drivers/w1/w1_int.c

   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 static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
  43                                        struct device_driver *driver,
  44                                        struct device *device)
  45 {
  46         struct w1_master *dev;
  47         int err;
  48
  49         /*
  50          * We are in process context(kernel thread), so can sleep.
  51          */
  52         dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
  53         if (!dev) {
  54                 printk(KERN_ERR
  55                         "Failed to allocate %zd bytes for new w1 device.\n",
  56                         sizeof(struct w1_master));
  57                 return NULL;
  58         }
  59
  60         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  61
  62         dev->bus_master = (struct w1_bus_master *)(dev + 1);
  63
  64         dev->owner              = THIS_MODULE;
  65         dev->max_slave_count    = slave_count;
  66         dev->slave_count        = 0;
  67         dev->attempts           = 0;
  68         dev->kpid               = -1;
  69         dev->initialized        = 0;
  70         dev->id                 = id;
  71         dev->slave_ttl          = slave_ttl;
  72         dev->search_count       = -1; /* continual scan */
  73
  74         atomic_set(&dev->refcnt, 2);
  75
  76         INIT_LIST_HEAD(&dev->slist);
  77         init_MUTEX(&dev->mutex);
  78
  79         init_completion(&dev->dev_released);
  80         init_completion(&dev->dev_exited);
  81
  82         memcpy(&dev->dev, device, sizeof(struct device));
  83         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
  84                   "w1_bus_master%u", dev->id);
  85         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
  86
  87         dev->driver = driver;
  88
  89         dev->groups = 23;
  90         dev->seq = 1;
  91         dev->nls = netlink_kernel_create(NETLINK_W1, NULL);
  92         if (!dev->nls) {
  93                 printk(KERN_ERR "Failed to create new netlink socket(%u) for w1 master %s.\n",
  94                         NETLINK_NFLOG, dev->dev.bus_id);
  95         }
  96
  97         err = device_register(&dev->dev);
  98         if (err) {
  99                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
 100                 if (dev->nls && dev->nls->sk_socket)
 101                         sock_release(dev->nls->sk_socket);
 102                 memset(dev, 0, sizeof(struct w1_master));
 103                 kfree(dev);
 104                 dev = NULL;
 105         }
 106
 107         return dev;
 108 }
 109
 110 static void w1_free_dev(struct w1_master *dev)
 111 {
 112         device_unregister(&dev->dev);
 113         if (dev->nls && dev->nls->sk_socket)
 114                 sock_release(dev->nls->sk_socket);
 115         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
 116         kfree(dev);
 117 }
 118
 119 int w1_add_master_device(struct w1_bus_master *master)
 120 {
 121         struct w1_master *dev;
 122         int retval = 0;
 123         struct w1_netlink_msg msg;
 124
 125         /* validate minimum functionality */
 126         if (!(master->touch_bit && master->reset_bus) &&
 127             !(master->write_bit && master->read_bit)) {
 128                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
 129                 return(-EINVAL);
 130         }
 131
 132         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_driver, &w1_device);
 133         if (!dev)
 134                 return -ENOMEM;
 135
 136         dev->kpid = kernel_thread(&w1_process, dev, 0);
 137         if (dev->kpid < 0) {
 138                 dev_err(&dev->dev,
 139                          "Failed to create new kernel thread. err=%d\n",
 140                          dev->kpid);
 141                 retval = dev->kpid;
 142                 goto err_out_free_dev;
 143         }
 144
 145         retval =  w1_create_master_attributes(dev);
 146         if (retval)
 147                 goto err_out_kill_thread;
 148
 149         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
 150
 151         dev->initialized = 1;
 152
 153         spin_lock(&w1_mlock);
 154         list_add(&dev->w1_master_entry, &w1_masters);
 155         spin_unlock(&w1_mlock);
 156
 157         msg.id.mst.id = dev->id;
 158         msg.id.mst.pid = dev->kpid;
 159         msg.type = W1_MASTER_ADD;
 160         w1_netlink_send(dev, &msg);
 161
 162         return 0;
 163
 164 err_out_kill_thread:
 165         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 166         if (kill_proc(dev->kpid, SIGTERM, 1))
 167                 dev_err(&dev->dev,
 168                          "Failed to send signal to w1 kernel thread %d.\n",
 169                          dev->kpid);
 170         wait_for_completion(&dev->dev_exited);
 171
 172 err_out_free_dev:
 173         w1_free_dev(dev);
 174
 175         return retval;
 176 }
 177
 178 void __w1_remove_master_device(struct w1_master *dev)
 179 {
 180         int err;
 181         struct w1_netlink_msg msg;
 182
 183         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 184         err = kill_proc(dev->kpid, SIGTERM, 1);
 185         if (err)
 186                 dev_err(&dev->dev,
 187                          "%s: Failed to send signal to w1 kernel thread %d.\n",
 188                          __func__, dev->kpid);
 189
 190         while (atomic_read(&dev->refcnt)) {
 191                 printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
 192                                 dev->name, atomic_read(&dev->refcnt));
 193
 194                 if (msleep_interruptible(1000))
 195                         flush_signals(current);
 196         }
 197
 198         msg.id.mst.id = dev->id;
 199         msg.id.mst.pid = dev->kpid;
 200         msg.type = W1_MASTER_REMOVE;
 201         w1_netlink_send(dev, &msg);
 202
 203         w1_free_dev(dev);
 204 }
 205
 206 void w1_remove_master_device(struct w1_bus_master *bm)
 207 {
 208         struct w1_master *dev = NULL;
 209
 210         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 211                 if (!dev->initialized)
 212                         continue;
 213
 214                 if (dev->bus_master->data == bm->data)
 215                         break;
 216         }
 217
 218         if (!dev) {
 219                 printk(KERN_ERR "Device doesn't exist.\n");
 220                 return;
 221         }
 222
 223         __w1_remove_master_device(dev);
 224 }
 225
 226 EXPORT_SYMBOL(w1_add_master_device);
 227 EXPORT_SYMBOL(w1_remove_master_device);