1/*
  2 * UWB PAL support.
  3 *
  4 * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU General Public License version
  8 * 2 as published by the Free Software Foundation.
  9 *
 10 * This program is distributed in the hope that it will be useful,
 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13 * GNU General Public License for more details.
 14 *
 15 * You should have received a copy of the GNU General Public License
 16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 17 */
 18#include <linux/kernel.h>
 19#include <linux/debugfs.h>
 20#include <linux/uwb.h>
 21#include <linux/export.h>
 22
 23#include "uwb-internal.h"
 24
 25/**
 26 * uwb_pal_init - initialize a UWB PAL
 27 * @pal: the PAL to initialize
 28 */
 29void uwb_pal_init(struct uwb_pal *pal)
 30{
 31	INIT_LIST_HEAD(&pal->node);
 32}
 33EXPORT_SYMBOL_GPL(uwb_pal_init);
 34
 35/**
 36 * uwb_pal_register - register a UWB PAL
 37 * @pal: the PAL
 38 *
 39 * The PAL must be initialized with uwb_pal_init().
 40 */
 41int uwb_pal_register(struct uwb_pal *pal)
 42{
 43	struct uwb_rc *rc = pal->rc;
 44	int ret;
 45
 46	if (pal->device) {
 47		/* create a link to the uwb_rc in the PAL device's directory. */
 48		ret = sysfs_create_link(&pal->device->kobj,
 49					&rc->uwb_dev.dev.kobj, "uwb_rc");
 50		if (ret < 0)
 51			return ret;
 52		/* create a link to the PAL in the UWB device's directory. */
 53		ret = sysfs_create_link(&rc->uwb_dev.dev.kobj,
 54					&pal->device->kobj, pal->name);
 55		if (ret < 0) {
 56			sysfs_remove_link(&pal->device->kobj, "uwb_rc");
 57			return ret;
 58		}
 59	}
 60
 61	pal->debugfs_dir = uwb_dbg_create_pal_dir(pal);
 62
 63	mutex_lock(&rc->uwb_dev.mutex);
 64	list_add(&pal->node, &rc->pals);
 65	mutex_unlock(&rc->uwb_dev.mutex);
 66
 67	return 0;
 68}
 69EXPORT_SYMBOL_GPL(uwb_pal_register);
 70
 71static int find_rc(struct device *dev, const void *data)
 72{
 73	const struct uwb_rc *target_rc = data;
 74	struct uwb_rc *rc = dev_get_drvdata(dev);
 75
 76	if (rc == NULL) {
 77		WARN_ON(1);
 78		return 0;
 79	}
 80	if (rc == target_rc) {
 81		if (rc->ready == 0)
 82			return 0;
 83		else
 84			return 1;
 85	}
 86	return 0;
 87}
 88
 89/**
 90 * Given a radio controller descriptor see if it is registered.
 91 *
 92 * @returns false if the rc does not exist or is quiescing; true otherwise.
 93 */
 94static bool uwb_rc_class_device_exists(struct uwb_rc *target_rc)
 95{
 96	struct device *dev;
 97
 98	dev = class_find_device(&uwb_rc_class, NULL, target_rc,	find_rc);
 99
100	return (dev != NULL);
101}
102
103/**
104 * uwb_pal_unregister - unregister a UWB PAL
105 * @pal: the PAL
106 */
107void uwb_pal_unregister(struct uwb_pal *pal)
108{
109	struct uwb_rc *rc = pal->rc;
110
111	uwb_radio_stop(pal);
112
113	mutex_lock(&rc->uwb_dev.mutex);
114	list_del(&pal->node);
115	mutex_unlock(&rc->uwb_dev.mutex);
116
117	debugfs_remove(pal->debugfs_dir);
118
119	if (pal->device) {
120		/* remove link to the PAL in the UWB device's directory. */
121		if (uwb_rc_class_device_exists(rc))
122			sysfs_remove_link(&rc->uwb_dev.dev.kobj, pal->name);
123
124		/* remove link to uwb_rc in the PAL device's directory. */
125		sysfs_remove_link(&pal->device->kobj, "uwb_rc");
126	}
127}
128EXPORT_SYMBOL_GPL(uwb_pal_unregister);
129
130/**
131 * uwb_rc_pal_init - initialize the PAL related parts of a radio controller
132 * @rc: the radio controller
133 */
134void uwb_rc_pal_init(struct uwb_rc *rc)
135{
136	INIT_LIST_HEAD(&rc->pals);
137}