exanic.c

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/*
 * Copyright (C) 2017 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <errno.h>
#include <byteswap.h>
#include <ipxe/netdevice.h>
#include <ipxe/ethernet.h>
#include <ipxe/if_ether.h>
#include <ipxe/iobuf.h>
#include <ipxe/malloc.h>
#include <ipxe/umalloc.h>
#include <ipxe/pci.h>
#include "exanic.h"

/** @file
 *
 * Exablaze ExaNIC driver
 *
 */

/* Disambiguate the various error causes */
#define EIO_ABORTED __einfo_error ( EINFO_EIO_ABORTED )
#define EINFO_EIO_ABORTED \
        __einfo_uniqify ( EINFO_EIO, 0x01, "Frame aborted" )
#define EIO_CORRUPT __einfo_error ( EINFO_EIO_CORRUPT )
#define EINFO_EIO_CORRUPT \
        __einfo_uniqify ( EINFO_EIO, 0x02, "CRC incorrect" )
#define EIO_HWOVFL __einfo_error ( EINFO_EIO_HWOVFL )
#define EINFO_EIO_HWOVFL \
        __einfo_uniqify ( EINFO_EIO, 0x03, "Hardware overflow" )
#define EIO_STATUS( status ) \
        EUNIQ ( EINFO_EIO, ( (status) & EXANIC_STATUS_ERROR_MASK ), \
                EIO_ABORTED, EIO_CORRUPT, EIO_HWOVFL )

/**
 * Write DMA base address register
 *
 * @v addr              DMA base address
 * @v reg               Register
 */
static void exanic_write_base ( physaddr_t addr, void *reg ) {
        uint32_t lo;
        uint32_t hi;

        /* Write high and low registers, setting flags as appropriate */
        lo = addr;
        if ( sizeof ( physaddr_t ) > sizeof ( uint32_t ) ) {
                /* 64-bit build; may be a 32-bit or 64-bit address */
                hi = ( ( ( uint64_t ) addr ) >> 32 );
                if ( ! hi )
                        lo |= EXANIC_DMA_32_BIT;
        } else {
                /* 32-bit build; always a 32-bit address */
                hi = 0;
                lo |= EXANIC_DMA_32_BIT;
        }
        writel ( hi, ( reg + 0 ) );
        writel ( lo, ( reg + 4 ) );
}

/**
 * Clear DMA base address register
 *
 * @v reg               Register
 */
static inline void exanic_clear_base ( void *reg ) {

        /* Clear both high and low registers */
        writel ( 0, ( reg + 0 ) );
        writel ( 0, ( reg + 4 ) );
}

/******************************************************************************
 *
 * Device reset
 *
 ******************************************************************************
 */

/**
 * Reset hardware
 *
 * @v exanic            ExaNIC device
 */
static void exanic_reset ( struct exanic *exanic ) {
        void *port_regs;
        unsigned int i;

        /* Disable all possible ports */
        for ( i = 0 ; i < EXANIC_MAX_PORTS ; i++ ) {
                port_regs = ( exanic->regs + EXANIC_PORT_REGS ( i ) );
                writel ( 0, ( port_regs + EXANIC_PORT_ENABLE ) );
                writel ( 0, ( port_regs + EXANIC_PORT_IRQ ) );
                exanic_clear_base ( port_regs + EXANIC_PORT_RX_BASE );
        }

        /* Disable transmit feedback */
        exanic_clear_base ( exanic->regs + EXANIC_TXF_BASE );
}

/******************************************************************************
 *
 * MAC address
 *
 ******************************************************************************
 */

/**
 * Read I2C line status
 *
 * @v basher            Bit-bashing interface
 * @v bit_id            Bit number
 * @ret zero            Input is a logic 0
 * @ret non-zero        Input is a logic 1
 */
static int exanic_i2c_read_bit ( struct bit_basher *basher,
                                 unsigned int bit_id ) {
        struct exanic *exanic =
                container_of ( basher, struct exanic, basher.basher );
        unsigned int shift;
        uint32_t i2c;

        /* Identify bit */
        assert ( bit_id == I2C_BIT_SDA );
        shift = exanic->i2cfg.getsda;

        /* Read I2C register */
        DBG_DISABLE ( DBGLVL_IO );
        i2c = readl ( exanic->regs + EXANIC_I2C );
        DBG_ENABLE ( DBGLVL_IO );
        return ( ( i2c >> shift ) & 1 );
}

