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 printk(KERN_ERR 54 "Failed to allocate %zd bytes for new w1 device.\n", 55 sizeof(struct w1_master)); 56 return NULL; 57 } 58 59 60 dev->bus_master = (struct w1_bus_master *)(dev + 1); 61 62 dev->owner = THIS_MODULE; 63 dev->max_slave_count = slave_count; 64 dev->slave_count = 0; 65 dev->attempts = 0; 66 dev->initialized = 0; 67 dev->id = id; 68 dev->slave_ttl = slave_ttl; 69 dev->search_count = w1_search_count; 70 dev->enable_pullup = w1_enable_pullup; 71 72 /* 1 for w1_process to decrement 73 * 1 for __w1_remove_master_device to decrement 74 */ 75 atomic_set(&dev->refcnt, 2); 76 77 INIT_LIST_HEAD(&dev->slist); 78 INIT_LIST_HEAD(&dev->async_list); 79 mutex_init(&dev->mutex); 80 mutex_init(&dev->bus_mutex); 81 mutex_init(&dev->list_mutex); 82 83 memcpy(&dev->dev, device, sizeof(struct device)); 84 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); 85 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 86 dev->dev.init_name = dev->name; 87 88 dev->driver = driver; 89 90 dev->seq = 1; 91 92 err = device_register(&dev->dev); 93 if (err) { 94 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 95 memset(dev, 0, sizeof(struct w1_master)); 96 kfree(dev); 97 dev = NULL; 98 } 99 100 return dev; 101 } 102 103 static void w1_free_dev(struct w1_master *dev) 104 { 105 device_unregister(&dev->dev); 106 } 107 108 /** 109 * w1_add_master_device() - registers a new master device 110 * @master: master bus device to register 111 */ 112 int w1_add_master_device(struct w1_bus_master *master) 113 { 114 struct w1_master *dev, *entry; 115 int retval = 0; 116 struct w1_netlink_msg msg; 117 int id, found; 118 119 /* validate minimum functionality */ 120 if (!(master->touch_bit && master->reset_bus) && 121 !(master->write_bit && master->read_bit) && 122 !(master->write_byte && master->read_byte && master->reset_bus)) { 123 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 124 return(-EINVAL); 125 } 126 127 /* Lock until the device is added (or not) to w1_masters. */ 128 mutex_lock(&w1_mlock); 129 /* Search for the first available id (starting at 1). */ 130 id = 0; 131 do { 132 ++id; 133 found = 0; 134 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 135 if (entry->id == id) { 136 found = 1; 137 break; 138 } 139 } 140 } while (found); 141 142 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 143 &w1_master_driver, &w1_master_device); 144 if (!dev) { 145 mutex_unlock(&w1_mlock); 146 return -ENOMEM; 147 } 148 149 retval = w1_create_master_attributes(dev); 150 if (retval) { 151 mutex_unlock(&w1_mlock); 152 goto err_out_free_dev; 153 } 154 155 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 156 157 dev->initialized = 1; 158 159 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 160 if (IS_ERR(dev->thread)) { 161 retval = PTR_ERR(dev->thread); 162 dev_err(&dev->dev, 163 "Failed to create new kernel thread. err=%d\n", 164 retval); 165 mutex_unlock(&w1_mlock); 166 goto err_out_rm_attr; 167 } 168 169 list_add(&dev->w1_master_entry, &w1_masters); 170 mutex_unlock(&w1_mlock); 171 172 memset(&msg, 0, sizeof(msg)); 173 msg.id.mst.id = dev->id; 174 msg.type = W1_MASTER_ADD; 175 w1_netlink_send(dev, &msg); 176 177 return 0; 178 179 #if 0 /* Thread cleanup code, not required currently. */ 180 err_out_kill_thread: 181 set_bit(W1_ABORT_SEARCH, &dev->flags); 182 kthread_stop(dev->thread); 183 #endif 184 err_out_rm_attr: 185 w1_destroy_master_attributes(dev); 186 err_out_free_dev: 187 w1_free_dev(dev); 188 189 return retval; 190 } 191 192 void __w1_remove_master_device(struct w1_master *dev) 193 { 194 struct w1_netlink_msg msg; 195 struct w1_slave *sl, *sln; 196 197 mutex_lock(&w1_mlock); 198 list_del(&dev->w1_master_entry); 199 mutex_unlock(&w1_mlock); 200 201 set_bit(W1_ABORT_SEARCH, &dev->flags); 202 kthread_stop(dev->thread); 203 204 mutex_lock(&dev->mutex); 205 mutex_lock(&dev->list_mutex); 206 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { 207 mutex_unlock(&dev->list_mutex); 208 w1_slave_detach(sl); 209 mutex_lock(&dev->list_mutex); 210 } 211 w1_destroy_master_attributes(dev); 212 mutex_unlock(&dev->list_mutex); 213 mutex_unlock(&dev->mutex); 214 atomic_dec(&dev->refcnt); 215 216 while (atomic_read(&dev->refcnt)) { 217 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 218 dev->name, atomic_read(&dev->refcnt)); 219 220 if (msleep_interruptible(1000)) 221 flush_signals(current); 222 mutex_lock(&dev->list_mutex); 223 w1_process_callbacks(dev); 224 mutex_unlock(&dev->list_mutex); 225 } 226 mutex_lock(&dev->list_mutex); 227 w1_process_callbacks(dev); 228 mutex_unlock(&dev->list_mutex); 229 230 memset(&msg, 0, sizeof(msg)); 231 msg.id.mst.id = dev->id; 232 msg.type = W1_MASTER_REMOVE; 233 w1_netlink_send(dev, &msg); 234 235 w1_free_dev(dev); 236 } 237 238 /** 239 * w1_remove_master_device() - unregister a master device 240 * @bm: master bus device to remove 241 */ 242 void w1_remove_master_device(struct w1_bus_master *bm) 243 { 244 struct w1_master *dev, *found = NULL; 245 246 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 247 if (!dev->initialized) 248 continue; 249 250 if (dev->bus_master->data == bm->data) { 251 found = dev; 252 break; 253 } 254 } 255 256 if (!found) { 257 printk(KERN_ERR "Device doesn't exist.\n"); 258 return; 259 } 260 261 __w1_remove_master_device(found); 262 } 263 264 EXPORT_SYMBOL(w1_add_master_device); 265 EXPORT_SYMBOL(w1_remove_master_device); 266