drivers/net/wireless/prism54/islpci_eth.c - kernel/msm-4.9 - Gitiles

 /*
  *
  *  Copyright (C) 2002 Intersil Americas Inc.
  *  Copyright (C) 2004 Aurelien Alleaume <slts@free.fr>
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  */

 #include <linux/module.h>

 #include <linux/pci.h>
 #include <linux/delay.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/if_arp.h>

 #include "prismcompat.h"
 #include "isl_38xx.h"
 #include "islpci_eth.h"
 #include "islpci_mgt.h"
 #include "oid_mgt.h"

 /******************************************************************************
     Network Interface functions
 ******************************************************************************/
 void
 islpci_eth_cleanup_transmit(islpci_private *priv,
 			    isl38xx_control_block *control_block)
 {
 	struct sk_buff *skb;
 	u32 index;

 	/* compare the control block read pointer with the free pointer */
 	while (priv->free_data_tx !=
 	       le32_to_cpu(control_block->
 			   device_curr_frag[ISL38XX_CB_TX_DATA_LQ])) {
 		/* read the index of the first fragment to be freed */
 		index = priv->free_data_tx % ISL38XX_CB_TX_QSIZE;

 		/* check for holes in the arrays caused by multi fragment frames
 		 * searching for the last fragment of a frame */
 		if (priv->pci_map_tx_address[index] != (dma_addr_t) NULL) {
 			/* entry is the last fragment of a frame
 			 * free the skb structure and unmap pci memory */
 			skb = priv->data_low_tx[index];

 #if VERBOSE > SHOW_ERROR_MESSAGES
 			DEBUG(SHOW_TRACING,
 			      "cleanup skb %p skb->data %p skb->len %u truesize %u\n ",
 			      skb, skb->data, skb->len, skb->truesize);
 #endif

 			pci_unmap_single(priv->pdev,
 					 priv->pci_map_tx_address[index],
 					 skb->len, PCI_DMA_TODEVICE);
 			dev_kfree_skb_irq(skb);
 			skb = NULL;
 		}
 		/* increment the free data low queue pointer */
 		priv->free_data_tx++;
 	}
 }

 int
 islpci_eth_transmit(struct sk_buff *skb, struct net_device *ndev)
 {
 	islpci_private *priv = netdev_priv(ndev);
 	isl38xx_control_block *cb = priv->control_block;
 	u32 index;
 	dma_addr_t pci_map_address;
 	int frame_size;
 	isl38xx_fragment *fragment;
 	int offset;
 	struct sk_buff *newskb;
 	int newskb_offset;
 	unsigned long flags;
 	unsigned char wds_mac[6];
 	u32 curr_frag;
 	int err = 0;

 #if VERBOSE > SHOW_ERROR_MESSAGES
 	DEBUG(SHOW_FUNCTION_CALLS, "islpci_eth_transmit \n");
 #endif

 	/* lock the driver code */
 	spin_lock_irqsave(&priv->slock, flags);

 	/* check whether the destination queue has enough fragments for the frame */
 	curr_frag = le32_to_cpu(cb->driver_curr_frag[ISL38XX_CB_TX_DATA_LQ]);
 	if (unlikely(curr_frag - priv->free_data_tx >= ISL38XX_CB_TX_QSIZE)) {
 		printk(KERN_ERR "%s: transmit device queue full when awake\n",
 		       ndev->name);
 		netif_stop_queue(ndev);

 		/* trigger the device */
 		isl38xx_w32_flush(priv->device_base, ISL38XX_DEV_INT_UPDATE,
 				  ISL38XX_DEV_INT_REG);
 		udelay(ISL38XX_WRITEIO_DELAY);

 		err = -EBUSY;
 		goto drop_free;
 	}
 	/* Check alignment and WDS frame formatting. The start of the packet should
 	 * be aligned on a 4-byte boundary. If WDS is enabled add another 6 bytes
 	 * and add WDS address information */
 	if (likely(((long) skb->data & 0x03) | init_wds)) {
 		/* get the number of bytes to add and re-allign */
 		offset = (4 - (long) skb->data) & 0x03;
 		offset += init_wds ? 6 : 0;

 		/* check whether the current skb can be used  */
 		if (!skb_cloned(skb) && (skb_tailroom(skb) >= offset)) {
 			unsigned char *src = skb->data;

 #if VERBOSE > SHOW_ERROR_MESSAGES
 			DEBUG(SHOW_TRACING, "skb offset %i wds %i\n", offset,
 			      init_wds);
 #endif

 			/* align the buffer on 4-byte boundary */
 			skb_reserve(skb, (4 - (long) skb->data) & 0x03);
 			if (init_wds) {
 				/* wds requires an additional address field of 6 bytes */
 				skb_put(skb, 6);
 #ifdef ISLPCI_ETH_DEBUG
 				printk("islpci_eth_transmit:wds_mac\n");
 #endif
 				memmove(skb->data + 6, src, skb->len);
 				memcpy(skb->data, wds_mac, 6);
 			} else {
 				memmove(skb->data, src, skb->len);
 			}