/**
 * Write I2C line status
 *
 * @v basher            Bit-bashing interface
 * @v bit_id            Bit number
 * @v data              Value to write
 */
static void exanic_i2c_write_bit ( struct bit_basher *basher,
                                   unsigned int bit_id, unsigned long data ) {
        struct exanic *exanic =
                container_of ( basher, struct exanic, basher.basher );
        unsigned int shift;
        uint32_t mask;
        uint32_t i2c;

        /* Identify shift */
        assert ( ( bit_id == I2C_BIT_SCL ) || ( bit_id == I2C_BIT_SDA ) );
        shift = ( ( bit_id == I2C_BIT_SCL ) ?
                  exanic->i2cfg.setscl : exanic->i2cfg.setsda );
        mask = ( 1UL << shift );

        /* Modify I2C register */
        DBG_DISABLE ( DBGLVL_IO );
        i2c = readl ( exanic->regs + EXANIC_I2C );
        i2c &= ~mask;
        if ( ! data )
                i2c |= mask;
        writel ( i2c, ( exanic->regs + EXANIC_I2C ) );
        DBG_ENABLE ( DBGLVL_IO );
}

/** I2C bit-bashing interface operations */
static struct bit_basher_operations exanic_i2c_basher_ops = {
        .read = exanic_i2c_read_bit,
        .write = exanic_i2c_write_bit,
};

/** Possible I2C bus configurations */
static struct exanic_i2c_config exanic_i2cfgs[] = {
        /* X2/X10 */
        { .setscl = 7, .setsda = 4, .getsda = 12 },
        /* X4 */
        { .setscl = 7, .setsda = 5, .getsda = 13 },
};

/**
 * Initialise EEPROM
 *
 * @v exanic            ExaNIC device
 * @v i2cfg             I2C bus configuration
 * @ret rc              Return status code
 */
static int exanic_try_init_eeprom ( struct exanic *exanic,
                                    struct exanic_i2c_config *i2cfg ) {
        int rc;

        /* Configure I2C bus */
        memcpy ( &exanic->i2cfg, i2cfg, sizeof ( exanic->i2cfg ) );

        /* Initialise I2C bus */
        if ( ( rc = init_i2c_bit_basher ( &exanic->basher,
                                          &exanic_i2c_basher_ops ) ) != 0 ) {
                DBGC2 ( exanic, "EXANIC %p found no I2C bus via %d/%d/%d\n",
                        exanic, exanic->i2cfg.setscl,
                        exanic->i2cfg.setsda, exanic->i2cfg.getsda );
                return rc;
        }

        /* Check for EEPROM presence */
        init_i2c_eeprom ( &exanic->eeprom, EXANIC_EEPROM_ADDRESS );
        if ( ( rc = i2c_check_presence ( &exanic->basher.i2c,
                                         &exanic->eeprom ) ) != 0 ) {
                DBGC2 ( exanic, "EXANIC %p found no EEPROM via %d/%d/%d\n",
                        exanic, exanic->i2cfg.setscl,
                        exanic->i2cfg.setsda, exanic->i2cfg.getsda );
                return rc;
        }

        DBGC ( exanic, "EXANIC %p found EEPROM via %d/%d/%d\n",
               exanic, exanic->i2cfg.setscl,
               exanic->i2cfg.setsda, exanic->i2cfg.getsda );
        return 0;
}

/**
 * Initialise EEPROM
 *
 * @v exanic            ExaNIC device
 * @ret rc              Return status code
 */
static int exanic_init_eeprom ( struct exanic *exanic ) {
        struct exanic_i2c_config *i2cfg;
        unsigned int i;
        int rc;

        /* Try all possible bus configurations */
        for ( i = 0 ; i < ( sizeof ( exanic_i2cfgs ) /
                            sizeof ( exanic_i2cfgs[0] ) ) ; i++ ) {
                i2cfg = &exanic_i2cfgs[i];
                if ( ( rc = exanic_try_init_eeprom ( exanic, i2cfg ) ) == 0 )
                        return 0;
        }

        DBGC ( exanic, "EXANIC %p found no EEPROM\n", exanic );
        return -ENODEV;
}

