/*
 * Copyright (c) 2005 Ammasso, Inc. All rights reserved.
 * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pci.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/inetdevice.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/ethtool.h>
#include <linux/mii.h>
#include <linux/if_vlan.h>
#include <linux/crc32.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/prefetch.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/byteorder.h>

#include <rdma/ib_smi.h>
#include "c2.h"
#include "c2_provider.h"

MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
MODULE_DESCRIPTION("Ammasso AMSO1100 Low-level iWARP Driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION(DRV_VERSION);

static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_LINK
    | NETIF_MSG_IFUP | NETIF_MSG_IFDOWN;

static int debug = -1;          /* defaults above */
module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");

static int c2_up(struct net_device *netdev);
static int c2_down(struct net_device *netdev);
static int c2_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
static void c2_tx_interrupt(struct net_device *netdev);
static void c2_rx_interrupt(struct net_device *netdev);
static irqreturn_t c2_interrupt(int irq, void *dev_id);
static void c2_tx_timeout(struct net_device *netdev);
static int c2_change_mtu(struct net_device *netdev, int new_mtu);
static void c2_reset(struct c2_port *c2_port);

static struct pci_device_id c2_pci_table[] = {
        { PCI_DEVICE(0x18b8, 0xb001) },
        { 0 }
};

MODULE_DEVICE_TABLE(pci, c2_pci_table);

static void c2_print_macaddr(struct net_device *netdev)
{
        pr_debug("%s: MAC %pM, IRQ %u\n", netdev->name, netdev->dev_addr, netdev->irq);
}

static void c2_set_rxbufsize(struct c2_port *c2_port)
{
        struct net_device *netdev = c2_port->netdev;

        if (netdev->mtu > RX_BUF_SIZE)
                c2_port->rx_buf_size =
                    netdev->mtu + ETH_HLEN + sizeof(struct c2_rxp_hdr) +
                    NET_IP_ALIGN;
        else
                c2_port->rx_buf_size = sizeof(struct c2_rxp_hdr) + RX_BUF_SIZE;
}

/*
 * Allocate TX ring elements and chain them together.
 * One-to-one association of adapter descriptors with ring elements.
 */
static int c2_tx_ring_alloc(struct c2_ring *tx_ring, void *vaddr,
                            dma_addr_t base, void __iomem * mmio_txp_ring)
{
        struct c2_tx_desc *tx_desc;
        struct c2_txp_desc __iomem *txp_desc;
        struct c2_element *elem;
        int i;

        tx_ring->start = kmalloc(sizeof(*elem) * tx_ring->count, GFP_KERNEL);
        if (!tx_ring->start)
                return -ENOMEM;

        elem = tx_ring->start;
        tx_desc = vaddr;
        txp_desc = mmio_txp_ring;
        for (i = 0; i < tx_ring->count; i++, elem++, tx_desc++, txp_desc++) {
                tx_desc->len = 0;
                tx_desc->status = 0;

                /* Set TXP_HTXD_UNINIT */
                __raw_writeq((__force u64) cpu_to_be64(0x1122334455667788ULL),
                             (void __iomem *) txp_desc + C2_TXP_ADDR);
                __raw_writew(0, (void __iomem *) txp_desc + C2_TXP_LEN);
                __raw_writew((__force u16) cpu_to_be16(TXP_HTXD_UNINIT),
                             (void __iomem *) txp_desc + C2_TXP_FLAGS);

                elem->skb = NULL;
                elem->ht_desc = tx_desc;
                elem->hw_desc = txp_desc;

                if (i == tx_ring->count - 1) {
                        elem->next = tx_ring->start;
                        tx_desc->next_offset = base;
                } else {
                        elem->next = elem + 1;
                        tx_desc->next_offset =
                            base + (i + 1) * sizeof(*tx_desc);
                }
        }

        tx_ring->to_use = tx_ring->to_clean = tx_ring->start;

        return 0;
}

/*
 * Allocate RX ring elements and chain them together.
 * One-to-one association of adapter descriptors with ring elements.
 */
static int c2_rx_ring_alloc(struct c2_ring *rx_ring, void *vaddr,
                            dma_addr_t base, void __iomem * mmio_rxp_ring)
{
        struct c2_rx_desc *rx_desc;
        struct c2_rxp_desc __iomem *rxp_desc;
        struct c2_element *elem;
        int i;

        rx_ring->start = kmalloc(sizeof(*elem) * rx_ring->count, GFP_KERNEL);
        if (!rx_ring->start)
                return -ENOMEM;

        elem = rx_ring->start;
        rx_desc = vaddr;
        rxp_desc = mmio_rxp_ring;
        for (i = 0; i < rx_ring->count; i++, elem++, rx_desc++, rxp_desc++) {
                rx_desc->len = 0;
                rx_desc->status = 0;