 #if VERBOSE > SHOW_ERROR_MESSAGES
 			DEBUG(SHOW_TRACING, "memmove %p %p %i \n", skb->data,
 			      src, skb->len);
 #endif
 		} else {
 			newskb =
 			    dev_alloc_skb(init_wds ? skb->len + 6 : skb->len);
 			if (unlikely(newskb == NULL)) {
 				printk(KERN_ERR "%s: Cannot allocate skb\n",
 				       ndev->name);
 				err = -ENOMEM;
 				goto drop_free;
 			}
 			newskb_offset = (4 - (long) newskb->data) & 0x03;

 			/* Check if newskb->data is aligned */
 			if (newskb_offset)
 				skb_reserve(newskb, newskb_offset);

 			skb_put(newskb, init_wds ? skb->len + 6 : skb->len);
 			if (init_wds) {
 				memcpy(newskb->data + 6, skb->data, skb->len);
 				memcpy(newskb->data, wds_mac, 6);
 #ifdef ISLPCI_ETH_DEBUG
 				printk("islpci_eth_transmit:wds_mac\n");
 #endif
 			} else
 				memcpy(newskb->data, skb->data, skb->len);

 #if VERBOSE > SHOW_ERROR_MESSAGES
 			DEBUG(SHOW_TRACING, "memcpy %p %p %i wds %i\n",
 			      newskb->data, skb->data, skb->len, init_wds);
 #endif

 			newskb->dev = skb->dev;
 			dev_kfree_skb(skb);
 			skb = newskb;
 		}
 	}
 	/* display the buffer contents for debugging */
 #if VERBOSE > SHOW_ERROR_MESSAGES
 	DEBUG(SHOW_BUFFER_CONTENTS, "\ntx %p ", skb->data);
 	display_buffer((char *) skb->data, skb->len);
 #endif

 	/* map the skb buffer to pci memory for DMA operation */
 	pci_map_address = pci_map_single(priv->pdev,
 					 (void *) skb->data, skb->len,
 					 PCI_DMA_TODEVICE);
 	if (unlikely(pci_map_address == 0)) {
 		printk(KERN_WARNING "%s: cannot map buffer to PCI\n",
 		       ndev->name);

 		err = -EIO;
 		goto drop_free;
 	}
 	/* Place the fragment in the control block structure. */
 	index = curr_frag % ISL38XX_CB_TX_QSIZE;
 	fragment = &cb->tx_data_low[index];

 	priv->pci_map_tx_address[index] = pci_map_address;
 	/* store the skb address for future freeing  */
 	priv->data_low_tx[index] = skb;
 	/* set the proper fragment start address and size information */
 	frame_size = skb->len;
 	fragment->size = cpu_to_le16(frame_size);
 	fragment->flags = cpu_to_le16(0);	/* set to 1 if more fragments */
 	fragment->address = cpu_to_le32(pci_map_address);
 	curr_frag++;

 	/* The fragment address in the control block must have been
 	 * written before announcing the frame buffer to device. */
 	wmb();
 	cb->driver_curr_frag[ISL38XX_CB_TX_DATA_LQ] = cpu_to_le32(curr_frag);

 	if (curr_frag - priv->free_data_tx + ISL38XX_MIN_QTHRESHOLD
 	    > ISL38XX_CB_TX_QSIZE) {
 		/* stop sends from upper layers */
 		netif_stop_queue(ndev);

 		/* set the full flag for the transmission queue */
 		priv->data_low_tx_full = 1;
 	}

 	/* trigger the device */
 	islpci_trigger(priv);

 	/* unlock the driver code */
 	spin_unlock_irqrestore(&priv->slock, flags);

 	/* set the transmission time */
 	ndev->trans_start = jiffies;
 	priv->statistics.tx_packets++;
 	priv->statistics.tx_bytes += skb->len;

 	return 0;

       drop_free:
 	priv->statistics.tx_dropped++;
 	spin_unlock_irqrestore(&priv->slock, flags);
 	dev_kfree_skb(skb);
 	return err;
 }

 static inline int
 islpci_monitor_rx(islpci_private *priv, struct sk_buff **skb)
 {
 	/* The card reports full 802.11 packets but with a 20 bytes
 	 * header and without the FCS. But there a is a bit that
 	 * indicates if the packet is corrupted :-) */
 	struct rfmon_header *hdr = (struct rfmon_header *) (*skb)->data;
 	if (hdr->flags & 0x01)
 		/* This one is bad. Drop it ! */
 		return -1;
 	if (priv->ndev->type == ARPHRD_IEEE80211_PRISM) {
 		struct avs_80211_1_header *avs;
 		/* extract the relevant data from the header */
 		u32 clock = le32_to_cpu(hdr->clock);
 		u8 rate = hdr->rate;
 		u16 freq = le16_to_cpu(hdr->freq);
 		u8 rssi = hdr->rssi;

