/*
   * rionet - Ethernet driver over RapidIO messaging services
   *
   * Copyright 2005 MontaVista Software, Inc.
   * Matt Porter <mporter@kernel.crashing.org>
   *
   * 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, or (at your
   * option) any later version.
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/dma-mapping.h>
  #include <linux/delay.h>
  #include <linux/rio.h>
  #include <linux/rio_drv.h>

  #include <linux/slab.h>

  #include <linux/rio_ids.h>
  
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/skbuff.h>
  #include <linux/crc32.h>
  #include <linux/ethtool.h>
  
  #define DRV_NAME        "rionet"
  #define DRV_VERSION     "0.2"
  #define DRV_AUTHOR      "Matt Porter <mporter@kernel.crashing.org>"
  #define DRV_DESC        "Ethernet over RapidIO"
  
  MODULE_AUTHOR(DRV_AUTHOR);
  MODULE_DESCRIPTION(DRV_DESC);
  MODULE_LICENSE("GPL");
  
  #define RIONET_DEFAULT_MSGLEVEL \
  			(NETIF_MSG_DRV          | \
  			 NETIF_MSG_LINK         | \
  			 NETIF_MSG_RX_ERR       | \
  			 NETIF_MSG_TX_ERR)
  
  #define RIONET_DOORBELL_JOIN	0x1000
  #define RIONET_DOORBELL_LEAVE	0x1001
  
  #define RIONET_MAILBOX		0
  
  #define RIONET_TX_RING_SIZE	CONFIG_RIONET_TX_SIZE
  #define RIONET_RX_RING_SIZE	CONFIG_RIONET_RX_SIZE
  
  static LIST_HEAD(rionet_peers);
  
  struct rionet_private {
  	struct rio_mport *mport;
  	struct sk_buff *rx_skb[RIONET_RX_RING_SIZE];
  	struct sk_buff *tx_skb[RIONET_TX_RING_SIZE];

  	int rx_slot;
  	int tx_slot;
  	int tx_cnt;
  	int ack_slot;
  	spinlock_t lock;
  	spinlock_t tx_lock;
  	u32 msg_enable;
  };
  
  struct rionet_peer {
  	struct list_head node;
  	struct rio_dev *rdev;
  	struct resource *res;
  };
  
  static int rionet_check = 0;
  static int rionet_capable = 1;
  
  /*

   * This is a fast lookup table for translating TX

   * Ethernet packets into a destination RIO device. It
   * could be made into a hash table to save memory depending
   * on system trade-offs.
   */

  static struct rio_dev **rionet_active;

  #define is_rionet_capable(src_ops, dst_ops)			\
  			((src_ops & RIO_SRC_OPS_DATA_MSG) &&	\
  			 (dst_ops & RIO_DST_OPS_DATA_MSG) &&	\

  			 (src_ops & RIO_SRC_OPS_DOORBELL) &&	\
  			 (dst_ops & RIO_DST_OPS_DOORBELL))
  #define dev_rionet_capable(dev) \

  	is_rionet_capable(dev->src_ops, dev->dst_ops)

  #define RIONET_MAC_MATCH(x)	(!memcmp((x), "\00\01\00\01", 4))
  #define RIONET_GET_DESTID(x)	((*((u8 *)x + 4) << 8) | *((u8 *)x + 5))

  static int rionet_rx_clean(struct net_device *ndev)
  {
  	int i;
  	int error = 0;

  	struct rionet_private *rnet = netdev_priv(ndev);

  	void *data;
  
  	i = rnet->rx_slot;
  
  	do {
  		if (!rnet->rx_skb[i])
  			continue;
  
  		if (!(data = rio_get_inb_message(rnet->mport, RIONET_MAILBOX)))
  			break;
  
  		rnet->rx_skb[i]->data = data;
  		skb_put(rnet->rx_skb[i], RIO_MAX_MSG_SIZE);

  		rnet->rx_skb[i]->protocol =
  		    eth_type_trans(rnet->rx_skb[i], ndev);
  		error = netif_rx(rnet->rx_skb[i]);
  
  		if (error == NET_RX_DROP) {

  			ndev->stats.rx_dropped++;

