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_master_driver;
  33 extern struct bus_type w1_bus_type;
  34 extern struct device w1_master_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_exited);
  80
  81         memcpy(&dev->dev, device, sizeof(struct device));
  82         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
  83                   "w1_bus_master%u", dev->id);
  84         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
  85
  86         dev->driver = driver;
  87
  88         dev->groups = 1;
  89         dev->seq = 1;
  90         dev_init_netlink(dev);
  91
  92         err = device_register(&dev->dev);
  93         if (err) {
  94                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
  95
  96                 dev_fini_netlink(dev);
  97
  98                 memset(dev, 0, sizeof(struct w1_master));
  99                 kfree(dev);
 100                 dev = NULL;
 101         }
 102
 103         return dev;
 104 }
 105
 106 void w1_free_dev(struct w1_master *dev)
 107 {
 108         device_unregister(&dev->dev);
 109 }
 110
 111 int w1_add_master_device(struct w1_bus_master *master)
 112 {
 113         struct w1_master *dev;
 114         int retval = 0;
 115         struct w1_netlink_msg msg;
 116
 117         /* validate minimum functionality */
 118         if (!(master->touch_bit && master->reset_bus) &&
 119             !(master->write_bit && master->read_bit)) {
 120                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
 121                 return(-EINVAL);
 122         }
 123
 124         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
 125         if (!dev)
 126                 return -ENOMEM;
 127
 128         dev->kpid = kernel_thread(&w1_process, dev, 0);
 129         if (dev->kpid < 0) {
 130                 dev_err(&dev->dev,
 131                          "Failed to create new kernel thread. err=%d\n",
 132                          dev->kpid);
 133                 retval = dev->kpid;
 134                 goto err_out_free_dev;
 135         }
 136
 137         retval =  w1_create_master_attributes(dev);
 138         if (retval)
 139                 goto err_out_kill_thread;
 140
 141         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
 142
 143         dev->initialized = 1;
 144
 145         spin_lock(&w1_mlock);
 146         list_add(&dev->w1_master_entry, &w1_masters);
 147         spin_unlock(&w1_mlock);
 148
 149         msg.id.mst.id = dev->id;
 150         msg.id.mst.pid = dev->kpid;
 151         msg.type = W1_MASTER_ADD;
 152         w1_netlink_send(dev, &msg);
 153
 154         return 0;
 155
 156 err_out_kill_thread:
 157         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 158         if (kill_proc(dev->kpid, SIGTERM, 1))
 159                 dev_err(&dev->dev,
 160                          "Failed to send signal to w1 kernel thread %d.\n",
 161                          dev->kpid);
 162         wait_for_completion(&dev->dev_exited);
 163
 164 err_out_free_dev:
 165         w1_free_dev(dev);
 166
 167         return retval;
 168 }
 169
 170 void __w1_remove_master_device(struct w1_master *dev)
 171 {
 172         int err;
 173         struct w1_netlink_msg msg;
 174
 175         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 176         err = kill_proc(dev->kpid, SIGTERM, 1);
 177         if (err)
 178                 dev_err(&dev->dev,
 179                          "%s: Failed to send signal to w1 kernel thread %d.\n",
 180                          __func__, dev->kpid);
 181
 182         while (atomic_read(&dev->refcnt)) {
 183                 dev_dbg(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
 184                                 dev->name, atomic_read(&dev->refcnt));
 185
 186                 if (msleep_interruptible(1000))
 187                         flush_signals(current);
 188         }
 189
 190         msg.id.mst.id = dev->id;
 191         msg.id.mst.pid = dev->kpid;
 192         msg.type = W1_MASTER_REMOVE;
 193         w1_netlink_send(dev, &msg);
 194
 195         w1_free_dev(dev);
 196 }
 197
 198 void w1_remove_master_device(struct w1_bus_master *bm)
 199 {
 200         struct w1_master *dev = NULL;
 201
 202         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 203                 if (!dev->initialized)
 204                         continue;
 205
 206                 if (dev->bus_master->data == bm->data)
 207                         break;
 208         }
 209
 210         if (!dev) {
 211                 printk(KERN_ERR "Device doesn't exist.\n");
 212                 return;
 213         }
 214
 215         __w1_remove_master_device(dev);
 216 }
 217
 218 EXPORT_SYMBOL(w1_add_master_device);
 219 EXPORT_SYMBOL(w1_remove_master_device);
 220
 221 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_W1);