realtek.c

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/*
 * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * (EEPROM code originally implemented for rtl8139.c)
 *
 * 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 <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/pci.h>
#include <ipxe/dma.h>
#include <ipxe/nvs.h>
#include <ipxe/threewire.h>
#include <ipxe/bitbash.h>
#include <ipxe/mii.h>
#include "realtek.h"

/** @file
 *
 * Realtek 10/100/1000 network card driver
 *
 * Based on the following datasheets:
 *
 *    http://www.datasheetarchive.com/dl/Datasheets-8/DSA-153536.pdf
 *    http://www.datasheetarchive.com/indexdl/Datasheet-028/DSA00494723.pdf
 */

/******************************************************************************
 *
 * Debugging
 *
 ******************************************************************************
 */

/**
 * Dump all registers (for debugging)
 *
 * @v rtl               Realtek device
 */
static __attribute__ (( unused )) void realtek_dump ( struct realtek_nic *rtl ){
        uint8_t regs[256];
        unsigned int i;

        /* Do nothing unless debug output is enabled */
        if ( ! DBG_LOG )
                return;

        /* Dump registers (via byte accesses; may not work for all registers) */
        for ( i = 0 ; i < sizeof ( regs ) ; i++ )
                regs[i] = readb ( rtl->regs + i );
        DBGC ( rtl, "REALTEK %p register dump:\n", rtl );
        DBGC_HDA ( rtl, 0, regs, sizeof ( regs ) );
}

/******************************************************************************
 *
 * EEPROM interface
 *
 ******************************************************************************
 */

/** Pin mapping for SPI bit-bashing interface */
static const uint8_t realtek_eeprom_bits[] = {
        [SPI_BIT_SCLK]  = RTL_9346CR_EESK,
        [SPI_BIT_MOSI]  = RTL_9346CR_EEDI,
        [SPI_BIT_MISO]  = RTL_9346CR_EEDO,
        [SPI_BIT_SS(0)] = RTL_9346CR_EECS,
};

/**
 * Open bit-bashing interface
 *
 * @v basher            Bit-bashing interface
 */
static void realtek_spi_open_bit ( struct bit_basher *basher ) {
        struct realtek_nic *rtl = container_of ( basher, struct realtek_nic,
                                                 spibit.basher );

        /* Enable EEPROM access */
        writeb ( RTL_9346CR_EEM_EEPROM, rtl->regs + RTL_9346CR );
        readb ( rtl->regs + RTL_9346CR ); /* Ensure write reaches chip */
}

/**
 * Close bit-bashing interface
 *
 * @v basher            Bit-bashing interface
 */
static void realtek_spi_close_bit ( struct bit_basher *basher ) {
        struct realtek_nic *rtl = container_of ( basher, struct realtek_nic,
                                                 spibit.basher );

        /* Disable EEPROM access */
        writeb ( RTL_9346CR_EEM_NORMAL, rtl->regs + RTL_9346CR );
        readb ( rtl->regs + RTL_9346CR ); /* Ensure write reaches chip */
}

/**
 * Read input bit
 *
 * @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 realtek_spi_read_bit ( struct bit_basher *basher,
                                  unsigned int bit_id ) {
        struct realtek_nic *rtl = container_of ( basher, struct realtek_nic,
                                                 spibit.basher );
        uint8_t mask = realtek_eeprom_bits[bit_id];
        uint8_t reg;

        DBG_DISABLE ( DBGLVL_IO );
        reg = readb ( rtl->regs + RTL_9346CR );
        DBG_ENABLE ( DBGLVL_IO );
        return ( reg & mask );
}

/**
 * Set/clear output bit
 *
 * @v basher            Bit-bashing interface
 * @v bit_id            Bit number
 * @v data              Value to write
 */
static void realtek_spi_write_bit ( struct bit_basher *basher,
                                    unsigned int bit_id, unsigned long data ) {
        struct realtek_nic *rtl = container_of ( basher, struct realtek_nic,
                                                 spibit.basher );
        uint8_t mask = realtek_eeprom_bits[bit_id];
        uint8_t reg;

        DBG_DISABLE ( DBGLVL_IO );
        reg = readb ( rtl->regs + RTL_9346CR );
        reg &= ~mask;
        reg |= ( data & mask );
        writeb ( reg, rtl->regs + RTL_9346CR );
        readb ( rtl->regs + RTL_9346CR ); /* Ensure write reaches chip */
        DBG_ENABLE ( DBGLVL_IO );
}

/** SPI bit-bashing interface */
static struct bit_basher_operations realtek_basher_ops = {
        .open = realtek_spi_open_bit,
        .close = realtek_spi_close_bit,
        .read = realtek_spi_read_bit,
        .write = realtek_spi_write_bit,
};

/**
 * Initialise EEPROM
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int realtek_init_eeprom ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        uint16_t id;
        int rc;

        /* Initialise SPI bit-bashing interface */
        rtl->spibit.basher.op = &realtek_basher_ops;
        rtl->spibit.bus.mode = SPI_MODE_THREEWIRE;
        init_spi_bit_basher ( &rtl->spibit );

        /* Detect EEPROM type and initialise three-wire device */
        if ( readl ( rtl->regs + RTL_RCR ) & RTL_RCR_9356SEL ) {
                DBGC ( rtl, "REALTEK %p EEPROM is a 93C56\n", rtl );
                init_at93c56 ( &rtl->eeprom, 16 );
        } else {
                DBGC ( rtl, "REALTEK %p EEPROM is a 93C46\n", rtl );
                init_at93c46 ( &rtl->eeprom, 16 );
        }

