/*
   *  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, see <http://www.gnu.org/licenses/>.
   *
   */
  
  #include <linux/module.h>
  #include <linux/gfp.h>
  
  #include <linux/pci.h>
  #include <linux/delay.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/if_arp.h>
  #include <asm/byteorder.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]) {
  			/* 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
   ",
  			      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++;
  	}
  }
  
  netdev_tx_t
  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;
  
  #if VERBOSE > SHOW_ERROR_MESSAGES
  	DEBUG(SHOW_FUNCTION_CALLS, "islpci_eth_transmit
  ");
  #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
  ",
  		       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);
  		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-align */
  		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
  ", 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
  ");
  #endif
  				memmove(skb->data + 6, src, skb->len);
  				skb_copy_to_linear_data(skb, wds_mac, 6);
  			} else {
  				memmove(skb->data, src, skb->len);
  			}
  
  #if VERBOSE > SHOW_ERROR_MESSAGES
  			DEBUG(SHOW_TRACING, "memmove %p %p %i
  ", 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
  ",
  				       ndev->name);
  				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) {
  				skb_copy_from_linear_data(skb,
  							  newskb->data + 6,
  							  skb->len);
  				skb_copy_to_linear_data(newskb, wds_mac, 6);
  #ifdef ISLPCI_ETH_DEBUG
  				printk("islpci_eth_transmit:wds_mac
  ");
  #endif
  			} else
  				skb_copy_from_linear_data(skb, newskb->data,
  							  skb->len);
  
  #if VERBOSE > SHOW_ERROR_MESSAGES
  			DEBUG(SHOW_TRACING, "memcpy %p %p %i wds %i
  ",
  			      newskb->data, skb->data, skb->len, init_wds);
  #endif
  
  			newskb->dev = skb->dev;
  			dev_kfree_skb_irq(skb);
  			skb = newskb;
  		}
  	}
  	/* display the buffer contents for debugging */
  #if VERBOSE > SHOW_ERROR_MESSAGES
  	DEBUG(SHOW_BUFFER_CONTENTS, "
  tx %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
  ",
  		       ndev->name);
  		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;
  	}
  
  	ndev->stats.tx_packets++;
  	ndev->stats.tx_bytes += skb->len;
  
  	/* trigger the device */
  	islpci_trigger(priv);
  
  	/* unlock the driver code */
  	spin_unlock_irqrestore(&priv->slock, flags);
  
  	return NETDEV_TX_OK;
  
        drop_free:
  	ndev->stats.tx_dropped++;
  	spin_unlock_irqrestore(&priv->slock, flags);
  	dev_kfree_skb(skb);
  	return NETDEV_TX_OK;
  }
  
  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(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_reset_mac_header(*skb);
  	(*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
  ");
  #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
   ",
  	      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 align 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, "
  rx %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
  ", size, skb);
  	DEBUG(SHOW_TRACING, "Skb data at %p, length %i
  ", skb->data, skb->len);
  
  	/* display the buffer contents for debugging */
  	DEBUG(SHOW_BUFFER_CONTENTS, "
  rx %p ", skb->data);
  	display_buffer((char *) skb->data, skb->len);
  #endif
  	/* take care of monitor mode and spy monitoring. */
  	if (unlikely(priv->iw_mode == IW_MODE_MONITOR)) {
  		skb->dev = ndev;
  		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);
  
  			skb_copy_from_linear_data(skb,
  						  (skb->data +
  						   sizeof(struct rfmon_header)),
  						  2 * ETH_ALEN);
  			skb_pull(skb, sizeof (struct rfmon_header));
  		}
  		skb->protocol = eth_type_trans(skb, ndev);
  	}
  	skb->ip_summed = CHECKSUM_NONE;
  	ndev->stats.rx_packets++;
  	ndev->stats.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
  ",
  	     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
  ");
  			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
   ",
  		      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])) {
  			/* error mapping the buffer to device accessible memory address */
  			DEBUG(SHOW_ERROR_MESSAGES,
  			      "Error mapping DMA address
  ");
  
  			/* free the skbuf structure before aborting */
  			dev_kfree_skb_irq(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 */
  		le32_add_cpu(&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(struct work_struct *work)
  {
  	islpci_private *priv = container_of(work, islpci_private, reset_task);
  
  	islpci_reset(priv, 1);
  	priv->reset_task_pending = 0;
  	smp_wmb();
  	netif_wake_queue(priv->ndev);
  }
  
  void
  islpci_eth_tx_timeout(struct net_device *ndev)
  {
  	islpci_private *priv = netdev_priv(ndev);
  
  	/* increment the transmit error counter */
  	ndev->stats.tx_errors++;
  
  	if (!priv->reset_task_pending) {
  		printk(KERN_WARNING
  			"%s: tx_timeout, scheduling reset", ndev->name);
  		netif_stop_queue(ndev);
  		priv->reset_task_pending = 1;
  		schedule_work(&priv->reset_task);
  	} else {
  		printk(KERN_WARNING
  			"%s: tx_timeout, waiting for reset", ndev->name);
  	}
  }