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