 		skb_pull(*skb, sizeof (struct rfmon_header));

 		if (skb_headroom(*skb) < sizeof (struct avs_80211_1_header)) {
 			struct sk_buff *newskb = skb_copy_expand(*skb,
 								 sizeof (struct
 									 avs_80211_1_header),
 								 0, GFP_ATOMIC);
 			if (newskb) {
 				dev_kfree_skb_irq(*skb);
 				*skb = newskb;
 			} else
 				return -1;
 			/* This behavior is not very subtile... */
 		}

 		/* make room for the new header and fill it. */
 		avs =
 		    (struct avs_80211_1_header *) skb_push(*skb,
 							   sizeof (struct
 								   avs_80211_1_header));

 		avs->version = cpu_to_be32(P80211CAPTURE_VERSION);
 		avs->length = cpu_to_be32(sizeof (struct avs_80211_1_header));
 		avs->mactime = cpu_to_be64(le64_to_cpu(clock));
 		avs->hosttime = cpu_to_be64(jiffies);
 		avs->phytype = cpu_to_be32(6);	/*OFDM: 6 for (g), 8 for (a) */
 		avs->channel = cpu_to_be32(channel_of_freq(freq));
 		avs->datarate = cpu_to_be32(rate * 5);
 		avs->antenna = cpu_to_be32(0);	/*unknown */
 		avs->priority = cpu_to_be32(0);	/*unknown */
 		avs->ssi_type = cpu_to_be32(3);	/*2: dBm, 3: raw RSSI */
 		avs->ssi_signal = cpu_to_be32(rssi & 0x7f);
 		avs->ssi_noise = cpu_to_be32(priv->local_iwstatistics.qual.noise);	/*better than 'undefined', I assume */
 		avs->preamble = cpu_to_be32(0);	/*unknown */
 		avs->encoding = cpu_to_be32(0);	/*unknown */
 	} else
 		skb_pull(*skb, sizeof (struct rfmon_header));

 	(*skb)->protocol = htons(ETH_P_802_2);
 	(*skb)->mac.raw = (*skb)->data;
 	(*skb)->pkt_type = PACKET_OTHERHOST;

 	return 0;
 }

 int
 islpci_eth_receive(islpci_private *priv)
 {
 	struct net_device *ndev = priv->ndev;
 	isl38xx_control_block *control_block = priv->control_block;
 	struct sk_buff *skb;
 	u16 size;
 	u32 index, offset;
 	unsigned char *src;
 	int discard = 0;

 #if VERBOSE > SHOW_ERROR_MESSAGES
 	DEBUG(SHOW_FUNCTION_CALLS, "islpci_eth_receive \n");
 #endif

 	/* the device has written an Ethernet frame in the data area
 	 * of the sk_buff without updating the structure, do it now */
 	index = priv->free_data_rx % ISL38XX_CB_RX_QSIZE;
 	size = le16_to_cpu(control_block->rx_data_low[index].size);
 	skb = priv->data_low_rx[index];
 	offset = ((unsigned long)
 		  le32_to_cpu(control_block->rx_data_low[index].address) -
 		  (unsigned long) skb->data) & 3;

 #if VERBOSE > SHOW_ERROR_MESSAGES
 	DEBUG(SHOW_TRACING,
 	      "frq->addr %x skb->data %p skb->len %u offset %u truesize %u\n ",
 	      control_block->rx_data_low[priv->free_data_rx].address, skb->data,
 	      skb->len, offset, skb->truesize);
 #endif

 	/* delete the streaming DMA mapping before processing the skb */
 	pci_unmap_single(priv->pdev,
 			 priv->pci_map_rx_address[index],
 			 MAX_FRAGMENT_SIZE_RX + 2, PCI_DMA_FROMDEVICE);

 	/* update the skb structure and allign the buffer */
 	skb_put(skb, size);
 	if (offset) {
 		/* shift the buffer allocation offset bytes to get the right frame */
 		skb_pull(skb, 2);
 		skb_put(skb, 2);
 	}
 #if VERBOSE > SHOW_ERROR_MESSAGES
 	/* display the buffer contents for debugging */
 	DEBUG(SHOW_BUFFER_CONTENTS, "\nrx %p ", skb->data);
 	display_buffer((char *) skb->data, skb->len);
 #endif

