drivers/net/wireless/libertas/rx.c

   1 /**
   2   * This file contains the handling of RX in wlan driver.
   3   */
   4 #include <linux/etherdevice.h>
   5 #include <linux/types.h>
   6
   7 #include "hostcmd.h"
   8 #include "radiotap.h"
   9 #include "decl.h"
  10 #include "dev.h"
  11 #include "wext.h"
  12
  13 struct eth803hdr {
  14         u8 dest_addr[6];
  15         u8 src_addr[6];
  16         u16 h803_len;
  17 } __attribute__ ((packed));
  18
  19 struct rfc1042hdr {
  20         u8 llc_dsap;
  21         u8 llc_ssap;
  22         u8 llc_ctrl;
  23         u8 snap_oui[3];
  24         u16 snap_type;
  25 } __attribute__ ((packed));
  26
  27 struct rxpackethdr {
  28         struct eth803hdr eth803_hdr;
  29         struct rfc1042hdr rfc1042_hdr;
  30 } __attribute__ ((packed));
  31
  32 struct rx80211packethdr {
  33         struct rxpd rx_pd;
  34         void *eth80211_hdr;
  35 } __attribute__ ((packed));
  36
  37 static int process_rxed_802_11_packet(struct lbs_private *priv,
  38         struct sk_buff *skb);
  39
  40 /**
  41  *  @brief This function computes the avgSNR .
  42  *
  43  *  @param priv    A pointer to struct lbs_private structure
  44  *  @return        avgSNR
  45  */
  46 static u8 lbs_getavgsnr(struct lbs_private *priv)
  47 {
  48         u8 i;
  49         u16 temp = 0;
  50         if (priv->numSNRNF == 0)
  51                 return 0;
  52         for (i = 0; i < priv->numSNRNF; i++)
  53                 temp += priv->rawSNR[i];
  54         return (u8) (temp / priv->numSNRNF);
  55
  56 }
  57
  58 /**
  59  *  @brief This function computes the AvgNF
  60  *
  61  *  @param priv    A pointer to struct lbs_private structure
  62  *  @return        AvgNF
  63  */
  64 static u8 lbs_getavgnf(struct lbs_private *priv)
  65 {
  66         u8 i;
  67         u16 temp = 0;
  68         if (priv->numSNRNF == 0)
  69                 return 0;
  70         for (i = 0; i < priv->numSNRNF; i++)
  71                 temp += priv->rawNF[i];
  72         return (u8) (temp / priv->numSNRNF);
  73
  74 }
  75
  76 /**
  77  *  @brief This function save the raw SNR/NF to our internel buffer
  78  *
  79  *  @param priv    A pointer to struct lbs_private structure
  80  *  @param prxpd   A pointer to rxpd structure of received packet
  81  *  @return        n/a
  82  */
  83 static void lbs_save_rawSNRNF(struct lbs_private *priv, struct rxpd *p_rx_pd)
  84 {
  85         if (priv->numSNRNF < DEFAULT_DATA_AVG_FACTOR)
  86                 priv->numSNRNF++;
  87         priv->rawSNR[priv->nextSNRNF] = p_rx_pd->snr;
  88         priv->rawNF[priv->nextSNRNF] = p_rx_pd->nf;
  89         priv->nextSNRNF++;
  90         if (priv->nextSNRNF >= DEFAULT_DATA_AVG_FACTOR)
  91                 priv->nextSNRNF = 0;
  92         return;
  93 }
  94
  95 /**
  96  *  @brief This function computes the RSSI in received packet.
