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_driver; 33 extern struct bus_type w1_bus_type; 34 extern struct device w1_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_released); 80 init_completion(&dev->dev_exited); 81 82 memcpy(&dev->dev, device, sizeof(struct device)); 83 snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id), 84 "w1_bus_master%u", dev->id); 85 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 86 87 dev->driver = driver; 88 89 dev->groups = 23; 90 dev->seq = 1; 91 dev->nls = netlink_kernel_create(NETLINK_NFLOG, NULL); 92 if (!dev->nls) { 93 printk(KERN_ERR "Failed to create new netlink socket(%u) for w1 master %s.\n", 94 NETLINK_NFLOG, dev->dev.bus_id); 95 } 96 97 err = device_register(&dev->dev); 98 if (err) { 99 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 100 if (dev->nls && dev->nls->sk_socket) 101 sock_release(dev->nls->sk_socket); 102 memset(dev, 0, sizeof(struct w1_master)); 103 kfree(dev); 104 dev = NULL; 105 } 106 107 return dev; 108 } 109 110 static void w1_free_dev(struct w1_master *dev) 111 { 112 device_unregister(&dev->dev); 113 if (dev->nls && dev->nls->sk_socket) 114 sock_release(dev->nls->sk_socket); 115 memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 116 kfree(dev); 117 } 118 119 int w1_add_master_device(struct w1_bus_master *master) 120 { 121 struct w1_master *dev; 122 int retval = 0; 123 struct w1_netlink_msg msg; 124 125 /* validate minimum functionality */ 126 if (!(master->touch_bit && master->reset_bus) && 127 !(master->write_bit && master->read_bit)) { 128 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 129 return(-EINVAL); 130 } 131 132 dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device); 133 if (!dev) 134 return -ENOMEM; 135 136 dev->kpid = kernel_thread(&w1_process, dev, 0); 137 if (dev->kpid < 0) { 138 dev_err(&dev->dev, 139 "Failed to create new kernel thread. err=%d\n", 140 dev->kpid); 141 retval = dev->kpid; 142 goto err_out_free_dev; 143 } 144 145 retval = w1_create_master_attributes(dev); 146 if (retval) 147 goto err_out_kill_thread; 148 149 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 150 151 dev->initialized = 1; 152 153 spin_lock(&w1_mlock); 154 list_add(&dev->w1_master_entry, &w1_masters); 155 spin_unlock(&w1_mlock); 156 157 msg.id.mst.id = dev->id; 158 msg.id.mst.pid = dev->kpid; 159 msg.type = W1_MASTER_ADD; 160 w1_netlink_send(dev, &msg); 161 162 return 0; 163 164 err_out_kill_thread: 165 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 166 if (kill_proc(dev->kpid, SIGTERM, 1)) 167 dev_err(&dev->dev, 168 "Failed to send signal to w1 kernel thread %d.\n", 169 dev->kpid); 170 wait_for_completion(&dev->dev_exited); 171 172 err_out_free_dev: 173 w1_free_dev(dev); 174 175 return retval; 176 } 177 178 void __w1_remove_master_device(struct w1_master *dev) 179 { 180 int err; 181 struct w1_netlink_msg msg; 182 183 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 184 err = kill_proc(dev->kpid, SIGTERM, 1); 185 if (err) 186 dev_err(&dev->dev, 187 "%s: Failed to send signal to w1 kernel thread %d.\n", 188 __func__, dev->kpid); 189 190 while (atomic_read(&dev->refcnt)) { 191 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n", 192 dev->name, atomic_read(&dev->refcnt)); 193 194 if (msleep_interruptible(1000)) 195 flush_signals(current); 196 } 197 198 msg.id.mst.id = dev->id; 199 msg.id.mst.pid = dev->kpid; 200 msg.type = W1_MASTER_REMOVE; 201 w1_netlink_send(dev, &msg); 202 203 w1_free_dev(dev); 204 } 205 206 void w1_remove_master_device(struct w1_bus_master *bm) 207 { 208 struct w1_master *dev = NULL; 209 210 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 211 if (!dev->initialized) 212 continue; 213 214 if (dev->bus_master->data == bm->data) 215 break; 216 } 217 218 if (!dev) { 219 printk(KERN_ERR "Device doesn't exist.\n"); 220 return; 221 } 222 223 __w1_remove_master_device(dev); 224 } 225 226 EXPORT_SYMBOL(w1_add_master_device); 227 EXPORT_SYMBOL(w1_remove_master_device); 228