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