        /* Check for EEPROM presence.  Some onboard NICs will have no
         * EEPROM connected, with the BIOS being responsible for
         * programming the initial register values.
         */
        if ( ( rc = nvs_read ( &rtl->eeprom.nvs, RTL_EEPROM_ID,
                               &id, sizeof ( id ) ) ) != 0 ) {
                DBGC ( rtl, "REALTEK %p could not read EEPROM ID: %s\n",
                       rtl, strerror ( rc ) );
                return rc;
        }
        if ( id != cpu_to_le16 ( RTL_EEPROM_ID_MAGIC ) ) {
                DBGC ( rtl, "REALTEK %p EEPROM ID incorrect (%#04x); assuming "
                       "no EEPROM\n", rtl, le16_to_cpu ( id ) );
                return -ENODEV;
        }

        /* Initialise space for non-volatile options, if available
         *
         * We use offset 0x40 (i.e. address 0x20), length 0x40.  This
         * block is marked as VPD in the Realtek datasheets, so we use
         * it only if we detect that the card is not supporting VPD.
         */
        if ( readb ( rtl->regs + RTL_CONFIG1 ) & RTL_CONFIG1_VPD ) {
                DBGC ( rtl, "REALTEK %p EEPROM in use for VPD; cannot use "
                       "for options\n", rtl );
        } else {
                nvo_init ( &rtl->nvo, &rtl->eeprom.nvs, RTL_EEPROM_VPD,
                           RTL_EEPROM_VPD_LEN, NULL, &netdev->refcnt );
        }

        return 0;
}

/******************************************************************************
 *
 * MII interface
 *
 ******************************************************************************
 */

/**
 * Read from MII register
 *
 * @v mdio              MII interface
 * @v phy               PHY address
 * @v reg               Register address
 * @ret value           Data read, or negative error
 */
static int realtek_mii_read ( struct mii_interface *mdio,
                              unsigned int phy __unused, unsigned int reg ) {
        struct realtek_nic *rtl =
                container_of ( mdio, struct realtek_nic, mdio );
        unsigned int i;
        uint32_t value;

        /* Fail if PHYAR register is not present */
        if ( ! rtl->have_phy_regs )
                return -ENOTSUP;

        /* Initiate read */
        writel ( RTL_PHYAR_VALUE ( 0, reg, 0 ), rtl->regs + RTL_PHYAR );

        /* Wait for read to complete */
        for ( i = 0 ; i < RTL_MII_MAX_WAIT_US ; i++ ) {

                /* If read is not complete, delay 1us and retry */
                value = readl ( rtl->regs + RTL_PHYAR );
                if ( ! ( value & RTL_PHYAR_FLAG ) ) {
                        udelay ( 1 );
                        continue;
                }

                /* Return register value */
                return ( RTL_PHYAR_DATA ( value ) );
        }

        DBGC ( rtl, "REALTEK %p timed out waiting for MII read\n", rtl );
        return -ETIMEDOUT;
}

/**
 * Write to MII register
 *
 * @v mdio              MII interface
 * @v phy               PHY address
 * @v reg               Register address
 * @v data              Data to write
 * @ret rc              Return status code
 */
static int realtek_mii_write ( struct mii_interface *mdio,
                               unsigned int phy __unused, unsigned int reg,
                               unsigned int data ) {
        struct realtek_nic *rtl =
                container_of ( mdio, struct realtek_nic, mdio );
        unsigned int i;

        /* Fail if PHYAR register is not present */
        if ( ! rtl->have_phy_regs )
                return -ENOTSUP;

        /* Initiate write */
        writel ( RTL_PHYAR_VALUE ( RTL_PHYAR_FLAG, reg, data ),
                 rtl->regs + RTL_PHYAR );

        /* Wait for write to complete */
        for ( i = 0 ; i < RTL_MII_MAX_WAIT_US ; i++ ) {

                /* If write is not complete, delay 1us and retry */
                if ( readl ( rtl->regs + RTL_PHYAR ) & RTL_PHYAR_FLAG ) {
                        udelay ( 1 );
                        continue;
                }

                return 0;
        }

        DBGC ( rtl, "REALTEK %p timed out waiting for MII write\n", rtl );
        return -ETIMEDOUT;
}

/** Realtek MII operations */
static struct mii_operations realtek_mii_operations = {
        .read = realtek_mii_read,
        .write = realtek_mii_write,
};

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

/**
 * Reset hardware
 *
 * @v rtl               Realtek device
 * @ret rc              Return status code
 */
static int realtek_reset ( struct realtek_nic *rtl ) {
        unsigned int i;

        /* Issue reset */
        writeb ( RTL_CR_RST, rtl->regs + RTL_CR );

        /* Wait for reset to complete */
        for ( i = 0 ; i < RTL_RESET_MAX_WAIT_MS ; i++ ) {

                /* If reset is not complete, delay 1ms and retry */
                if ( readb ( rtl->regs + RTL_CR ) & RTL_CR_RST ) {
                        mdelay ( 1 );
                        continue;
                }

                return 0;
        }

        DBGC ( rtl, "REALTEK %p timed out waiting for reset\n", rtl );
        return -ETIMEDOUT;
}

/**
 * Configure PHY for Gigabit operation
 *
 * @v rtl               Realtek device
 * @ret rc              Return status code
 */
static int realtek_phy_speed ( struct realtek_nic *rtl ) {
        int ctrl1000;
        int rc;

        /* Read CTRL1000 register */
        ctrl1000 = mii_read ( &rtl->mii, MII_CTRL1000 );
        if ( ctrl1000 < 0 ) {
                rc = ctrl1000;
                DBGC ( rtl, "REALTEK %p could not read CTRL1000: %s\n",
                       rtl, strerror ( rc ) );
                return rc;
        }