                /* Set RXP_HRXD_UNINIT */
                __raw_writew((__force u16) cpu_to_be16(RXP_HRXD_OK),
                       (void __iomem *) rxp_desc + C2_RXP_STATUS);
                __raw_writew(0, (void __iomem *) rxp_desc + C2_RXP_COUNT);
                __raw_writew(0, (void __iomem *) rxp_desc + C2_RXP_LEN);
                __raw_writeq((__force u64) cpu_to_be64(0x99aabbccddeeffULL),
                             (void __iomem *) rxp_desc + C2_RXP_ADDR);
                __raw_writew((__force u16) cpu_to_be16(RXP_HRXD_UNINIT),
                             (void __iomem *) rxp_desc + C2_RXP_FLAGS);

                elem->skb = NULL;
                elem->ht_desc = rx_desc;
                elem->hw_desc = rxp_desc;

                if (i == rx_ring->count - 1) {
                        elem->next = rx_ring->start;
                        rx_desc->next_offset = base;
                } else {
                        elem->next = elem + 1;
                        rx_desc->next_offset =
                            base + (i + 1) * sizeof(*rx_desc);
                }
        }

        rx_ring->to_use = rx_ring->to_clean = rx_ring->start;

        return 0;
}

/* Setup buffer for receiving */
static inline int c2_rx_alloc(struct c2_port *c2_port, struct c2_element *elem)
{
        struct c2_dev *c2dev = c2_port->c2dev;
        struct c2_rx_desc *rx_desc = elem->ht_desc;
        struct sk_buff *skb;
        dma_addr_t mapaddr;
        u32 maplen;
        struct c2_rxp_hdr *rxp_hdr;

        skb = dev_alloc_skb(c2_port->rx_buf_size);
        if (unlikely(!skb)) {
                pr_debug("%s: out of memory for receive\n",
                        c2_port->netdev->name);
                return -ENOMEM;
        }

        /* Zero out the rxp hdr in the sk_buff */
        memset(skb->data, 0, sizeof(*rxp_hdr));

        skb->dev = c2_port->netdev;

        maplen = c2_port->rx_buf_size;
        mapaddr =
            pci_map_single(c2dev->pcidev, skb->data, maplen,
                           PCI_DMA_FROMDEVICE);

        /* Set the sk_buff RXP_header to RXP_HRXD_READY */
        rxp_hdr = (struct c2_rxp_hdr *) skb->data;
        rxp_hdr->flags = RXP_HRXD_READY;

        __raw_writew(0, elem->hw_desc + C2_RXP_STATUS);
        __raw_writew((__force u16) cpu_to_be16((u16) maplen - sizeof(*rxp_hdr)),
                     elem->hw_desc + C2_RXP_LEN);
        __raw_writeq((__force u64) cpu_to_be64(mapaddr), elem->hw_desc + C2_RXP_ADDR);
        __raw_writew((__force u16) cpu_to_be16(RXP_HRXD_READY),
                     elem->hw_desc + C2_RXP_FLAGS);

        elem->skb = skb;
        elem->mapaddr = mapaddr;
        elem->maplen = maplen;
        rx_desc->len = maplen;

        return 0;
}

/*
 * Allocate buffers for the Rx ring
 * For receive:  rx_ring.to_clean is next received frame
 */
static int c2_rx_fill(struct c2_port *c2_port)
{
        struct c2_ring *rx_ring = &c2_port->rx_ring;
        struct c2_element *elem;
        int ret = 0;

        elem = rx_ring->start;
        do {
                if (c2_rx_alloc(c2_port, elem)) {
                        ret = 1;
                        break;
                }
        } while ((elem = elem->next) != rx_ring->start);

        rx_ring->to_clean = rx_ring->start;
        return ret;
}

/* Free all buffers in RX ring, assumes receiver stopped */
static void c2_rx_clean(struct c2_port *c2_port)
{
        struct c2_dev *c2dev = c2_port->c2dev;
        struct c2_ring *rx_ring = &c2_port->rx_ring;
        struct c2_element *elem;
        struct c2_rx_desc *rx_desc;

        elem = rx_ring->start;
        do {
                rx_desc = elem->ht_desc;
                rx_desc->len = 0;

                __raw_writew(0, elem->hw_desc + C2_RXP_STATUS);
                __raw_writew(0, elem->hw_desc + C2_RXP_COUNT);
                __raw_writew(0, elem->hw_desc + C2_RXP_LEN);
                __raw_writeq((__force u64) cpu_to_be64(0x99aabbccddeeffULL),
                             elem->hw_desc + C2_RXP_ADDR);
                __raw_writew((__force u16) cpu_to_be16(RXP_HRXD_UNINIT),
                             elem->hw_desc + C2_RXP_FLAGS);

                if (elem->skb) {
                        pci_unmap_single(c2dev->pcidev, elem->mapaddr,
                                         elem->maplen, PCI_DMA_FROMDEVICE);
                        dev_kfree_skb(elem->skb);
                        elem->skb = NULL;
                }
        } while ((elem = elem->next) != rx_ring->start);
}

static inline int c2_tx_free(struct c2_dev *c2dev, struct c2_element *elem)
{
        struct c2_tx_desc *tx_desc = elem->ht_desc;

        tx_desc->len = 0;

        pci_unmap_single(c2dev->pcidev, elem->mapaddr, elem->maplen,
                         PCI_DMA_TODEVICE);

        if (elem->skb) {
                dev_kfree_skb_any(elem->skb);
                elem->skb = NULL;
        }

        return 0;
}

/* Free all buffers in TX ring, assumes transmitter stopped */
static void c2_tx_clean(struct c2_port *c2_port)
{
        struct c2_ring *tx_ring = &c2_port->tx_ring;
        struct c2_element *elem;
        struct c2_txp_desc txp_htxd;
        int retry;
        unsigned long flags;

        spin_lock_irqsave(&c2_port->tx_lock, flags);

        elem = tx_ring->start;

        do {
                retry = 0;
                do {
                        txp_htxd.flags =
                            readw(elem->hw_desc + C2_TXP_FLAGS);

