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 #include "w1_int.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->kpid               = -1;
  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         init_completion(&dev->dev_exited);
  71
  72         memcpy(&dev->dev, device, sizeof(struct device));
  73         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
  74                   "w1_bus_master%u", dev->id);
  75         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
  76
  77         dev->driver = driver;
  78
  79         dev->groups = 1;
  80         dev->seq = 1;
  81         dev_init_netlink(dev);
  82
  83         err = device_register(&dev->dev);
  84         if (err) {
  85                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
  86
  87                 dev_fini_netlink(dev);
  88
  89                 memset(dev, 0, sizeof(struct w1_master));
  90                 kfree(dev);
  91                 dev = NULL;
  92         }
  93
  94         return dev;
  95 }
  96
  97 static void w1_free_dev(struct w1_master *dev)
  98 {
  99         device_unregister(&dev->dev);
 100 }
 101
 102 int w1_add_master_device(struct w1_bus_master *master)
 103 {
 104         struct w1_master *dev;
 105         int retval = 0;
 106         struct w1_netlink_msg msg;
 107
 108         /* validate minimum functionality */
 109         if (!(master->touch_bit && master->reset_bus) &&
 110             !(master->write_bit && master->read_bit)) {
 111                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
 112                 return(-EINVAL);
 113         }
 114
 115         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
 116         if (!dev)
 117                 return -ENOMEM;
 118
 119         dev->kpid = kernel_thread(&w1_process, dev, 0);
 120         if (dev->kpid < 0) {
 121                 dev_err(&dev->dev,
 122                          "Failed to create new kernel thread. err=%d\n",
 123                          dev->kpid);
 124                 retval = dev->kpid;
 125                 goto err_out_free_dev;
 126         }
 127
 128         retval =  w1_create_master_attributes(dev);
 129         if (retval)
 130                 goto err_out_kill_thread;
 131
 132         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
 133
 134         dev->initialized = 1;
 135
 136         spin_lock(&w1_mlock);
 137         list_add(&dev->w1_master_entry, &w1_masters);
 138         spin_unlock(&w1_mlock);
 139
 140         msg.id.mst.id = dev->id;
 141         msg.id.mst.pid = dev->kpid;
 142         msg.type = W1_MASTER_ADD;
 143         w1_netlink_send(dev, &msg);
 144
 145         return 0;
 146
 147 err_out_kill_thread:
 148         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 149         if (kill_proc(dev->kpid, SIGTERM, 1))
 150                 dev_err(&dev->dev,
 151                          "Failed to send signal to w1 kernel thread %d.\n",
 152                          dev->kpid);
 153         wait_for_completion(&dev->dev_exited);
 154
 155 err_out_free_dev:
 156         w1_free_dev(dev);
 157
 158         return retval;
 159 }
 160
 161 void __w1_remove_master_device(struct w1_master *dev)
 162 {
 163         int err;
 164         struct w1_netlink_msg msg;
 165
 166         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 167         err = kill_proc(dev->kpid, SIGTERM, 1);
 168         if (err)
 169                 dev_err(&dev->dev,
 170                          "%s: Failed to send signal to w1 kernel thread %d.\n",
 171                          __func__, dev->kpid);
 172
 173         while (atomic_read(&dev->refcnt)) {
 174                 dev_dbg(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
 175                                 dev->name, atomic_read(&dev->refcnt));
 176
 177                 if (msleep_interruptible(1000))
 178                         flush_signals(current);
 179         }
 180
 181         msg.id.mst.id = dev->id;
 182         msg.id.mst.pid = dev->kpid;
 183         msg.type = W1_MASTER_REMOVE;
 184         w1_netlink_send(dev, &msg);
 185
 186         w1_free_dev(dev);
 187 }
 188
 189 void w1_remove_master_device(struct w1_bus_master *bm)
 190 {
 191         struct w1_master *dev = NULL;
 192
 193         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 194                 if (!dev->initialized)
 195                         continue;
 196
 197                 if (dev->bus_master->data == bm->data)
 198                         break;
 199         }
 200
 201         if (!dev) {
 202                 printk(KERN_ERR "Device doesn't exist.\n");
 203                 return;
 204         }
 205
 206         __w1_remove_master_device(dev);
 207 }
 208
 209 EXPORT_SYMBOL(w1_add_master_device);
 210 EXPORT_SYMBOL(w1_remove_master_device);
 211
 212 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_W1);