        /* Advertise 1000Mbps speeds */
        ctrl1000 |= ( ADVERTISE_1000FULL | ADVERTISE_1000HALF );
        if ( ( rc = mii_write ( &rtl->mii, MII_CTRL1000, ctrl1000 ) ) != 0 ) {
                DBGC ( rtl, "REALTEK %p could not write CTRL1000: %s\n",
                       rtl, strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Reset PHY
 *
 * @v rtl               Realtek device
 * @ret rc              Return status code
 */
static int realtek_phy_reset ( struct realtek_nic *rtl ) {
        int rc;

        /* Do nothing if we have no separate PHY register access */
        if ( ! rtl->have_phy_regs )
                return 0;

        /* Perform MII reset */
        if ( ( rc = mii_reset ( &rtl->mii ) ) != 0 ) {
                DBGC ( rtl, "REALTEK %p could not reset MII: %s\n",
                       rtl, strerror ( rc ) );
                return rc;
        }

        /* Some cards (e.g. RTL8169SC) do not advertise Gigabit by
         * default.  Try to enable advertisement of Gigabit speeds.
         */
        if ( ( rc = realtek_phy_speed ( rtl ) ) != 0 ) {
                /* Ignore failures, since the register may not be
                 * present on non-Gigabit PHYs (e.g. RTL8101).
                 */
        }

        /* Some cards (e.g. RTL8211B) have a hardware errata that
         * requires the MII_MMD_DATA register to be cleared before the
         * link will come up.
         */
        if ( ( rc = mii_write ( &rtl->mii, MII_MMD_DATA, 0 ) ) != 0 ) {
                /* Ignore failures, since the register may not be
                 * present on all PHYs.
                 */
        }

        /* Restart autonegotiation */
        if ( ( rc = mii_restart ( &rtl->mii ) ) != 0 ) {
                DBGC ( rtl, "REALTEK %p could not restart MII: %s\n",
                       rtl, strerror ( rc ) );
                return rc;
        }

        return 0;
}

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

/**
 * Check link state
 *
 * @v netdev            Network device
 */
static void realtek_check_link ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        uint8_t phystatus;
        uint8_t msr;
        int link_up;

        /* Determine link state */
        if ( rtl->have_phy_regs ) {
                mii_dump ( &rtl->mii );
                phystatus = readb ( rtl->regs + RTL_PHYSTATUS );
                link_up = ( phystatus & RTL_PHYSTATUS_LINKSTS );
                DBGC ( rtl, "REALTEK %p PHY status is %02x (%s%s%s%s%s%s, "
                       "Link%s, %sDuplex)\n", rtl, phystatus,
                       ( ( phystatus & RTL_PHYSTATUS_ENTBI ) ? "TBI" : "GMII" ),
                       ( ( phystatus & RTL_PHYSTATUS_TXFLOW ) ?
                         ", TxFlow" : "" ),
                       ( ( phystatus & RTL_PHYSTATUS_RXFLOW ) ?
                         ", RxFlow" : "" ),
                       ( ( phystatus & RTL_PHYSTATUS_1000MF ) ?
                         ", 1000Mbps" : "" ),
                       ( ( phystatus & RTL_PHYSTATUS_100M ) ?
                         ", 100Mbps" : "" ),
                       ( ( phystatus & RTL_PHYSTATUS_10M ) ?
                         ", 10Mbps" : "" ),
                       ( ( phystatus & RTL_PHYSTATUS_LINKSTS ) ?
                         "Up" : "Down" ),
                       ( ( phystatus & RTL_PHYSTATUS_FULLDUP ) ?
                         "Full" : "Half" ) );
        } else {
                msr = readb ( rtl->regs + RTL_MSR );
                link_up = ( ! ( msr & RTL_MSR_LINKB ) );
                DBGC ( rtl, "REALTEK %p media status is %02x (Link%s, "
                       "%dMbps%s%s%s%s%s)\n", rtl, msr,
                       ( ( msr & RTL_MSR_LINKB ) ? "Down" : "Up" ),
                       ( ( msr & RTL_MSR_SPEED_10 ) ? 10 : 100 ),
                       ( ( msr & RTL_MSR_TXFCE ) ? ", TxFlow" : "" ),
                       ( ( msr & RTL_MSR_RXFCE ) ? ", RxFlow" : "" ),
                       ( ( msr & RTL_MSR_AUX_STATUS ) ? ", AuxPwr" : "" ),
                       ( ( msr & RTL_MSR_TXPF ) ? ", TxPause" : "" ),
                       ( ( msr & RTL_MSR_RXPF ) ? ", RxPause" : "" ) );
        }

        /* Report link state */
        if ( link_up ) {
                netdev_link_up ( netdev );
        } else {
                netdev_link_down ( netdev );
        }
}

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

/**
 * Create receive buffer (legacy mode)
 *
 * @v rtl               Realtek device
 * @ret rc              Return status code
 */
static int realtek_create_buffer ( struct realtek_nic *rtl ) {
        struct realtek_rx_buffer *rxbuf = &rtl->rxbuf;
        size_t len = ( RTL_RXBUF_LEN + RTL_RXBUF_PAD );

        /* Do nothing unless in legacy mode */
        if ( ! rtl->legacy )
                return 0;

        /* Allocate buffer */
        rxbuf->data = dma_alloc ( rtl->dma, &rxbuf->map, len,
                                  RTL_RXBUF_ALIGN );
        if ( ! rxbuf->data )
                return -ENOMEM;