  		} else {

  			ndev->stats.rx_packets++;
  			ndev->stats.rx_bytes += RIO_MAX_MSG_SIZE;

  		}
  
  	} while ((i = (i + 1) % RIONET_RX_RING_SIZE) != rnet->rx_slot);
  
  	return i;
  }
  
  static void rionet_rx_fill(struct net_device *ndev, int end)
  {
  	int i;

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	i = rnet->rx_slot;
  	do {
  		rnet->rx_skb[i] = dev_alloc_skb(RIO_MAX_MSG_SIZE);
  
  		if (!rnet->rx_skb[i])
  			break;
  
  		rio_add_inb_buffer(rnet->mport, RIONET_MAILBOX,
  				   rnet->rx_skb[i]->data);
  	} while ((i = (i + 1) % RIONET_RX_RING_SIZE) != end);
  
  	rnet->rx_slot = i;
  }
  
  static int rionet_queue_tx_msg(struct sk_buff *skb, struct net_device *ndev,
  			       struct rio_dev *rdev)
  {

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	rio_add_outb_message(rnet->mport, rdev, 0, skb->data, skb->len);
  	rnet->tx_skb[rnet->tx_slot] = skb;

  	ndev->stats.tx_packets++;
  	ndev->stats.tx_bytes += skb->len;

  
  	if (++rnet->tx_cnt == RIONET_TX_RING_SIZE)
  		netif_stop_queue(ndev);
  
  	++rnet->tx_slot;
  	rnet->tx_slot &= (RIONET_TX_RING_SIZE - 1);
  
  	if (netif_msg_tx_queued(rnet))

  		printk(KERN_INFO "%s: queued skb len %8.8x
  ", DRV_NAME,
  		       skb->len);

  
  	return 0;
  }
  
  static int rionet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
  {
  	int i;

  	struct rionet_private *rnet = netdev_priv(ndev);

  	struct ethhdr *eth = (struct ethhdr *)skb->data;
  	u16 destid;
  	unsigned long flags;
  
  	local_irq_save(flags);
  	if (!spin_trylock(&rnet->tx_lock)) {
  		local_irq_restore(flags);
  		return NETDEV_TX_LOCKED;
  	}
  
  	if ((rnet->tx_cnt + 1) > RIONET_TX_RING_SIZE) {
  		netif_stop_queue(ndev);
  		spin_unlock_irqrestore(&rnet->tx_lock, flags);
  		printk(KERN_ERR "%s: BUG! Tx Ring full when queue awake!
  ",
  		       ndev->name);
  		return NETDEV_TX_BUSY;
  	}

  	if (is_multicast_ether_addr(eth->h_dest)) {

  		for (i = 0; i < RIO_MAX_ROUTE_ENTRIES(rnet->mport->sys_size);
  				i++)

  			if (rionet_active[i])
  				rionet_queue_tx_msg(skb, ndev,
  						    rionet_active[i]);
  	} else if (RIONET_MAC_MATCH(eth->h_dest)) {
  		destid = RIONET_GET_DESTID(eth->h_dest);
  		if (rionet_active[destid])
  			rionet_queue_tx_msg(skb, ndev, rionet_active[destid]);
  	}
  
  	spin_unlock_irqrestore(&rnet->tx_lock, flags);

  	return NETDEV_TX_OK;

  }
  
  static void rionet_dbell_event(struct rio_mport *mport, void *dev_id, u16 sid, u16 tid,
  			       u16 info)
  {
  	struct net_device *ndev = dev_id;

  	struct rionet_private *rnet = netdev_priv(ndev);

  	struct rionet_peer *peer;
  
