| 1 | /* |
| 2 | * w1_int.c |
| 3 | * |
| 4 | * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> |
| 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 | #include <linux/slab.h> |
| 27 | #include <linux/export.h> |
| 28 | #include <linux/moduleparam.h> |
| 29 | |
| 30 | #include "w1.h" |
| 31 | #include "w1_log.h" |
| 32 | #include "w1_netlink.h" |
| 33 | #include "w1_int.h" |
| 34 | |
| 35 | static int w1_search_count = -1; /* Default is continual scan */ |
| 36 | module_param_named(search_count, w1_search_count, int, 0); |
| 37 | |
| 38 | static int w1_enable_pullup = 1; |
| 39 | module_param_named(enable_pullup, w1_enable_pullup, int, 0); |
| 40 | |
| 41 | static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl, |
| 42 | struct device_driver *driver, |
| 43 | 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 = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); |
| 52 | if (!dev) { |
| 53 | pr_err("Failed to allocate %zd bytes for new w1 device.\n", |
| 54 | sizeof(struct w1_master)); |
| 55 | return NULL; |
| 56 | } |
| 57 | |
| 58 | |
| 59 | dev->bus_master = (struct w1_bus_master *)(dev + 1); |
| 60 | |
| 61 | dev->owner = THIS_MODULE; |
| 62 | dev->max_slave_count = slave_count; |
| 63 | dev->slave_count = 0; |
| 64 | dev->attempts = 0; |
| 65 | dev->initialized = 0; |
| 66 | dev->id = id; |
| 67 | dev->slave_ttl = slave_ttl; |
| 68 | dev->search_count = w1_search_count; |
| 69 | dev->enable_pullup = w1_enable_pullup; |
| 70 | |
| 71 | /* 1 for w1_process to decrement |
| 72 | * 1 for __w1_remove_master_device to decrement |
| 73 | */ |
| 74 | atomic_set(&dev->refcnt, 2); |
| 75 | |
| 76 | INIT_LIST_HEAD(&dev->slist); |
| 77 | INIT_LIST_HEAD(&dev->async_list); |
| 78 | mutex_init(&dev->mutex); |
| 79 | mutex_init(&dev->bus_mutex); |
| 80 | mutex_init(&dev->list_mutex); |
| 81 | |
| 82 | memcpy(&dev->dev, device, sizeof(struct device)); |
| 83 | dev_set_name(&dev->dev, "w1_bus_master%u", dev->id); |
| 84 | snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id); |
| 85 | dev->dev.init_name = dev->name; |
| 86 | |
| 87 | dev->driver = driver; |
| 88 | |
| 89 | dev->seq = 1; |
| 90 | |
| 91 | err = device_register(&dev->dev); |
| 92 | if (err) { |
| 93 | pr_err("Failed to register master device. err=%d\n", err); |
| 94 | put_device(&dev->dev); |
| 95 | dev = NULL; |
| 96 | } |
| 97 | |
| 98 | return dev; |
| 99 | } |
| 100 | |
| 101 | static void w1_free_dev(struct w1_master *dev) |
| 102 | { |
| 103 | device_unregister(&dev->dev); |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * w1_add_master_device() - registers a new master device |
| 108 | * @master: master bus device to register |
| 109 | */ |
| 110 | int w1_add_master_device(struct w1_bus_master *master) |
| 111 | { |
| 112 | struct w1_master *dev, *entry; |
| 113 | int retval = 0; |
| 114 | struct w1_netlink_msg msg; |
| 115 | int id, found; |
| 116 | |
| 117 | /* validate minimum functionality */ |
| 118 | if (!(master->touch_bit && master->reset_bus) && |
| 119 | !(master->write_bit && master->read_bit) && |
| 120 | !(master->write_byte && master->read_byte && master->reset_bus)) { |
| 121 | pr_err("w1_add_master_device: invalid function set\n"); |
| 122 | return(-EINVAL); |
| 123 | } |
| 124 | |
| 125 | /* Lock until the device is added (or not) to w1_masters. */ |
| 126 | mutex_lock(&w1_mlock); |
| 127 | /* Search for the first available id (starting at 1). */ |
| 128 | id = 0; |
| 129 | do { |
| 130 | ++id; |
| 131 | found = 0; |
| 132 | list_for_each_entry(entry, &w1_masters, w1_master_entry) { |
| 133 | if (entry->id == id) { |
| 134 | found = 1; |
| 135 | break; |
| 136 | } |
| 137 | } |
| 138 | } while (found); |
| 139 | |
| 140 | dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl, |