        /* Program buffer address */
        writel ( dma ( &rxbuf->map, rxbuf->data ), rtl->regs + RTL_RBSTART );
        DBGC ( rtl, "REALTEK %p receive buffer is at [%08lx,%08lx,%08lx)\n",
               rtl, virt_to_phys ( rxbuf->data ),
               ( virt_to_phys ( rxbuf->data ) + RTL_RXBUF_LEN ),
               ( virt_to_phys ( rxbuf->data ) + len ) );

        return 0;
}

/**
 * Destroy receive buffer (legacy mode)
 *
 * @v rtl               Realtek device
 */
static void realtek_destroy_buffer ( struct realtek_nic *rtl ) {
        struct realtek_rx_buffer *rxbuf = &rtl->rxbuf;
        size_t len = ( RTL_RXBUF_LEN + RTL_RXBUF_PAD );

        /* Do nothing unless in legacy mode */
        if ( ! rtl->legacy )
                return;

        /* Clear buffer address */
        writel ( 0, rtl->regs + RTL_RBSTART );

        /* Free buffer */
        dma_free ( &rxbuf->map, rxbuf->data, len );
        rxbuf->data = NULL;
        rxbuf->offset = 0;
}

/**
 * Create descriptor ring
 *
 * @v rtl               Realtek device
 * @v ring              Descriptor ring
 * @ret rc              Return status code
 */
static int realtek_create_ring ( struct realtek_nic *rtl,
                                 struct realtek_ring *ring ) {
        physaddr_t address;

        /* Do nothing in legacy mode */
        if ( rtl->legacy )
                return 0;

        /* Allocate descriptor ring */
        ring->desc = dma_alloc ( rtl->dma, &ring->map, ring->len,
                                 RTL_RING_ALIGN );
        if ( ! ring->desc )
                return -ENOMEM;

        /* Initialise descriptor ring */
        memset ( ring->desc, 0, ring->len );

        /* Program ring address */
        address = dma ( &ring->map, ring->desc );
        writel ( ( ( ( uint64_t ) address ) >> 32 ),
                 rtl->regs + ring->reg + 4 );
        writel ( ( address & 0xffffffffUL ), rtl->regs + ring->reg );
        DBGC ( rtl, "REALTEK %p ring %02x is at [%08lx,%08lx)\n",
               rtl, ring->reg, virt_to_phys ( ring->desc ),
               ( virt_to_phys ( ring->desc ) + ring->len ) );

        return 0;
}

/**
 * Destroy descriptor ring
 *
 * @v rtl               Realtek device
 * @v ring              Descriptor ring
 */
static void realtek_destroy_ring ( struct realtek_nic *rtl,
                                   struct realtek_ring *ring ) {

        /* Reset producer and consumer counters */
        ring->prod = 0;
        ring->cons = 0;

        /* Do nothing more if in legacy mode */
        if ( rtl->legacy )
                return;

        /* Clear ring address */
        writel ( 0, rtl->regs + ring->reg );
        writel ( 0, rtl->regs + ring->reg + 4 );

        /* Free descriptor ring */
        dma_free ( &ring->map, ring->desc, ring->len );
        ring->desc = NULL;
}

/**
 * Refill receive descriptor ring
 *
 * @v rtl               Realtek device
 */
static void realtek_refill_rx ( struct realtek_nic *rtl ) {
        struct realtek_descriptor *rx;
        struct io_buffer *iobuf;
        unsigned int rx_idx;
        int is_last;

        /* Do nothing in legacy mode */
        if ( rtl->legacy )
                return;

        while ( ( rtl->rx.prod - rtl->rx.cons ) < RTL_NUM_RX_DESC ) {

                /* Allocate I/O buffer */
                iobuf = alloc_rx_iob ( RTL_RX_MAX_LEN, rtl->dma );
                if ( ! iobuf ) {
                        /* Wait for next refill */
                        return;
                }

                /* Get next receive descriptor */
                rx_idx = ( rtl->rx.prod++ % RTL_NUM_RX_DESC );
                is_last = ( rx_idx == ( RTL_NUM_RX_DESC - 1 ) );
                rx = &rtl->rx.desc[rx_idx];

                /* Populate receive descriptor */
                rx->address = cpu_to_le64 ( iob_dma ( iobuf ) );
                rx->length = cpu_to_le16 ( RTL_RX_MAX_LEN );
                wmb();
                rx->flags = ( cpu_to_le16 ( RTL_DESC_OWN ) |
                              ( is_last ? cpu_to_le16 ( RTL_DESC_EOR ) : 0 ) );
                wmb();

                /* Record I/O buffer */
                assert ( rtl->rx_iobuf[rx_idx] == NULL );
                rtl->rx_iobuf[rx_idx] = iobuf;

                DBGC2 ( rtl, "REALTEK %p RX %d is [%lx,%lx)\n",
                        rtl, rx_idx, virt_to_phys ( iobuf->data ),
                        ( virt_to_phys ( iobuf->data ) + RTL_RX_MAX_LEN ) );
        }
}

/**
 * Open network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int realtek_open ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        uint32_t tcr;
        uint32_t rcr;
        int rc;

        /* Create transmit descriptor ring */
        if ( ( rc = realtek_create_ring ( rtl, &rtl->tx ) ) != 0 )
                goto err_create_tx;

        /* Create receive descriptor ring */
        if ( ( rc = realtek_create_ring ( rtl, &rtl->rx ) ) != 0 )
                goto err_create_rx;

        /* Create receive buffer */
        if ( ( rc = realtek_create_buffer ( rtl ) ) != 0 )
                goto err_create_buffer;

