myri10ge.c

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/************************************************* -*- linux-c -*-
 * Myricom 10Gb Network Interface Card Software
 * Copyright 2009, Myricom, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 ****************************************************************/

FILE_LICENCE ( GPL2_ONLY );

/*
 * Author: Glenn Brown <glenn@myri.com>
 */

/*
 * General Theory of Operation
 *
 * This is a minimal Myricom 10 gigabit Ethernet driver for network
 * boot.
 *
 * Initialization
 *
 * myri10ge_pci_probe() is called by gPXE during initialization.
 * Minimal NIC initialization is performed to minimize resources
 * consumed when the driver is resident but unused.
 *
 * Network Boot
 *
 * myri10ge_net_open() is called by gPXE before attempting to network
 * boot from the card.  Packet buffers are allocated and the NIC
 * interface is initialized.
 *
 * Transmit
 *
 * myri10ge_net_transmit() enqueues frames for transmission by writing
 * discriptors to the NIC's tx ring.  For simplicity and to avoid
 * copies, we always have the NIC DMA up the packet.  The sent I/O
 * buffer is released once the NIC signals myri10ge_interrupt_handler()
 * that the send has completed.
 *
 * Receive
 *
 * Receives are posted to the NIC's receive ring.  The NIC fills a
 * DMAable receive_completion ring with completion notifications.
 * myri10ge_net_poll() polls for these receive notifications, posts
 * replacement receive buffers to the NIC, and passes received frames
 * to netdev_rx().
 */

/*
 * Debugging levels:
 *      - DBG() is for any errors, i.e. failed alloc_iob(), malloc_dma(),
 *        TX overflow, corrupted packets, ...
 *      - DBG2() is for successful events, like packet received,
 *        packet transmitted, and other general notifications.
 *      - DBGP() prints the name of each called function on entry
 */

#include <stdint.h>

#include <byteswap.h>
#include <errno.h>
#include <gpxe/ethernet.h>
#include <gpxe/if_ether.h>
#include <gpxe/iobuf.h>
#include <gpxe/malloc.h>
#include <gpxe/netdevice.h>
#include <gpxe/pci.h>
#include <gpxe/timer.h>

#include "myri10ge_mcp.h"

/****************************************************************
 * Forward declarations
 ****************************************************************/

/* PCI driver entry points */

static int      myri10ge_pci_probe ( struct pci_device*,
                                     const struct pci_device_id* );
static void     myri10ge_pci_remove ( struct pci_device* );

/* Network device operations */

static void     myri10ge_net_close ( struct net_device* );
static void     myri10ge_net_irq ( struct net_device*, int enable );
static int      myri10ge_net_open ( struct net_device* );
static void     myri10ge_net_poll ( struct net_device* );
static int      myri10ge_net_transmit ( struct net_device*, struct io_buffer* );

/****************************************************************
 * Constants
 ****************************************************************/

/* Maximum ring indices, used to wrap ring indices.  These must be 2**N-1. */

#define MYRI10GE_TRANSMIT_WRAP                  1U
#define MYRI10GE_RECEIVE_WRAP                   7U
#define MYRI10GE_RECEIVE_COMPLETION_WRAP        31U

/****************************************************************
 * Driver internal data types.
 ****************************************************************/

/* Structure holding all DMA buffers for a NIC, which we will
   allocated as contiguous read/write DMAable memory when the NIC is
   initialized. */

struct myri10ge_dma_buffers
{
        /* The NIC DMAs receive completion notifications into this ring */

        mcp_slot_t receive_completion[1+MYRI10GE_RECEIVE_COMPLETION_WRAP];

        /* Interrupt details are DMAd here before interrupting. */

        mcp_irq_data_t irq_data; /* 64B */

        /* NIC command completion status is DMAd here. */

        mcp_cmd_response_t command_response; /* 8B */
};

struct myri10ge_private
{
        /* Interrupt support */

        uint32  *irq_claim;     /* in NIC SRAM */
        uint32  *irq_deassert;  /* in NIC SRAM */

        /* DMA buffers. */

        struct myri10ge_dma_buffers     *dma;