                        if (txp_htxd.flags == TXP_HTXD_READY) {
                                retry = 1;
                                __raw_writew(0,
                                             elem->hw_desc + C2_TXP_LEN);
                                __raw_writeq(0,
                                             elem->hw_desc + C2_TXP_ADDR);
                                __raw_writew((__force u16) cpu_to_be16(TXP_HTXD_DONE),
                                             elem->hw_desc + C2_TXP_FLAGS);
                                c2_port->netdev->stats.tx_dropped++;
                                break;
                        } else {
                                __raw_writew(0,
                                             elem->hw_desc + C2_TXP_LEN);
                                __raw_writeq((__force u64) cpu_to_be64(0x1122334455667788ULL),
                                             elem->hw_desc + C2_TXP_ADDR);
                                __raw_writew((__force u16) cpu_to_be16(TXP_HTXD_UNINIT),
                                             elem->hw_desc + C2_TXP_FLAGS);
                        }

                        c2_tx_free(c2_port->c2dev, elem);

                } while ((elem = elem->next) != tx_ring->start);
        } while (retry);

        c2_port->tx_avail = c2_port->tx_ring.count - 1;
        c2_port->c2dev->cur_tx = tx_ring->to_use - tx_ring->start;

        if (c2_port->tx_avail > MAX_SKB_FRAGS + 1)
                netif_wake_queue(c2_port->netdev);

        spin_unlock_irqrestore(&c2_port->tx_lock, flags);
}

/*
 * Process transmit descriptors marked 'DONE' by the firmware,
 * freeing up their unneeded sk_buffs.
 */
static void c2_tx_interrupt(struct net_device *netdev)
{
        struct c2_port *c2_port = netdev_priv(netdev);
        struct c2_dev *c2dev = c2_port->c2dev;
        struct c2_ring *tx_ring = &c2_port->tx_ring;
        struct c2_element *elem;
        struct c2_txp_desc txp_htxd;

        spin_lock(&c2_port->tx_lock);

        for (elem = tx_ring->to_clean; elem != tx_ring->to_use;
             elem = elem->next) {
                txp_htxd.flags =
                    be16_to_cpu((__force __be16) readw(elem->hw_desc + C2_TXP_FLAGS));

                if (txp_htxd.flags != TXP_HTXD_DONE)
                        break;

                if (netif_msg_tx_done(c2_port)) {
                        /* PCI reads are expensive in fast path */
                        txp_htxd.len =
                            be16_to_cpu((__force __be16) readw(elem->hw_desc + C2_TXP_LEN));
                        pr_debug("%s: tx done slot %3Zu status 0x%x len "
                                "%5u bytes\n",
                                netdev->name, elem - tx_ring->start,
                                txp_htxd.flags, txp_htxd.len);
                }

                c2_tx_free(c2dev, elem);
                ++(c2_port->tx_avail);
        }

        tx_ring->to_clean = elem;

        if (netif_queue_stopped(netdev)
            && c2_port->tx_avail > MAX_SKB_FRAGS + 1)
                netif_wake_queue(netdev);

        spin_unlock(&c2_port->tx_lock);
}

static void c2_rx_error(struct c2_port *c2_port, struct c2_element *elem)
{
        struct c2_rx_desc *rx_desc = elem->ht_desc;
        struct c2_rxp_hdr *rxp_hdr = (struct c2_rxp_hdr *) elem->skb->data;

        if (rxp_hdr->status != RXP_HRXD_OK ||
            rxp_hdr->len > (rx_desc->len - sizeof(*rxp_hdr))) {
                pr_debug("BAD RXP_HRXD\n");
                pr_debug("  rx_desc : %p\n", rx_desc);
                pr_debug("    index : %Zu\n",
                        elem - c2_port->rx_ring.start);
                pr_debug("    len   : %u\n", rx_desc->len);
                pr_debug("  rxp_hdr : %p [PA %p]\n", rxp_hdr,
                        (void *) __pa((unsigned long) rxp_hdr));
                pr_debug("    flags : 0x%x\n", rxp_hdr->flags);
                pr_debug("    status: 0x%x\n", rxp_hdr->status);
                pr_debug("    len   : %u\n", rxp_hdr->len);
                pr_debug("    rsvd  : 0x%x\n", rxp_hdr->rsvd);
        }

        /* Setup the skb for reuse since we're dropping this pkt */
        elem->skb->data = elem->skb->head;
        skb_reset_tail_pointer(elem->skb);

        /* Zero out the rxp hdr in the sk_buff */
        memset(elem->skb->data, 0, sizeof(*rxp_hdr));

        /* Write the descriptor to the adapter's rx ring */
        __raw_writew(0, elem->hw_desc + C2_RXP_STATUS);
        __raw_writew(0, elem->hw_desc + C2_RXP_COUNT);
        __raw_writew((__force u16) cpu_to_be16((u16) elem->maplen - sizeof(*rxp_hdr)),
                     elem->hw_desc + C2_RXP_LEN);
        __raw_writeq((__force u64) cpu_to_be64(elem->mapaddr),
                     elem->hw_desc + C2_RXP_ADDR);
        __raw_writew((__force u16) cpu_to_be16(RXP_HRXD_READY),
                     elem->hw_desc + C2_RXP_FLAGS);

        pr_debug("packet dropped\n");
        c2_port->netdev->stats.rx_dropped++;
}

static void c2_rx_interrupt(struct net_device *netdev)
{
        struct c2_port *c2_port = netdev_priv(netdev);
        struct c2_dev *c2dev = c2_port->c2dev;
        struct c2_ring *rx_ring = &c2_port->rx_ring;
        struct c2_element *elem;
        struct c2_rx_desc *rx_desc;
        struct c2_rxp_hdr *rxp_hdr;
        struct sk_buff *skb;
        dma_addr_t mapaddr;
        u32 maplen, buflen;
        unsigned long flags;

        spin_lock_irqsave(&c2dev->lock, flags);

