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 #include <linux/kthread.h> 26 27 #include "w1.h" 28 #include "w1_log.h" 29 #include "w1_netlink.h" 30 #include "w1_int.h" 31 32 static u32 w1_ids = 1; 33 34 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl, 35 struct device_driver *driver, 36 struct device *device) 37 { 38 struct w1_master *dev; 39 int err; 40 41 /* 42 * We are in process context(kernel thread), so can sleep. 43 */ 44 dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); 45 if (!dev) { 46 printk(KERN_ERR 47 "Failed to allocate %zd bytes for new w1 device.\n", 48 sizeof(struct w1_master)); 49 return NULL; 50 } 51 52 memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master)); 53 54 dev->bus_master = (struct w1_bus_master *)(dev + 1); 55 56 dev->owner = THIS_MODULE; 57 dev->max_slave_count = slave_count; 58 dev->slave_count = 0; 59 dev->attempts = 0; 60 dev->initialized = 0; 61 dev->id = id; 62 dev->slave_ttl = slave_ttl; 63 dev->search_count = -1; /* continual scan */ 64 65 atomic_set(&dev->refcnt, 2); 66 67 INIT_LIST_HEAD(&dev->slist); 68 mutex_init(&dev->mutex); 69 70 memcpy(&dev->dev, device, sizeof(struct device)); 71 snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id), 72 "w1_bus_master%u", dev->id); 73 snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); 74 75 dev->driver = driver; 76 77 dev->seq = 1; 78 79 err = device_register(&dev->dev); 80 if (err) { 81 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 82 memset(dev, 0, sizeof(struct w1_master)); 83 kfree(dev); 84 dev = NULL; 85 } 86 87 return dev; 88 } 89 90 static void w1_free_dev(struct w1_master *dev) 91 { 92 device_unregister(&dev->dev); 93 } 94 95 int w1_add_master_device(struct w1_bus_master *master) 96 { 97 struct w1_master *dev; 98 int retval = 0; 99 struct w1_netlink_msg msg; 100 101 /* validate minimum functionality */ 102 if (!(master->touch_bit && master->reset_bus) && 103 !(master->write_bit && master->read_bit)) { 104 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 105 return(-EINVAL); 106 } 107 108 dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device); 109 if (!dev) 110 return -ENOMEM; 111 112 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 113 if (IS_ERR(dev->thread)) { 114 retval = PTR_ERR(dev->thread); 115 dev_err(&dev->dev, 116 "Failed to create new kernel thread. err=%d\n", 117 retval); 118 goto err_out_free_dev; 119 } 120 121 retval = w1_create_master_attributes(dev); 122 if (retval) 123 goto err_out_kill_thread; 124 125 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 126 127 dev->initialized = 1; 128 129 mutex_lock(&w1_mlock); 130 list_add(&dev->w1_master_entry, &w1_masters); 131 mutex_unlock(&w1_mlock); 132 133 memset(&msg, 0, sizeof(msg)); 134 msg.id.mst.id = dev->id; 135 msg.type = W1_MASTER_ADD; 136 w1_netlink_send(dev, &msg); 137 138 return 0; 139 140 err_out_kill_thread: 141 kthread_stop(dev->thread); 142 err_out_free_dev: 143 w1_free_dev(dev); 144 145 return retval; 146 } 147 148 void __w1_remove_master_device(struct w1_master *dev) 149 { 150 struct w1_netlink_msg msg; 151 152 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 153 kthread_stop(dev->thread); 154 155 while (atomic_read(&dev->refcnt)) { 156 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 157 dev->name, atomic_read(&dev->refcnt)); 158 159 if (msleep_interruptible(1000)) 160 flush_signals(current); 161 } 162 163 memset(&msg, 0, sizeof(msg)); 164 msg.id.mst.id = dev->id; 165 msg.type = W1_MASTER_REMOVE; 166 w1_netlink_send(dev, &msg); 167 168 w1_free_dev(dev); 169 } 170 171 void w1_remove_master_device(struct w1_bus_master *bm) 172 { 173 struct w1_master *dev = NULL; 174 175 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 176 if (!dev->initialized) 177 continue; 178 179 if (dev->bus_master->data == bm->data) 180 break; 181 } 182 183 if (!dev) { 184 printk(KERN_ERR "Device doesn't exist.\n"); 185 return; 186 } 187 188 __w1_remove_master_device(dev); 189 } 190 191 EXPORT_SYMBOL(w1_add_master_device); 192 EXPORT_SYMBOL(w1_remove_master_device); 193