        /*
         * Transmit state.
         *
         * The counts here are uint32 for easy comparison with
         * priv->dma->irq_data.send_done_count and with each other.
         */

        mcp_kreq_ether_send_t   *transmit_ring; /* in NIC SRAM */
        uint32                   transmit_ring_wrap;
        uint32                   transmits_posted;
        uint32                   transmits_done;
        struct io_buffer        *transmit_iob[1 + MYRI10GE_TRANSMIT_WRAP];

        /*
         * Receive state.
         */

        mcp_kreq_ether_recv_t   *receive_post_ring;     /* in NIC SRAM */
        unsigned int             receive_post_ring_wrap;
        unsigned int             receives_posted;
        unsigned int             receives_done;
        struct io_buffer        *receive_iob[1 + MYRI10GE_RECEIVE_WRAP];

        /* Address for writing commands to the firmware.
           BEWARE: the value must be written 32 bits at a time. */

        mcp_cmd_t       *command;
};

/****************************************************************
 * Driver internal functions.
 ****************************************************************/

/* Print ring status when debugging.  Use this only after a printed
   value changes. */

#define DBG2_RINGS( priv )                                              \
        DBG2 ( "tx %x/%x rx %x/%x in %s() \n",                          \
               ( priv ) ->transmits_done, ( priv ) -> transmits_posted, \
               ( priv ) ->receives_done, ( priv ) -> receives_posted,   \
               __FUNCTION__ )

/*
 * Return a pointer to the driver private data for a network device.
 *
 * @v netdev    Network device created by this driver.
 * @ret priv    The corresponding driver private data.
 */
static inline struct myri10ge_private *myri10ge_priv ( struct net_device *nd )
{
        /* Our private data always follows the network device in memory,
           since we use alloc_netdev() to allocate the storage. */

        return ( struct myri10ge_private * ) ( nd + 1 );
}

/*
 * Pass a receive buffer to the NIC to be filled.
 *
 * @v priv      The network device to receive the buffer.
 * @v iob       The I/O buffer to fill.
 *
 * Receive buffers are filled in FIFO order.
 */
static void myri10ge_post_receive ( struct myri10ge_private *priv,
                                    struct io_buffer *iob )
{
        unsigned int             receives_posted;
        mcp_kreq_ether_recv_t   *request;

        /* Record the posted I/O buffer, to be passed to netdev_rx() on
           receive. */

        receives_posted = priv->receives_posted;
        priv->receive_iob[receives_posted & MYRI10GE_RECEIVE_WRAP] = iob;

        /* Post the receive. */

        request = &priv->receive_post_ring[receives_posted
                                           & priv->receive_post_ring_wrap];
        request->addr_high = 0;
        wmb();
        request->addr_low = htonl ( virt_to_bus ( iob->data ) );
        priv->receives_posted = ++receives_posted;
}

/*
 * Execute a command on the NIC.
 *
 * @v priv      NIC to perform the command.
 * @v cmd       The command to perform.
 * @v data      I/O copy buffer for parameters/results
 * @ret rc      0 on success, else an error code.
 */
static int myri10ge_command ( struct myri10ge_private *priv,
                              uint32 cmd,
                              uint32 data[3] )
{
        int                              i;
        mcp_cmd_t                       *command;
        uint32                           result;
        unsigned int                     slept_ms;
        volatile mcp_cmd_response_t     *response;

        DBGP ( "myri10ge_command ( ,%d, ) \n", cmd );
        command = priv->command;
        response = &priv->dma->command_response;

        /* Mark the command as incomplete. */

        response->result = 0xFFFFFFFF;

        /* Pass the command to the NIC. */

        command->cmd                = htonl ( cmd );
        command->data0              = htonl ( data[0] );
        command->data1              = htonl ( data[1] );
        command->data2              = htonl ( data[2] );
        command->response_addr.high = 0;
        command->response_addr.low
                = htonl ( virt_to_bus ( &priv->dma->command_response ) );
        for ( i=0; i<36; i+=4 )
                * ( uint32 * ) &command->pad[i] = 0;
        wmb();
        * ( uint32 * ) &command->pad[36] = 0;

