orinoco.c

底层驱动开发

	int len, data_len, data_off;
	struct hermes_tx_descriptor desc;
	unsigned long flags;

	TRACE_ENTER(dev->name);

	if (! netif_running(dev)) {
		printk(KERN_ERR "%s: Tx on stopped device!\n",
		       dev->name);
		TRACE_EXIT(dev->name);
		return 1;
	}
	
	if (netif_queue_stopped(dev)) {
		printk(KERN_DEBUG "%s: Tx while transmitter busy!\n", 
		       dev->name);
		TRACE_EXIT(dev->name);
		return 1;
	}
	
	if (orinoco_lock(priv, &flags) != 0) {
		printk(KERN_ERR "%s: orinoco_xmit() called while hw_unavailable\n",
		       dev->name);
		TRACE_EXIT(dev->name);
		return 1;
	}

	if (! netif_carrier_ok(dev) || (priv->iw_mode == IW_MODE_MONITOR)) {
		/* Oops, the firmware hasn't established a connection,
                   silently drop the packet (this seems to be the
                   safest approach). */
		stats->tx_errors++;
		orinoco_unlock(priv, &flags);
		dev_kfree_skb(skb);
		TRACE_EXIT(dev->name);
		return 0;
	}

	/* Check packet length, pad short packets, round up odd length */
	len = max_t(int, ALIGN(skb->len, 2), ETH_ZLEN);
	if (skb->len < len) {
		skb = skb_padto(skb, len);
		if (skb == NULL)
			goto fail;
	}
	len -= ETH_HLEN;

	eh = (struct ethhdr *)skb->data;

	memset(&desc, 0, sizeof(desc));
 	desc.tx_control = cpu_to_le16(HERMES_TXCTRL_TX_OK | HERMES_TXCTRL_TX_EX);
	err = hermes_bap_pwrite(hw, USER_BAP, &desc, sizeof(desc), txfid, 0);
	if (err) {
		if (net_ratelimit())
			printk(KERN_ERR "%s: Error %d writing Tx descriptor "
			       "to BAP\n", dev->name, err);
		stats->tx_errors++;
		goto fail;
	}

	/* Clear the 802.11 header and data length fields - some
	 * firmwares (e.g. Lucent/Agere 8.xx) appear to get confused
	 * if this isn't done. */
	hermes_clear_words(hw, HERMES_DATA0,
			   HERMES_802_3_OFFSET - HERMES_802_11_OFFSET);

	/* Encapsulate Ethernet-II frames */
	if (ntohs(eh->h_proto) > ETH_DATA_LEN) { /* Ethernet-II frame */
		struct header_struct hdr;
		data_len = len;
		data_off = HERMES_802_3_OFFSET + sizeof(hdr);
		p = skb->data + ETH_HLEN;

		/* 802.3 header */
		memcpy(hdr.dest, eh->h_dest, ETH_ALEN);
		memcpy(hdr.src, eh->h_source, ETH_ALEN);
		hdr.len = htons(data_len + ENCAPS_OVERHEAD);
		
		/* 802.2 header */
		memcpy(&hdr.dsap, &encaps_hdr, sizeof(encaps_hdr));
			
		hdr.ethertype = eh->h_proto;
		err  = hermes_bap_pwrite(hw, USER_BAP, &hdr, sizeof(hdr),
					 txfid, HERMES_802_3_OFFSET);
		if (err) {
			if (net_ratelimit())
				printk(KERN_ERR "%s: Error %d writing packet "
				       "header to BAP\n", dev->name, err);
			stats->tx_errors++;
			goto fail;
		}
	} else { /* IEEE 802.3 frame */
		data_len = len + ETH_HLEN;
		data_off = HERMES_802_3_OFFSET;
		p = skb->data;
	}

	err = hermes_bap_pwrite(hw, USER_BAP, p, data_len,
				txfid, data_off);
	if (err) {
		printk(KERN_ERR "%s: Error %d writing packet to BAP\n",
		       dev->name, err);
		stats->tx_errors++;
		goto fail;
	}