  97  *
  98  *  @param priv    A pointer to struct lbs_private structure
  99  *  @param prxpd   A pointer to rxpd structure of received packet
 100  *  @return        n/a
 101  */
 102 static void lbs_compute_rssi(struct lbs_private *priv, struct rxpd *p_rx_pd)
 103 {
 104
 105         lbs_deb_enter(LBS_DEB_RX);
 106
 107         lbs_deb_rx("rxpd: SNR %d, NF %d\n", p_rx_pd->snr, p_rx_pd->nf);
 108         lbs_deb_rx("before computing SNR: SNR-avg = %d, NF-avg = %d\n",
 109                priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
 110                priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
 111
 112         priv->SNR[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->snr;
 113         priv->NF[TYPE_RXPD][TYPE_NOAVG] = p_rx_pd->nf;
 114         lbs_save_rawSNRNF(priv, p_rx_pd);
 115
 116         priv->SNR[TYPE_RXPD][TYPE_AVG] = lbs_getavgsnr(priv) * AVG_SCALE;
 117         priv->NF[TYPE_RXPD][TYPE_AVG] = lbs_getavgnf(priv) * AVG_SCALE;
 118         lbs_deb_rx("after computing SNR: SNR-avg = %d, NF-avg = %d\n",
 119                priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
 120                priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
 121
 122         priv->RSSI[TYPE_RXPD][TYPE_NOAVG] =
 123             CAL_RSSI(priv->SNR[TYPE_RXPD][TYPE_NOAVG],
 124                      priv->NF[TYPE_RXPD][TYPE_NOAVG]);
 125
 126         priv->RSSI[TYPE_RXPD][TYPE_AVG] =
 127             CAL_RSSI(priv->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE,
 128                      priv->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE);
 129
 130         lbs_deb_leave(LBS_DEB_RX);
 131 }
 132
 133 /**
 134  *  @brief This function processes received packet and forwards it
 135  *  to kernel/upper layer
 136  *
 137  *  @param priv    A pointer to struct lbs_private
 138  *  @param skb     A pointer to skb which includes the received packet
 139  *  @return        0 or -1
 140  */
 141 int lbs_process_rxed_packet(struct lbs_private *priv, struct sk_buff *skb)
 142 {
 143         int ret = 0;
 144         struct net_device *dev = priv->dev;
 145         struct rxpackethdr *p_rx_pkt;
 146         struct rxpd *p_rx_pd;
 147         int hdrchop;
 148         struct ethhdr *p_ethhdr;
 149         const u8 rfc1042_eth_hdr[] = { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
 150
 151         lbs_deb_enter(LBS_DEB_RX);
 152
 153         BUG_ON(!skb);
 154
 155         skb->ip_summed = CHECKSUM_NONE;
 156
 157         if (priv->monitormode)
 158                 return process_rxed_802_11_packet(priv, skb);
 159
 160         p_rx_pd = (struct rxpd *) skb->data;
 161         p_rx_pkt = (struct rxpackethdr *) ((u8 *)p_rx_pd +
 162                 le32_to_cpu(p_rx_pd->pkt_ptr));
 163         if (priv->mesh_dev) {
 164                 if (priv->mesh_fw_ver == MESH_FW_OLD) {
 165                         if (p_rx_pd->rx_control & RxPD_MESH_FRAME)
 166                                 dev = priv->mesh_dev;
 167                 } else if (priv->mesh_fw_ver == MESH_FW_NEW) {
 168                         if (p_rx_pd->u.bss.bss_num == MESH_IFACE_ID)
 169                                 dev = priv->mesh_dev;
 170                 }
 171         }
 172
 173         lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data,
 174                  min_t(unsigned int, skb->len, 100));
 175
 176         if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
 177                 lbs_deb_rx("rx err: frame received with bad length\n");
 178                 dev->stats.rx_length_errors++;
 179                 ret = 0;
 180                 dev_kfree_skb(skb);
 181                 goto done;
 182         }
 183
 184         lbs_deb_rx("rx data: skb->len - pkt_ptr = %d-%zd = %zd\n",
 185                 skb->len, (size_t)le32_to_cpu(p_rx_pd->pkt_ptr),
 186                 skb->len - (size_t)le32_to_cpu(p_rx_pd->pkt_ptr));
 187
 188         lbs_deb_hex(LBS_DEB_RX, "RX Data: Dest", p_rx_pkt->eth803_hdr.dest_addr,
 189                 sizeof(p_rx_pkt->eth803_hdr.dest_addr));
 190         lbs_deb_hex(LBS_DEB_RX, "RX Data: Src", p_rx_pkt->eth803_hdr.src_addr,
 191                 sizeof(p_rx_pkt->eth803_hdr.src_addr));
 192
 193         if (memcmp(&p_rx_pkt->rfc1042_hdr,
 194                    rfc1042_eth_hdr, sizeof(rfc1042_eth_hdr)) == 0) {
 195                 /*
 196                  *  Replace the 803 header and rfc1042 header (llc/snap) with an
 197                  *    EthernetII header, keep the src/dst and snap_type (ethertype)
 198                  *
 199                  *  The firmware only passes up SNAP frames converting
 200                  *    all RX Data from 802.11 to 802.2/LLC/SNAP frames.
