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