        /* Accept all packets */
        writel ( 0xffffffffUL, rtl->regs + RTL_MAR0 );
        writel ( 0xffffffffUL, rtl->regs + RTL_MAR4 );

        /* Enable transmitter and receiver.  RTL8139 requires that
         * this happens before writing to RCR.
         */
        writeb ( ( RTL_CR_TE | RTL_CR_RE ), rtl->regs + RTL_CR );

        /* Configure transmitter */
        tcr = readl ( rtl->regs + RTL_TCR );
        tcr &= ~RTL_TCR_MXDMA_MASK;
        tcr |= RTL_TCR_MXDMA_DEFAULT;
        writel ( tcr, rtl->regs + RTL_TCR );

        /* Configure receiver */
        rcr = readl ( rtl->regs + RTL_RCR );
        rcr &= ~( RTL_RCR_STOP_WORKING | RTL_RCR_RXFTH_MASK |
                  RTL_RCR_RBLEN_MASK | RTL_RCR_MXDMA_MASK );
        rcr |= ( RTL_RCR_RXFTH_DEFAULT | RTL_RCR_RBLEN_DEFAULT |
                 RTL_RCR_MXDMA_DEFAULT | RTL_RCR_WRAP | RTL_RCR_AB |
                 RTL_RCR_AM | RTL_RCR_APM | RTL_RCR_AAP );
        writel ( rcr, rtl->regs + RTL_RCR );

        /* Fill receive ring */
        realtek_refill_rx ( rtl );

        /* Update link state */
        realtek_check_link ( netdev );

        return 0;

        realtek_destroy_buffer ( rtl );
 err_create_buffer:
        realtek_destroy_ring ( rtl, &rtl->rx );
 err_create_rx:
        realtek_destroy_ring ( rtl, &rtl->tx );
 err_create_tx:
        return rc;
}

/**
 * Close network device
 *
 * @v netdev            Network device
 */
static void realtek_close ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        unsigned int i;

        /* Disable receiver and transmitter */
        writeb ( 0, rtl->regs + RTL_CR );

        /* Destroy receive buffer */
        realtek_destroy_buffer ( rtl );

        /* Destroy receive descriptor ring */
        realtek_destroy_ring ( rtl, &rtl->rx );

        /* Discard any unused receive buffers */
        for ( i = 0 ; i < RTL_NUM_RX_DESC ; i++ ) {
                if ( rtl->rx_iobuf[i] )
                        free_rx_iob ( rtl->rx_iobuf[i] );
                rtl->rx_iobuf[i] = NULL;
        }

        /* Destroy transmit descriptor ring */
        realtek_destroy_ring ( rtl, &rtl->tx );

        /* Reset legacy transmit descriptor index, if applicable */
        if ( rtl->legacy )
                realtek_reset ( rtl );
}

/**
 * Transmit packet
 *
 * @v netdev            Network device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int realtek_transmit ( struct net_device *netdev,
                              struct io_buffer *iobuf ) {
        struct realtek_nic *rtl = netdev->priv;
        struct realtek_descriptor *tx;
        unsigned int tx_idx;
        int is_last;
        int rc;

        /* Get next transmit descriptor */
        if ( ( rtl->tx.prod - rtl->tx.cons ) >= RTL_NUM_TX_DESC ) {
                netdev_tx_defer ( netdev, iobuf );
                return 0;
        }
        tx_idx = ( rtl->tx.prod % RTL_NUM_TX_DESC );

        /* Pad and align packet, if needed */
        if ( rtl->legacy )
                iob_pad ( iobuf, ETH_ZLEN );

        /* Map I/O buffer */
        if ( ( rc = iob_map_tx ( iobuf, rtl->dma ) ) != 0 )
                return rc;

        /* Update producer index */
        rtl->tx.prod++;

        /* Transmit packet */
        if ( rtl->legacy ) {

                /* Add to transmit ring */
                writel ( iob_dma ( iobuf ), rtl->regs + RTL_TSAD ( tx_idx ) );
                writel ( ( RTL_TSD_ERTXTH_DEFAULT | iob_len ( iobuf ) ),
                         rtl->regs + RTL_TSD ( tx_idx ) );

        } else {

                /* Populate transmit descriptor */
                is_last = ( tx_idx == ( RTL_NUM_TX_DESC - 1 ) );
                tx = &rtl->tx.desc[tx_idx];
                tx->address = cpu_to_le64 ( iob_dma ( iobuf ) );
                tx->length = cpu_to_le16 ( iob_len ( iobuf ) );
                wmb();
                tx->flags = ( cpu_to_le16 ( RTL_DESC_OWN | RTL_DESC_FS |
                                            RTL_DESC_LS ) |
                              ( is_last ? cpu_to_le16 ( RTL_DESC_EOR ) : 0 ) );
                wmb();

                /* Notify card that there are packets ready to transmit */
                writeb ( RTL_TPPOLL_NPQ, rtl->regs + rtl->tppoll );
        }

        DBGC2 ( rtl, "REALTEK %p TX %d is [%lx,%lx)\n",
                rtl, tx_idx, virt_to_phys ( iobuf->data ),
                virt_to_phys ( iobuf->data ) + iob_len ( iobuf ) );

        return 0;
}

/**
 * Poll for completed packets
 *
 * @v netdev            Network device
 */
static void realtek_poll_tx ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        struct realtek_descriptor *tx;
        unsigned int tx_idx;

        /* Check for completed packets */
        while ( rtl->tx.cons != rtl->tx.prod ) {

                /* Get next transmit descriptor */
                tx_idx = ( rtl->tx.cons % RTL_NUM_TX_DESC );

