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 init_MUTEX(&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->groups = 1; 78 dev->seq = 1; 79 dev_init_netlink(dev); 80 81 err = device_register(&dev->dev); 82 if (err) { 83 printk(KERN_ERR "Failed to register master device. err=%d\n", err); 84 85 dev_fini_netlink(dev); 86 87 memset(dev, 0, sizeof(struct w1_master)); 88 kfree(dev); 89 dev = NULL; 90 } 91 92 return dev; 93 } 94 95 static void w1_free_dev(struct w1_master *dev) 96 { 97 device_unregister(&dev->dev); 98 } 99 100 int w1_add_master_device(struct w1_bus_master *master) 101 { 102 struct w1_master *dev; 103 int retval = 0; 104 struct w1_netlink_msg msg; 105 106 /* validate minimum functionality */ 107 if (!(master->touch_bit && master->reset_bus) && 108 !(master->write_bit && master->read_bit)) { 109 printk(KERN_ERR "w1_add_master_device: invalid function set\n"); 110 return(-EINVAL); 111 } 112 113 dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device); 114 if (!dev) 115 return -ENOMEM; 116 117 dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); 118 if (IS_ERR(dev->thread)) { 119 retval = PTR_ERR(dev->thread); 120 dev_err(&dev->dev, 121 "Failed to create new kernel thread. err=%d\n", 122 retval); 123 goto err_out_free_dev; 124 } 125 126 retval = w1_create_master_attributes(dev); 127 if (retval) 128 goto err_out_kill_thread; 129 130 memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); 131 132 dev->initialized = 1; 133 134 spin_lock(&w1_mlock); 135 list_add(&dev->w1_master_entry, &w1_masters); 136 spin_unlock(&w1_mlock); 137 138 msg.id.mst.id = dev->id; 139 msg.id.mst.pid = dev->thread->pid; 140 msg.type = W1_MASTER_ADD; 141 w1_netlink_send(dev, &msg); 142 143 return 0; 144 145 err_out_kill_thread: 146 kthread_stop(dev->thread); 147 err_out_free_dev: 148 w1_free_dev(dev); 149 150 return retval; 151 } 152 153 void __w1_remove_master_device(struct w1_master *dev) 154 { 155 struct w1_netlink_msg msg; 156 pid_t pid = dev->thread->pid; 157 158 set_bit(W1_MASTER_NEED_EXIT, &dev->flags); 159 kthread_stop(dev->thread); 160 161 while (atomic_read(&dev->refcnt)) { 162 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", 163 dev->name, atomic_read(&dev->refcnt)); 164 165 if (msleep_interruptible(1000)) 166 flush_signals(current); 167 } 168 169 msg.id.mst.id = dev->id; 170 msg.id.mst.pid = pid; 171 msg.type = W1_MASTER_REMOVE; 172 w1_netlink_send(dev, &msg); 173 174 w1_free_dev(dev); 175 } 176 177 void w1_remove_master_device(struct w1_bus_master *bm) 178 { 179 struct w1_master *dev = NULL; 180 181 list_for_each_entry(dev, &w1_masters, w1_master_entry) { 182 if (!dev->initialized) 183 continue; 184 185 if (dev->bus_master->data == bm->data) 186 break; 187 } 188 189 if (!dev) { 190 printk(KERN_ERR "Device doesn't exist.\n"); 191 return; 192 } 193 194 __w1_remove_master_device(dev); 195 } 196 197 EXPORT_SYMBOL(w1_add_master_device); 198 EXPORT_SYMBOL(w1_remove_master_device); 199