uwb: reference count reservations
[linux-2.6.git] / drivers / usb / wusbcore / reservation.c
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
31 static 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  */
47 static void wusbhc_rsv_complete_cb(struct uwb_rsv *rsv)
48 {
49         struct wusbhc *wusbhc = rsv->pal_priv;
50         struct device *dev = wusbhc->dev;
51         char buf[72];
52
53         switch (rsv->state) {
54         case UWB_RSV_STATE_O_ESTABLISHED:
55                 bitmap_scnprintf(buf, sizeof(buf), rsv->mas.bm, UWB_NUM_MAS);
56                 dev_dbg(dev, "established reservation: %s\n", buf);
57                 wusbhc_bwa_set(wusbhc, rsv->stream, &rsv->mas);
58                 break;
59         case UWB_RSV_STATE_NONE:
60                 dev_dbg(dev, "removed reservation\n");
61                 wusbhc_bwa_set(wusbhc, 0, NULL);
62                 break;
63         default:
64                 dev_dbg(dev, "unexpected reservation state: %d\n", rsv->state);
65                 break;
66         }
67 }
68
69
70 /**
71  * wusbhc_rsv_establish - establish a reservation for the cluster
72  * @wusbhc: the WUSB HC requesting a bandwith reservation
73  */
74 int wusbhc_rsv_establish(struct wusbhc *wusbhc)
75 {
76         struct uwb_rc *rc = wusbhc->uwb_rc;
77         struct uwb_rsv *rsv;
78         struct uwb_dev_addr bcid;
79         int ret;
80
81         rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);
82         if (rsv == NULL)
83                 return -ENOMEM;
84
85         bcid.data[0] = wusbhc->cluster_id;
86         bcid.data[1] = 0;
87
88         rsv->owner = &rc->uwb_dev;
89         rsv->target.type = UWB_RSV_TARGET_DEVADDR;
90         rsv->target.devaddr = bcid;
91         rsv->type = UWB_DRP_TYPE_PRIVATE;
92         rsv->max_mas = 256;
93         rsv->min_mas = 16;  /* one MAS per zone? */
94         rsv->sparsity = 16; /* at least one MAS in each zone? */
95         rsv->is_multicast = true;
96
97         ret = uwb_rsv_establish(rsv);
98         if (ret == 0)
99                 wusbhc->rsv = rsv;
100         else
101                 uwb_rsv_destroy(rsv);
102         return ret;
103 }
104
105
106 /**
107  * wusbhc_rsv_terminate - terminate the cluster reservation
108  * @wusbhc: the WUSB host whose reservation is to be terminated
109  */
110 void wusbhc_rsv_terminate(struct wusbhc *wusbhc)
111 {
112         uwb_rsv_terminate(wusbhc->rsv);
113         uwb_rsv_destroy(wusbhc->rsv);
114 }