drivers/uwb/drp-ie.c

   1 /*
   2  * UWB DRP IE management.
   3  *
   4  * Copyright (C) 2005-2006 Intel Corporation
   5  * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include <linux/kernel.h>
  20 #include <linux/random.h>
  21 #include <linux/uwb.h>
  22
  23 #include "uwb-internal.h"
  24
  25 /*
  26  * Allocate a DRP IE.
  27  *
  28  * To save having to free/allocate a DRP IE when its MAS changes,
  29  * enough memory is allocated for the maxiumum number of DRP
  30  * allocation fields.  This gives an overhead per reservation of up to
  31  * (UWB_NUM_ZONES - 1) * 4 = 60 octets.
  32  */
  33 static struct uwb_ie_drp *uwb_drp_ie_alloc(void)
  34 {
  35         struct uwb_ie_drp *drp_ie;
  36         unsigned tiebreaker;
  37
  38         drp_ie = kzalloc(sizeof(struct uwb_ie_drp) +
  39                         UWB_NUM_ZONES * sizeof(struct uwb_drp_alloc),
  40                         GFP_KERNEL);
  41         if (drp_ie) {
  42                 drp_ie->hdr.element_id = UWB_IE_DRP;
  43
  44                 get_random_bytes(&tiebreaker, sizeof(unsigned));
  45                 uwb_ie_drp_set_tiebreaker(drp_ie, tiebreaker & 1);
  46         }
  47         return drp_ie;
  48 }
  49
  50
  51 /*
  52  * Fill a DRP IE's allocation fields from a MAS bitmap.
  53  */
  54 static void uwb_drp_ie_from_bm(struct uwb_ie_drp *drp_ie,
  55                                struct uwb_mas_bm *mas)
  56 {
  57         int z, i, num_fields = 0, next = 0;
  58         struct uwb_drp_alloc *zones;
  59         __le16 current_bmp;
  60         DECLARE_BITMAP(tmp_bmp, UWB_NUM_MAS);
  61         DECLARE_BITMAP(tmp_mas_bm, UWB_MAS_PER_ZONE);
  62
  63         zones = drp_ie->allocs;
  64
  65         bitmap_copy(tmp_bmp, mas->bm, UWB_NUM_MAS);
  66
  67         /* Determine unique MAS bitmaps in zones from bitmap. */
  68         for (z = 0; z < UWB_NUM_ZONES; z++) {
  69                 bitmap_copy(tmp_mas_bm, tmp_bmp, UWB_MAS_PER_ZONE);
  70                 if (bitmap_weight(tmp_mas_bm, UWB_MAS_PER_ZONE) > 0) {
  71                         bool found = false;
  72                         current_bmp = (__le16) *tmp_mas_bm;
  73                         for (i = 0; i < next; i++) {
  74                                 if (current_bmp == zones[i].mas_bm) {
  75                                         zones[i].zone_bm |= 1 << z;
  76                                         found = true;
  77                                         break;
  78                                 }
  79                         }
  80                         if (!found)  {
  81                                 num_fields++;
  82                                 zones[next].zone_bm = 1 << z;
  83                                 zones[next].mas_bm = current_bmp;
  84                                 next++;
  85                         }
  86                 }
  87                 bitmap_shift_right(tmp_bmp, tmp_bmp, UWB_MAS_PER_ZONE, UWB_NUM_MAS);
  88         }
  89
  90         /* Store in format ready for transmission (le16). */
  91         for (i = 0; i < num_fields; i++) {
  92                 drp_ie->allocs[i].zone_bm = cpu_to_le16(zones[i].zone_bm);
  93                 drp_ie->allocs[i].mas_bm = cpu_to_le16(zones[i].mas_bm);
  94         }
  95
  96         drp_ie->hdr.length = sizeof(struct uwb_ie_drp) - sizeof(struct uwb_ie_hdr)
  97                 + num_fields * sizeof(struct uwb_drp_alloc);
  98 }
  99
 100 /**
 101  * uwb_drp_ie_update - update a reservation's DRP IE
 102  * @rsv: the reservation
 103  */
 104 int uwb_drp_ie_update(struct uwb_rsv *rsv)
 105 {
 106         struct device *dev = &rsv->rc->uwb_dev.dev;
 107         struct uwb_ie_drp *drp_ie;
 108         int reason_code, status;
 109
 110         switch (rsv->state) {
 111         case UWB_RSV_STATE_NONE:
 112                 kfree(rsv->drp_ie);
 113                 rsv->drp_ie = NULL;
 114                 return 0;
 115         case UWB_RSV_STATE_O_INITIATED:
 116                 reason_code = UWB_DRP_REASON_ACCEPTED;
 117                 status = 0;
 118                 break;
 119         case UWB_RSV_STATE_O_PENDING:
 120                 reason_code = UWB_DRP_REASON_ACCEPTED;
 121                 status = 0;
 122                 break;
 123         case UWB_RSV_STATE_O_MODIFIED:
 124                 reason_code = UWB_DRP_REASON_MODIFIED;