        /* Begin where we left off */
        rx_ring->to_clean = rx_ring->start + c2dev->cur_rx;

        for (elem = rx_ring->to_clean; elem->next != rx_ring->to_clean;
             elem = elem->next) {
                rx_desc = elem->ht_desc;
                mapaddr = elem->mapaddr;
                maplen = elem->maplen;
                skb = elem->skb;
                rxp_hdr = (struct c2_rxp_hdr *) skb->data;

                if (rxp_hdr->flags != RXP_HRXD_DONE)
                        break;
                buflen = rxp_hdr->len;

                /* Sanity check the RXP header */
                if (rxp_hdr->status != RXP_HRXD_OK ||
                    buflen > (rx_desc->len - sizeof(*rxp_hdr))) {
                        c2_rx_error(c2_port, elem);
                        continue;
                }

                /*
                 * Allocate and map a new skb for replenishing the host
                 * RX desc
                 */
                if (c2_rx_alloc(c2_port, elem)) {
                        c2_rx_error(c2_port, elem);
                        continue;
                }

                /* Unmap the old skb */
                pci_unmap_single(c2dev->pcidev, mapaddr, maplen,
                                 PCI_DMA_FROMDEVICE);

                prefetch(skb->data);

                /*
                 * Skip past the leading 8 bytes comprising of the
                 * "struct c2_rxp_hdr", prepended by the adapter
                 * to the usual Ethernet header ("struct ethhdr"),
                 * to the start of the raw Ethernet packet.
                 *
                 * Fix up the various fields in the sk_buff before
                 * passing it up to netif_rx(). The transfer size
                 * (in bytes) specified by the adapter len field of
                 * the "struct rxp_hdr_t" does NOT include the
                 * "sizeof(struct c2_rxp_hdr)".
                 */
                skb->data += sizeof(*rxp_hdr);
                skb_set_tail_pointer(skb, buflen);
                skb->len = buflen;
                skb->protocol = eth_type_trans(skb, netdev);

                netif_rx(skb);

                netdev->stats.rx_packets++;
                netdev->stats.rx_bytes += buflen;
        }

        /* Save where we left off */
        rx_ring->to_clean = elem;
        c2dev->cur_rx = elem - rx_ring->start;
        C2_SET_CUR_RX(c2dev, c2dev->cur_rx);

        spin_unlock_irqrestore(&c2dev->lock, flags);
}

/*
 * Handle netisr0 TX & RX interrupts.
 */
static irqreturn_t c2_interrupt(int irq, void *dev_id)
{
        unsigned int netisr0, dmaisr;
        int handled = 0;
        struct c2_dev *c2dev = (struct c2_dev *) dev_id;

        /* Process CCILNET interrupts */
        netisr0 = readl(c2dev->regs + C2_NISR0);
        if (netisr0) {

                /*
                 * There is an issue with the firmware that always
                 * provides the status of RX for both TX & RX
                 * interrupts.  So process both queues here.
                 */
                c2_rx_interrupt(c2dev->netdev);
                c2_tx_interrupt(c2dev->netdev);

                /* Clear the interrupt */
                writel(netisr0, c2dev->regs + C2_NISR0);
                handled++;
        }

        /* Process RNIC interrupts */
        dmaisr = readl(c2dev->regs + C2_DISR);
        if (dmaisr) {
                writel(dmaisr, c2dev->regs + C2_DISR);
                c2_rnic_interrupt(c2dev);
                handled++;
        }

        if (handled) {
                return IRQ_HANDLED;
        } else {
                return IRQ_NONE;
        }
}

static int c2_up(struct net_device *netdev)
{
        struct c2_port *c2_port = netdev_priv(netdev);
        struct c2_dev *c2dev = c2_port->c2dev;
        struct c2_element *elem;
        struct c2_rxp_hdr *rxp_hdr;
        struct in_device *in_dev;
        size_t rx_size, tx_size;
        int ret, i;
        unsigned int netimr0;

        if (netif_msg_ifup(c2_port))
                pr_debug("%s: enabling interface\n", netdev->name);

        /* Set the Rx buffer size based on MTU */
        c2_set_rxbufsize(c2_port);

        /* Allocate DMA'able memory for Tx/Rx host descriptor rings */
        rx_size = c2_port->rx_ring.count * sizeof(struct c2_rx_desc);
        tx_size = c2_port->tx_ring.count * sizeof(struct c2_tx_desc);

        c2_port->mem_size = tx_size + rx_size;
        c2_port->mem = pci_alloc_consistent(c2dev->pcidev, c2_port->mem_size,
                                            &c2_port->dma);
        if (c2_port->mem == NULL) {
                pr_debug("Unable to allocate memory for "
                        "host descriptor rings\n");
                return -ENOMEM;
        }

        memset(c2_port->mem, 0, c2_port->mem_size);

        /* Create the Rx host descriptor ring */
        if ((ret =
             c2_rx_ring_alloc(&c2_port->rx_ring, c2_port->mem, c2_port->dma,
                              c2dev->mmio_rxp_ring))) {
                pr_debug("Unable to create RX ring\n");
                goto bail0;
        }

        /* Allocate Rx buffers for the host descriptor ring */
        if (c2_rx_fill(c2_port)) {
                pr_debug("Unable to fill RX ring\n");
                goto bail1;
        }

