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 } 120 121 /* Lock until the device is added (or not) to w1_masters. */ 122 mutex_lock(&w1_mlock); 123 /* Search for the first available id (starting at 1). */ 124 id = 0; 125 do { 126 ++id; 127 found = 0; 128 list_for_each_entry(entry, &w1_masters, w1_master_entry) { 129 if (entry->id == id) { 130 found = 1; 131 break; 132 } 133 } 134 } while (found); 135 136 dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, 137 &w1_master_driver, &w1_master_device); 138 if (!dev) { 139 mutex_unlock(&w1_mlock); 140 return -ENOMEM; 141 } 142 143 retval = w1_create_master_attributes(dev); 144 if (retval) { 145 mutex_unlock(&w1_mlock); 146 goto err_out_free_dev; 147 } 148 149 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 150 151 dev->initialized = 1; 152 153 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 154 if (IS_ERR(dev->thread)) { 155 retval = PTR_ERR(dev->thread); 156 dev_err(&dev->dev, 157 "Failed to create new kernel thread. err=%d\n", 158 retval); 159 mutex_unlock(&w1_mlock); 160 goto err_out_rm_attr; 161 } 162 163 list_add(&dev->w1_master_entry, &w1_masters); 164 mutex_unlock(&w1_mlock); 165 166 memset(&msg, 0, sizeof(msg)); 167 msg.id.mst.id = dev->id; 168 msg.type = W1_MASTER_ADD; 169 w1_netlink_send(dev, &msg); 170 171 return 0; 172 173 #if 0 /* Thread cleanup code, not required currently. */ 174 err_out_kill_thread: 175 kthread_stop(dev->thread); 176 #endif 177 err_out_rm_attr: 178 w1_destroy_master_attributes(dev); 179 err_out_free_dev: 180 w1_free_dev(dev); 181 182 return retval; 183 } 184 185 void __w1_remove_master_device(struct w1_master *dev) 186 { 187 struct w1_netlink_msg msg; 188 struct w1_slave *sl, *sln; 189 190 kthread_stop(dev->thread); 191 192 mutex_lock(&w1_mlock); 193 list_del(&dev->w1_master_entry); 194 mutex_unlock(&w1_mlock); 195 196 mutex_lock(&dev->mutex); 197 list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) 198 w1_slave_detach(sl); 199 w1_destroy_master_attributes(dev); 200 mutex_unlock(&dev->mutex); 201 atomic_dec(&dev->refcnt); 202 203 while (atomic_read(&dev->refcnt)) { 204 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 205 dev->name, atomic_read(&dev->refcnt)); 206 207 if (msleep_interruptible(1000)) 208 flush_signals(current); 209 } 210 211 memset(&msg, 0, sizeof(msg)); 212 msg.id.mst.id = dev->id; 213 msg.type = W1_MASTER_REMOVE; 214 w1_netlink_send(dev, &msg); 215 216 w1_free_dev(dev); 217 } 218 219 void w1_remove_master_device(struct w1_bus_master *bm) 220 { 221 struct w1_master *dev, *found = NULL; 222 223 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 224 if (!dev->initialized) 225 continue; 226 227 if (dev->bus_master->data == bm->data) { 228 found = dev; 229 break; 230 } 231 } 232 233 if (!found) { 234 printk(KERN_ERR "Device doesn't exist.\n"); 235 return; 236 } 237 238 __w1_remove_master_device(found); 239 } 240 241 EXPORT_SYMBOL(w1_add_master_device); 242 EXPORT_SYMBOL(w1_remove_master_device); 243