1 /* 2 * w1_int.c 3 * 4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> 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 28 #include "w1.h" 29 #include "w1_log.h" 30 #include "w1_netlink.h" 31 #include "w1_int.h" 32 33 static int w1_search_count = -1; /* Default is continual scan */ 34 module_param_named(search_count, w1_search_count, int, 0); 35 36 static int w1_enable_pullup = 1; 37 module_param_named(enable_pullup, w1_enable_pullup, int, 0); 38 39 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl, 40 struct device_driver *driver, 41 struct device *device) 42 { 43 struct w1_master *dev; 44 int err; 45 46 /* 47 * We are in process context(kernel thread), so can sleep. 48 */ 49 dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); 50 if (!dev) { 51 printk(KERN_ERR 52 "Failed to allocate %zd bytes for new w1 device.\n", 53 sizeof(struct w1_master)); 54 return NULL; 55 } 56 57 58 dev->bus_master = (struct w1_bus_master *)(dev + 1); 59 60 dev->owner = THIS_MODULE; 61 dev->max_slave_count = slave_count; 62 dev->slave_count = 0; 63 dev->attempts = 0; 64 dev->initialized = 0; 65 dev->id = id; 66 dev->slave_ttl = slave_ttl; 67 dev->search_count = w1_search_count; 68 dev->enable_pullup = w1_enable_pullup; 69 70 /* 1 for w1_process to decrement 71 * 1 for __w1_remove_master_device to decrement 72 */ 73 atomic_set(&dev->refcnt, 2); 74 75 INIT_LIST_HEAD(&dev->slist); 76 mutex_init(&dev->mutex); 77 78 memcpy(&dev->dev, device, sizeof(struct device)); 79 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); 80 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 81 82 dev->driver = driver; 83 84 dev->seq = 1; 85 86 err = device_register(&dev->dev); 87 if (err) { 88 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 89 memset(dev, 0, sizeof(struct w1_master)); 90 kfree(dev); 91 dev = NULL; 92 } 93 94 return dev; 95 } 96 97 static void w1_free_dev(struct w1_master *dev) 98 { 99 device_unregister(&dev->dev); 100 } 101 102 int w1_add_master_device(struct w1_bus_master *master) 103 { 104 struct w1_master *dev, *entry; 105 int retval = 0; 106 struct w1_netlink_msg msg; 107 int id, found; 108 109 /* validate minimum functionality */ 110 if (!(master->touch_bit && master->reset_bus) && 111 !(master->write_bit && master->read_bit) && 112 !(master->write_byte && master->read_byte && master->reset_bus)) { 113 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 114 return(-EINVAL); 115 } 116 /* While it would be electrically possible to make a device that 117 * generated a strong pullup in bit bang mode, only hardare that 118 * controls 1-wire time frames are even expected to support a strong 119 * pullup. w1_io.c would need to support calling set_pullup before 120 * the last write_bit operation of a w1_write_8 which it currently 121 * doesn't. 122 */ 123 if (!master->write_byte && !master->touch_bit && master->set_pullup) { 124 printk(KERN_ERR "w1_add_master_device: set_pullup requires " 125 "write_byte or touch_bit, disabling\n"); 126 master->set_pullup = NULL; 127 } 128 129 /* Lock until the device is added (or not) to w1_masters. */ 130 mutex_lock(&w1_mlock); 131 /* Search for the first available id (starting at 1). */ 132 id = 0; 133 do { 134 ++id; 135 found = 0; 136 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 137 if (entry->id == id) { 138 found = 1; 139 break; 140 } 141 } 142 } while (found); 143 144 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 145 &w1_master_driver, &w1_master_device); 146 if (!dev) { 147 mutex_unlock(&w1_mlock); 148 return -ENOMEM; 149 } 150 151 retval = w1_create_master_attributes(dev); 152 if (retval) { 153 mutex_unlock(&w1_mlock); 154 goto err_out_free_dev; 155 } 156 157 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 158 159 dev->initialized = 1; 160 161 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 162 if (IS_ERR(dev->thread)) { 163 retval = PTR_ERR(dev->thread); 164 dev_err(&dev->dev, 165 "Failed to create new kernel thread. err=%d\n", 166 retval); 167 mutex_unlock(&w1_mlock); 168 goto err_out_rm_attr; 169 } 170 171 list_add(&dev->w1_master_entry, &w1_masters); 172 mutex_unlock(&w1_mlock); 173 174 memset(&msg, 0, sizeof(msg)); 175 msg.id.mst.id = dev->id; 176 msg.type = W1_MASTER_ADD; 177 w1_netlink_send(dev, &msg); 178 179 return 0; 180 181 #if 0 /* Thread cleanup code, not required currently. */ 182 err_out_kill_thread: 183 kthread_stop(dev->thread); 184 #endif 185 err_out_rm_attr: 186 w1_destroy_master_attributes(dev); 187 err_out_free_dev: 188 w1_free_dev(dev); 189 190 return retval; 191 } 192 193 void __w1_remove_master_device(struct w1_master *dev) 194 { 195 struct w1_netlink_msg msg; 196 struct w1_slave *sl, *sln; 197 198 kthread_stop(dev->thread); 199 200 mutex_lock(&w1_mlock); 201 list_del(&dev->w1_master_entry); 202 mutex_unlock(&w1_mlock); 203 204 mutex_lock(&dev->mutex); 205 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) 206 w1_slave_detach(sl); 207 w1_destroy_master_attributes(dev); 208 mutex_unlock(&dev->mutex); 209 atomic_dec(&dev->refcnt); 210 211 while (atomic_read(&dev->refcnt)) { 212 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 213 dev->name, atomic_read(&dev->refcnt)); 214 215 if (msleep_interruptible(1000)) 216 flush_signals(current); 217 } 218 219 memset(&msg, 0, sizeof(msg)); 220 msg.id.mst.id = dev->id; 221 msg.type = W1_MASTER_REMOVE; 222 w1_netlink_send(dev, &msg); 223 224 w1_free_dev(dev); 225 } 226 227 void w1_remove_master_device(struct w1_bus_master *bm) 228 { 229 struct w1_master *dev, *found = NULL; 230 231 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 232 if (!dev->initialized) 233 continue; 234 235 if (dev->bus_master->data == bm->data) { 236 found = dev; 237 break; 238 } 239 } 240 241 if (!found) { 242 printk(KERN_ERR "Device doesn't exist.\n"); 243 return; 244 } 245 246 __w1_remove_master_device(found); 247 } 248 249 EXPORT_SYMBOL(w1_add_master_device); 250 EXPORT_SYMBOL(w1_remove_master_device); 251