        /* Wait up to 2 seconds for a response. */

        for ( slept_ms=0; slept_ms<2000; slept_ms++ ) {
                result = response->result;
                if ( result == 0 ) {
                        data[0] = ntohl ( response->data );
                        return 0;
                } else if ( result != 0xFFFFFFFF ) {
                        DBG ( "cmd%d:0x%x\n",
                              cmd,
                              ntohl ( response->result ) );
                        return -EIO;
                }
                udelay ( 1000 );
                rmb();
        }
        DBG ( "cmd%d:timed out\n", cmd );
        return -ETIMEDOUT;
}

/*
 * Handle any pending interrupt.
 *
 * @v netdev            Device being polled for interrupts.
 *
 * This is called periodically to let the driver check for interrupts.
 */
static void myri10ge_interrupt_handler ( struct net_device *netdev )
{
        struct myri10ge_private *priv;
        mcp_irq_data_t          *irq_data;
        uint8                    valid;

        priv = myri10ge_priv ( netdev );
        irq_data = &priv->dma->irq_data;

        /* Return if there was no interrupt. */

        rmb();
        valid = irq_data->valid;
        if ( !valid )
                return;
        DBG2 ( "irq " );

        /* Tell the NIC to deassert the interrupt and clear
           irq_data->valid.*/

        *priv->irq_deassert = 0;        /* any value is OK. */
        mb();

        /* Handle any new receives. */

        if ( valid & 1 ) {

                /* Pass the receive interrupt token back to the NIC. */

                DBG2 ( "rx " );
                *priv->irq_claim = htonl ( 3 );
                wmb();
        }

        /* Handle any sent packet by freeing its I/O buffer, now that
           we know it has been DMAd. */

        if ( valid & 2 ) {
                unsigned int nic_done_count;

                DBG2 ( "snt " );
                nic_done_count = ntohl ( priv->dma->irq_data.send_done_count );
                while ( priv->transmits_done != nic_done_count ) {
                        struct io_buffer *iob;

                        iob = priv->transmit_iob [priv->transmits_done
                                                  & MYRI10GE_TRANSMIT_WRAP];
                        DBG2 ( "%p ", iob );
                        netdev_tx_complete ( netdev, iob );
                        ++priv->transmits_done;
                }
        }

        /* Record any statistics update. */

        if ( irq_data->stats_updated ) {

                /* Update the link status. */

                DBG2 ( "stats " );
                if ( ntohl ( irq_data->link_up ) == MXGEFW_LINK_UP )
                        netdev_link_up ( netdev );
                else
                        netdev_link_down ( netdev );

                /* Ignore all error counters from the NIC. */
        }

        /* Wait for the interrupt to be deasserted, as indicated by
           irq_data->valid, which is set by the NIC after the deassert. */

        DBG2 ( "wait " );
        do {
                mb();
        } while ( irq_data->valid );

        /* Claim the interrupt to enable future interrupt generation. */

        DBG2 ( "claim\n" );
        * ( priv->irq_claim + 1 ) = htonl ( 3 );
        mb();
}

/* Constants for reading the STRING_SPECS via the Myricom
   Vendor Specific PCI configuration space capability. */

#define VS_ADDR ( vs + 0x18 )
#define VS_DATA ( vs + 0x14 )
#define VS_MODE ( vs + 0x10 )
#define         VS_MODE_READ32 0x3
#define         VS_MODE_LOCATE 0x8
#define                 VS_LOCATE_STRING_SPECS 0x3

/*
 * Read MAC address from its 'string specs' via the vendor-specific
 * capability.  (This capability allows NIC SRAM and ROM to be read
 * before it is mapped.)
 *
 * @v pci               The device.
 * @v mac               Buffer to store the MAC address.
 * @ret rc              Returns 0 on success, else an error code.
 */
static int mac_address_from_string_specs ( struct pci_device *pci,
                                                   uint8 mac[ETH_ALEN] )
{
        char string_specs[256];
        char *ptr, *limit;
        char *to = string_specs;
        uint32 addr;
        uint32 len;
        unsigned int vs;
        int mac_set = 0;

        /* Find the "vendor specific" capability. */

        vs = pci_find_capability ( pci, 9 );
        if ( vs == 0 ) {
                DBG ( "no VS\n" );
                return -ENOTSUP;
        }