  	if (netif_msg_intr(rnet))
  		printk(KERN_INFO "%s: doorbell sid %4.4x tid %4.4x info %4.4x",
  		       DRV_NAME, sid, tid, info);
  	if (info == RIONET_DOORBELL_JOIN) {
  		if (!rionet_active[sid]) {
  			list_for_each_entry(peer, &rionet_peers, node) {
  				if (peer->rdev->destid == sid)
  					rionet_active[sid] = peer->rdev;
  			}
  			rio_mport_send_doorbell(mport, sid,
  						RIONET_DOORBELL_JOIN);
  		}
  	} else if (info == RIONET_DOORBELL_LEAVE) {
  		rionet_active[sid] = NULL;
  	} else {
  		if (netif_msg_intr(rnet))
  			printk(KERN_WARNING "%s: unhandled doorbell
  ",
  			       DRV_NAME);
  	}
  }
  
  static void rionet_inb_msg_event(struct rio_mport *mport, void *dev_id, int mbox, int slot)
  {
  	int n;
  	struct net_device *ndev = dev_id;

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	if (netif_msg_intr(rnet))
  		printk(KERN_INFO "%s: inbound message event, mbox %d slot %d
  ",
  		       DRV_NAME, mbox, slot);
  
  	spin_lock(&rnet->lock);
  	if ((n = rionet_rx_clean(ndev)) != rnet->rx_slot)
  		rionet_rx_fill(ndev, n);
  	spin_unlock(&rnet->lock);
  }
  
  static void rionet_outb_msg_event(struct rio_mport *mport, void *dev_id, int mbox, int slot)
  {
  	struct net_device *ndev = dev_id;

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	spin_lock(&rnet->lock);
  
  	if (netif_msg_intr(rnet))
  		printk(KERN_INFO
  		       "%s: outbound message event, mbox %d slot %d
  ",
  		       DRV_NAME, mbox, slot);
  
  	while (rnet->tx_cnt && (rnet->ack_slot != slot)) {
  		/* dma unmap single */
  		dev_kfree_skb_irq(rnet->tx_skb[rnet->ack_slot]);
  		rnet->tx_skb[rnet->ack_slot] = NULL;
  		++rnet->ack_slot;
  		rnet->ack_slot &= (RIONET_TX_RING_SIZE - 1);
  		rnet->tx_cnt--;
  	}
  
  	if (rnet->tx_cnt < RIONET_TX_RING_SIZE)
  		netif_wake_queue(ndev);
  
  	spin_unlock(&rnet->lock);
  }
  
  static int rionet_open(struct net_device *ndev)
  {
  	int i, rc = 0;
  	struct rionet_peer *peer, *tmp;

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	if (netif_msg_ifup(rnet))
  		printk(KERN_INFO "%s: open
  ", DRV_NAME);
  
  	if ((rc = rio_request_inb_dbell(rnet->mport,
  					(void *)ndev,
  					RIONET_DOORBELL_JOIN,
  					RIONET_DOORBELL_LEAVE,
  					rionet_dbell_event)) < 0)
  		goto out;
  
  	if ((rc = rio_request_inb_mbox(rnet->mport,
  				       (void *)ndev,
  				       RIONET_MAILBOX,
  				       RIONET_RX_RING_SIZE,
  				       rionet_inb_msg_event)) < 0)
  		goto out;
  
  	if ((rc = rio_request_outb_mbox(rnet->mport,
  					(void *)ndev,
  					RIONET_MAILBOX,
  					RIONET_TX_RING_SIZE,
  					rionet_outb_msg_event)) < 0)
  		goto out;
  
  	/* Initialize inbound message ring */
  	for (i = 0; i < RIONET_RX_RING_SIZE; i++)
  		rnet->rx_skb[i] = NULL;
  	rnet->rx_slot = 0;
  	rionet_rx_fill(ndev, 0);
  
  	rnet->tx_slot = 0;
  	rnet->tx_cnt = 0;
  	rnet->ack_slot = 0;
  
  	netif_carrier_on(ndev);
  	netif_start_queue(ndev);
  
  	list_for_each_entry_safe(peer, tmp, &rionet_peers, node) {
  		if (!(peer->res = rio_request_outb_dbell(peer->rdev,
  							 RIONET_DOORBELL_JOIN,
  							 RIONET_DOORBELL_LEAVE)))
  		{
  			printk(KERN_ERR "%s: error requesting doorbells
  ",
  			       DRV_NAME);
  			continue;
  		}