 	/* check whether WDS is enabled and whether the data frame is a WDS frame */

 	if (init_wds) {
 		/* WDS enabled, check for the wds address on the first 6 bytes of the buffer */
 		src = skb->data + 6;
 		memmove(skb->data, src, skb->len - 6);
 		skb_trim(skb, skb->len - 6);
 	}
 #if VERBOSE > SHOW_ERROR_MESSAGES
 	DEBUG(SHOW_TRACING, "Fragment size %i in skb at %p\n", size, skb);
 	DEBUG(SHOW_TRACING, "Skb data at %p, length %i\n", skb->data, skb->len);

 	/* display the buffer contents for debugging */
 	DEBUG(SHOW_BUFFER_CONTENTS, "\nrx %p ", skb->data);
 	display_buffer((char *) skb->data, skb->len);
 #endif

 	/* do some additional sk_buff and network layer parameters */
 	skb->dev = ndev;

 	/* take care of monitor mode and spy monitoring. */
 	if (unlikely(priv->iw_mode == IW_MODE_MONITOR))
 		discard = islpci_monitor_rx(priv, &skb);
 	else {
 		if (unlikely(skb->data[2 * ETH_ALEN] == 0)) {
 			/* The packet has a rx_annex. Read it for spy monitoring, Then
 			 * remove it, while keeping the 2 leading MAC addr.
 			 */
 			struct iw_quality wstats;
 			struct rx_annex_header *annex =
 			    (struct rx_annex_header *) skb->data;
 			wstats.level = annex->rfmon.rssi;
 			/* The noise value can be a bit outdated if nobody's
 			 * reading wireless stats... */
 			wstats.noise = priv->local_iwstatistics.qual.noise;
 			wstats.qual = wstats.level - wstats.noise;
 			wstats.updated = 0x07;
 			/* Update spy records */
 			wireless_spy_update(ndev, annex->addr2, &wstats);

 			memcpy(skb->data + sizeof (struct rfmon_header),
 			       skb->data, 2 * ETH_ALEN);
 			skb_pull(skb, sizeof (struct rfmon_header));
 		}
 		skb->protocol = eth_type_trans(skb, ndev);
 	}
 	skb->ip_summed = CHECKSUM_NONE;
 	priv->statistics.rx_packets++;
 	priv->statistics.rx_bytes += size;

 	/* deliver the skb to the network layer */
 #ifdef ISLPCI_ETH_DEBUG
 	printk
 	    ("islpci_eth_receive:netif_rx %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
 	     skb->data[0], skb->data[1], skb->data[2], skb->data[3],
 	     skb->data[4], skb->data[5]);
 #endif
 	if (unlikely(discard)) {
 		dev_kfree_skb_irq(skb);
 		skb = NULL;
 	} else
 		netif_rx(skb);

 	/* increment the read index for the rx data low queue */
 	priv->free_data_rx++;

 	/* add one or more sk_buff structures */
 	while (index =
 	       le32_to_cpu(control_block->
 			   driver_curr_frag[ISL38XX_CB_RX_DATA_LQ]),
 	       index - priv->free_data_rx < ISL38XX_CB_RX_QSIZE) {
 		/* allocate an sk_buff for received data frames storage
 		 * include any required allignment operations */
 		skb = dev_alloc_skb(MAX_FRAGMENT_SIZE_RX + 2);
 		if (unlikely(skb == NULL)) {
 			/* error allocating an sk_buff structure elements */
 			DEBUG(SHOW_ERROR_MESSAGES, "Error allocating skb \n");
 			break;
 		}
 		skb_reserve(skb, (4 - (long) skb->data) & 0x03);
 		/* store the new skb structure pointer */
 		index = index % ISL38XX_CB_RX_QSIZE;
 		priv->data_low_rx[index] = skb;

 #if VERBOSE > SHOW_ERROR_MESSAGES
 		DEBUG(SHOW_TRACING,
 		      "new alloc skb %p skb->data %p skb->len %u index %u truesize %u\n ",
 		      skb, skb->data, skb->len, index, skb->truesize);
 #endif

 		/* set the streaming DMA mapping for proper PCI bus operation */
 		priv->pci_map_rx_address[index] =
 		    pci_map_single(priv->pdev, (void *) skb->data,
 				   MAX_FRAGMENT_SIZE_RX + 2,
 				   PCI_DMA_FROMDEVICE);
 		if (unlikely(priv->pci_map_rx_address[index] == (dma_addr_t) NULL)) {
 			/* error mapping the buffer to device accessable memory address */
 			DEBUG(SHOW_ERROR_MESSAGES,
 			      "Error mapping DMA address\n");

 			/* free the skbuf structure before aborting */
 			dev_kfree_skb_irq((struct sk_buff *) skb);
 			skb = NULL;
 			break;
 		}
 		/* update the fragment address */
 		control_block->rx_data_low[index].address = cpu_to_le32((u32)
 									priv->
 									pci_map_rx_address
 									[index]);
 		wmb();