/**
 * Fetch base MAC address
 *
 * @v exanic            ExaNIC device
 * @ret rc              Return status code
 */
static int exanic_fetch_mac ( struct exanic *exanic ) {
        struct i2c_interface *i2c = &exanic->basher.i2c;
        int rc;

        /* Initialise EEPROM */
        if ( ( rc = exanic_init_eeprom ( exanic ) ) != 0 )
                return rc;

        /* Fetch base MAC address */
        if ( ( rc = i2c->read ( i2c, &exanic->eeprom, 0, exanic->mac,
                                sizeof ( exanic->mac ) ) ) != 0 ) {
                DBGC ( exanic, "EXANIC %p could not read MAC address: %s\n",
                       exanic, strerror ( rc ) );
                return rc;
        }

        return 0;
}

/******************************************************************************
 *
 * Link state
 *
 ******************************************************************************
 */

/**
 * Check link state
 *
 * @v netdev            Network device
 */
static void exanic_check_link ( struct net_device *netdev ) {
        struct exanic_port *port = netdev->priv;
        uint32_t status;
        uint32_t speed;

        /* Report port status changes */
        status = readl ( port->regs + EXANIC_PORT_STATUS );
        speed = readl ( port->regs + EXANIC_PORT_SPEED );
        if ( status != port->status ) {
                DBGC ( port, "EXANIC %s port status %#08x speed %dMbps\n",
                       netdev->name, status, speed );
                if ( status & EXANIC_PORT_STATUS_LINK ) {
                        netdev_link_up ( netdev );
                } else {
                        netdev_link_down ( netdev );
                }
                port->status = status;
        }
}

/**
 * Check link state periodically
 *
 * @v retry             Link state check timer
 * @v over              Failure indicator
 */
static void exanic_expired ( struct retry_timer *timer, int over __unused ) {
        struct exanic_port *port =
                container_of ( timer, struct exanic_port, timer );
        struct net_device *netdev = port->netdev;
        static const uint32_t speeds[] = {
                100, 1000, 10000, 40000, 100000,
        };
        unsigned int index;

        /* Restart timer */
        start_timer_fixed ( timer, EXANIC_LINK_INTERVAL );

        /* Check link state */
        exanic_check_link ( netdev );

        /* Do nothing further if link is already up */
        if ( netdev_link_ok ( netdev ) )
                return;

        /* Do nothing further unless we have a valid list of supported speeds */
        if ( ! port->speeds )
                return;

        /* Autonegotiation is not supported; try manually selecting
         * the next supported link speed.
         */
        do {
                if ( ! port->speed )
                        port->speed = ( 8 * sizeof ( port->speeds ) );
                port->speed--;
        } while ( ! ( ( 1UL << port->speed ) & port->speeds ) );
        index = ( port->speed - ( ffs ( EXANIC_CAPS_SPEED_MASK ) - 1 ) );
        assert ( index < ( sizeof ( speeds ) / sizeof ( speeds[0] ) ) );

        /* Attempt the selected speed */
        DBGC ( netdev, "EXANIC %s attempting %dMbps\n",
               netdev->name, speeds[index] );
        writel ( speeds[index], ( port->regs + EXANIC_PORT_SPEED ) );
}

/******************************************************************************
 *
 * Network device interface
 *
 ******************************************************************************
 */

/**
 * Open network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int exanic_open ( struct net_device *netdev ) {
        struct exanic_port *port = netdev->priv;
        struct exanic_tx_chunk *tx;
        unsigned int i;

        /* Reset transmit region contents */
        for ( i = 0 ; i < port->tx_count ; i++ ) {
                tx = ( port->tx + ( i * sizeof ( *tx ) ) );
                writew ( port->txf_slot, &tx->desc.txf_slot );
                writeb ( EXANIC_TYPE_RAW, &tx->desc.type );
                writeb ( 0, &tx->desc.flags );
                writew ( 0, &tx->pad );
        }

        /* Reset receive region contents */
        memset_user ( port->rx, 0, 0xff, EXANIC_RX_LEN );

        /* Reset transmit feedback region */
        *(port->txf) = 0;

        /* Reset counters */
        port->tx_prod = 0;
        port->tx_cons = 0;
        port->rx_cons = 0;

        /* Map receive region */
        exanic_write_base ( phys_to_bus ( user_to_phys ( port->rx, 0 ) ),
                            ( port->regs + EXANIC_PORT_RX_BASE ) );

