c2.c

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/*
 * 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 <[email protected]>");
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 __devinit 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 __devexit 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 = __devexit_p(c2_remove),
};

static int __init c2_init_module(void)
{
    return pci_register_driver(&c2_pci_driver);
}

static void __exit c2_exit_module(void)
{
    pci_unregister_driver(&c2_pci_driver);
}

module_init(c2_init_module);
module_exit(c2_exit_module);