        /* Create the Tx host descriptor ring */
        if ((ret = c2_tx_ring_alloc(&c2_port->tx_ring, c2_port->mem + rx_size,
                                    c2_port->dma + rx_size,
                                    c2dev->mmio_txp_ring))) {
                pr_debug("Unable to create TX ring\n");
                goto bail1;
        }

        /* Set the TX pointer to where we left off */
        c2_port->tx_avail = c2_port->tx_ring.count - 1;
        c2_port->tx_ring.to_use = c2_port->tx_ring.to_clean =
            c2_port->tx_ring.start + c2dev->cur_tx;

        /* missing: Initialize MAC */

        BUG_ON(c2_port->tx_ring.to_use != c2_port->tx_ring.to_clean);

        /* Reset the adapter, ensures the driver is in sync with the RXP */
        c2_reset(c2_port);

        /* Reset the READY bit in the sk_buff RXP headers & adapter HRXDQ */
        for (i = 0, elem = c2_port->rx_ring.start; i < c2_port->rx_ring.count;
             i++, elem++) {
                rxp_hdr = (struct c2_rxp_hdr *) elem->skb->data;
                rxp_hdr->flags = 0;
                __raw_writew((__force u16) cpu_to_be16(RXP_HRXD_READY),
                             elem->hw_desc + C2_RXP_FLAGS);
        }

        /* Enable network packets */
        netif_start_queue(netdev);

        /* Enable IRQ */
        writel(0, c2dev->regs + C2_IDIS);
        netimr0 = readl(c2dev->regs + C2_NIMR0);
        netimr0 &= ~(C2_PCI_HTX_INT | C2_PCI_HRX_INT);
        writel(netimr0, c2dev->regs + C2_NIMR0);

        /* Tell the stack to ignore arp requests for ipaddrs bound to
         * other interfaces.  This is needed to prevent the host stack
         * from responding to arp requests to the ipaddr bound on the
         * rdma interface.
         */
        in_dev = in_dev_get(netdev);
        IN_DEV_CONF_SET(in_dev, ARP_IGNORE, 1);
        in_dev_put(in_dev);

        return 0;

      bail1:
        c2_rx_clean(c2_port);
        kfree(c2_port->rx_ring.start);

      bail0:
        pci_free_consistent(c2dev->pcidev, c2_port->mem_size, c2_port->mem,
                            c2_port->dma);

        return ret;
}

static int c2_down(struct net_device *netdev)
{
        struct c2_port *c2_port = netdev_priv(netdev);
        struct c2_dev *c2dev = c2_port->c2dev;

        if (netif_msg_ifdown(c2_port))
                pr_debug("%s: disabling interface\n",
                        netdev->name);

        /* Wait for all the queued packets to get sent */
        c2_tx_interrupt(netdev);

        /* Disable network packets */
        netif_stop_queue(netdev);

        /* Disable IRQs by clearing the interrupt mask */
        writel(1, c2dev->regs + C2_IDIS);
        writel(0, c2dev->regs + C2_NIMR0);

        /* missing: Stop transmitter */

        /* missing: Stop receiver */

        /* Reset the adapter, ensures the driver is in sync with the RXP */
        c2_reset(c2_port);

        /* missing: Turn off LEDs here */

        /* Free all buffers in the host descriptor rings */
        c2_tx_clean(c2_port);
        c2_rx_clean(c2_port);

        /* Free the host descriptor rings */
        kfree(c2_port->rx_ring.start);
        kfree(c2_port->tx_ring.start);
        pci_free_consistent(c2dev->pcidev, c2_port->mem_size, c2_port->mem,
                            c2_port->dma);

        return 0;
}

static void c2_reset(struct c2_port *c2_port)
{
        struct c2_dev *c2dev = c2_port->c2dev;
        unsigned int cur_rx = c2dev->cur_rx;

        /* Tell the hardware to quiesce */
        C2_SET_CUR_RX(c2dev, cur_rx | C2_PCI_HRX_QUI);

        /*
         * The hardware will reset the C2_PCI_HRX_QUI bit once
         * the RXP is quiesced.  Wait 2 seconds for this.
         */
        ssleep(2);

        cur_rx = C2_GET_CUR_RX(c2dev);

        if (cur_rx & C2_PCI_HRX_QUI)
                pr_debug("c2_reset: failed to quiesce the hardware!\n");

        cur_rx &= ~C2_PCI_HRX_QUI;

        c2dev->cur_rx = cur_rx;

        pr_debug("Current RX: %u\n", c2dev->cur_rx);
}

static int c2_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
{
        struct c2_port *c2_port = netdev_priv(netdev);
        struct c2_dev *c2dev = c2_port->c2dev;
        struct c2_ring *tx_ring = &c2_port->tx_ring;
        struct c2_element *elem;
        dma_addr_t mapaddr;
        u32 maplen;
        unsigned long flags;
        unsigned int i;

        spin_lock_irqsave(&c2_port->tx_lock, flags);

        if (unlikely(c2_port->tx_avail < (skb_shinfo(skb)->nr_frags + 1))) {
                netif_stop_queue(netdev);
                spin_unlock_irqrestore(&c2_port->tx_lock, flags);

                pr_debug("%s: Tx ring full when queue awake!\n",
                        netdev->name);
                return NETDEV_TX_BUSY;
        }

        maplen = skb_headlen(skb);
        mapaddr =
            pci_map_single(c2dev->pcidev, skb->data, maplen, PCI_DMA_TODEVICE);

        elem = tx_ring->to_use;
        elem->skb = skb;
        elem->mapaddr = mapaddr;
        elem->maplen = maplen;