                /* Stop if descriptor is still in use */
                if ( rtl->legacy ) {

                        /* Check ownership bit in transmit status register */
                        if ( ! ( readl ( rtl->regs + RTL_TSD ( tx_idx ) ) &
                                 RTL_TSD_OWN ) )
                                return;

                } else {

                        /* Check ownership bit in descriptor */
                        tx = &rtl->tx.desc[tx_idx];
                        if ( tx->flags & cpu_to_le16 ( RTL_DESC_OWN ) )
                                return;
                }

                DBGC2 ( rtl, "REALTEK %p TX %d complete\n", rtl, tx_idx );

                /* Complete TX descriptor */
                rtl->tx.cons++;
                netdev_tx_complete_next ( netdev );
        }
}

/**
 * Poll for received packets (legacy mode)
 *
 * @v netdev            Network device
 */
static void realtek_legacy_poll_rx ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        struct realtek_legacy_header *rx;
        struct io_buffer *iobuf;
        size_t len;

        /* Check for received packets */
        while ( ! ( readb ( rtl->regs + RTL_CR ) & RTL_CR_BUFE ) ) {

                /* Extract packet from receive buffer */
                rx = ( rtl->rxbuf.data + rtl->rxbuf.offset );
                len = le16_to_cpu ( rx->length );
                if ( rx->status & cpu_to_le16 ( RTL_STAT_ROK ) ) {

                        DBGC2 ( rtl, "REALTEK %p RX offset %x+%zx\n",
                                rtl, rtl->rxbuf.offset, len );

                        /* Allocate I/O buffer */
                        iobuf = alloc_iob ( len );
                        if ( ! iobuf ) {
                                netdev_rx_err ( netdev, NULL, -ENOMEM );
                                /* Leave packet for next poll */
                                break;
                        }

                        /* Copy data to I/O buffer */
                        memcpy ( iob_put ( iobuf, len ), rx->data, len );
                        iob_unput ( iobuf, 4 /* strip CRC */ );

                        /* Hand off to network stack */
                        netdev_rx ( netdev, iobuf );

                } else {

                        DBGC ( rtl, "REALTEK %p RX offset %x+%zx error %04x\n",
                               rtl, rtl->rxbuf.offset, len,
                               le16_to_cpu ( rx->status ) );
                        netdev_rx_err ( netdev, NULL, -EIO );
                }

                /* Update buffer offset */
                rtl->rxbuf.offset += ( sizeof ( *rx ) + len );
                rtl->rxbuf.offset = ( ( rtl->rxbuf.offset + 3 ) & ~3 );
                rtl->rxbuf.offset = ( rtl->rxbuf.offset % RTL_RXBUF_LEN );
                writew ( ( rtl->rxbuf.offset - 16 ), rtl->regs + RTL_CAPR );

                /* Give chip time to react before rechecking RTL_CR */
                readw ( rtl->regs + RTL_CAPR );
        }
}

/**
 * Poll for received packets
 *
 * @v netdev            Network device
 */
static void realtek_poll_rx ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        struct realtek_descriptor *rx;
        struct io_buffer *iobuf;
        unsigned int rx_idx;
        size_t len;

        /* Poll receive buffer if in legacy mode */
        if ( rtl->legacy ) {
                realtek_legacy_poll_rx ( netdev );
                return;
        }

        /* Check for received packets */
        while ( rtl->rx.cons != rtl->rx.prod ) {

                /* Get next receive descriptor */
                rx_idx = ( rtl->rx.cons % RTL_NUM_RX_DESC );
                rx = &rtl->rx.desc[rx_idx];

                /* Stop if descriptor is still in use */
                if ( rx->flags & cpu_to_le16 ( RTL_DESC_OWN ) )
                        return;

                /* Populate I/O buffer */
                iobuf = rtl->rx_iobuf[rx_idx];
                rtl->rx_iobuf[rx_idx] = NULL;
                len = ( le16_to_cpu ( rx->length ) & RTL_DESC_SIZE_MASK );
                iob_put ( iobuf, ( len - 4 /* strip CRC */ ) );

                /* Hand off to network stack */
                if ( rx->flags & cpu_to_le16 ( RTL_DESC_RES ) ) {
                        DBGC ( rtl, "REALTEK %p RX %d error (length %zd, "
                               "flags %04x)\n", rtl, rx_idx, len,
                               le16_to_cpu ( rx->flags ) );
                        netdev_rx_err ( netdev, iobuf, -EIO );
                } else {
                        DBGC2 ( rtl, "REALTEK %p RX %d complete (length "
                                "%zd)\n", rtl, rx_idx, len );
                        netdev_rx ( netdev, iobuf );
                }
                rtl->rx.cons++;
        }
}

/**
 * Poll for completed and received packets
 *
 * @v netdev            Network device
 */
static void realtek_poll ( struct net_device *netdev ) {
        struct realtek_nic *rtl = netdev->priv;
        uint16_t isr;

        /* Check for and acknowledge interrupts */
        isr = readw ( rtl->regs + RTL_ISR );
        if ( ! isr )
                return;
        writew ( isr, rtl->regs + RTL_ISR );

        /* Poll for TX completions, if applicable */
        if ( isr & ( RTL_IRQ_TER | RTL_IRQ_TOK ) )
                realtek_poll_tx ( netdev );

        /* Poll for RX completionsm, if applicable */
        if ( isr & ( RTL_IRQ_RER | RTL_IRQ_ROK ) )
                realtek_poll_rx ( netdev );

        /* Check link state, if applicable */
        if ( isr & RTL_IRQ_PUN_LINKCHG )
                realtek_check_link ( netdev );