	/* Finally, we actually initiate the send */
	netif_stop_queue(dev);

	err = hermes_docmd_wait(hw, HERMES_CMD_TX | HERMES_CMD_RECL,
				txfid, NULL);
	if (err) {
		netif_start_queue(dev);
		if (net_ratelimit())
			printk(KERN_ERR "%s: Error %d transmitting packet\n",
				dev->name, err);
		stats->tx_errors++;
		goto fail;
	}

	dev->trans_start = jiffies;
	stats->tx_bytes += data_off + data_len;

	orinoco_unlock(priv, &flags);

	dev_kfree_skb(skb);

	TRACE_EXIT(dev->name);

	return 0;
 fail:
	TRACE_EXIT(dev->name);

	orinoco_unlock(priv, &flags);
	return err;
}

static void __orinoco_ev_alloc(struct net_device *dev, hermes_t *hw)
{
	struct orinoco_private *priv = netdev_priv(dev);
	u16 fid = hermes_read_regn(hw, ALLOCFID);

	if (fid != priv->txfid) {
		if (fid != DUMMY_FID)
			printk(KERN_WARNING "%s: Allocate event on unexpected fid (%04X)\n",
			       dev->name, fid);
		return;
	}

	hermes_write_regn(hw, ALLOCFID, DUMMY_FID);
}

static void __orinoco_ev_tx(struct net_device *dev, hermes_t *hw)
{
	struct orinoco_private *priv = netdev_priv(dev);
	struct net_device_stats *stats = &priv->stats;

	stats->tx_packets++;

	netif_wake_queue(dev);

	hermes_write_regn(hw, TXCOMPLFID, DUMMY_FID);
}

static void __orinoco_ev_txexc(struct net_device *dev, hermes_t *hw)
{
	struct orinoco_private *priv = netdev_priv(dev);
	struct net_device_stats *stats = &priv->stats;
	u16 fid = hermes_read_regn(hw, TXCOMPLFID);
	struct hermes_tx_descriptor_802_11 hdr;
	int err = 0;

	if (fid == DUMMY_FID)
		return; /* Nothing's really happened */

	/* Read the frame header */
	err = hermes_bap_pread(hw, IRQ_BAP, &hdr,
			       sizeof(struct hermes_tx_descriptor) +
			       sizeof(struct ieee80211_hdr),
			       fid, 0);

	hermes_write_regn(hw, TXCOMPLFID, DUMMY_FID);
	stats->tx_errors++;

	if (err) {
		printk(KERN_WARNING "%s: Unable to read descriptor on Tx error "
		       "(FID=%04X error %d)\n",
		       dev->name, fid, err);
		return;
	}
	
	DEBUG(1, "%s: Tx error, err %d (FID=%04X)\n", dev->name,
	      err, fid);
    
	/* We produce a TXDROP event only for retry or lifetime
	 * exceeded, because that's the only status that really mean
	 * that this particular node went away.
	 * Other errors means that *we* screwed up. - Jean II */
	hdr.status = le16_to_cpu(hdr.status);
	if (hdr.status & (HERMES_TXSTAT_RETRYERR | HERMES_TXSTAT_AGEDERR)) {
		union iwreq_data	wrqu;

		/* Copy 802.11 dest address.
		 * We use the 802.11 header because the frame may
		 * not be 802.3 or may be mangled...
		 * In Ad-Hoc mode, it will be the node address.
		 * In managed mode, it will be most likely the AP addr
		 * User space will figure out how to convert it to
		 * whatever it needs (IP address or else).
		 * - Jean II */
		memcpy(wrqu.addr.sa_data, hdr.addr1, ETH_ALEN);
		wrqu.addr.sa_family = ARPHRD_ETHER;

		/* Send event to user space */
		wireless_send_event(dev, IWEVTXDROP, &wrqu, NULL);
	}

	netif_wake_queue(dev);
}

static void orinoco_tx_timeout(struct net_device *dev)
{
	struct orinoco_private *priv = netdev_priv(dev);
	struct net_device_stats *stats = &priv->stats;
	struct hermes *hw = &priv->hw;

	printk(KERN_WARNING "%s: Tx timeout! "
	       "ALLOCFID=%04x, TXCOMPLFID=%04x, EVSTAT=%04x\n",
	       dev->name, hermes_read_regn(hw, ALLOCFID),
	       hermes_read_regn(hw, TXCOMPLFID), hermes_read_regn(hw, EVSTAT));

	stats->tx_errors++;

	schedule_work(&priv->reset_work);
}

/********************************************************************/
/* Rx path (data frames)                                            */
/********************************************************************/