        /* Tell HW to xmit */
        __raw_writeq((__force u64) cpu_to_be64(mapaddr),
                     elem->hw_desc + C2_TXP_ADDR);
        __raw_writew((__force u16) cpu_to_be16(maplen),
                     elem->hw_desc + C2_TXP_LEN);
        __raw_writew((__force u16) cpu_to_be16(TXP_HTXD_READY),
                     elem->hw_desc + C2_TXP_FLAGS);

        netdev->stats.tx_packets++;
        netdev->stats.tx_bytes += maplen;

        /* Loop thru additional data fragments and queue them */
        if (skb_shinfo(skb)->nr_frags) {
                for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                        const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
                        maplen = skb_frag_size(frag);
                        mapaddr = skb_frag_dma_map(&c2dev->pcidev->dev, frag,
                                                   0, maplen, DMA_TO_DEVICE);
                        elem = elem->next;
                        elem->skb = NULL;
                        elem->mapaddr = mapaddr;
                        elem->maplen = maplen;

                        /* Tell HW to xmit */
                        __raw_writeq((__force u64) cpu_to_be64(mapaddr),
                                     elem->hw_desc + C2_TXP_ADDR);
                        __raw_writew((__force u16) cpu_to_be16(maplen),
                                     elem->hw_desc + C2_TXP_LEN);
                        __raw_writew((__force u16) cpu_to_be16(TXP_HTXD_READY),
                                     elem->hw_desc + C2_TXP_FLAGS);

                        netdev->stats.tx_packets++;
                        netdev->stats.tx_bytes += maplen;
                }
        }

        tx_ring->to_use = elem->next;
        c2_port->tx_avail -= (skb_shinfo(skb)->nr_frags + 1);

        if (c2_port->tx_avail <= MAX_SKB_FRAGS + 1) {
                netif_stop_queue(netdev);
                if (netif_msg_tx_queued(c2_port))
                        pr_debug("%s: transmit queue full\n",
                                netdev->name);
        }

        spin_unlock_irqrestore(&c2_port->tx_lock, flags);

        netdev->trans_start = jiffies;

        return NETDEV_TX_OK;
}

static void c2_tx_timeout(struct net_device *netdev)
{
        struct c2_port *c2_port = netdev_priv(netdev);

        if (netif_msg_timer(c2_port))
                pr_debug("%s: tx timeout\n", netdev->name);

        c2_tx_clean(c2_port);
}

static int c2_change_mtu(struct net_device *netdev, int new_mtu)
{
        int ret = 0;

        if (new_mtu < ETH_ZLEN || new_mtu > ETH_JUMBO_MTU)
                return -EINVAL;

        netdev->mtu = new_mtu;

        if (netif_running(netdev)) {
                c2_down(netdev);

                c2_up(netdev);
        }

        return ret;
}

static const struct net_device_ops c2_netdev = {
        .ndo_open               = c2_up,
        .ndo_stop               = c2_down,
        .ndo_start_xmit         = c2_xmit_frame,
        .ndo_tx_timeout         = c2_tx_timeout,
        .ndo_change_mtu         = c2_change_mtu,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_validate_addr      = eth_validate_addr,
};

/* Initialize network device */
static struct net_device *c2_devinit(struct c2_dev *c2dev,
                                     void __iomem * mmio_addr)
{
        struct c2_port *c2_port = NULL;
        struct net_device *netdev = alloc_etherdev(sizeof(*c2_port));

        if (!netdev) {
                pr_debug("c2_port etherdev alloc failed");
                return NULL;
        }

        SET_NETDEV_DEV(netdev, &c2dev->pcidev->dev);

        netdev->netdev_ops = &c2_netdev;
        netdev->watchdog_timeo = C2_TX_TIMEOUT;
        netdev->irq = c2dev->pcidev->irq;

        c2_port = netdev_priv(netdev);
        c2_port->netdev = netdev;
        c2_port->c2dev = c2dev;
        c2_port->msg_enable = netif_msg_init(debug, default_msg);
        c2_port->tx_ring.count = C2_NUM_TX_DESC;
        c2_port->rx_ring.count = C2_NUM_RX_DESC;

        spin_lock_init(&c2_port->tx_lock);

        /* Copy our 48-bit ethernet hardware address */
        memcpy_fromio(netdev->dev_addr, mmio_addr + C2_REGS_ENADDR, 6);

        /* Validate the MAC address */
        if (!is_valid_ether_addr(netdev->dev_addr)) {
                pr_debug("Invalid MAC Address\n");
                c2_print_macaddr(netdev);
                free_netdev(netdev);
                return NULL;
        }

        c2dev->netdev = netdev;

        return netdev;
}

static int c2_probe(struct pci_dev *pcidev, const struct pci_device_id *ent)
{
        int ret = 0, i;
        unsigned long reg0_start, reg0_flags, reg0_len;
        unsigned long reg2_start, reg2_flags, reg2_len;
        unsigned long reg4_start, reg4_flags, reg4_len;
        unsigned kva_map_size;
        struct net_device *netdev = NULL;
        struct c2_dev *c2dev = NULL;
        void __iomem *mmio_regs = NULL;

        printk(KERN_INFO PFX "AMSO1100 Gigabit Ethernet driver v%s loaded\n",
                DRV_VERSION);