        /* Refill RX ring */
        realtek_refill_rx ( rtl );
}

/**
 * Enable or disable interrupts
 *
 * @v netdev            Network device
 * @v enable            Interrupts should be enabled
 */
static void realtek_irq ( struct net_device *netdev, int enable ) {
        struct realtek_nic *rtl = netdev->priv;
        uint16_t imr;

        /* Set interrupt mask */
        imr = ( enable ? ( RTL_IRQ_PUN_LINKCHG | RTL_IRQ_TER | RTL_IRQ_TOK |
                           RTL_IRQ_RER | RTL_IRQ_ROK ) : 0 );
        writew ( imr, rtl->regs + RTL_IMR );
}

/** Realtek network device operations */
static struct net_device_operations realtek_operations = {
        .open           = realtek_open,
        .close          = realtek_close,
        .transmit       = realtek_transmit,
        .poll           = realtek_poll,
        .irq            = realtek_irq,
};

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

/**
 * Detect device type
 *
 * @v rtl               Realtek device
 */
static void realtek_detect ( struct realtek_nic *rtl ) {
        uint16_t rms;
        uint16_t check_rms;
        uint16_t cpcr;
        uint16_t check_cpcr;

        /* The RX Packet Maximum Size register is present only on
         * 8169.  Try to set to our intended MTU.
         */
        rms = RTL_RX_MAX_LEN;
        writew ( rms, rtl->regs + RTL_RMS );
        check_rms = readw ( rtl->regs + RTL_RMS );

        /* The C+ Command register is present only on 8169 and 8139C+.
         * Try to enable C+ mode and PCI Dual Address Cycle (for
         * 64-bit systems), if supported.
         *
         * Note that enabling DAC seems to cause bizarre behaviour
         * (lockups, garbage data on the wire) on some systems, even
         * if only 32-bit addresses are used.
         *
         * Disable VLAN offload, since some cards seem to have it
         * enabled by default.
         */
        cpcr = readw ( rtl->regs + RTL_CPCR );
        cpcr |= ( RTL_CPCR_MULRW | RTL_CPCR_CPRX | RTL_CPCR_CPTX );
        if ( sizeof ( physaddr_t ) > sizeof ( uint32_t ) )
                cpcr |= RTL_CPCR_DAC;
        cpcr &= ~RTL_CPCR_VLAN;
        writew ( cpcr, rtl->regs + RTL_CPCR );
        check_cpcr = readw ( rtl->regs + RTL_CPCR );

        /* Detect device type */
        if ( check_rms == rms ) {
                DBGC ( rtl, "REALTEK %p appears to be an RTL8169\n", rtl );
                rtl->have_phy_regs = 1;
                rtl->tppoll = RTL_TPPOLL_8169;
                dma_set_mask_64bit ( rtl->dma );
        } else {
                if ( ( check_cpcr == cpcr ) && ( cpcr != 0xffff ) ) {
                        DBGC ( rtl, "REALTEK %p appears to be an RTL8139C+\n",
                               rtl );
                        rtl->tppoll = RTL_TPPOLL_8139CP;
                        dma_set_mask_64bit ( rtl->dma );
                } else {
                        DBGC ( rtl, "REALTEK %p appears to be an RTL8139\n",
                               rtl );
                        rtl->legacy = 1;
                }
                rtl->eeprom.bus = &rtl->spibit.bus;
        }
}

/**
 * Probe PCI device
 *
 * @v pci               PCI device
 * @ret rc              Return status code
 */
static int realtek_probe ( struct pci_device *pci ) {
        struct net_device *netdev;
        struct realtek_nic *rtl;
        unsigned int i;
        int rc;

        /* Allocate and initialise net device */
        netdev = alloc_etherdev ( sizeof ( *rtl ) );
        if ( ! netdev ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        netdev_init ( netdev, &realtek_operations );
        rtl = netdev->priv;
        pci_set_drvdata ( pci, netdev );
        netdev->dev = &pci->dev;
        memset ( rtl, 0, sizeof ( *rtl ) );
        realtek_init_ring ( &rtl->tx, RTL_NUM_TX_DESC, RTL_TNPDS );
        realtek_init_ring ( &rtl->rx, RTL_NUM_RX_DESC, RTL_RDSAR );

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

        /* Map registers */
        rtl->regs = pci_ioremap ( pci, pci->membase, RTL_BAR_SIZE );
        if ( ! rtl->regs ) {
                rc = -ENODEV;
                goto err_ioremap;
        }

        /* Configure DMA */
        rtl->dma = &pci->dma;

        /* Reset the NIC */
        if ( ( rc = realtek_reset ( rtl ) ) != 0 )
                goto err_reset;

        /* Detect device type */
        realtek_detect ( rtl );

        /* Initialise EEPROM */
        if ( rtl->eeprom.bus &&
             ( ( rc = realtek_init_eeprom ( netdev ) ) == 0 ) ) {

                /* Read MAC address from EEPROM */
                if ( ( rc = nvs_read ( &rtl->eeprom.nvs, RTL_EEPROM_MAC,
                                       netdev->hw_addr, ETH_ALEN ) ) != 0 ) {
                        DBGC ( rtl, "REALTEK %p could not read MAC address: "
                               "%s\n", rtl, strerror ( rc ) );
                        goto err_nvs_read;
                }

        } else {

                /* EEPROM not present.  Fall back to reading the
                 * current ID register value, which will hopefully
                 * have been programmed by the platform firmware.
                 */
                for ( i = 0 ; i < ETH_ALEN ; i++ )
                        netdev->hw_addr[i] = readb ( rtl->regs + RTL_IDR0 + i );
        }

