drivers/uwb/driver.c

   1 /*
   2  * Ultra Wide Band
   3  * Driver initialization, etc
   4  *
   5  * Copyright (C) 2005-2006 Intel Corporation
   6  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License version
  10  * 2 as published by the Free Software Foundation.
  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., 51 Franklin Street, Fifth Floor, Boston, MA
  20  * 02110-1301, USA.
  21  *
  22  *
  23  * FIXME: docs
  24  *
  25  * Life cycle: FIXME: explain
  26  *
  27  *  UWB radio controller:
  28  *
  29  *    1. alloc a uwb_rc, zero it
  30  *    2. call uwb_rc_init() on it to set it up + ops (won't do any
  31  *       kind of allocation)
  32  *    3. register (now it is owned by the UWB stack--deregister before
  33  *       freeing/destroying).
  34  *    4. It lives on it's own now (UWB stack handles)--when it
  35  *       disconnects, call unregister()
  36  *    5. free it.
  37  *
  38  *    Make sure you have a reference to the uwb_rc before calling
  39  *    any of the UWB API functions.
  40  *
  41  * TODO:
  42  *
  43  * 1. Locking and life cycle management is crappy still. All entry
  44  *    points to the UWB HCD API assume you have a reference on the
  45  *    uwb_rc structure and that it won't go away. They mutex lock it
  46  *    before doing anything.
  47  */
  48
  49 #include <linux/kernel.h>
  50 #include <linux/init.h>
  51 #include <linux/module.h>
  52 #include <linux/device.h>
  53 #include <linux/err.h>
  54 #include <linux/kdev_t.h>
  55 #include <linux/random.h>
  56
  57 #include "uwb-internal.h"
  58
  59
  60 /* UWB stack attributes (or 'global' constants) */
  61
  62
  63 /**
  64  * If a beacon disappears for longer than this, then we consider the
  65  * device who was represented by that beacon to be gone.
  66  *
  67  * ECMA-368[17.2.3, last para] establishes that a device must not
  68  * consider a device to be its neighbour if he doesn't receive a beacon
  69  * for more than mMaxLostBeacons. mMaxLostBeacons is defined in
  70  * ECMA-368[17.16] as 3; because we can get only one beacon per
  71  * superframe, that'd be 3 * 65ms = 195 ~ 200 ms. Let's give it time
  72  * for jitter and stuff and make it 500 ms.
  73  */
  74 unsigned long beacon_timeout_ms = 500;
  75
  76 static
  77 ssize_t beacon_timeout_ms_show(struct class *class,
  78                                 struct class_attribute *attr,
  79                                 char *buf)
  80 {
  81         return scnprintf(buf, PAGE_SIZE, "%lu\n", beacon_timeout_ms);
  82 }
  83
  84 static
  85 ssize_t beacon_timeout_ms_store(struct class *class,
  86                                 struct class_attribute *attr,
  87                                 const char *buf, size_t size)
  88 {
  89         unsigned long bt;
  90         ssize_t result;
  91         result = sscanf(buf, "%lu", &bt);
  92         if (result != 1)
  93                 return -EINVAL;
  94         beacon_timeout_ms = bt;
  95         return size;
  96 }
  97
  98 static struct class_attribute uwb_class_attrs[] = {
  99         __ATTR(beacon_timeout_ms, S_IWUSR | S_IRUGO,
 100                beacon_timeout_ms_show, beacon_timeout_ms_store),
 101         __ATTR_NULL,
 102 };
 103
 104 /** Device model classes */
 105 struct class uwb_rc_class = {
 106         .name        = "uwb_rc",
 107         .class_attrs = uwb_class_attrs,
 108 };
 109
 110
 111 static int __init uwb_subsys_init(void)
 112 {
 113         int result = 0;
 114
 115         result = uwb_est_create();
 116         if (result < 0) {
 117                 printk(KERN_ERR "uwb: Can't initialize EST subsystem\n");
 118                 goto error_est_init;
 119         }
 120
 121         result = class_register(&uwb_rc_class);
 122         if (result < 0)
 123                 goto error_uwb_rc_class_register;
 124
 125         /* Register the UWB bus */
 126         result = bus_register(&uwb_bus_type);
 127         if (result) {
 128                 pr_err("%s - registering bus driver failed\n", __func__);
 129                 goto exit_bus;
 130         }
 131
 132         uwb_dbg_init();
 133         return 0;
 134
 135 exit_bus:
 136         class_unregister(&uwb_rc_class);
 137 error_uwb_rc_class_register:
 138         uwb_est_destroy();
 139 error_est_init:
 140         return result;
 141 }
 142 module_init(uwb_subsys_init);
 143
 144 static void __exit uwb_subsys_exit(void)
 145 {
 146         uwb_dbg_exit();
 147         bus_unregister(&uwb_bus_type);
 148         class_unregister(&uwb_rc_class);
 149         uwb_est_destroy();
 150         return;
 151 }
 152 module_exit(uwb_subsys_exit);
 153
 154 MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
 155 MODULE_DESCRIPTION("Ultra Wide Band core");
 156 MODULE_LICENSE("GPL");