drivers/usb/wusbcore/reservation.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * WUSB cluster reservation management
   4  *
   5  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/uwb.h>
   9
  10 #include "wusbhc.h"
  11
  12 /*
  13  * WUSB cluster reservations are multicast reservations with the
  14  * broadcast cluster ID (BCID) as the target DevAddr.
  15  *
  16  * FIXME: consider adjusting the reservation depending on what devices
  17  * are attached.
  18  */
  19
  20 static int wusbhc_bwa_set(struct wusbhc *wusbhc, u8 stream,
  21         const struct uwb_mas_bm *mas)
  22 {
  23         if (mas == NULL)
  24                 mas = &uwb_mas_bm_zero;
  25         return wusbhc->bwa_set(wusbhc, stream, mas);
  26 }
  27
  28 /**
  29  * wusbhc_rsv_complete_cb - WUSB HC reservation complete callback
  30  * @rsv:    the reservation
  31  *
  32  * Either set or clear the HC's view of the reservation.
  33  *
  34  * FIXME: when a reservation is denied the HC should be stopped.
  35  */
  36 static void wusbhc_rsv_complete_cb(struct uwb_rsv *rsv)
  37 {
  38         struct wusbhc *wusbhc = rsv->pal_priv;
  39         struct device *dev = wusbhc->dev;
  40         struct uwb_mas_bm mas;
  41
  42         dev_dbg(dev, "%s: state = %d\n", __func__, rsv->state);
  43         switch (rsv->state) {
  44         case UWB_RSV_STATE_O_ESTABLISHED:
  45                 uwb_rsv_get_usable_mas(rsv, &mas);
  46                 dev_dbg(dev, "established reservation: %*pb\n",
  47                         UWB_NUM_MAS, mas.bm);
  48                 wusbhc_bwa_set(wusbhc, rsv->stream, &mas);
  49                 break;
  50         case UWB_RSV_STATE_NONE:
  51                 dev_dbg(dev, "removed reservation\n");
  52                 wusbhc_bwa_set(wusbhc, 0, NULL);
  53                 break;
  54         default:
  55                 dev_dbg(dev, "unexpected reservation state: %d\n", rsv->state);
  56                 break;
  57         }
  58 }
  59
  60
  61 /**
  62  * wusbhc_rsv_establish - establish a reservation for the cluster
  63  * @wusbhc: the WUSB HC requesting a bandwidth reservation
  64  */
  65 int wusbhc_rsv_establish(struct wusbhc *wusbhc)
  66 {
  67         struct uwb_rc *rc = wusbhc->uwb_rc;
  68         struct uwb_rsv *rsv;
  69         struct uwb_dev_addr bcid;
  70         int ret;
  71
  72         if (rc == NULL)
  73                 return -ENODEV;
  74
  75         rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);
  76         if (rsv == NULL)
  77                 return -ENOMEM;
  78
  79         bcid.data[0] = wusbhc->cluster_id;
  80         bcid.data[1] = 0;
  81
  82         rsv->target.type = UWB_RSV_TARGET_DEVADDR;
  83         rsv->target.devaddr = bcid;
  84         rsv->type = UWB_DRP_TYPE_PRIVATE;
  85         rsv->max_mas = 256; /* try to get as much as possible */
  86         rsv->min_mas = 15;  /* one MAS per zone */
  87         rsv->max_interval = 1; /* max latency is one zone */
  88         rsv->is_multicast = true;
  89
  90         ret = uwb_rsv_establish(rsv);
  91         if (ret == 0)
  92                 wusbhc->rsv = rsv;
  93         else
  94                 uwb_rsv_destroy(rsv);
  95         return ret;
  96 }
  97
  98
  99 /**
 100  * wusbhc_rsv_terminate - terminate the cluster reservation
 101  * @wusbhc: the WUSB host whose reservation is to be terminated
 102  */
 103 void wusbhc_rsv_terminate(struct wusbhc *wusbhc)
 104 {
 105         if (wusbhc->rsv) {
 106                 uwb_rsv_terminate(wusbhc->rsv);
 107                 uwb_rsv_destroy(wusbhc->rsv);
 108                 wusbhc->rsv = NULL;
 109         }
 110 }