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         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  */
  76 int 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  */
 114 void 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 }