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 mutex_init(&dev->mutex); 79 mutex_init(&dev->bus_mutex); 80 81 memcpy(&dev->dev, device, sizeof(struct device)); 82 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); 83 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 84 dev->dev.init_name = dev->name; 85 86 dev->driver = driver; 87 88 dev->seq = 1; 89 90 err = device_register(&dev->dev); 91 if (err) { 92 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 93 memset(dev, 0, sizeof(struct w1_master)); 94 kfree(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 int w1_add_master_device(struct w1_bus_master *master) 107 { 108 struct w1_master *dev, *entry; 109 int retval = 0; 110 struct w1_netlink_msg msg; 111 int id, found; 112 113 /* validate minimum functionality */ 114 if (!(master->touch_bit && master->reset_bus) && 115 !(master->write_bit && master->read_bit) && 116 !(master->write_byte && master->read_byte && master->reset_bus)) { 117 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 118 return(-EINVAL); 119 } 120 /* While it would be electrically possible to make a device that 121 * generated a strong pullup in bit bang mode, only hardware that 122 * controls 1-wire time frames are even expected to support a strong 123 * pullup. w1_io.c would need to support calling set_pullup before 124 * the last write_bit operation of a w1_write_8 which it currently 125 * doesn't. 126 */ 127 if (!master->write_byte && !master->touch_bit && master->set_pullup) { 128 printk(KERN_ERR "w1_add_master_device: set_pullup requires " 129 "write_byte or touch_bit, disabling\n"); 130 master->set_pullup = NULL; 131 } 132 133 /* Lock until the device is added (or not) to w1_masters. */ 134 mutex_lock(&w1_mlock); 135 /* Search for the first available id (starting at 1). */ 136 id = 0; 137 do { 138 ++id; 139 found = 0; 140 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 141 if (entry->id == id) { 142 found = 1; 143 break; 144 } 145 } 146 } while (found); 147 148 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 149 &w1_master_driver, &w1_master_device); 150 if (!dev) { 151 mutex_unlock(&w1_mlock); 152 return -ENOMEM; 153 } 154 155 retval = w1_create_master_attributes(dev); 156 if (retval) { 157 mutex_unlock(&w1_mlock); 158 goto err_out_free_dev; 159 } 160 161 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 162 163 dev->initialized = 1; 164 165 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 166 if (IS_ERR(dev->thread)) { 167 retval = PTR_ERR(dev->thread); 168 dev_err(&dev->dev, 169 "Failed to create new kernel thread. err=%d\n", 170 retval); 171 mutex_unlock(&w1_mlock); 172 goto err_out_rm_attr; 173 } 174 175 list_add(&dev->w1_master_entry, &w1_masters); 176 mutex_unlock(&w1_mlock); 177 178 memset(&msg, 0, sizeof(msg)); 179 msg.id.mst.id = dev->id; 180 msg.type = W1_MASTER_ADD; 181 w1_netlink_send(dev, &msg); 182 183 return 0; 184 185 #if 0 /* Thread cleanup code, not required currently. */ 186 err_out_kill_thread: 187 kthread_stop(dev->thread); 188 #endif 189 err_out_rm_attr: 190 w1_destroy_master_attributes(dev); 191 err_out_free_dev: 192 w1_free_dev(dev); 193 194 return retval; 195 } 196 197 void __w1_remove_master_device(struct w1_master *dev) 198 { 199 struct w1_netlink_msg msg; 200 struct w1_slave *sl, *sln; 201 202 kthread_stop(dev->thread); 203 204 mutex_lock(&w1_mlock); 205 list_del(&dev->w1_master_entry); 206 mutex_unlock(&w1_mlock); 207 208 mutex_lock(&dev->mutex); 209 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) 210 w1_slave_detach(sl); 211 w1_destroy_master_attributes(dev); 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 } 222 223 memset(&msg, 0, sizeof(msg)); 224 msg.id.mst.id = dev->id; 225 msg.type = W1_MASTER_REMOVE; 226 w1_netlink_send(dev, &msg); 227 228 w1_free_dev(dev); 229 } 230 231 void w1_remove_master_device(struct w1_bus_master *bm) 232 { 233 struct w1_master *dev, *found = NULL; 234 235 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 236 if (!dev->initialized) 237 continue; 238 239 if (dev->bus_master->data == bm->data) { 240 found = dev; 241 break; 242 } 243 } 244 245 if (!found) { 246 printk(KERN_ERR "Device doesn't exist.\n"); 247 return; 248 } 249 250 __w1_remove_master_device(found); 251 } 252 253 EXPORT_SYMBOL(w1_add_master_device); 254 EXPORT_SYMBOL(w1_remove_master_device); 255