        /* Enable PCI device */
        ret = pci_enable_device(pcidev);
        if (ret) {
                printk(KERN_ERR PFX "%s: Unable to enable PCI device\n",
                        pci_name(pcidev));
                goto bail0;
        }

        reg0_start = pci_resource_start(pcidev, BAR_0);
        reg0_len = pci_resource_len(pcidev, BAR_0);
        reg0_flags = pci_resource_flags(pcidev, BAR_0);

        reg2_start = pci_resource_start(pcidev, BAR_2);
        reg2_len = pci_resource_len(pcidev, BAR_2);
        reg2_flags = pci_resource_flags(pcidev, BAR_2);

        reg4_start = pci_resource_start(pcidev, BAR_4);
        reg4_len = pci_resource_len(pcidev, BAR_4);
        reg4_flags = pci_resource_flags(pcidev, BAR_4);

        pr_debug("BAR0 size = 0x%lX bytes\n", reg0_len);
        pr_debug("BAR2 size = 0x%lX bytes\n", reg2_len);
        pr_debug("BAR4 size = 0x%lX bytes\n", reg4_len);

        /* Make sure PCI base addr are MMIO */
        if (!(reg0_flags & IORESOURCE_MEM) ||
            !(reg2_flags & IORESOURCE_MEM) || !(reg4_flags & IORESOURCE_MEM)) {
                printk(KERN_ERR PFX "PCI regions not an MMIO resource\n");
                ret = -ENODEV;
                goto bail1;
        }

        /* Check for weird/broken PCI region reporting */
        if ((reg0_len < C2_REG0_SIZE) ||
            (reg2_len < C2_REG2_SIZE) || (reg4_len < C2_REG4_SIZE)) {
                printk(KERN_ERR PFX "Invalid PCI region sizes\n");
                ret = -ENODEV;
                goto bail1;
        }

        /* Reserve PCI I/O and memory resources */
        ret = pci_request_regions(pcidev, DRV_NAME);
        if (ret) {
                printk(KERN_ERR PFX "%s: Unable to request regions\n",
                        pci_name(pcidev));
                goto bail1;
        }

        if ((sizeof(dma_addr_t) > 4)) {
                ret = pci_set_dma_mask(pcidev, DMA_BIT_MASK(64));
                if (ret < 0) {
                        printk(KERN_ERR PFX "64b DMA configuration failed\n");
                        goto bail2;
                }
        } else {
                ret = pci_set_dma_mask(pcidev, DMA_BIT_MASK(32));
                if (ret < 0) {
                        printk(KERN_ERR PFX "32b DMA configuration failed\n");
                        goto bail2;
                }
        }

        /* Enables bus-mastering on the device */
        pci_set_master(pcidev);

        /* Remap the adapter PCI registers in BAR4 */
        mmio_regs = ioremap_nocache(reg4_start + C2_PCI_REGS_OFFSET,
                                    sizeof(struct c2_adapter_pci_regs));
        if (!mmio_regs) {
                printk(KERN_ERR PFX
                        "Unable to remap adapter PCI registers in BAR4\n");
                ret = -EIO;
                goto bail2;
        }

        /* Validate PCI regs magic */
        for (i = 0; i < sizeof(c2_magic); i++) {
                if (c2_magic[i] != readb(mmio_regs + C2_REGS_MAGIC + i)) {
                        printk(KERN_ERR PFX "Downlevel Firmware boot loader "
                                "[%d/%Zd: got 0x%x, exp 0x%x]. Use the cc_flash "
                               "utility to update your boot loader\n",
                                i + 1, sizeof(c2_magic),
                                readb(mmio_regs + C2_REGS_MAGIC + i),
                                c2_magic[i]);
                        printk(KERN_ERR PFX "Adapter not claimed\n");
                        iounmap(mmio_regs);
                        ret = -EIO;
                        goto bail2;
                }
        }

        /* Validate the adapter version */
        if (be32_to_cpu((__force __be32) readl(mmio_regs + C2_REGS_VERS)) != C2_VERSION) {
                printk(KERN_ERR PFX "Version mismatch "
                        "[fw=%u, c2=%u], Adapter not claimed\n",
                        be32_to_cpu((__force __be32) readl(mmio_regs + C2_REGS_VERS)),
                        C2_VERSION);
                ret = -EINVAL;
                iounmap(mmio_regs);
                goto bail2;
        }

        /* Validate the adapter IVN */
        if (be32_to_cpu((__force __be32) readl(mmio_regs + C2_REGS_IVN)) != C2_IVN) {
                printk(KERN_ERR PFX "Downlevel FIrmware level. You should be using "
                       "the OpenIB device support kit. "
                       "[fw=0x%x, c2=0x%x], Adapter not claimed\n",
                       be32_to_cpu((__force __be32) readl(mmio_regs + C2_REGS_IVN)),
                       C2_IVN);
                ret = -EINVAL;
                iounmap(mmio_regs);
                goto bail2;
        }

        /* Allocate hardware structure */
        c2dev = (struct c2_dev *) ib_alloc_device(sizeof(*c2dev));
        if (!c2dev) {
                printk(KERN_ERR PFX "%s: Unable to alloc hardware struct\n",
                        pci_name(pcidev));
                ret = -ENOMEM;
                iounmap(mmio_regs);
                goto bail2;
        }

        memset(c2dev, 0, sizeof(*c2dev));
        spin_lock_init(&c2dev->lock);
        c2dev->pcidev = pcidev;
        c2dev->cur_tx = 0;