        /* Enable promiscuous mode */
        writel ( EXANIC_PORT_FLAGS_PROMISC,
                 ( port->regs + EXANIC_PORT_FLAGS ) );

        /* Reset to default speed and clear cached status */
        writel ( port->default_speed, ( port->regs + EXANIC_PORT_SPEED ) );
        port->speed = 0;
        port->status = 0;

        /* Enable port */
        wmb();
        writel ( EXANIC_PORT_ENABLE_ENABLED,
                 ( port->regs + EXANIC_PORT_ENABLE ) );

        /* Start link state timer */
        start_timer_fixed ( &port->timer, EXANIC_LINK_INTERVAL );

        return 0;
}

/**
 * Close network device
 *
 * @v netdev            Network device
 */
static void exanic_close ( struct net_device *netdev ) {
        struct exanic_port *port = netdev->priv;

        /* Stop link state timer */
        stop_timer ( &port->timer );

        /* Disable port */
        writel ( 0, ( port->regs + EXANIC_PORT_ENABLE ) );
        wmb();

        /* Clear receive region */
        exanic_clear_base ( port->regs + EXANIC_PORT_RX_BASE );

        /* Discard any in-progress receive */
        if ( port->rx_iobuf ) {
                netdev_rx_err ( netdev, port->rx_iobuf, -ECANCELED );
                port->rx_iobuf = NULL;
        }
}

/**
 * Transmit packet
 *
 * @v netdev            Network device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int exanic_transmit ( struct net_device *netdev,
                             struct io_buffer *iobuf ) {
        struct exanic_port *port = netdev->priv;
        struct exanic_tx_chunk *tx;
        unsigned int tx_fill;
        unsigned int tx_index;
        size_t offset;
        size_t len;
        uint8_t *src;
        uint8_t *dst;

        /* Sanity check */
        len = iob_len ( iobuf );
        if ( len > sizeof ( tx->data ) ) {
                DBGC ( port, "EXANIC %s transmit too large\n", netdev->name );
                return -ENOTSUP;
        }

        /* Get next transmit descriptor */
        tx_fill = ( port->tx_prod - port->tx_cons );
        if ( tx_fill >= port->tx_count ) {
                DBGC ( port, "EXANIC %s out of transmit descriptors\n",
                       netdev->name );
                return -ENOBUFS;
        }
        tx_index = ( port->tx_prod & ( port->tx_count - 1 ) );
        offset = ( tx_index * sizeof ( *tx ) );
        tx = ( port->tx + offset );
        DBGC2 ( port, "EXANIC %s TX %04x at [%05zx,%05zx)\n",
                netdev->name, port->tx_prod, ( port->tx_offset + offset ),
                ( port->tx_offset + offset +
                  offsetof ( typeof ( *tx ), data ) + len ) );
        port->tx_prod++;

        /* Populate transmit descriptor */
        writew ( port->tx_prod, &tx->desc.txf_id );
        writew ( ( sizeof ( tx->pad ) + len ), &tx->desc.len );

        /* Copy data to transmit region.  There is no DMA on the
         * transmit data path.
         */
        src = iobuf->data;
        dst = tx->data;
        while ( len-- )
                writeb ( *(src++), dst++ );

        /* Send transmit command */
        wmb();
        writel ( ( port->tx_offset + offset ),
                 ( port->regs + EXANIC_PORT_TX_COMMAND ) );

        return 0;
}

/**
 * Poll for completed packets
 *
 * @v netdev            Network device
 */
static void exanic_poll_tx ( struct net_device *netdev ) {
        struct exanic_port *port = netdev->priv;

        /* Report any completed packets */
        while ( port->tx_cons != *(port->txf) ) {
                DBGC2 ( port, "EXANIC %s TX %04x complete\n",
                        netdev->name, port->tx_cons );
                netdev_tx_complete_next ( netdev );
                port->tx_cons++;
        }
}

/**
 * Poll for received packets
 *
 * @v netdev            Network device
 */
static void exanic_poll_rx ( struct net_device *netdev ) {
        struct exanic_port *port = netdev->priv;
        struct exanic_rx_chunk *rx;
        struct exanic_rx_descriptor desc;
        uint8_t current;
        uint8_t previous;
        size_t offset;
        size_t len;

        for ( ; ; port->rx_cons++ ) {

                /* Fetch descriptor */
                offset = ( ( port->rx_cons * sizeof ( *rx ) ) % EXANIC_RX_LEN );
                copy_from_user ( &desc, port->rx,
                                 ( offset + offsetof ( typeof ( *rx ), desc ) ),
                                 sizeof ( desc ) );