        /* Locate the String specs in LANai SRAM. */

        pci_write_config_byte ( pci, VS_MODE, VS_MODE_LOCATE );
        pci_write_config_dword ( pci, VS_ADDR, VS_LOCATE_STRING_SPECS );
        pci_read_config_dword ( pci, VS_ADDR, &addr );
        pci_read_config_dword ( pci, VS_DATA, &len );
        DBG2 ( "ss@%x,%x\n", addr, len );

        /* Copy in the string specs.  Use 32-bit reads for performance. */

        if ( len > sizeof ( string_specs ) || ( len & 3 ) ) {
                DBG ( "SS too big\n" );
                return -ENOTSUP;
        }

        pci_write_config_byte ( pci, VS_MODE, VS_MODE_READ32 );
        while ( len >= 4 ) {
                uint32 tmp;

                pci_write_config_byte ( pci, VS_ADDR, addr );
                pci_read_config_dword ( pci, VS_DATA, &tmp );
                tmp = ntohl ( tmp );
                memcpy ( to, &tmp, 4 );
                to += 4;
                addr += 4;
                len -= 4;
        }
        pci_write_config_byte ( pci, VS_MODE, 0 );

        /* Parse the string specs. */

        DBG2 ( "STRING_SPECS:\n" );
        ptr = string_specs;
        limit = string_specs + sizeof ( string_specs );
        while ( *ptr != '\0' && ptr < limit ) {
                DBG2 ( "%s\n", ptr );
                if ( memcmp ( ptr, "MAC=", 4 ) == 0 ) {
                        unsigned int i;

                        ptr += 4;
                        for ( i=0; i<6; i++ ) {
                                if ( ( ptr + 2 ) > limit ) {
                                        DBG ( "bad MAC addr\n" );
                                        return -ENOTSUP;
                                }
                                mac[i] = strtoul ( ptr, &ptr, 16 );
                                ptr += 1;
                        }
                        mac_set = 1;
                }
                else
                        while ( ptr < limit && *ptr++ );
        }

        /* Verify we parsed all we need. */

        if ( !mac_set ) {
                DBG ( "no MAC addr\n" );
                return -ENOTSUP;
        }

        DBG2 ( "MAC %02x:%02x:%02x:%02x:%02x:%02x\n",
               mac[0], mac[1], mac[2], mac[3], mac[4], mac[5] );

        return 0;
}

/****************************************************************
 * gPXE PCI Device Driver API functions
 ****************************************************************/

/*
 * Initialize the PCI device.
 *
 * @v pci               The device's associated pci_device structure.
 * @v id                The PCI device + vendor id.
 * @ret rc              Returns zero if successfully initialized.
 *
 * This function is called very early on, while gPXE is initializing.
 * This is a gPXE PCI Device Driver API function.
 */
static int myri10ge_pci_probe ( struct pci_device *pci,
                                const struct pci_device_id *id __unused )
{
        static struct net_device_operations myri10ge_operations = {
                .open     = myri10ge_net_open,
                .close    = myri10ge_net_close,
                .transmit = myri10ge_net_transmit,
                .poll     = myri10ge_net_poll,
                .irq      = myri10ge_net_irq
        };

        const char *dbg;
        int rc;
        struct net_device *netdev;
        struct myri10ge_private *priv;

        DBGP ( "myri10ge_pci_probe: " );

        netdev = alloc_etherdev ( sizeof ( *priv ) );
        if ( !netdev ) {
                rc = -ENOMEM;
                dbg = "alloc_etherdev";
                goto abort_with_nothing;
        }

        netdev_init ( netdev, &myri10ge_operations );
        priv = myri10ge_priv ( netdev );

        pci_set_drvdata ( pci, netdev );
        netdev->dev = &pci->dev;

        /* Make sure interrupts are disabled. */

        myri10ge_net_irq ( netdev, 0 );

        /* Read the NIC HW address. */

        rc = mac_address_from_string_specs ( pci, netdev->hw_addr );
        if ( rc ) {
                dbg = "mac_from_ss";
                goto abort_with_netdev_init;
        }
        DBGP ( "mac " );

        /* Enable bus master, etc. */

        adjust_pci_device ( pci );
        DBGP ( "pci " );

        /* Register the initialized network device. */

        rc = register_netdev ( netdev );
        if ( rc ) {
                dbg = "register_netdev";
                goto abort_with_netdev_init;
        }

