drivers/uwb/driver.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Ultra Wide Band
   4  * Driver initialization, etc
   5  *
   6  * Copyright (C) 2005-2006 Intel Corporation
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  *
   9  * FIXME: docs
  10  *
  11  * Life cycle: FIXME: explain
  12  *
  13  *  UWB radio controller:
  14  *
  15  *    1. alloc a uwb_rc, zero it
  16  *    2. call uwb_rc_init() on it to set it up + ops (won't do any
  17  *       kind of allocation)
  18  *    3. register (now it is owned by the UWB stack--deregister before
  19  *       freeing/destroying).
  20  *    4. It lives on it's own now (UWB stack handles)--when it
  21  *       disconnects, call unregister()
  22  *    5. free it.
  23  *
  24  *    Make sure you have a reference to the uwb_rc before calling
  25  *    any of the UWB API functions.
  26  *
  27  * TODO:
  28  *
  29  * 1. Locking and life cycle management is crappy still. All entry
  30  *    points to the UWB HCD API assume you have a reference on the
  31  *    uwb_rc structure and that it won't go away. They mutex lock it
  32  *    before doing anything.
  33  */
  34
  35 #include <linux/kernel.h>
  36 #include <linux/init.h>
  37 #include <linux/module.h>
  38 #include <linux/device.h>
  39 #include <linux/err.h>
  40 #include <linux/kdev_t.h>
  41 #include <linux/random.h>
  42
  43 #include "uwb-internal.h"
  44
  45
  46 /* UWB stack attributes (or 'global' constants) */
  47
  48
  49 /**
  50  * If a beacon disappears for longer than this, then we consider the
  51  * device who was represented by that beacon to be gone.
  52  *
  53  * ECMA-368[17.2.3, last para] establishes that a device must not
  54  * consider a device to be its neighbour if he doesn't receive a beacon
  55  * for more than mMaxLostBeacons. mMaxLostBeacons is defined in
  56  * ECMA-368[17.16] as 3; because we can get only one beacon per
  57  * superframe, that'd be 3 * 65ms = 195 ~ 200 ms. Let's give it time
  58  * for jitter and stuff and make it 500 ms.
  59  */
  60 unsigned long beacon_timeout_ms = 500;
  61
  62 static
  63 ssize_t beacon_timeout_ms_show(struct class *class,
  64                                 struct class_attribute *attr,
  65                                 char *buf)
  66 {
  67         return scnprintf(buf, PAGE_SIZE, "%lu\n", beacon_timeout_ms);
  68 }
  69
  70 static
  71 ssize_t beacon_timeout_ms_store(struct class *class,
  72                                 struct class_attribute *attr,
  73                                 const char *buf, size_t size)
  74 {
  75         unsigned long bt;
  76         ssize_t result;
  77         result = sscanf(buf, "%lu", &bt);
  78         if (result != 1)
  79                 return -EINVAL;
  80         beacon_timeout_ms = bt;
  81         return size;
  82 }
  83 static CLASS_ATTR_RW(beacon_timeout_ms);
  84
  85 static struct attribute *uwb_class_attrs[] = {
  86         &class_attr_beacon_timeout_ms.attr,
  87         NULL,
  88 };
  89 ATTRIBUTE_GROUPS(uwb_class);
  90
  91 /** Device model classes */
  92 struct class uwb_rc_class = {
  93         .name        = "uwb_rc",
  94         .class_groups = uwb_class_groups,
  95 };
  96
  97
  98 static int __init uwb_subsys_init(void)
  99 {
 100         int result = 0;
 101
 102         result = uwb_est_create();
 103         if (result < 0) {
 104                 printk(KERN_ERR "uwb: Can't initialize EST subsystem\n");
 105                 goto error_est_init;
 106         }
 107
 108         result = class_register(&uwb_rc_class);
 109         if (result < 0)
 110                 goto error_uwb_rc_class_register;
 111
 112         /* Register the UWB bus */
 113         result = bus_register(&uwb_bus_type);
 114         if (result) {
 115                 pr_err("%s - registering bus driver failed\n", __func__);
 116                 goto exit_bus;
 117         }
 118
 119         uwb_dbg_init();
 120         return 0;
 121
 122 exit_bus:
 123         class_unregister(&uwb_rc_class);
 124 error_uwb_rc_class_register:
 125         uwb_est_destroy();
 126 error_est_init:
 127         return result;
 128 }
 129 module_init(uwb_subsys_init);
 130
 131 static void __exit uwb_subsys_exit(void)
 132 {
 133         uwb_dbg_exit();
 134         bus_unregister(&uwb_bus_type);
 135         class_unregister(&uwb_rc_class);
 136         uwb_est_destroy();
 137         return;
 138 }
 139 module_exit(uwb_subsys_exit);
 140
 141 MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
 142 MODULE_DESCRIPTION("Ultra Wide Band core");
 143 MODULE_LICENSE("GPL");