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 80 memcpy(&dev->dev, device, sizeof(struct device)); 81 dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); 82 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 83 dev->dev.init_name = dev->name; 84 85 dev->driver = driver; 86 87 dev->seq = 1; 88 89 err = device_register(&dev->dev); 90 if (err) { 91 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 92 memset(dev, 0, sizeof(struct w1_master)); 93 kfree(dev); 94 dev = NULL; 95 } 96 97 return dev; 98 } 99 100 static void w1_free_dev(struct w1_master *dev) 101 { 102 device_unregister(&dev->dev); 103 } 104 105 int w1_add_master_device(struct w1_bus_master *master) 106 { 107 struct w1_master *dev, *entry; 108 int retval = 0; 109 struct w1_netlink_msg msg; 110 int id, found; 111 112 /* validate minimum functionality */ 113 if (!(master->touch_bit && master->reset_bus) && 114 !(master->write_bit && master->read_bit) && 115 !(master->write_byte && master->read_byte && master->reset_bus)) { 116 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 117 return(-EINVAL); 118 } 119 /* While it would be electrically possible to make a device that 120 * generated a strong pullup in bit bang mode, only hardare that 121 * controls 1-wire time frames are even expected to support a strong 122 * pullup. w1_io.c would need to support calling set_pullup before 123 * the last write_bit operation of a w1_write_8 which it currently 124 * doesn't. 125 */ 126 if (!master->write_byte && !master->touch_bit && master->set_pullup) { 127 printk(KERN_ERR "w1_add_master_device: set_pullup requires " 128 "write_byte or touch_bit, disabling\n"); 129 master->set_pullup = NULL; 130 } 131 132 /* Lock until the device is added (or not) to w1_masters. */ 133 mutex_lock(&w1_mlock); 134 /* Search for the first available id (starting at 1). */ 135 id = 0; 136 do { 137 ++id; 138 found = 0; 139 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 140 if (entry->id == id) { 141 found = 1; 142 break; 143 } 144 } 145 } while (found); 146 147 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 148 &w1_master_driver, &w1_master_device); 149 if (!dev) { 150 mutex_unlock(&w1_mlock); 151 return -ENOMEM; 152 } 153 154 retval = w1_create_master_attributes(dev); 155 if (retval) { 156 mutex_unlock(&w1_mlock); 157 goto err_out_free_dev; 158 } 159 160 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 161 162 dev->initialized = 1; 163 164 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 165 if (IS_ERR(dev->thread)) { 166 retval = PTR_ERR(dev->thread); 167 dev_err(&dev->dev, 168 "Failed to create new kernel thread. err=%d\n", 169 retval); 170 mutex_unlock(&w1_mlock); 171 goto err_out_rm_attr; 172 } 173 174 list_add(&dev->w1_master_entry, &w1_masters); 175 mutex_unlock(&w1_mlock); 176 177 memset(&msg, 0, sizeof(msg)); 178 msg.id.mst.id = dev->id; 179 msg.type = W1_MASTER_ADD; 180 w1_netlink_send(dev, &msg); 181 182 return 0; 183 184 #if 0 /* Thread cleanup code, not required currently. */ 185 err_out_kill_thread: 186 kthread_stop(dev->thread); 187 #endif 188 err_out_rm_attr: 189 w1_destroy_master_attributes(dev); 190 err_out_free_dev: 191 w1_free_dev(dev); 192 193 return retval; 194 } 195 196 void __w1_remove_master_device(struct w1_master *dev) 197 { 198 struct w1_netlink_msg msg; 199 struct w1_slave *sl, *sln; 200 201 kthread_stop(dev->thread); 202 203 mutex_lock(&w1_mlock); 204 list_del(&dev->w1_master_entry); 205 mutex_unlock(&w1_mlock); 206 207 mutex_lock(&dev->mutex); 208 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) 209 w1_slave_detach(sl); 210 w1_destroy_master_attributes(dev); 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 } 221 222 memset(&msg, 0, sizeof(msg)); 223 msg.id.mst.id = dev->id; 224 msg.type = W1_MASTER_REMOVE; 225 w1_netlink_send(dev, &msg); 226 227 w1_free_dev(dev); 228 } 229 230 void w1_remove_master_device(struct w1_bus_master *bm) 231 { 232 struct w1_master *dev, *found = NULL; 233 234 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 235 if (!dev->initialized) 236 continue; 237 238 if (dev->bus_master->data == bm->data) { 239 found = dev; 240 break; 241 } 242 } 243 244 if (!found) { 245 printk(KERN_ERR "Device doesn't exist.\n"); 246 return; 247 } 248 249 __w1_remove_master_device(found); 250 } 251 252 EXPORT_SYMBOL(w1_add_master_device); 253 EXPORT_SYMBOL(w1_remove_master_device); 254