        DBGP ( "done\n" );

        return 0;

abort_with_netdev_init:
        netdev_nullify ( netdev );
        netdev_put ( netdev );
abort_with_nothing:
        DBG ( "%s:%s\n", dbg, strerror ( rc ) );
        return rc;
}

/*
 * Remove a device from the PCI device list.
 *
 * @v pci               PCI device to remove.
 *
 * This is a PCI Device Driver API function.
 */
static void myri10ge_pci_remove ( struct pci_device *pci )
{
        struct net_device       *netdev;

        DBGP ( "myri10ge_pci_remove\n" );
        netdev = pci_get_drvdata ( pci );

        unregister_netdev ( netdev );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
}

/****************************************************************
 * gPXE Network Device Driver Operations
 ****************************************************************/

/*
 * Close a network device.
 *
 * @v netdev            Device to close.
 *
 * This is a gPXE Network Device Driver API function.
 */
static void myri10ge_net_close ( struct net_device *netdev )
{
        struct myri10ge_private *priv;
        uint32                   data[3];

        DBGP ( "myri10ge_net_close\n" );
        priv = myri10ge_priv ( netdev );

        /* disable interrupts */

        myri10ge_net_irq ( netdev, 0 );

        /* Reset the NIC interface, so we won't get any more events from
           the NIC. */

        myri10ge_command ( priv, MXGEFW_CMD_RESET, data );

        /* Free receive buffers that were never filled. */

        while ( priv->receives_done != priv->receives_posted ) {
                free_iob ( priv->receive_iob[priv->receives_done
                                             & MYRI10GE_RECEIVE_WRAP] );
                ++priv->receives_done;
        }

        /* Release DMAable memory. */

        free_dma ( priv->dma, sizeof ( *priv->dma ) );

        /* Erase all state from the open. */

        memset ( priv, 0, sizeof ( *priv ) );

        DBG2_RINGS ( priv );
}

/*
 * Enable or disable IRQ masking.
 *
 * @v netdev            Device to control.
 * @v enable            Zero to mask off IRQ, non-zero to enable IRQ.
 *
 * This is a gPXE Network Driver API function.
 */
static void myri10ge_net_irq ( struct net_device *netdev, int enable )
{
        struct pci_device       *pci_dev;
        uint16                   val;

        DBGP ( "myri10ge_net_irq\n" );
        pci_dev = ( struct pci_device * ) netdev->dev;

        /* Adjust the Interrupt Disable bit in the Command register of the
           PCI Device. */

        pci_read_config_word ( pci_dev, PCI_COMMAND, &val );
        if ( enable )
                val &= ~PCI_COMMAND_INTX_DISABLE;
        else
                val |= PCI_COMMAND_INTX_DISABLE;
        pci_write_config_word ( pci_dev, PCI_COMMAND, val );
}

/*
 * Opens a network device.
 *
 * @v netdev            Device to be opened.
 * @ret rc              Non-zero if failed to open.
 *
 * This enables tx and rx on the device.
 * This is a gPXE Network Device Driver API function.
 */
static int myri10ge_net_open ( struct net_device *netdev )
{
        const char              *dbg;   /* printed upon error return */
        int                      rc;
        struct io_buffer        *iob;
        struct myri10ge_private *priv;
        uint32                   data[3];
        struct pci_device       *pci_dev;
        void                    *membase;

        DBGP ( "myri10ge_net_open\n" );
        priv    = myri10ge_priv ( netdev );
        pci_dev = ( struct pci_device * ) netdev->dev;
        membase = phys_to_virt ( pci_dev->membase );

        /* Compute address for passing commands to the firmware. */

        priv->command = membase + MXGEFW_ETH_CMD;

        /* Ensure interrupts are disabled. */

        myri10ge_net_irq ( netdev, 0 );

        /* Allocate cleared DMAable buffers. */

        priv->dma = malloc_dma ( sizeof ( *priv->dma ) , 128 );
        if ( !priv->dma ) {
                rc = -ENOMEM;
                dbg = "DMA";
                goto abort_with_nothing;
        }
        memset ( priv->dma, 0, sizeof ( *priv->dma ) );