 125                 status = 1;
 126                 break;
 127         case UWB_RSV_STATE_O_ESTABLISHED:
 128                 reason_code = UWB_DRP_REASON_ACCEPTED;
 129                 status = 1;
 130                 break;
 131         case UWB_RSV_STATE_T_ACCEPTED:
 132                 reason_code = UWB_DRP_REASON_ACCEPTED;
 133                 status = 1;
 134                 break;
 135         case UWB_RSV_STATE_T_DENIED:
 136                 reason_code = UWB_DRP_REASON_DENIED;
 137                 status = 0;
 138                 break;
 139         default:
 140                 dev_dbg(dev, "rsv with unhandled state (%d)\n", rsv->state);
 141                 return -EINVAL;
 142         }
 143
 144         if (rsv->drp_ie == NULL) {
 145                 rsv->drp_ie = uwb_drp_ie_alloc();
 146                 if (rsv->drp_ie == NULL)
 147                         return -ENOMEM;
 148         }
 149         drp_ie = rsv->drp_ie;
 150
 151         uwb_ie_drp_set_owner(drp_ie,        uwb_rsv_is_owner(rsv));
 152         uwb_ie_drp_set_status(drp_ie,       status);
 153         uwb_ie_drp_set_reason_code(drp_ie,  reason_code);
 154         uwb_ie_drp_set_stream_index(drp_ie, rsv->stream);
 155         uwb_ie_drp_set_type(drp_ie,         rsv->type);
 156
 157         if (uwb_rsv_is_owner(rsv)) {
 158                 switch (rsv->target.type) {
 159                 case UWB_RSV_TARGET_DEV:
 160                         drp_ie->dev_addr = rsv->target.dev->dev_addr;
 161                         break;
 162                 case UWB_RSV_TARGET_DEVADDR:
 163                         drp_ie->dev_addr = rsv->target.devaddr;
 164                         break;
 165                 }
 166         } else
 167                 drp_ie->dev_addr = rsv->owner->dev_addr;
 168
 169         uwb_drp_ie_from_bm(drp_ie, &rsv->mas);
 170
 171         rsv->ie_valid = true;
 172         return 0;
 173 }
 174
 175 /*
 176  * Set MAS bits from given MAS bitmap in a single zone of large bitmap.
 177  *
 178  * We are given a zone id and the MAS bitmap of bits that need to be set in
 179  * this zone. Note that this zone may already have bits set and this only
 180  * adds settings - we cannot simply assign the MAS bitmap contents to the
 181  * zone contents. We iterate over the the bits (MAS) in the zone and set the
 182  * bits that are set in the given MAS bitmap.
 183  */
 184 static
 185 void uwb_drp_ie_single_zone_to_bm(struct uwb_mas_bm *bm, u8 zone, u16 mas_bm)
 186 {
 187         int mas;
 188         u16 mas_mask;
 189
 190         for (mas = 0; mas < UWB_MAS_PER_ZONE; mas++) {
 191                 mas_mask = 1 << mas;
 192                 if (mas_bm & mas_mask)
 193                         set_bit(zone * UWB_NUM_ZONES + mas, bm->bm);
 194         }
 195 }
 196
 197 /**
 198  * uwb_drp_ie_zones_to_bm - convert DRP allocation fields to a bitmap
 199  * @mas:    MAS bitmap that will be populated to correspond to the
 200  *          allocation fields in the DRP IE
 201  * @drp_ie: the DRP IE that contains the allocation fields.
 202  *
 203  * The input format is an array of MAS allocation fields (16 bit Zone
 204  * bitmap, 16 bit MAS bitmap) as described in [ECMA-368] section
 205  * 16.8.6. The output is a full 256 bit MAS bitmap.
 206  *
 207  * We go over all the allocation fields, for each allocation field we
 208  * know which zones are impacted. We iterate over all the zones
 209  * impacted and call a function that will set the correct MAS bits in
 210  * each zone.
 211  */
 212 void uwb_drp_ie_to_bm(struct uwb_mas_bm *bm, const struct uwb_ie_drp *drp_ie)
 213 {
 214         int numallocs = (drp_ie->hdr.length - 4) / 4;
 215         const struct uwb_drp_alloc *alloc;
 216         int cnt;
 217         u16 zone_bm, mas_bm;
 218         u8 zone;
 219         u16 zone_mask;
 220
 221         for (cnt = 0; cnt < numallocs; cnt++) {
 222                 alloc = &drp_ie->allocs[cnt];
 223                 zone_bm = le16_to_cpu(alloc->zone_bm);
 224                 mas_bm = le16_to_cpu(alloc->mas_bm);
 225                 for (zone = 0; zone < UWB_NUM_ZONES; zone++)   {
 226                         zone_mask = 1 << zone;
 227                         if (zone_bm & zone_mask)
 228                                 uwb_drp_ie_single_zone_to_bm(bm, zone, mas_bm);
 229                 }
 230         }
 231 }