 		/* increment the driver read pointer */
 		add_le32p((u32 *) &control_block->
 			  driver_curr_frag[ISL38XX_CB_RX_DATA_LQ], 1);
 	}

 	/* trigger the device */
 	islpci_trigger(priv);

 	return 0;
 }

 void
 islpci_do_reset_and_wake(void *data)
 {
 	islpci_private *priv = (islpci_private *) data;
 	islpci_reset(priv, 1);
 	netif_wake_queue(priv->ndev);
 	priv->reset_task_pending = 0;
 }

 void
 islpci_eth_tx_timeout(struct net_device *ndev)
 {
 	islpci_private *priv = netdev_priv(ndev);
 	struct net_device_stats *statistics = &priv->statistics;

 	/* increment the transmit error counter */
 	statistics->tx_errors++;

 	printk(KERN_WARNING "%s: tx_timeout", ndev->name);
 	if (!priv->reset_task_pending) {
 		priv->reset_task_pending = 1;
 		printk(", scheduling a reset");
 		netif_stop_queue(ndev);
 		schedule_work(&priv->reset_task);
 	}
 	printk("\n");
 }
	/*
	*
	* Copyright (C) 2002 Intersil Americas Inc.
	* Copyright (C) 2004 Aurelien Alleaume <slts@free.fr>
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	*/

	#include <linux/module.h>

	#include <linux/pci.h>
	#include <linux/delay.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/if_arp.h>

	#include "prismcompat.h"
	#include "isl_38xx.h"
	#include "islpci_eth.h"
	#include "islpci_mgt.h"
	#include "oid_mgt.h"

	/******************************************************************************
	Network Interface functions
	******************************************************************************/
	void
	islpci_eth_cleanup_transmit(islpci_private *priv,
	isl38xx_control_block *control_block)
	{
	struct sk_buff *skb;
	u32 index;

	/* compare the control block read pointer with the free pointer */
	while (priv->free_data_tx !=
	le32_to_cpu(control_block->
	device_curr_frag[ISL38XX_CB_TX_DATA_LQ])) {
	/* read the index of the first fragment to be freed */
	index = priv->free_data_tx % ISL38XX_CB_TX_QSIZE;

	/* check for holes in the arrays caused by multi fragment frames
	* searching for the last fragment of a frame */
	if (priv->pci_map_tx_address[index] != (dma_addr_t) NULL) {
	/* entry is the last fragment of a frame
	* free the skb structure and unmap pci memory */
	skb = priv->data_low_tx[index];

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING,
	"cleanup skb %p skb->data %p skb->len %u truesize %u\n ",
	skb, skb->data, skb->len, skb->truesize);
	#endif

	pci_unmap_single(priv->pdev,
	priv->pci_map_tx_address[index],
	skb->len, PCI_DMA_TODEVICE);
	dev_kfree_skb_irq(skb);
	skb = NULL;
	}
	/* increment the free data low queue pointer */
	priv->free_data_tx++;
	}
	}

	int
	islpci_eth_transmit(struct sk_buff skb, struct net_device ndev)
	{
	islpci_private *priv = netdev_priv(ndev);
	isl38xx_control_block *cb = priv->control_block;
	u32 index;
	dma_addr_t pci_map_address;
	int frame_size;
	isl38xx_fragment *fragment;
	int offset;
	struct sk_buff *newskb;
	int newskb_offset;
	unsigned long flags;
	unsigned char wds_mac[6];
	u32 curr_frag;
	int err = 0;

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_FUNCTION_CALLS, "islpci_eth_transmit \n");
	#endif

	/* lock the driver code */
	spin_lock_irqsave(&priv->slock, flags);

	/* check whether the destination queue has enough fragments for the frame */
	curr_frag = le32_to_cpu(cb->driver_curr_frag[ISL38XX_CB_TX_DATA_LQ]);
	if (unlikely(curr_frag - priv->free_data_tx >= ISL38XX_CB_TX_QSIZE)) {
	printk(KERN_ERR "%s: transmit device queue full when awake\n",
	ndev->name);
	netif_stop_queue(ndev);

	/* trigger the device */
	isl38xx_w32_flush(priv->device_base, ISL38XX_DEV_INT_UPDATE,
	ISL38XX_DEV_INT_REG);
	udelay(ISL38XX_WRITEIO_DELAY);

	err = -EBUSY;
	goto drop_free;
	}
	/* Check alignment and WDS frame formatting. The start of the packet should
	* be aligned on a 4-byte boundary. If WDS is enabled add another 6 bytes
	* and add WDS address information */
	if (likely(((long) skb->data & 0x03) \| init_wds)) {
	/* get the number of bytes to add and re-allign */
	offset = (4 - (long) skb->data) & 0x03;
	offset += init_wds ? 6 : 0;

	/* check whether the current skb can be used */
	if (!skb_cloned(skb) && (skb_tailroom(skb) >= offset)) {
	unsigned char *src = skb->data;