/* Does the frame have a SNAP header indicating it should be
 * de-encapsulated to Ethernet-II? */
static inline int is_ethersnap(void *_hdr)
{
	u8 *hdr = _hdr;

	/* We de-encapsulate all packets which, a) have SNAP headers
	 * (i.e. SSAP=DSAP=0xaa and CTRL=0x3 in the 802.2 LLC header
	 * and where b) the OUI of the SNAP header is 00:00:00 or
	 * 00:00:f8 - we need both because different APs appear to use
	 * different OUIs for some reason */
	return (memcmp(hdr, &encaps_hdr, 5) == 0)
		&& ( (hdr[5] == 0x00) || (hdr[5] == 0xf8) );
}

static inline void orinoco_spy_gather(struct net_device *dev, u_char *mac,
				      int level, int noise)
{
	struct orinoco_private *priv = netdev_priv(dev);
	int i;

	/* Gather wireless spy statistics: for each packet, compare the
	 * source address with out list, and if match, get the stats... */
	for (i = 0; i < priv->spy_number; i++)
		if (!memcmp(mac, priv->spy_address[i], ETH_ALEN)) {
			priv->spy_stat[i].level = level - 0x95;
			priv->spy_stat[i].noise = noise - 0x95;
			priv->spy_stat[i].qual = (level > noise) ? (level - noise) : 0;
			priv->spy_stat[i].updated = 7;
		}
}

static void orinoco_stat_gather(struct net_device *dev,
				struct sk_buff *skb,
				struct hermes_rx_descriptor *desc)
{
	struct orinoco_private *priv = netdev_priv(dev);

	/* Using spy support with lots of Rx packets, like in an
	 * infrastructure (AP), will really slow down everything, because
	 * the MAC address must be compared to each entry of the spy list.
	 * If the user really asks for it (set some address in the
	 * spy list), we do it, but he will pay the price.
	 * Note that to get here, you need both WIRELESS_SPY
	 * compiled in AND some addresses in the list !!!
	 */
	/* Note : gcc will optimise the whole section away if
	 * WIRELESS_SPY is not defined... - Jean II */
	if (SPY_NUMBER(priv)) {
		orinoco_spy_gather(dev, skb->mac.raw + ETH_ALEN,
				   desc->signal, desc->silence);
	}
}

/*
 * orinoco_rx_monitor - handle received monitor frames.
 *
 * Arguments:
 *	dev		network device
 *	rxfid		received FID
 *	desc		rx descriptor of the frame
 *
 * Call context: interrupt
 */
static void orinoco_rx_monitor(struct net_device *dev, u16 rxfid,
			       struct hermes_rx_descriptor *desc)
{
	u32 hdrlen = 30;	/* return full header by default */
	u32 datalen = 0;
	u16 fc;
	int err;
	int len;
	struct sk_buff *skb;
	struct orinoco_private *priv = netdev_priv(dev);
	struct net_device_stats *stats = &priv->stats;
	hermes_t *hw = &priv->hw;

	len = le16_to_cpu(desc->data_len);

	/* Determine the size of the header and the data */
	fc = le16_to_cpu(desc->frame_ctl);
	switch (fc & IEEE80211_FCTL_FTYPE) {
	case IEEE80211_FTYPE_DATA:
		if ((fc & IEEE80211_FCTL_TODS)
		    && (fc & IEEE80211_FCTL_FROMDS))
			hdrlen = 30;
		else
			hdrlen = 24;
		datalen = len;
		break;
	case IEEE80211_FTYPE_MGMT:
		hdrlen = 24;
		datalen = len;
		break;
	case IEEE80211_FTYPE_CTL:
		switch (fc & IEEE80211_FCTL_STYPE) {
		case IEEE80211_STYPE_PSPOLL:
		case IEEE80211_STYPE_RTS:
		case IEEE80211_STYPE_CFEND:
		case IEEE80211_STYPE_CFENDACK:
			hdrlen = 16;
			break;
		case IEEE80211_STYPE_CTS:
		case IEEE80211_STYPE_ACK:
			hdrlen = 10;
			break;
		}
		break;
	default:
		/* Unknown frame type */
		break;
	}