 201                  *
 202                  *  To create the Ethernet II, just move the src, dst address right
 203                  *    before the snap_type.
 204                  */
 205                 p_ethhdr = (struct ethhdr *)
 206                     ((u8 *) & p_rx_pkt->eth803_hdr
 207                      + sizeof(p_rx_pkt->eth803_hdr) + sizeof(p_rx_pkt->rfc1042_hdr)
 208                      - sizeof(p_rx_pkt->eth803_hdr.dest_addr)
 209                      - sizeof(p_rx_pkt->eth803_hdr.src_addr)
 210                      - sizeof(p_rx_pkt->rfc1042_hdr.snap_type));
 211
 212                 memcpy(p_ethhdr->h_source, p_rx_pkt->eth803_hdr.src_addr,
 213                        sizeof(p_ethhdr->h_source));
 214                 memcpy(p_ethhdr->h_dest, p_rx_pkt->eth803_hdr.dest_addr,
 215                        sizeof(p_ethhdr->h_dest));
 216
 217                 /* Chop off the rxpd + the excess memory from the 802.2/llc/snap header
 218                  *   that was removed
 219                  */
 220                 hdrchop = (u8 *)p_ethhdr - (u8 *)p_rx_pd;
 221         } else {
 222                 lbs_deb_hex(LBS_DEB_RX, "RX Data: LLC/SNAP",
 223                         (u8 *) & p_rx_pkt->rfc1042_hdr,
 224                         sizeof(p_rx_pkt->rfc1042_hdr));
 225
 226                 /* Chop off the rxpd */
 227                 hdrchop = (u8 *)&p_rx_pkt->eth803_hdr - (u8 *)p_rx_pd;
 228         }
 229
 230         /* Chop off the leading header bytes so the skb points to the start of
 231          *   either the reconstructed EthII frame or the 802.2/llc/snap frame
 232          */
 233         skb_pull(skb, hdrchop);
 234
 235         /* Take the data rate from the rxpd structure
 236          * only if the rate is auto
 237          */
 238         if (priv->enablehwauto)
 239                 priv->cur_rate = lbs_fw_index_to_data_rate(p_rx_pd->rx_rate);
 240
 241         lbs_compute_rssi(priv, p_rx_pd);
 242
 243         lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
 244         dev->stats.rx_bytes += skb->len;
 245         dev->stats.rx_packets++;
 246
 247         skb->protocol = eth_type_trans(skb, dev);
 248         if (in_interrupt())
 249                 netif_rx(skb);
 250         else
 251                 netif_rx_ni(skb);
 252
 253         ret = 0;
 254 done:
 255         lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
 256         return ret;
 257 }
 258 EXPORT_SYMBOL_GPL(lbs_process_rxed_packet);
 259
 260 /**
 261  *  @brief This function converts Tx/Rx rates from the Marvell WLAN format
 262  *  (see Table 2 in Section 3.1) to IEEE80211_RADIOTAP_RATE units (500 Kb/s)
 263  *
 264  *  @param rate    Input rate
 265  *  @return        Output Rate (0 if invalid)
 266  */
 267 static u8 convert_mv_rate_to_radiotap(u8 rate)
 268 {
 269         switch (rate) {
 270         case 0:         /*   1 Mbps */
 271                 return 2;
 272         case 1:         /*   2 Mbps */
 273                 return 4;
 274         case 2:         /* 5.5 Mbps */
 275                 return 11;
 276         case 3:         /*  11 Mbps */
 277                 return 22;
 278         /* case 4: reserved */
 279         case 5:         /*   6 Mbps */
 280                 return 12;
 281         case 6:         /*   9 Mbps */
 282                 return 18;
 283         case 7:         /*  12 Mbps */
 284                 return 24;
 285         case 8:         /*  18 Mbps */
 286                 return 36;
 287         case 9:         /*  24 Mbps */
 288                 return 48;
 289         case 10:                /*  36 Mbps */
 290                 return 72;
