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 struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl, 43 struct device_driver *driver, 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 = kmalloc(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 memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 60 61 dev->bus_master = (struct w1_bus_master *)(dev + 1); 62 63 dev->owner = THIS_MODULE; 64 dev->max_slave_count = slave_count; 65 dev->slave_count = 0; 66 dev->attempts = 0; 67 dev->kpid = -1; 68 dev->initialized = 0; 69 dev->id = id; 70 dev->slave_ttl = slave_ttl; 71 72 atomic_set(&dev->refcnt, 2); 73 74 INIT_LIST_HEAD(&dev->slist); 75 init_MUTEX(&dev->mutex); 76 77 init_completion(&dev->dev_released); 78 init_completion(&dev->dev_exited); 79 80 memcpy(&dev->dev, device, sizeof(struct device)); 81 snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id), 82 "w1_bus_master%u", dev->id); 83 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 84 85 dev->driver = driver; 86 87 dev->groups = 23; 88 dev->seq = 1; 89 dev->nls = netlink_kernel_create(NETLINK_NFLOG, NULL); 90 if (!dev->nls) { 91 printk(KERN_ERR "Failed to create new netlink socket(%u) for w1 master %s.\n", 92 NETLINK_NFLOG, dev->dev.bus_id); 93 } 94 95 err = device_register(&dev->dev); 96 if (err) { 97 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 98 if (dev->nls && dev->nls->sk_socket) 99 sock_release(dev->nls->sk_socket); 100 memset(dev, 0, sizeof(struct w1_master)); 101 kfree(dev); 102 dev = NULL; 103 } 104 105 return dev; 106 } 107 108 void w1_free_dev(struct w1_master *dev) 109 { 110 device_unregister(&dev->dev); 111 if (dev->nls && dev->nls->sk_socket) 112 sock_release(dev->nls->sk_socket); 113 memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 114 kfree(dev); 115 } 116 117 int w1_add_master_device(struct w1_bus_master *master) 118 { 119 struct w1_master *dev; 120 int retval = 0; 121 struct w1_netlink_msg msg; 122 123 dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device); 124 if (!dev) 125 return -ENOMEM; 126 127 dev->kpid = kernel_thread(&w1_process, dev, 0); 128 if (dev->kpid < 0) { 129 dev_err(&dev->dev, 130 "Failed to create new kernel thread. err=%d\n", 131 dev->kpid); 132 retval = dev->kpid; 133 goto err_out_free_dev; 134 } 135 136 retval = w1_create_master_attributes(dev); 137 if (retval) 138 goto err_out_kill_thread; 139 140 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 141 142 dev->initialized = 1; 143 144 spin_lock(&w1_mlock); 145 list_add(&dev->w1_master_entry, &w1_masters); 146 spin_unlock(&w1_mlock); 147 148 msg.id.mst.id = dev->id; 149 msg.id.mst.pid = dev->kpid; 150 msg.type = W1_MASTER_ADD; 151 w1_netlink_send(dev, &msg); 152 153 return 0; 154 155 err_out_kill_thread: 156 dev->need_exit = 1; 157 if (kill_proc(dev->kpid, SIGTERM, 1)) 158 dev_err(&dev->dev, 159 "Failed to send signal to w1 kernel thread %d.\n", 160 dev->kpid); 161 wait_for_completion(&dev->dev_exited); 162 163 err_out_free_dev: 164 w1_free_dev(dev); 165 166 return retval; 167 } 168 169 void __w1_remove_master_device(struct w1_master *dev) 170 { 171 int err; 172 struct w1_netlink_msg msg; 173 174 dev->need_exit = 1; 175 err = kill_proc(dev->kpid, SIGTERM, 1); 176 if (err) 177 dev_err(&dev->dev, 178 "%s: Failed to send signal to w1 kernel thread %d.\n", 179 __func__, dev->kpid); 180 181 while (atomic_read(&dev->refcnt)) { 182 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n", 183 dev->name, atomic_read(&dev->refcnt)); 184 185 if (msleep_interruptible(1000)) 186 flush_signals(current); 187 } 188 189 msg.id.mst.id = dev->id; 190 msg.id.mst.pid = dev->kpid; 191 msg.type = W1_MASTER_REMOVE; 192 w1_netlink_send(dev, &msg); 193 194 w1_free_dev(dev); 195 } 196 197 void w1_remove_master_device(struct w1_bus_master *bm) 198 { 199 struct w1_master *dev = NULL; 200 struct list_head *ent, *n; 201 202 list_for_each_safe(ent, n, &w1_masters) { 203 dev = list_entry(ent, struct w1_master, w1_master_entry); 204 if (!dev->initialized) 205 continue; 206 207 if (dev->bus_master->data == bm->data) 208 break; 209 } 210 211 if (!dev) { 212 printk(KERN_ERR "Device doesn't exist.\n"); 213 return; 214 } 215 216 __w1_remove_master_device(dev); 217 } 218 219 EXPORT_SYMBOL(w1_add_master_device); 220 EXPORT_SYMBOL(w1_remove_master_device); 221