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING, "skb offset %i wds %i\n", offset,
	init_wds);
	#endif

	/* align the buffer on 4-byte boundary */
	skb_reserve(skb, (4 - (long) skb->data) & 0x03);
	if (init_wds) {
	/* wds requires an additional address field of 6 bytes */
	skb_put(skb, 6);
	#ifdef ISLPCI_ETH_DEBUG
	printk("islpci_eth_transmit:wds_mac\n");
	#endif
	memmove(skb->data + 6, src, skb->len);
	memcpy(skb->data, wds_mac, 6);
	} else {
	memmove(skb->data, src, skb->len);
	}

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING, "memmove %p %p %i \n", skb->data,
	src, skb->len);
	#endif
	} else {
	newskb =
	dev_alloc_skb(init_wds ? skb->len + 6 : skb->len);
	if (unlikely(newskb == NULL)) {
	printk(KERN_ERR "%s: Cannot allocate skb\n",
	ndev->name);
	err = -ENOMEM;
	goto drop_free;
	}
	newskb_offset = (4 - (long) newskb->data) & 0x03;

	/* Check if newskb->data is aligned */
	if (newskb_offset)
	skb_reserve(newskb, newskb_offset);

	skb_put(newskb, init_wds ? skb->len + 6 : skb->len);
	if (init_wds) {
	memcpy(newskb->data + 6, skb->data, skb->len);
	memcpy(newskb->data, wds_mac, 6);
	#ifdef ISLPCI_ETH_DEBUG
	printk("islpci_eth_transmit:wds_mac\n");
	#endif
	} else
	memcpy(newskb->data, skb->data, skb->len);

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING, "memcpy %p %p %i wds %i\n",
	newskb->data, skb->data, skb->len, init_wds);
	#endif

	newskb->dev = skb->dev;
	dev_kfree_skb(skb);
	skb = newskb;
	}
	}
	/* display the buffer contents for debugging */
	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_BUFFER_CONTENTS, "\ntx %p ", skb->data);
	display_buffer((char *) skb->data, skb->len);
	#endif

	/* map the skb buffer to pci memory for DMA operation */
	pci_map_address = pci_map_single(priv->pdev,
	(void *) skb->data, skb->len,
	PCI_DMA_TODEVICE);
	if (unlikely(pci_map_address == 0)) {
	printk(KERN_WARNING "%s: cannot map buffer to PCI\n",
	ndev->name);

	err = -EIO;
	goto drop_free;
	}
	/* Place the fragment in the control block structure. */
	index = curr_frag % ISL38XX_CB_TX_QSIZE;
	fragment = &cb->tx_data_low[index];

	priv->pci_map_tx_address[index] = pci_map_address;
	/* store the skb address for future freeing */
	priv->data_low_tx[index] = skb;
	/* set the proper fragment start address and size information */
	frame_size = skb->len;
	fragment->size = cpu_to_le16(frame_size);
	fragment->flags = cpu_to_le16(0); /* set to 1 if more fragments */
	fragment->address = cpu_to_le32(pci_map_address);
	curr_frag++;

	/* The fragment address in the control block must have been
	* written before announcing the frame buffer to device. */
	wmb();
	cb->driver_curr_frag[ISL38XX_CB_TX_DATA_LQ] = cpu_to_le32(curr_frag);

	if (curr_frag - priv->free_data_tx + ISL38XX_MIN_QTHRESHOLD
	> ISL38XX_CB_TX_QSIZE) {
	/* stop sends from upper layers */
	netif_stop_queue(ndev);

	/* set the full flag for the transmission queue */
	priv->data_low_tx_full = 1;
	}

	/* trigger the device */
	islpci_trigger(priv);

	/* unlock the driver code */
	spin_unlock_irqrestore(&priv->slock, flags);

	/* set the transmission time */
	ndev->trans_start = jiffies;
	priv->statistics.tx_packets++;
	priv->statistics.tx_bytes += skb->len;

	return 0;

	drop_free:
	priv->statistics.tx_dropped++;
	spin_unlock_irqrestore(&priv->slock, flags);
	dev_kfree_skb(skb);
	return err;
	}

	static inline int
	islpci_monitor_rx(islpci_private priv, struct sk_buff *skb)
	{
	/* The card reports full 802.11 packets but with a 20 bytes
	* header and without the FCS. But there a is a bit that
	* indicates if the packet is corrupted :-) */
	struct rfmon_header hdr = (struct rfmon_header ) (*skb)->data;
	if (hdr->flags & 0x01)
	/* This one is bad. Drop it ! */
	return -1;
	if (priv->ndev->type == ARPHRD_IEEE80211_PRISM) {
	struct avs_80211_1_header *avs;
	/* extract the relevant data from the header */
	u32 clock = le32_to_cpu(hdr->clock);
	u8 rate = hdr->rate;
	u16 freq = le16_to_cpu(hdr->freq);
	u8 rssi = hdr->rssi;

	skb_pull(*skb, sizeof (struct rfmon_header));

	if (skb_headroom(*skb) < sizeof (struct avs_80211_1_header)) {
	struct sk_buff newskb = skb_copy_expand(skb,
	sizeof (struct
	avs_80211_1_header),
	0, GFP_ATOMIC);
	if (newskb) {
	dev_kfree_skb_irq(*skb);
	*skb = newskb;
	} else
	return -1;
	/* This behavior is not very subtile... */
	}

