reservation.c revision 5b37717a23b8e40f6cf7ad85a26ddcf41c171e2c 
1/*
2 * WUSB cluster reservation management
3 *
4 * Copyright (C) 2007 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/uwb.h>
20
21#include "wusbhc.h"
22
23/*
24 * WUSB cluster reservations are multicast reservations with the
25 * broadcast cluster ID (BCID) as the target DevAddr.
26 *
27 * FIXME: consider adjusting the reservation depending on what devices
28 * are attached.
29 */
30
31static int wusbhc_bwa_set(struct wusbhc *wusbhc, u8 stream,
32	const struct uwb_mas_bm *mas)
33{
34	if (mas == NULL)
35		mas = &uwb_mas_bm_zero;
36	return wusbhc->bwa_set(wusbhc, stream, mas);
37}
38
39/**
40 * wusbhc_rsv_complete_cb - WUSB HC reservation complete callback
41 * @rsv:    the reservation
42 *
43 * Either set or clear the HC's view of the reservation.
44 *
45 * FIXME: when a reservation is denied the HC should be stopped.
46 */
47static void wusbhc_rsv_complete_cb(struct uwb_rsv *rsv)
48{
49	struct wusbhc *wusbhc = rsv->pal_priv;
50	struct device *dev = wusbhc->dev;
51	struct uwb_mas_bm mas;
52	char buf[72];
53
54	switch (rsv->state) {
55	case UWB_RSV_STATE_O_ESTABLISHED:
56		uwb_rsv_get_usable_mas(rsv, &mas);
57		bitmap_scnprintf(buf, sizeof(buf), mas.bm, UWB_NUM_MAS);
58		dev_dbg(dev, "established reservation: %s\n", buf);
59		wusbhc_bwa_set(wusbhc, rsv->stream, &mas);
60		break;
61	case UWB_RSV_STATE_NONE:
62		dev_dbg(dev, "removed reservation\n");
63		wusbhc_bwa_set(wusbhc, 0, NULL);
64		break;
65	default:
66		dev_dbg(dev, "unexpected reservation state: %d\n", rsv->state);
67		break;
68	}
69}
70
71
72/**
73 * wusbhc_rsv_establish - establish a reservation for the cluster
74 * @wusbhc: the WUSB HC requesting a bandwith reservation
75 */
76int wusbhc_rsv_establish(struct wusbhc *wusbhc)
77{
78	struct uwb_rc *rc = wusbhc->uwb_rc;
79	struct uwb_rsv *rsv;
80	struct uwb_dev_addr bcid;
81	int ret;
82
83	rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);
84	if (rsv == NULL)
85		return -ENOMEM;
86
87	bcid.data[0] = wusbhc->cluster_id;
88	bcid.data[1] = 0;
89
90	rsv->target.type = UWB_RSV_TARGET_DEVADDR;
91	rsv->target.devaddr = bcid;
92	rsv->type = UWB_DRP_TYPE_PRIVATE;
93	rsv->max_mas = 256; /* try to get as much as possible */
94	rsv->min_mas = 15;  /* one MAS per zone */
95	rsv->max_interval = 1; /* max latency is one zone */
96	rsv->is_multicast = true;
97
98	ret = uwb_rsv_establish(rsv);
99	if (ret == 0)
100		wusbhc->rsv = rsv;
101	else
102		uwb_rsv_destroy(rsv);
103	return ret;
104}
105
106
107/**
108 * wusbhc_rsv_terminate - terminate the cluster reservation
109 * @wusbhc: the WUSB host whose reservation is to be terminated
110 */
111void wusbhc_rsv_terminate(struct wusbhc *wusbhc)
112{
113	uwb_rsv_terminate(wusbhc->rsv);
114	uwb_rsv_destroy(wusbhc->rsv);
115}
116