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 #include <linux/kthread.h>
  26
  27 #include "w1.h"
  28 #include "w1_log.h"
  29 #include "w1_netlink.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->initialized        = 0;
  60         dev->id                 = id;
  61         dev->slave_ttl          = slave_ttl;
  62         dev->search_count       = -1; /* continual scan */
  63
  64         atomic_set(&dev->refcnt, 2);
  65
  66         INIT_LIST_HEAD(&dev->slist);
  67         mutex_init(&dev->mutex);
  68
  69         memcpy(&dev->dev, device, sizeof(struct device));
  70         snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
  71                   "w1_bus_master%u", dev->id);
  72         snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
  73
  74         dev->driver = driver;
  75
  76         dev->seq = 1;
  77
  78         err = device_register(&dev->dev);
  79         if (err) {
  80                 printk(KERN_ERR "Failed to register master device. err=%d\n", err);
  81                 memset(dev, 0, sizeof(struct w1_master));
  82                 kfree(dev);
  83                 dev = NULL;
  84         }
  85
  86         return dev;
  87 }
  88
  89 static void w1_free_dev(struct w1_master *dev)
  90 {
  91         device_unregister(&dev->dev);
  92 }
  93
  94 int w1_add_master_device(struct w1_bus_master *master)
  95 {
  96         struct w1_master *dev;
  97         int retval = 0;
  98         struct w1_netlink_msg msg;
  99
 100         /* validate minimum functionality */
 101         if (!(master->touch_bit && master->reset_bus) &&
 102             !(master->write_bit && master->read_bit)) {
 103                 printk(KERN_ERR "w1_add_master_device: invalid function set\n");
 104                 return(-EINVAL);
 105         }
 106
 107         dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
 108         if (!dev)
 109                 return -ENOMEM;
 110
 111         dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
 112         if (IS_ERR(dev->thread)) {
 113                 retval = PTR_ERR(dev->thread);
 114                 dev_err(&dev->dev,
 115                          "Failed to create new kernel thread. err=%d\n",
 116                          retval);
 117                 goto err_out_free_dev;
 118         }
 119
 120         retval =  w1_create_master_attributes(dev);
 121         if (retval)
 122                 goto err_out_kill_thread;
 123
 124         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
 125
 126         dev->initialized = 1;
 127
 128         mutex_lock(&w1_mlock);
 129         list_add(&dev->w1_master_entry, &w1_masters);
 130         mutex_unlock(&w1_mlock);
 131
 132         memset(&msg, 0, sizeof(msg));
 133         msg.id.mst.id = dev->id;
 134         msg.type = W1_MASTER_ADD;
 135         w1_netlink_send(dev, &msg);
 136
 137         return 0;
 138
 139 err_out_kill_thread:
 140         kthread_stop(dev->thread);
 141 err_out_free_dev:
 142         w1_free_dev(dev);
 143
 144         return retval;
 145 }
 146
 147 void __w1_remove_master_device(struct w1_master *dev)
 148 {
 149         struct w1_netlink_msg msg;
 150
 151         set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 152         kthread_stop(dev->thread);
 153
 154         while (atomic_read(&dev->refcnt)) {
 155                 dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
 156                                 dev->name, atomic_read(&dev->refcnt));
 157
 158                 if (msleep_interruptible(1000))
 159                         flush_signals(current);
 160         }
 161
 162         memset(&msg, 0, sizeof(msg));
 163         msg.id.mst.id = dev->id;
 164         msg.type = W1_MASTER_REMOVE;
 165         w1_netlink_send(dev, &msg);
 166
 167         w1_free_dev(dev);
 168 }
 169
 170 void w1_remove_master_device(struct w1_bus_master *bm)
 171 {
 172         struct w1_master *dev = NULL;
 173
 174         list_for_each_entry(dev, &w1_masters, w1_master_entry) {
 175                 if (!dev->initialized)
 176                         continue;
 177
 178                 if (dev->bus_master->data == bm->data)
 179                         break;
 180         }
 181
 182         if (!dev) {
 183                 printk(KERN_ERR "Device doesn't exist.\n");
 184                 return;
 185         }
 186
 187         __w1_remove_master_device(dev);
 188 }
 189
 190 EXPORT_SYMBOL(w1_add_master_device);
 191 EXPORT_SYMBOL(w1_remove_master_device);