| 141 | &w1_master_driver, &w1_master_device); |
| 142 | if (!dev) { |
| 143 | mutex_unlock(&w1_mlock); |
| 144 | return -ENOMEM; |
| 145 | } |
| 146 | |
| 147 | retval = w1_create_master_attributes(dev); |
| 148 | if (retval) { |
| 149 | mutex_unlock(&w1_mlock); |
| 150 | goto err_out_free_dev; |
| 151 | } |
| 152 | |
| 153 | memcpy(dev->bus_master, master, sizeof(struct w1_bus_master)); |
| 154 | |
| 155 | dev->initialized = 1; |
| 156 | |
| 157 | dev->thread = kthread_run(&w1_process, dev, "%s", dev->name); |
| 158 | if (IS_ERR(dev->thread)) { |
| 159 | retval = PTR_ERR(dev->thread); |
| 160 | dev_err(&dev->dev, |
| 161 | "Failed to create new kernel thread. err=%d\n", |
| 162 | retval); |
| 163 | mutex_unlock(&w1_mlock); |
| 164 | goto err_out_rm_attr; |
| 165 | } |
| 166 | |
| 167 | list_add(&dev->w1_master_entry, &w1_masters); |
| 168 | mutex_unlock(&w1_mlock); |
| 169 | |
| 170 | memset(&msg, 0, sizeof(msg)); |
| 171 | msg.id.mst.id = dev->id; |
| 172 | msg.type = W1_MASTER_ADD; |
| 173 | w1_netlink_send(dev, &msg); |
| 174 | |
| 175 | return 0; |
| 176 | |
| 177 | #if 0 /* Thread cleanup code, not required currently. */ |
| 178 | err_out_kill_thread: |
| 179 | set_bit(W1_ABORT_SEARCH, &dev->flags); |
| 180 | kthread_stop(dev->thread); |
| 181 | #endif |
| 182 | err_out_rm_attr: |
| 183 | w1_destroy_master_attributes(dev); |
| 184 | err_out_free_dev: |
| 185 | w1_free_dev(dev); |
| 186 | |
| 187 | return retval; |
| 188 | } |
| 189 | |
| 190 | void __w1_remove_master_device(struct w1_master *dev) |
| 191 | { |
| 192 | struct w1_netlink_msg msg; |
| 193 | struct w1_slave *sl, *sln; |
| 194 | |
| 195 | mutex_lock(&w1_mlock); |
| 196 | list_del(&dev->w1_master_entry); |
| 197 | mutex_unlock(&w1_mlock); |
| 198 | |
| 199 | set_bit(W1_ABORT_SEARCH, &dev->flags); |
| 200 | kthread_stop(dev->thread); |
| 201 | |
| 202 | mutex_lock(&dev->mutex); |
| 203 | mutex_lock(&dev->list_mutex); |
| 204 | list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) { |
| 205 | mutex_unlock(&dev->list_mutex); |
| 206 | w1_slave_detach(sl); |
| 207 | mutex_lock(&dev->list_mutex); |
| 208 | } |
| 209 | w1_destroy_master_attributes(dev); |
| 210 | mutex_unlock(&dev->list_mutex); |
| 211 | mutex_unlock(&dev->mutex); |
| 212 | atomic_dec(&dev->refcnt); |
| 213 | |
| 214 | while (atomic_read(&dev->refcnt)) { |
| 215 | dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", |
| 216 | dev->name, atomic_read(&dev->refcnt)); |
| 217 | |
| 218 | if (msleep_interruptible(1000)) |
| 219 | flush_signals(current); |
| 220 | mutex_lock(&dev->list_mutex); |
| 221 | w1_process_callbacks(dev); |
| 222 | mutex_unlock(&dev->list_mutex); |
| 223 | } |
| 224 | mutex_lock(&dev->list_mutex); |
| 225 | w1_process_callbacks(dev); |
| 226 | mutex_unlock(&dev->list_mutex); |
| 227 | |
| 228 | memset(&msg, 0, sizeof(msg)); |
| 229 | msg.id.mst.id = dev->id; |
| 230 | msg.type = W1_MASTER_REMOVE; |
| 231 | w1_netlink_send(dev, &msg); |
| 232 | |
| 233 | w1_free_dev(dev); |
| 234 | } |
| 235 | |
| 236 | /** |
| 237 | * w1_remove_master_device() - unregister a master device |
| 238 | * @bm: master bus device to remove |
| 239 | */ |
| 240 | void w1_remove_master_device(struct w1_bus_master *bm) |
| 241 | { |
| 242 | struct w1_master *dev, *found = NULL; |
| 243 | |
| 244 | list_for_each_entry(dev, &w1_masters, w1_master_entry) { |
| 245 | if (!dev->initialized) |
| 246 | continue; |
| 247 | |
| 248 | if (dev->bus_master->data == bm->data) { |
| 249 | found = dev; |
| 250 | break; |
| 251 | } |
| 252 | } |
| 253 | |
| 254 | if (!found) { |
| 255 | pr_err("Device doesn't exist.\n"); |
| 256 | return; |
| 257 | } |
| 258 | |
| 259 | __w1_remove_master_device(found); |
| 260 | } |
| 261 | |
| 262 | EXPORT_SYMBOL(w1_add_master_device); |
| 263 | EXPORT_SYMBOL(w1_remove_master_device); |