                /* Calculate generation */
                current = ( port->rx_cons / ( EXANIC_RX_LEN / sizeof ( *rx ) ));
                previous = ( current - 1 );

                /* Do nothing if no chunk is ready */
                if ( desc.generation == previous )
                        break;

                /* Allocate I/O buffer if needed */
                if ( ! port->rx_iobuf ) {
                        port->rx_iobuf = alloc_iob ( EXANIC_MAX_RX_LEN );
                        if ( ! port->rx_iobuf ) {
                                /* Wait for next poll */
                                break;
                        }
                        port->rx_rc = 0;
                }

                /* Calculate chunk length */
                len = ( desc.len ? desc.len : sizeof ( rx->data ) );

                /* Append data to I/O buffer */
                if ( len <= iob_tailroom ( port->rx_iobuf ) ) {
                        copy_from_user ( iob_put ( port->rx_iobuf, len ),
                                         port->rx,
                                         ( offset + offsetof ( typeof ( *rx ),
                                                               data ) ), len );
                } else {
                        DBGC ( port, "EXANIC %s RX too large\n",
                               netdev->name );
                        port->rx_rc = -ERANGE;
                }

                /* Check for overrun */
                rmb();
                copy_from_user ( &desc.generation, port->rx,
                                 ( offset + offsetof ( typeof ( *rx ),
                                                       desc.generation ) ),
                                 sizeof ( desc.generation ) );
                if ( desc.generation != current ) {
                        DBGC ( port, "EXANIC %s RX overrun\n", netdev->name );
                        port->rx_rc = -ENOBUFS;
                        continue;
                }

                /* Wait for end of packet */
                if ( ! desc.len )
                        continue;

                /* Check for receive errors */
                if ( desc.status & EXANIC_STATUS_ERROR_MASK ) {
                        port->rx_rc = -EIO_STATUS ( desc.status );
                        DBGC ( port, "EXANIC %s RX %04x error: %s\n",
                               netdev->name, port->rx_cons,
                               strerror ( port->rx_rc ) );
                } else {
                        DBGC2 ( port, "EXANIC %s RX %04x\n",
                                netdev->name, port->rx_cons );
                }

                /* Hand off to network stack */
                if ( port->rx_rc ) {
                        netdev_rx_err ( netdev, port->rx_iobuf, port->rx_rc );
                } else {
                        iob_unput ( port->rx_iobuf, 4 /* strip CRC */ );
                        netdev_rx ( netdev, port->rx_iobuf );
                }
                port->rx_iobuf = NULL;
        }
}

/**
 * Poll for completed and received packets
 *
 * @v netdev            Network device
 */
static void exanic_poll ( struct net_device *netdev ) {

        /* Poll for completed packets */
        exanic_poll_tx ( netdev );

        /* Poll for received packets */
        exanic_poll_rx ( netdev );
}

/** ExaNIC network device operations */
static struct net_device_operations exanic_operations = {
        .open           = exanic_open,
        .close          = exanic_close,
        .transmit       = exanic_transmit,
        .poll           = exanic_poll,
};

/******************************************************************************
 *
 * PCI interface
 *
 ******************************************************************************
 */

/**
 * Probe port
 *
 * @v exanic            ExaNIC device
 * @v dev               Parent device
 * @v index             Port number
 * @ret rc              Return status code
 */
static int exanic_probe_port ( struct exanic *exanic, struct device *dev,
                               unsigned int index ) {
        struct net_device *netdev;
        struct exanic_port *port;
        void *port_regs;
        uint32_t status;
        size_t tx_len;
        int rc;

        /* Do nothing if port is not physically present */
        port_regs = ( exanic->regs + EXANIC_PORT_REGS ( index ) );
        status = readl ( port_regs + EXANIC_PORT_STATUS );
        tx_len = readl ( port_regs + EXANIC_PORT_TX_LEN );
        if ( ( status & EXANIC_PORT_STATUS_ABSENT ) || ( tx_len == 0 ) ) {
                rc = 0;
                goto absent;
        }