        /* Initialise and reset MII interface */
        mdio_init ( &rtl->mdio, &realtek_mii_operations );
        mii_init ( &rtl->mii, &rtl->mdio, 0 );
        if ( ( rc = realtek_phy_reset ( rtl ) ) != 0 )
                goto err_phy_reset;

        /* Register network device */
        if ( ( rc = register_netdev ( netdev ) ) != 0 )
                goto err_register_netdev;

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

        /* Register non-volatile options, if applicable */
        if ( rtl->nvo.nvs ) {
                if ( ( rc = register_nvo ( &rtl->nvo,
                                           netdev_settings ( netdev ) ) ) != 0)
                        goto err_register_nvo;
        }

        return 0;

 err_register_nvo:
        unregister_netdev ( netdev );
 err_register_netdev:
 err_phy_reset:
 err_nvs_read:
        realtek_reset ( rtl );
 err_reset:
        iounmap ( rtl->regs );
 err_ioremap:
        netdev_nullify ( netdev );
        netdev_put ( netdev );
 err_alloc:
        return rc;
}

/**
 * Remove PCI device
 *
 * @v pci               PCI device
 */
static void realtek_remove ( struct pci_device *pci ) {
        struct net_device *netdev = pci_get_drvdata ( pci );
        struct realtek_nic *rtl = netdev->priv;

        /* Unregister non-volatile options, if applicable */
        if ( rtl->nvo.nvs )
                unregister_nvo ( &rtl->nvo );

        /* Unregister network device */
        unregister_netdev ( netdev );

        /* Reset card */
        realtek_reset ( rtl );

        /* Free network device */
        iounmap ( rtl->regs );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
}

/** Realtek PCI device IDs */
static struct pci_device_id realtek_nics[] = {
        PCI_ROM ( 0x0001, 0x8168, "clone8169",  "Cloned 8169", 0 ),
        PCI_ROM ( 0x018a, 0x0106, "fpc0106tx",  "LevelOne FPC-0106TX", 0 ),
        PCI_ROM ( 0x021b, 0x8139, "hne300",     "Compaq HNE-300", 0 ),
        PCI_ROM ( 0x02ac, 0x1012, "s1012",      "SpeedStream 1012", 0 ),
        PCI_ROM ( 0x0357, 0x000a, "ttpmon",     "TTTech TTP-Monitoring", 0 ),
        PCI_ROM ( 0x10ec, 0x8129, "rtl8129",    "RTL-8129", 0 ),
        PCI_ROM ( 0x10ec, 0x8136, "rtl8136",    "RTL8101E/RTL8102E", 0 ),
        PCI_ROM ( 0x10ec, 0x8138, "rtl8138",    "RT8139 (B/C)", 0 ),
        PCI_ROM ( 0x10ec, 0x8139, "rtl8139",    "RTL-8139/8139C/8139C+", 0 ),
        PCI_ROM ( 0x10ec, 0x8167, "rtl8167",    "RTL-8110SC/8169SC", 0 ),
        PCI_ROM ( 0x10ec, 0x8168, "rtl8168",    "RTL8111/8168B", 0 ),
        PCI_ROM ( 0x10ec, 0x8169, "rtl8169",    "RTL-8169", 0 ),
        PCI_ROM ( 0x1113, 0x1211, "smc1211",    "SMC2-1211TX", 0 ),
        PCI_ROM ( 0x1186, 0x1300, "dfe538",     "DFE530TX+/DFE538TX", 0 ),
        PCI_ROM ( 0x1186, 0x1340, "dfe690",     "DFE-690TXD", 0 ),
        PCI_ROM ( 0x1186, 0x4300, "dge528t",    "DGE-528T", 0 ),
        PCI_ROM ( 0x11db, 0x1234, "sega8139",   "Sega Enterprises 8139", 0 ),
        PCI_ROM ( 0x1259, 0xa117, "allied8139", "Allied Telesyn 8139", 0 ),
        PCI_ROM ( 0x1259, 0xa11e, "allied81xx", "Allied Telesyn 81xx", 0 ),
        PCI_ROM ( 0x1259, 0xc107, "allied8169", "Allied Telesyn 8169", 0 ),
        PCI_ROM ( 0x126c, 0x1211, "northen8139","Northern Telecom 8139", 0 ),
        PCI_ROM ( 0x13d1, 0xab06, "fe2000vx",   "Abocom FE2000VX", 0 ),
        PCI_ROM ( 0x1432, 0x9130, "edi8139",    "Edimax 8139", 0 ),
        PCI_ROM ( 0x14ea, 0xab06, "fnw3603tx",  "Planex FNW-3603-TX", 0 ),
        PCI_ROM ( 0x14ea, 0xab07, "fnw3800tx",  "Planex FNW-3800-TX", 0 ),
        PCI_ROM ( 0x1500, 0x1360, "delta8139",  "Delta Electronics 8139", 0 ),
        PCI_ROM ( 0x16ec, 0x0116, "usr997902",  "USR997902", 0 ),
        PCI_ROM ( 0x1737, 0x1032, "linksys8169","Linksys 8169", 0 ),
        PCI_ROM ( 0x1743, 0x8139, "rolf100",    "Peppercorn ROL/F-100", 0 ),
        PCI_ROM ( 0x4033, 0x1360, "addron8139", "Addtron 8139", 0 ),
        PCI_ROM ( 0xffff, 0x8139, "clonse8139", "Cloned 8139", 0 ),
};

/** Realtek PCI driver */
struct pci_driver realtek_driver __pci_driver = {
        .ids = realtek_nics,
        .id_count = ( sizeof ( realtek_nics ) / sizeof ( realtek_nics[0] ) ),
        .probe = realtek_probe,
        .remove = realtek_remove,
};