	/* sanity check the length */
	if (datalen > IEEE80211_DATA_LEN + 12) {
		printk(KERN_DEBUG "%s: oversized monitor frame, "
		       "data length = %d\n", dev->name, datalen);
		err = -EIO;
		stats->rx_length_errors++;
		goto update_stats;
	}

	skb = dev_alloc_skb(hdrlen + datalen);
	if (!skb) {
		printk(KERN_WARNING "%s: Cannot allocate skb for monitor frame\n",
		       dev->name);
		err = -ENOMEM;
		goto drop;
	}

	/* Copy the 802.11 header to the skb */
	memcpy(skb_put(skb, hdrlen), &(desc->frame_ctl), hdrlen);
	skb->mac.raw = skb->data;

	/* If any, copy the data from the card to the skb */
	if (datalen > 0) {
		err = hermes_bap_pread(hw, IRQ_BAP, skb_put(skb, datalen),
				       ALIGN(datalen, 2), rxfid,
				       HERMES_802_2_OFFSET);
		if (err) {
			printk(KERN_ERR "%s: error %d reading monitor frame\n",
			       dev->name, err);
			goto drop;
		}
	}

	skb->dev = dev;
	skb->ip_summed = CHECKSUM_NONE;
	skb->pkt_type = PACKET_OTHERHOST;
	skb->protocol = __constant_htons(ETH_P_802_2);
	
	dev->last_rx = jiffies;
	stats->rx_packets++;
	stats->rx_bytes += skb->len;

	netif_rx(skb);
	return;

 drop:
	dev_kfree_skb_irq(skb);
 update_stats:
	stats->rx_errors++;
	stats->rx_dropped++;
}

static void __orinoco_ev_rx(struct net_device *dev, hermes_t *hw)
{
	struct orinoco_private *priv = netdev_priv(dev);
	struct net_device_stats *stats = &priv->stats;
	struct iw_statistics *wstats = &priv->wstats;
	struct sk_buff *skb = NULL;
	u16 rxfid, status, fc;
	int length;
	struct hermes_rx_descriptor desc;
	struct ethhdr *hdr;
	int err;

	rxfid = hermes_read_regn(hw, RXFID);

	err = hermes_bap_pread(hw, IRQ_BAP, &desc, sizeof(desc),
			       rxfid, 0);
	if (err) {
		printk(KERN_ERR "%s: error %d reading Rx descriptor. "
		       "Frame dropped.\n", dev->name, err);
		goto update_stats;
	}

	status = le16_to_cpu(desc.status);

	if (status & HERMES_RXSTAT_BADCRC) {
		DEBUG(1, "%s: Bad CRC on Rx. Frame dropped.\n",
		      dev->name);
		stats->rx_crc_errors++;
		goto update_stats;
	}

	/* Handle frames in monitor mode */
	if (priv->iw_mode == IW_MODE_MONITOR) {
		orinoco_rx_monitor(dev, rxfid, &desc);
		return;
	}

	if (status & HERMES_RXSTAT_UNDECRYPTABLE) {
		DEBUG(1, "%s: Undecryptable frame on Rx. Frame dropped.\n",
		      dev->name);
		wstats->discard.code++;
		goto update_stats;
	}

	length = le16_to_cpu(desc.data_len);
	fc = le16_to_cpu(desc.frame_ctl);

	/* Sanity checks */
	if (length < 3) { /* No for even an 802.2 LLC header */
		/* At least on Symbol firmware with PCF we get quite a
                   lot of these legitimately - Poll frames with no
                   data. */
		return;
	}
	if (length > IEEE80211_DATA_LEN) {
		printk(KERN_WARNING "%s: Oversized frame received (%d bytes)\n",
		       dev->name, length);
		stats->rx_length_errors++;
		goto update_stats;
	}

	/* We need space for the packet data itself, plus an ethernet