        /* Get the last RX index */
        c2dev->cur_rx =
            (be32_to_cpu((__force __be32) readl(mmio_regs + C2_REGS_HRX_CUR)) -
             0xffffc000) / sizeof(struct c2_rxp_desc);

        /* Request an interrupt line for the driver */
        ret = request_irq(pcidev->irq, c2_interrupt, IRQF_SHARED, DRV_NAME, c2dev);
        if (ret) {
                printk(KERN_ERR PFX "%s: requested IRQ %u is busy\n",
                        pci_name(pcidev), pcidev->irq);
                iounmap(mmio_regs);
                goto bail3;
        }

        /* Set driver specific data */
        pci_set_drvdata(pcidev, c2dev);

        /* Initialize network device */
        if ((netdev = c2_devinit(c2dev, mmio_regs)) == NULL) {
                iounmap(mmio_regs);
                goto bail4;
        }

        /* Save off the actual size prior to unmapping mmio_regs */
        kva_map_size = be32_to_cpu((__force __be32) readl(mmio_regs + C2_REGS_PCI_WINSIZE));

        /* Unmap the adapter PCI registers in BAR4 */
        iounmap(mmio_regs);

        /* Register network device */
        ret = register_netdev(netdev);
        if (ret) {
                printk(KERN_ERR PFX "Unable to register netdev, ret = %d\n",
                        ret);
                goto bail5;
        }

        /* Disable network packets */
        netif_stop_queue(netdev);

        /* Remap the adapter HRXDQ PA space to kernel VA space */
        c2dev->mmio_rxp_ring = ioremap_nocache(reg4_start + C2_RXP_HRXDQ_OFFSET,
                                               C2_RXP_HRXDQ_SIZE);
        if (!c2dev->mmio_rxp_ring) {
                printk(KERN_ERR PFX "Unable to remap MMIO HRXDQ region\n");
                ret = -EIO;
                goto bail6;
        }

        /* Remap the adapter HTXDQ PA space to kernel VA space */
        c2dev->mmio_txp_ring = ioremap_nocache(reg4_start + C2_TXP_HTXDQ_OFFSET,
                                               C2_TXP_HTXDQ_SIZE);
        if (!c2dev->mmio_txp_ring) {
                printk(KERN_ERR PFX "Unable to remap MMIO HTXDQ region\n");
                ret = -EIO;
                goto bail7;
        }

        /* Save off the current RX index in the last 4 bytes of the TXP Ring */
        C2_SET_CUR_RX(c2dev, c2dev->cur_rx);

        /* Remap the PCI registers in adapter BAR0 to kernel VA space */
        c2dev->regs = ioremap_nocache(reg0_start, reg0_len);
        if (!c2dev->regs) {
                printk(KERN_ERR PFX "Unable to remap BAR0\n");
                ret = -EIO;
                goto bail8;
        }

        /* Remap the PCI registers in adapter BAR4 to kernel VA space */
        c2dev->pa = reg4_start + C2_PCI_REGS_OFFSET;
        c2dev->kva = ioremap_nocache(reg4_start + C2_PCI_REGS_OFFSET,
                                     kva_map_size);
        if (!c2dev->kva) {
                printk(KERN_ERR PFX "Unable to remap BAR4\n");
                ret = -EIO;
                goto bail9;
        }

        /* Print out the MAC address */
        c2_print_macaddr(netdev);

        ret = c2_rnic_init(c2dev);
        if (ret) {
                printk(KERN_ERR PFX "c2_rnic_init failed: %d\n", ret);
                goto bail10;
        }

        if (c2_register_device(c2dev))
                goto bail10;

        return 0;

 bail10:
        iounmap(c2dev->kva);

 bail9:
        iounmap(c2dev->regs);

 bail8:
        iounmap(c2dev->mmio_txp_ring);

 bail7:
        iounmap(c2dev->mmio_rxp_ring);

 bail6:
        unregister_netdev(netdev);

 bail5:
        free_netdev(netdev);

 bail4:
        free_irq(pcidev->irq, c2dev);

 bail3:
        ib_dealloc_device(&c2dev->ibdev);

 bail2:
        pci_release_regions(pcidev);

 bail1:
        pci_disable_device(pcidev);

 bail0:
        return ret;
}

static void c2_remove(struct pci_dev *pcidev)
{
        struct c2_dev *c2dev = pci_get_drvdata(pcidev);
        struct net_device *netdev = c2dev->netdev;

        /* Unregister with OpenIB */
        c2_unregister_device(c2dev);

        /* Clean up the RNIC resources */
        c2_rnic_term(c2dev);

        /* Remove network device from the kernel */
        unregister_netdev(netdev);

        /* Free network device */
        free_netdev(netdev);

        /* Free the interrupt line */
        free_irq(pcidev->irq, c2dev);

        /* missing: Turn LEDs off here */

        /* Unmap adapter PA space */
        iounmap(c2dev->kva);
        iounmap(c2dev->regs);
        iounmap(c2dev->mmio_txp_ring);
        iounmap(c2dev->mmio_rxp_ring);

        /* Free the hardware structure */
        ib_dealloc_device(&c2dev->ibdev);

        /* Release reserved PCI I/O and memory resources */
        pci_release_regions(pcidev);

        /* Disable PCI device */
        pci_disable_device(pcidev);

        /* Clear driver specific data */
        pci_set_drvdata(pcidev, NULL);
}

static struct pci_driver c2_pci_driver = {
        .name = DRV_NAME,
        .id_table = c2_pci_table,
        .probe = c2_probe,
        .remove = c2_remove,
};

module_pci_driver(c2_pci_driver);