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