_bit && master->reset_bus) && 119 !(master->write_bit && master->read_bit) && 120 !(master->write_byte && master->read_byte && master->reset_bus)) { 121 pr_err("w1_add_master_device: invalid function set\n"); 122 return(-EINVAL); 123 } 124 125 /* Lock until the device is added (or not) to w1_masters. */ 126 mutex_lock(&w1_mlock); 127 /* Search for the first available id (starting at 1). */ 128 id = 0; 129 do { 130 ++id; 131 found = 0; 132 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 133 if (entry->id == id) { 134 found = 1; 135 break; 136 } 137 } 138 } while (found); 139 140 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 141 &w1_master_driver, &w1_master_device); 142 if (!dev) { 143 mutex_unlock(&w1_mlock); 144 return -ENOMEM; 145 } 146 147 retval = w1_create_master_attributes(dev); 148 if (retval) { 149 mutex_unlock(&w1_mlock); 150 goto err_out_free_dev; 151 } 152 153 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 154 155 dev->initialized = 1; 156 157 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 158 if (IS_ERR(dev->thread)) { 159 retval = PTR_ERR(dev->thread); 160 dev_err(&dev->dev, 161 "Failed to create new kernel thread. err=%d\n", 162 retval); 163 mutex_unlock(&w1_mlock); 164 goto err_out_rm_attr; 165 } 166 167 list_add(&dev->w1_master_entry, &w1_masters); 168 mutex_unlock(&w1_mlock); 169 170 memset(&msg, 0, sizeof(msg)); 171 msg.id.mst.id = dev->id; 172 msg.type = W1_MASTER_ADD; 173 w1_netlink_send(dev, &msg); 174 175 return 0; 176 177 #if 0 /* Thread cleanup code, not required currently. */ 178 err_out_kill_thread: 179 set_bit(W1_ABORT_SEARCH, &dev->flags); 180 kthread_stop(dev->thread); 181 #endif 182 err_out_rm_attr: 183 w1_destroy_master_attributes(dev); 184 err_out_free_dev: 185 w1_free_dev(dev); 186 187 return retval; 188 } 189 190 void __w1_remove_master_device(struct w1_master *dev) 191 { 192 struct w1_netlink_msg msg; 193 struct w1_slave *sl, *sln; 194 195 mutex_lock(&w1_mlock); 196 list_del(&dev->w1_master_entry); 197 mutex_unlock(&w1_mlock); 198 199 set_bit(W1_ABORT_SEARCH, &dev->flags); 200 kthread_stop(dev->thread); 201 202 mutex_lock(&dev->mutex); 203 mutex_lock(&dev->list_mutex); 204 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 205 mutex_unlock(&dev->list_mutex); 206 w1_slave_detach(sl); 207 mutex_lock(&dev->list_mutex); 208 } 209 w1_destroy_master_attributes(dev); 210 mutex_unlock(&dev->list_mutex); 211 mutex_unlock(&dev->mutex); 212 atomic_dec(&dev->refcnt); 213 214 while (atomic_read(&dev->refcnt)) { 215 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 216 dev->name, atomic_read(&dev->refcnt)); 217 218 if (msleep_interruptible(1000)) 219 flush_signals(current); 220 mutex_lock(&dev->list_mutex); 221 w1_process_callbacks(dev); 222 mutex_unlock(&dev->list_mutex); 223 } 224 mutex_lock(&dev->list_mutex); 225 w1_process_callbacks(dev); 226 mutex_unlock(&dev->list_mutex); 227 228 memset(&msg, 0, sizeof(msg)); 229 msg.id.mst.id = dev->id; 230 msg.type = W1_MASTER_REMOVE; 231 w1_netlink_send(dev, &msg); 232 233 w1_free_dev(dev); 234 } 235 236 /** 237 * w1_remove_master_device() - unregister a master device 238 * @bm: master bus device to remove 239 */ 240 void w1_remove_master_device(struct w1_bus_master *bm) 241 { 242 struct w1_master *dev, *found = NULL; 243 244 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 245 if (!dev->initialized) 246 continue; 247 248 if (dev->bus_master->data == bm->data) { 249 found = dev; 250 break; 251 } 252 } 253 254 if (!found) { 255 pr_err("Device doesn't exist.\n"); 256 return; 257 } 258 259 __w1_remove_master_device(found); 260 } 261 262 EXPORT_SYMBOL(w1_add_master_device); 263 EXPORT_SYMBOL(w1_remove_master_device); 264