        /* Allocate network device */
        netdev = alloc_etherdev ( sizeof ( *port ) );
        if ( ! netdev ) {
                rc = -ENOMEM;
                goto err_alloc_netdev;
        }
        netdev_init ( netdev, &exanic_operations );
        netdev->dev = dev;
        port = netdev->priv;
        memset ( port, 0, sizeof ( *port ) );
        exanic->port[index] = port;
        port->netdev = netdev;
        port->regs = port_regs;
        timer_init ( &port->timer, exanic_expired, &netdev->refcnt );

        /* Identify transmit region */
        port->tx_offset = readl ( port->regs + EXANIC_PORT_TX_OFFSET );
        if ( tx_len > EXANIC_MAX_TX_LEN )
                tx_len = EXANIC_MAX_TX_LEN;
        assert ( ! ( tx_len & ( tx_len - 1 ) ) );
        port->tx = ( exanic->tx + port->tx_offset );
        port->tx_count = ( tx_len / sizeof ( struct exanic_tx_chunk ) );

        /* Identify transmit feedback region */
        port->txf_slot = EXANIC_TXF_SLOT ( index );
        port->txf = ( exanic->txf +
                      ( port->txf_slot * sizeof ( *(port->txf) ) ) );

        /* Allocate receive region (via umalloc()) */
        port->rx = umalloc ( EXANIC_RX_LEN );
        if ( ! port->rx ) {
                rc = -ENOMEM;
                goto err_alloc_rx;
        }

        /* Set MAC address */
        memcpy ( netdev->hw_addr, exanic->mac, ETH_ALEN );
        netdev->hw_addr[ ETH_ALEN - 1 ] += index;

        /* Record default link speed and supported speeds */
        port->default_speed = readl ( port->regs + EXANIC_PORT_SPEED );
        port->speeds = ( exanic->caps & EXANIC_CAPS_SPEED_MASK );

        /* Register network device */
        if ( ( rc = register_netdev ( netdev ) ) != 0 )
                goto err_register_netdev;
        DBGC ( port, "EXANIC %s port %d TX [%#05zx,%#05zx) TXF %#02x RX "
               "[%#lx,%#lx)\n", netdev->name, index, port->tx_offset,
               ( port->tx_offset + tx_len ), port->txf_slot,
               user_to_phys ( port->rx, 0 ),
               user_to_phys ( port->rx, EXANIC_RX_LEN ) );

        /* Set initial link state */
        exanic_check_link ( netdev );

        return 0;

        unregister_netdev ( netdev );
 err_register_netdev:
        ufree ( port->rx );
 err_alloc_rx:
        netdev_nullify ( netdev );
        netdev_put ( netdev );
 err_alloc_netdev:
 absent:
        return rc;
}

/**
 * Probe port
 *
 * @v exanic            ExaNIC device
 * @v index             Port number
 */
static void exanic_remove_port ( struct exanic *exanic, unsigned int index ) {
        struct exanic_port *port;

        /* Do nothing if port is not physically present */
        port = exanic->port[index];
        if ( ! port )
                return;

        /* Unregister network device */
        unregister_netdev ( port->netdev );

        /* Free receive region */
        ufree ( port->rx );

        /* Free network device */
        netdev_nullify ( port->netdev );
        netdev_put ( port->netdev );
}

/**
 * Probe PCI device
 *
 * @v pci               PCI device
 * @ret rc              Return status code
 */
static int exanic_probe ( struct pci_device *pci ) {
        struct exanic *exanic;
        unsigned long regs_bar_start;
        unsigned long tx_bar_start;
        size_t tx_bar_len;
        int i;
        int rc;

        /* Allocate and initialise structure */
        exanic = zalloc ( sizeof ( *exanic ) );
        if ( ! exanic ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        pci_set_drvdata ( pci, exanic );

        /* Fix up PCI device */
        adjust_pci_device ( pci );

        /* Map registers */
        regs_bar_start = pci_bar_start ( pci, EXANIC_REGS_BAR );
        exanic->regs = pci_ioremap ( pci, regs_bar_start, EXANIC_REGS_LEN );
        if ( ! exanic->regs ) {
                rc = -ENODEV;
                goto err_ioremap_regs;
        }

        /* Reset device */
        exanic_reset ( exanic );

        /* Read capabilities */
        exanic->caps = readl ( exanic->regs + EXANIC_CAPS );

