LXR linux/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
  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
  53        dev_dbg(dev, "%s: state = %d\n", __func__, rsv->state);
  54        switch (rsv->state) {
  55        case UWB_RSV_STATE_O_ESTABLISHED:
  56                uwb_rsv_get_usable_mas(rsv, &mas);
  57                dev_dbg(dev, "established reservation: %*pb\n",
  58                        UWB_NUM_MAS, mas.bm);
  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 bandwidth 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        if (rc == NULL)
  84                return -ENODEV;
  85
  86        rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);
  87        if (rsv == NULL)
  88                return -ENOMEM;
  89
  90        bcid.data[0] = wusbhc->cluster_id;
  91        bcid.data[1] = 0;
  92
  93        rsv->target.type = UWB_RSV_TARGET_DEVADDR;
  94        rsv->target.devaddr = bcid;
  95        rsv->type = UWB_DRP_TYPE_PRIVATE;
  96        rsv->max_mas = 256; /* try to get as much as possible */
  97        rsv->min_mas = 15;  /* one MAS per zone */
  98        rsv->max_interval = 1; /* max latency is one zone */
  99        rsv->is_multicast = true;
 100
 101        ret = uwb_rsv_establish(rsv);
 102        if (ret == 0)
 103                wusbhc->rsv = rsv;
 104        else
 105                uwb_rsv_destroy(rsv);
 106        return ret;
 107}
 108
 109
 110/**
 111 * wusbhc_rsv_terminate - terminate the cluster reservation
 112 * @wusbhc: the WUSB host whose reservation is to be terminated
 113 */
 114void wusbhc_rsv_terminate(struct wusbhc *wusbhc)
 115{
 116        if (wusbhc->rsv) {
 117                uwb_rsv_terminate(wusbhc->rsv);
 118                uwb_rsv_destroy(wusbhc->rsv);
 119                wusbhc->rsv = NULL;
 120        }
 121}
 122