	/* make room for the new header and fill it. */
	avs =
	(struct avs_80211_1_header ) skb_push(skb,
	sizeof (struct
	avs_80211_1_header));

	avs->version = cpu_to_be32(P80211CAPTURE_VERSION);
	avs->length = cpu_to_be32(sizeof (struct avs_80211_1_header));
	avs->mactime = cpu_to_be64(le64_to_cpu(clock));
	avs->hosttime = cpu_to_be64(jiffies);
	avs->phytype = cpu_to_be32(6); /OFDM: 6 for (g), 8 for (a) /
	avs->channel = cpu_to_be32(channel_of_freq(freq));
	avs->datarate = cpu_to_be32(rate * 5);
	avs->antenna = cpu_to_be32(0); /unknown /
	avs->priority = cpu_to_be32(0); /unknown /
	avs->ssi_type = cpu_to_be32(3); /2: dBm, 3: raw RSSI /
	avs->ssi_signal = cpu_to_be32(rssi & 0x7f);
	avs->ssi_noise = cpu_to_be32(priv->local_iwstatistics.qual.noise); /better than 'undefined', I assume /
	avs->preamble = cpu_to_be32(0); /unknown /
	avs->encoding = cpu_to_be32(0); /unknown /
	} else
	skb_pull(*skb, sizeof (struct rfmon_header));

	(*skb)->protocol = htons(ETH_P_802_2);
	(skb)->mac.raw = (skb)->data;
	(*skb)->pkt_type = PACKET_OTHERHOST;

	return 0;
	}

	int
	islpci_eth_receive(islpci_private *priv)
	{
	struct net_device *ndev = priv->ndev;
	isl38xx_control_block *control_block = priv->control_block;
	struct sk_buff *skb;
	u16 size;
	u32 index, offset;
	unsigned char *src;
	int discard = 0;

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_FUNCTION_CALLS, "islpci_eth_receive \n");
	#endif

	/* the device has written an Ethernet frame in the data area
	* of the sk_buff without updating the structure, do it now */
	index = priv->free_data_rx % ISL38XX_CB_RX_QSIZE;
	size = le16_to_cpu(control_block->rx_data_low[index].size);
	skb = priv->data_low_rx[index];
	offset = ((unsigned long)
	le32_to_cpu(control_block->rx_data_low[index].address) -
	(unsigned long) skb->data) & 3;

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING,
	"frq->addr %x skb->data %p skb->len %u offset %u truesize %u\n ",
	control_block->rx_data_low[priv->free_data_rx].address, skb->data,
	skb->len, offset, skb->truesize);
	#endif

	/* delete the streaming DMA mapping before processing the skb */
	pci_unmap_single(priv->pdev,
	priv->pci_map_rx_address[index],
	MAX_FRAGMENT_SIZE_RX + 2, PCI_DMA_FROMDEVICE);

	/* update the skb structure and allign the buffer */
	skb_put(skb, size);
	if (offset) {
	/* shift the buffer allocation offset bytes to get the right frame */
	skb_pull(skb, 2);
	skb_put(skb, 2);
	}
	#if VERBOSE > SHOW_ERROR_MESSAGES
	/* display the buffer contents for debugging */
	DEBUG(SHOW_BUFFER_CONTENTS, "\nrx %p ", skb->data);
	display_buffer((char *) skb->data, skb->len);
	#endif

	/* check whether WDS is enabled and whether the data frame is a WDS frame */

	if (init_wds) {
	/* WDS enabled, check for the wds address on the first 6 bytes of the buffer */
	src = skb->data + 6;
	memmove(skb->data, src, skb->len - 6);
	skb_trim(skb, skb->len - 6);
	}
	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING, "Fragment size %i in skb at %p\n", size, skb);
	DEBUG(SHOW_TRACING, "Skb data at %p, length %i\n", skb->data, skb->len);

	/* display the buffer contents for debugging */
	DEBUG(SHOW_BUFFER_CONTENTS, "\nrx %p ", skb->data);
	display_buffer((char *) skb->data, skb->len);
	#endif

	/* do some additional sk_buff and network layer parameters */
	skb->dev = ndev;

