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
  25 #include "w1.h"
  26 #include "w1_log.h"
  27 #include "w1_netlink.h"
  28
  29 static u32 w1_ids = 1;
  30
  31 extern struct device_driver w1_driver;
  32 extern struct bus_type w1_bus_type;
  33 extern struct device w1_device;
  34 extern int w1_max_slave_count;
  35 extern struct list_head w1_masters;
  36 extern spinlock_t w1_mlock;
  37
  38 extern int w1_process(void *);
  39
  40 struct w1_master * w1_alloc_dev(u32 id, int slave_count,
  41               struct device_driver *driver, struct device *device)
  42 {
  43         struct w1_master *dev;
  44         int err;
  45
  46         /*
  47          * We are in process context(kernel thread), so can sleep.
  48          */
  49         dev = kmalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
  50         if (!dev) {
  51                 printk(KERN_ERR
  52                         "Failed to allocate %zd bytes for new w1 device.\n",
  53                         sizeof(struct w1_master));
  54                 return NULL;
  55         }
  56
  57         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
  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->kpid               = -1;
  66         dev->initialized        = 0;
  67         dev->id                 = id;
  68
  69         atomic_set(&dev->refcnt, 2);
  70
  71         INIT_LIST_HEAD(&dev->slist);
  72         init_MUTEX(&dev->mutex);
  73
  74         init_waitqueue_head(&dev->kwait);
  75         init_completion(&dev->dev_released);
  76         init_completion(&dev->dev_exited);
  77
  78         memcpy(&dev->dev, device, sizeof(struct device));
  79         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
  80                   "w1_bus_master%u", dev->id);
  81         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
  82
  83         dev->driver = driver;
  84
  85         dev->groups = 23;
  86         dev->seq = 1;
  87         dev->nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
  88         if (!dev->nls) {
  89                 printk(KERN_ERR "Failed to create new netlink socket(%u).\n",
  90                         NETLINK_NFLOG);
  91                 memset(dev, 0, sizeof(struct w1_master));
  92                 kfree(dev);
  93                 dev = NULL;
  94         }
  95
  96         err = device_register(&dev->dev);
  97         if (err) {
  98                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
  99                 if (dev->nls->sk_socket)
 100                         sock_release(dev->nls->sk_socket);
 101                 memset(dev, 0, sizeof(struct w1_master));
 102                 kfree(dev);
 103                 dev = NULL;
 104         }
 105
 106         return dev;
 107 }
 108
 109 void w1_free_dev(struct w1_master *dev)
 110 {
 111         device_unregister(&dev->dev);
 112         if (dev->nls->sk_socket)
 113                 sock_release(dev->nls->sk_socket);
 114         memset(dev, 0, sizeof(struct w1_master) + sizeof(struct w1_bus_master));
 115         kfree(dev);
 116 }
 117
 118 int w1_add_master_device(struct w1_bus_master *master)
 119 {
 120         struct w1_master *dev;
 121         int retval = 0;
 122         struct w1_netlink_msg msg;
 123
 124         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, &w1_driver, &w1_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         dev->need_exit = 1;
 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         dev->need_exit = 1;
 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                 schedule_timeout(10);
 184
 185         msg.id.mst.id = dev->id;
 186         msg.id.mst.pid = dev->kpid;
 187         msg.type = W1_MASTER_REMOVE;
 188         w1_netlink_send(dev, &msg);
 189
 190         w1_free_dev(dev);
 191 }
 192
 193 void w1_remove_master_device(struct w1_bus_master *bm)
 194 {
 195         struct w1_master *dev = NULL;
 196         struct list_head *ent, *n;
 197
 198         list_for_each_safe(ent, n, &w1_masters) {
 199                 dev = list_entry(ent, struct w1_master, w1_master_entry);
 200                 if (!dev->initialized)
 201                         continue;
 202
 203                 if (dev->bus_master->data == bm->data)
 204                         break;
 205         }
 206
 207         if (!dev) {
 208                 printk(KERN_ERR "Device doesn't exist.\n");
 209                 return;
 210         }
 211
 212         __w1_remove_master_device(dev);
 213 }
 214
 215 EXPORT_SYMBOL(w1_alloc_dev);
 216 EXPORT_SYMBOL(w1_free_dev);
 217 EXPORT_SYMBOL(w1_add_master_device);
 218 EXPORT_SYMBOL(w1_remove_master_device);
 219 EXPORT_SYMBOL(__w1_remove_master_device);