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 26 #include "w1.h" 27 #include "w1_log.h" 28 #include "w1_netlink.h" 29 30 static u32 w1_ids = 1; 31 32 extern struct device_driver w1_master_driver; 33 extern struct bus_type w1_bus_type; 34 extern struct device w1_master_device; 35 extern int w1_max_slave_count; 36 extern int w1_max_slave_ttl; 37 extern struct list_head w1_masters; 38 extern spinlock_t w1_mlock; 39 40 extern int w1_process(void *); 41 42 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl, 43 struct device_driver *driver, 44 struct device *device) 45 { 46 struct w1_master *dev; 47 int err; 48 49 /* 50 * We are in process context(kernel thread), so can sleep. 51 */ 52 dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); 53 if (!dev) { 54 printk(KERN_ERR 55 "Failed to allocate %zd bytes for new w1 device.\n", 56 sizeof(struct w1_master)); 57 return NULL; 58 } 59 60 memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 61 62 dev->bus_master = (struct w1_bus_master *)(dev + 1); 63 64 dev->owner = THIS_MODULE; 65 dev->max_slave_count = slave_count; 66 dev->slave_count = 0; 67 dev->attempts = 0; 68 dev->kpid = -1; 69 dev->initialized = 0; 70 dev->id = id; 71 dev->slave_ttl = slave_ttl; 72 dev->search_count = -1; /* continual scan */ 73 74 atomic_set(&dev->refcnt, 2); 75 76 INIT_LIST_HEAD(&dev->slist); 77 init_MUTEX(&dev->mutex); 78 79 init_completion(&dev->dev_exited); 80 81 memcpy(&dev->dev, device, sizeof(struct device)); 82 snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id), 83 "w1_bus_master%u", dev->id); 84 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 85 86 dev->driver = driver; 87 88 dev->groups = 1; 89 dev->seq = 1; 90 dev_init_netlink(dev); 91 92 err = device_register(&dev->dev); 93 if (err) { 94 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 95 96 dev_fini_netlink(dev); 97 98 memset(dev, 0, sizeof(struct w1_master)); 99 kfree(dev); 100 dev = NULL; 101 } 102 103 return dev; 104 } 105 106 void w1_free_dev(struct w1_master *dev) 107 { 108 device_unregister(&dev->dev); 109 } 110 111 int w1_add_master_device(struct w1_bus_master *master) 112 { 113 struct w1_master *dev; 114 int retval = 0; 115 struct w1_netlink_msg msg; 116 117 /* validate minimum functionality */ 118 if (!(master->touch_bit && master->reset_bus) && 119 !(master->write_bit && master->read_bit)) { 120 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 121 return(-EINVAL); 122 } 123 124 dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device); 125 if (!dev) 126 return -ENOMEM; 127 128 dev->kpid = kernel_thread(&w1_process, dev, 0); 129 if (dev->kpid < 0) { 130 dev_err(&dev->dev, 131 "Failed to create new kernel thread. err=%d\n", 132 dev->kpid); 133 retval = dev->kpid; 134 goto err_out_free_dev; 135 } 136 137 retval = w1_create_master_attributes(dev); 138 if (retval) 139 goto err_out_kill_thread; 140 141 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 142 143 dev->initialized = 1; 144 145 spin_lock(&w1_mlock); 146 list_add(&dev->w1_master_entry, &w1_masters); 147 spin_unlock(&w1_mlock); 148 149 msg.id.mst.id = dev->id; 150 msg.id.mst.pid = dev->kpid; 151 msg.type = W1_MASTER_ADD; 152 w1_netlink_send(dev, &msg); 153 154 return 0; 155 156 err_out_kill_thread: 157 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 158 if (kill_proc(dev->kpid, SIGTERM, 1)) 159 dev_err(&dev->dev, 160 "Failed to send signal to w1 kernel thread %d.\n", 161 dev->kpid); 162 wait_for_completion(&dev->dev_exited); 163 164 err_out_free_dev: 165 w1_free_dev(dev); 166 167 return retval; 168 } 169 170 void __w1_remove_master_device(struct w1_master *dev) 171 { 172 int err; 173 struct w1_netlink_msg msg; 174 175 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 176 err = kill_proc(dev->kpid, SIGTERM, 1); 177 if (err) 178 dev_err(&dev->dev, 179 "%s: Failed to send signal to w1 kernel thread %d.\n", 180 __func__, dev->kpid); 181 182 while (atomic_read(&dev->refcnt)) { 183 dev_dbg(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 184 dev->name, atomic_read(&dev->refcnt)); 185 186 if (msleep_interruptible(1000)) 187 flush_signals(current); 188 } 189 190 msg.id.mst.id = dev->id; 191 msg.id.mst.pid = dev->kpid; 192 msg.type = W1_MASTER_REMOVE; 193 w1_netlink_send(dev, &msg); 194 195 w1_free_dev(dev); 196 } 197 198 void w1_remove_master_device(struct w1_bus_master *bm) 199 { 200 struct w1_master *dev = NULL; 201 202 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 203 if (!dev->initialized) 204 continue; 205 206 if (dev->bus_master->data == bm->data) 207 break; 208 } 209 210 if (!dev) { 211 printk(KERN_ERR "Device doesn't exist.\n"); 212 return; 213 } 214 215 __w1_remove_master_device(dev); 216 } 217 218 EXPORT_SYMBOL(w1_add_master_device); 219 EXPORT_SYMBOL(w1_remove_master_device); 220 221 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_W1); 222