  		/* Send a join message */
  		rio_send_doorbell(peer->rdev, RIONET_DOORBELL_JOIN);

  	}
  
        out:
  	return rc;
  }
  
  static int rionet_close(struct net_device *ndev)
  {

  	struct rionet_private *rnet = netdev_priv(ndev);

  	struct rionet_peer *peer, *tmp;
  	int i;
  
  	if (netif_msg_ifup(rnet))
  		printk(KERN_INFO "%s: close
  ", DRV_NAME);
  
  	netif_stop_queue(ndev);
  	netif_carrier_off(ndev);
  
  	for (i = 0; i < RIONET_RX_RING_SIZE; i++)

  		kfree_skb(rnet->rx_skb[i]);

  
  	list_for_each_entry_safe(peer, tmp, &rionet_peers, node) {
  		if (rionet_active[peer->rdev->destid]) {
  			rio_send_doorbell(peer->rdev, RIONET_DOORBELL_LEAVE);
  			rionet_active[peer->rdev->destid] = NULL;
  		}
  		rio_release_outb_dbell(peer->rdev, peer->res);
  	}
  
  	rio_release_inb_dbell(rnet->mport, RIONET_DOORBELL_JOIN,
  			      RIONET_DOORBELL_LEAVE);
  	rio_release_inb_mbox(rnet->mport, RIONET_MAILBOX);
  	rio_release_outb_mbox(rnet->mport, RIONET_MAILBOX);
  
  	return 0;
  }
  
  static void rionet_remove(struct rio_dev *rdev)
  {

  	struct net_device *ndev = rio_get_drvdata(rdev);

  	struct rionet_peer *peer, *tmp;

  	free_pages((unsigned long)rionet_active, rdev->net->hport->sys_size ?

  					__fls(sizeof(void *)) + 4 : 0);

  	unregister_netdev(ndev);

  	free_netdev(ndev);

  
  	list_for_each_entry_safe(peer, tmp, &rionet_peers, node) {
  		list_del(&peer->node);
  		kfree(peer);
  	}
  }
  
  static void rionet_get_drvinfo(struct net_device *ndev,
  			       struct ethtool_drvinfo *info)
  {

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	strcpy(info->driver, DRV_NAME);
  	strcpy(info->version, DRV_VERSION);
  	strcpy(info->fw_version, "n/a");
  	strcpy(info->bus_info, rnet->mport->name);
  }
  
  static u32 rionet_get_msglevel(struct net_device *ndev)
  {

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	return rnet->msg_enable;
  }
  
  static void rionet_set_msglevel(struct net_device *ndev, u32 value)
  {

  	struct rionet_private *rnet = netdev_priv(ndev);

  
  	rnet->msg_enable = value;
  }

  static const struct ethtool_ops rionet_ethtool_ops = {

  	.get_drvinfo = rionet_get_drvinfo,
  	.get_msglevel = rionet_get_msglevel,
  	.set_msglevel = rionet_set_msglevel,
  	.get_link = ethtool_op_get_link,
  };

  static const struct net_device_ops rionet_netdev_ops = {
  	.ndo_open		= rionet_open,
  	.ndo_stop		= rionet_close,
  	.ndo_start_xmit		= rionet_start_xmit,
  	.ndo_change_mtu		= eth_change_mtu,
  	.ndo_validate_addr	= eth_validate_addr,
  	.ndo_set_mac_address	= eth_mac_addr,
  };

  static int rionet_setup_netdev(struct rio_mport *mport, struct net_device *ndev)

  {
  	int rc = 0;

  	struct rionet_private *rnet;
  	u16 device_id;

  	rionet_active = (struct rio_dev **)__get_free_pages(GFP_KERNEL,

  			mport->sys_size ? __fls(sizeof(void *)) + 4 : 0);

  	if (!rionet_active) {
  		rc = -ENOMEM;
  		goto out;
  	}
  	memset((void *)rionet_active, 0, sizeof(void *) *
  				RIO_MAX_ROUTE_ENTRIES(mport->sys_size));

  	/* Set up private area */

  	rnet = netdev_priv(ndev);

  	rnet->mport = mport;
  