 291         case 11:                /*  48 Mbps */
 292                 return 96;
 293         case 12:                /*  54 Mbps */
 294                 return 108;
 295         }
 296         lbs_pr_alert("Invalid Marvell WLAN rate %i\n", rate);
 297         return 0;
 298 }
 299
 300 /**
 301  *  @brief This function processes a received 802.11 packet and forwards it
 302  *  to kernel/upper layer
 303  *
 304  *  @param priv    A pointer to struct lbs_private
 305  *  @param skb     A pointer to skb which includes the received packet
 306  *  @return        0 or -1
 307  */
 308 static int process_rxed_802_11_packet(struct lbs_private *priv,
 309         struct sk_buff *skb)
 310 {
 311         int ret = 0;
 312         struct net_device *dev = priv->dev;
 313         struct rx80211packethdr *p_rx_pkt;
 314         struct rxpd *prxpd;
 315         struct rx_radiotap_hdr radiotap_hdr;
 316         struct rx_radiotap_hdr *pradiotap_hdr;
 317
 318         lbs_deb_enter(LBS_DEB_RX);
 319
 320         p_rx_pkt = (struct rx80211packethdr *) skb->data;
 321         prxpd = &p_rx_pkt->rx_pd;
 322
 323         // lbs_deb_hex(LBS_DEB_RX, "RX Data: Before chop rxpd", skb->data, min(skb->len, 100));
 324
 325         if (skb->len < (ETH_HLEN + 8 + sizeof(struct rxpd))) {
 326                 lbs_deb_rx("rx err: frame received with bad length\n");
 327                 dev->stats.rx_length_errors++;
 328                 ret = -EINVAL;
 329                 kfree_skb(skb);
 330                 goto done;
 331         }
 332
 333         lbs_deb_rx("rx data: skb->len-sizeof(RxPd) = %d-%zd = %zd\n",
 334                skb->len, sizeof(struct rxpd), skb->len - sizeof(struct rxpd));
 335
 336         /* create the exported radio header */
 337
 338         /* radiotap header */
 339         radiotap_hdr.hdr.it_version = 0;
 340         /* XXX must check this value for pad */
 341         radiotap_hdr.hdr.it_pad = 0;
 342         radiotap_hdr.hdr.it_len = cpu_to_le16 (sizeof(struct rx_radiotap_hdr));
 343         radiotap_hdr.hdr.it_present = cpu_to_le32 (RX_RADIOTAP_PRESENT);
 344         radiotap_hdr.rate = convert_mv_rate_to_radiotap(prxpd->rx_rate);
 345         /* XXX must check no carryout */
 346         radiotap_hdr.antsignal = prxpd->snr + prxpd->nf;
 347
 348         /* chop the rxpd */
 349         skb_pull(skb, sizeof(struct rxpd));
 350
 351         /* add space for the new radio header */
 352         if ((skb_headroom(skb) < sizeof(struct rx_radiotap_hdr)) &&
 353             pskb_expand_head(skb, sizeof(struct rx_radiotap_hdr), 0, GFP_ATOMIC)) {
 354                 lbs_pr_alert("%s: couldn't pskb_expand_head\n", __func__);
 355                 ret = -ENOMEM;
 356                 kfree_skb(skb);
 357                 goto done;
 358         }
 359
 360         pradiotap_hdr = (void *)skb_push(skb, sizeof(struct rx_radiotap_hdr));
 361         memcpy(pradiotap_hdr, &radiotap_hdr, sizeof(struct rx_radiotap_hdr));
 362
 363         /* Take the data rate from the rxpd structure
 364          * only if the rate is auto
 365          */
 366         if (priv->enablehwauto)
 367                 priv->cur_rate = lbs_fw_index_to_data_rate(prxpd->rx_rate);
 368
 369         lbs_compute_rssi(priv, prxpd);
 370
 371         lbs_deb_rx("rx data: size of actual packet %d\n", skb->len);
 372         dev->stats.rx_bytes += skb->len;
 373         dev->stats.rx_packets++;
 374
 375         skb->protocol = eth_type_trans(skb, priv->rtap_net_dev);
 376         netif_rx(skb);
 377
 378         ret = 0;
 379
 380 done:
 381         lbs_deb_leave_args(LBS_DEB_RX, "ret %d", ret);
 382         return ret;
 383 }