	/* take care of monitor mode and spy monitoring. */
	if (unlikely(priv->iw_mode == IW_MODE_MONITOR))
	discard = islpci_monitor_rx(priv, &skb);
	else {
	if (unlikely(skb->data[2 * ETH_ALEN] == 0)) {
	/* The packet has a rx_annex. Read it for spy monitoring, Then
	* remove it, while keeping the 2 leading MAC addr.
	*/
	struct iw_quality wstats;
	struct rx_annex_header *annex =
	(struct rx_annex_header *) skb->data;
	wstats.level = annex->rfmon.rssi;
	/* The noise value can be a bit outdated if nobody's
	* reading wireless stats... */
	wstats.noise = priv->local_iwstatistics.qual.noise;
	wstats.qual = wstats.level - wstats.noise;
	wstats.updated = 0x07;
	/* Update spy records */
	wireless_spy_update(ndev, annex->addr2, &wstats);

	memcpy(skb->data + sizeof (struct rfmon_header),
	skb->data, 2 * ETH_ALEN);
	skb_pull(skb, sizeof (struct rfmon_header));
	}
	skb->protocol = eth_type_trans(skb, ndev);
	}
	skb->ip_summed = CHECKSUM_NONE;
	priv->statistics.rx_packets++;
	priv->statistics.rx_bytes += size;

	/* deliver the skb to the network layer */
	#ifdef ISLPCI_ETH_DEBUG
	printk
	("islpci_eth_receive:netif_rx %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
	skb->data[0], skb->data[1], skb->data[2], skb->data[3],
	skb->data[4], skb->data[5]);
	#endif
	if (unlikely(discard)) {
	dev_kfree_skb_irq(skb);
	skb = NULL;
	} else
	netif_rx(skb);

	/* increment the read index for the rx data low queue */
	priv->free_data_rx++;

	/* add one or more sk_buff structures */
	while (index =
	le32_to_cpu(control_block->
	driver_curr_frag[ISL38XX_CB_RX_DATA_LQ]),
	index - priv->free_data_rx < ISL38XX_CB_RX_QSIZE) {
	/* allocate an sk_buff for received data frames storage
	* include any required allignment operations */
	skb = dev_alloc_skb(MAX_FRAGMENT_SIZE_RX + 2);
	if (unlikely(skb == NULL)) {
	/* error allocating an sk_buff structure elements */
	DEBUG(SHOW_ERROR_MESSAGES, "Error allocating skb \n");
	break;
	}
	skb_reserve(skb, (4 - (long) skb->data) & 0x03);
	/* store the new skb structure pointer */
	index = index % ISL38XX_CB_RX_QSIZE;
	priv->data_low_rx[index] = skb;

	#if VERBOSE > SHOW_ERROR_MESSAGES
	DEBUG(SHOW_TRACING,
	"new alloc skb %p skb->data %p skb->len %u index %u truesize %u\n ",
	skb, skb->data, skb->len, index, skb->truesize);
	#endif

	/* set the streaming DMA mapping for proper PCI bus operation */
	priv->pci_map_rx_address[index] =
	pci_map_single(priv->pdev, (void *) skb->data,
	MAX_FRAGMENT_SIZE_RX + 2,
	PCI_DMA_FROMDEVICE);
	if (unlikely(priv->pci_map_rx_address[index] == (dma_addr_t) NULL)) {
	/* error mapping the buffer to device accessable memory address */
	DEBUG(SHOW_ERROR_MESSAGES,
	"Error mapping DMA address\n");

	/* free the skbuf structure before aborting */
	dev_kfree_skb_irq((struct sk_buff *) skb);
	skb = NULL;
	break;
	}
	/* update the fragment address */
	control_block->rx_data_low[index].address = cpu_to_le32((u32)
	priv->
	pci_map_rx_address
	[index]);
	wmb();

	/* increment the driver read pointer */
	add_le32p((u32 *) &control_block->
	driver_curr_frag[ISL38XX_CB_RX_DATA_LQ], 1);
	}

	/* trigger the device */
	islpci_trigger(priv);

	return 0;
	}

	void
	islpci_do_reset_and_wake(void *data)
	{
	islpci_private priv = (islpci_private ) data;
	islpci_reset(priv, 1);
	netif_wake_queue(priv->ndev);
	priv->reset_task_pending = 0;
	}

	void
	islpci_eth_tx_timeout(struct net_device *ndev)
	{
	islpci_private *priv = netdev_priv(ndev);
	struct net_device_stats *statistics = &priv->statistics;

	/* increment the transmit error counter */
	statistics->tx_errors++;

	printk(KERN_WARNING "%s: tx_timeout", ndev->name);
	if (!priv->reset_task_pending) {
	priv->reset_task_pending = 1;
	printk(", scheduling a reset");
	netif_stop_queue(ndev);
	schedule_work(&priv->reset_task);
	}
	printk("\n");
	}