  	/* Set the default MAC address */
  	device_id = rio_local_get_device_id(mport);
  	ndev->dev_addr[0] = 0x00;
  	ndev->dev_addr[1] = 0x01;
  	ndev->dev_addr[2] = 0x00;
  	ndev->dev_addr[3] = 0x01;
  	ndev->dev_addr[4] = device_id >> 8;
  	ndev->dev_addr[5] = device_id & 0xff;

  	ndev->netdev_ops = &rionet_netdev_ops;

  	ndev->mtu = RIO_MAX_MSG_SIZE - 14;
  	ndev->features = NETIF_F_LLTX;
  	SET_ETHTOOL_OPS(ndev, &rionet_ethtool_ops);

  	spin_lock_init(&rnet->lock);
  	spin_lock_init(&rnet->tx_lock);
  
  	rnet->msg_enable = RIONET_DEFAULT_MSGLEVEL;
  
  	rc = register_netdev(ndev);
  	if (rc != 0)
  		goto out;

  	printk("%s: %s %s Version %s, MAC %pM
  ",

  	       ndev->name,
  	       DRV_NAME,
  	       DRV_DESC,
  	       DRV_VERSION,

  	       ndev->dev_addr);

  
        out:
  	return rc;
  }
  
  /*
   * XXX Make multi-net safe
   */
  static int rionet_probe(struct rio_dev *rdev, const struct rio_device_id *id)
  {
  	int rc = -ENODEV;

  	u32 lsrc_ops, ldst_ops;

  	struct rionet_peer *peer;

  	struct net_device *ndev = NULL;

  
  	/* If local device is not rionet capable, give up quickly */
  	if (!rionet_capable)
  		goto out;

  	/* Allocate our net_device structure */
  	ndev = alloc_etherdev(sizeof(struct rionet_private));
  	if (ndev == NULL) {
  		printk(KERN_INFO "%s: could not allocate ethernet device.
  ",
  		       DRV_NAME);
  		rc = -ENOMEM;
  		goto out;
  	}

  	/*
  	 * First time through, make sure local device is rionet
  	 * capable, setup netdev,  and set flags so this is skipped
  	 * on later probes
  	 */
  	if (!rionet_check) {

  		rio_local_read_config_32(rdev->net->hport, RIO_SRC_OPS_CAR,
  					 &lsrc_ops);
  		rio_local_read_config_32(rdev->net->hport, RIO_DST_OPS_CAR,
  					 &ldst_ops);

  		if (!is_rionet_capable(lsrc_ops, ldst_ops)) {

  			printk(KERN_ERR
  			       "%s: local device is not network capable
  ",
  			       DRV_NAME);
  			rionet_check = 1;
  			rionet_capable = 0;
  			goto out;
  		}

  		rc = rionet_setup_netdev(rdev->net->hport, ndev);

  		rionet_check = 1;
  	}
  
  	/*
  	 * If the remote device has mailbox/doorbell capabilities,
  	 * add it to the peer list.
  	 */
  	if (dev_rionet_capable(rdev)) {
  		if (!(peer = kmalloc(sizeof(struct rionet_peer), GFP_KERNEL))) {
  			rc = -ENOMEM;
  			goto out;
  		}
  		peer->rdev = rdev;
  		list_add_tail(&peer->node, &rionet_peers);
  	}

  	rio_set_drvdata(rdev, ndev);

        out:
  	return rc;
  }
  
  static struct rio_device_id rionet_id_table[] = {
  	{RIO_DEVICE(RIO_ANY_ID, RIO_ANY_ID)}
  };
  
  static struct rio_driver rionet_driver = {
  	.name = "rionet",
  	.id_table = rionet_id_table,
  	.probe = rionet_probe,
  	.remove = rionet_remove,
  };
  
  static int __init rionet_init(void)
  {
  	return rio_register_driver(&rionet_driver);
  }
  
  static void __exit rionet_exit(void)
  {
  	rio_unregister_driver(&rionet_driver);
  }

  late_initcall(rionet_init);

  module_exit(rionet_exit);