        /* Power up PHYs */
        writel ( EXANIC_POWER_ON, ( exanic->regs + EXANIC_POWER ) );

        /* Fetch base MAC address */
        if ( ( rc = exanic_fetch_mac ( exanic ) ) != 0 )
                goto err_fetch_mac;
        DBGC ( exanic, "EXANIC %p capabilities %#08x base MAC %s\n",
               exanic, exanic->caps, eth_ntoa ( exanic->mac ) );

        /* Map transmit region */
        tx_bar_start = pci_bar_start ( pci, EXANIC_TX_BAR );
        tx_bar_len = pci_bar_size ( pci, EXANIC_TX_BAR );
        exanic->tx = pci_ioremap ( pci, tx_bar_start, tx_bar_len );
        if ( ! exanic->tx ) {
                rc = -ENODEV;
                goto err_ioremap_tx;
        }

        /* Allocate transmit feedback region (shared between all ports) */
        exanic->txf = malloc_phys ( EXANIC_TXF_LEN, EXANIC_ALIGN );
        if ( ! exanic->txf ) {
                rc = -ENOMEM;
                goto err_alloc_txf;
        }
        memset ( exanic->txf, 0, EXANIC_TXF_LEN );
        exanic_write_base ( virt_to_bus ( exanic->txf ),
                            ( exanic->regs + EXANIC_TXF_BASE ) );

        /* Allocate and initialise per-port network devices */
        for ( i = 0 ; i < EXANIC_MAX_PORTS ; i++ ) {
                if ( ( rc = exanic_probe_port ( exanic, &pci->dev, i ) ) != 0 )
                        goto err_probe_port;
        }

        return 0;

        i = EXANIC_MAX_PORTS;
 err_probe_port:
        for ( i-- ; i >= 0 ; i-- )
                exanic_remove_port ( exanic, i );
        exanic_reset ( exanic );
        free_phys ( exanic->txf, EXANIC_TXF_LEN );
 err_alloc_txf:
        iounmap ( exanic->tx );
 err_ioremap_tx:
        iounmap ( exanic->regs );
 err_fetch_mac:
 err_ioremap_regs:
        free ( exanic );
 err_alloc:
        return rc;
}

/**
 * Remove PCI device
 *
 * @v pci               PCI device
 */
static void exanic_remove ( struct pci_device *pci ) {
        struct exanic *exanic = pci_get_drvdata ( pci );
        unsigned int i;

        /* Remove all ports */
        for ( i = 0 ; i < EXANIC_MAX_PORTS ; i++ )
                exanic_remove_port ( exanic, i );

        /* Reset device */
        exanic_reset ( exanic );

        /* Free transmit feedback region */
        free_phys ( exanic->txf, EXANIC_TXF_LEN );

        /* Unmap transmit region */
        iounmap ( exanic->tx );

        /* Unmap registers */
        iounmap ( exanic->regs );

        /* Free device */
        free ( exanic );
}

/** ExaNIC PCI device IDs */
static struct pci_device_id exanic_ids[] = {
        PCI_ROM ( 0x10ee, 0x2b00, "exanic-old", "ExaNIC (old)", 0 ),
        PCI_ROM ( 0x1ce4, 0x0001, "exanic-x4", "ExaNIC X4", 0 ),
        PCI_ROM ( 0x1ce4, 0x0002, "exanic-x2", "ExaNIC X2", 0 ),
        PCI_ROM ( 0x1ce4, 0x0003, "exanic-x10", "ExaNIC X10", 0 ),
        PCI_ROM ( 0x1ce4, 0x0004, "exanic-x10gm", "ExaNIC X10 GM", 0 ),
        PCI_ROM ( 0x1ce4, 0x0005, "exanic-x40", "ExaNIC X40", 0 ),
        PCI_ROM ( 0x1ce4, 0x0006, "exanic-x10hpt", "ExaNIC X10 HPT", 0 ),
        PCI_ROM ( 0x1ce4, 0x0007, "exanic-x40g", "ExaNIC X40", 0 ),
};

/** ExaNIC PCI driver */
struct pci_driver exanic_driver __pci_driver = {
        .ids = exanic_ids,
        .id_count = ( sizeof ( exanic_ids ) / sizeof ( exanic_ids[0] ) ),
        .probe = exanic_probe,
        .remove = exanic_remove,
};