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