        /* Simplify following code. */

#define TRY( prefix, base, suffix ) do {                \
                rc = myri10ge_command ( priv,           \
                                        MXGEFW_         \
                                        ## prefix       \
                                        ## base         \
                                        ## suffix,      \
                                        data );         \
                if ( rc ) {                             \
                        dbg = #base;                    \
                        goto abort_with_dma;            \
                }                                       \
        } while ( 0 )

        /* Send a reset command to the card to see if it is alive,
           and to reset its queue state. */

        TRY ( CMD_, RESET , );

        /* Set the interrupt queue size. */

        data[0] = ( sizeof ( priv->dma->receive_completion )
                    | MXGEFW_CMD_SET_INTRQ_SIZE_FLAG_NO_STRICT_SIZE_CHECK );
        TRY ( CMD_SET_ , INTRQ_SIZE , );

        /* Set the interrupt queue DMA address. */

        data[0] = virt_to_bus ( &priv->dma->receive_completion );
        data[1] = 0;
        TRY ( CMD_SET_, INTRQ_DMA, );

        /* Get the NIC interrupt claim address. */

        TRY ( CMD_GET_, IRQ_ACK, _OFFSET );
        priv->irq_claim = membase + data[0];

        /* Get the NIC interrupt assert address. */

        TRY ( CMD_GET_, IRQ_DEASSERT, _OFFSET );
        priv->irq_deassert = membase + data[0];

        /* Disable interrupt coalescing, which is inappropriate for the
           minimal buffering we provide. */

        TRY ( CMD_GET_, INTR_COAL, _DELAY_OFFSET );
        * ( ( uint32 * ) ( membase + data[0] ) ) = 0;

        /* Set the NIC mac address. */

        data[0] = ( netdev->ll_addr[0] << 24
                    | netdev->ll_addr[1] << 16
                    | netdev->ll_addr[2] << 8
                    | netdev->ll_addr[3] );
        data[1] = ( ( netdev->ll_addr[4] << 8 )
                     | netdev->ll_addr[5] );
        TRY ( SET_ , MAC_ADDRESS , );

        /* Enable multicast receives, because some gPXE clients don't work
           without multicast. . */

        TRY ( ENABLE_ , ALLMULTI , );

        /* Disable Ethernet flow control, so the NIC cannot deadlock the
           network under any circumstances. */

        TRY ( DISABLE_ , FLOW , _CONTROL );

        /* Compute transmit ring sizes. */

        data[0] = 0;            /* slice 0 */
        TRY ( CMD_GET_, SEND_RING, _SIZE );
        priv->transmit_ring_wrap
                = data[0] / sizeof ( mcp_kreq_ether_send_t ) - 1;
        if ( priv->transmit_ring_wrap
             & ( priv->transmit_ring_wrap + 1 ) ) {
                rc = -EPROTO;
                dbg = "TX_RING";
                goto abort_with_dma;
        }

        /* Compute receive ring sizes. */

        data[0] = 0;            /* slice 0 */
        TRY ( CMD_GET_ , RX_RING , _SIZE );
        priv->receive_post_ring_wrap = data[0] / sizeof ( mcp_dma_addr_t ) - 1;
        if ( priv->receive_post_ring_wrap
             & ( priv->receive_post_ring_wrap + 1 ) ) {
                rc = -EPROTO;
                dbg = "RX_RING";
                goto abort_with_dma;
        }

        /* Get NIC transmit ring address. */

        data[0] = 0;            /* slice 0. */
        TRY ( CMD_GET_, SEND, _OFFSET );
        priv->transmit_ring = membase + data[0];

        /* Get the NIC receive ring address. */

        data[0] = 0;            /* slice 0. */
        TRY ( CMD_GET_, SMALL_RX, _OFFSET );
        priv->receive_post_ring = membase + data[0];

        /* Set the Nic MTU. */

        data[0] = ETH_FRAME_LEN;
        TRY ( CMD_SET_, MTU, );

        /* Tell the NIC our buffer sizes. ( We use only small buffers, so we
           set both buffer sizes to the same value, which will force all
           received frames to use small buffers. ) */

        data[0] = MXGEFW_PAD + ETH_FRAME_LEN;
        TRY ( CMD_SET_, SMALL_BUFFER, _SIZE );
        data[0] = MXGEFW_PAD + ETH_FRAME_LEN;
        TRY ( CMD_SET_, BIG_BUFFER, _SIZE );

        /* Tell firmware where to DMA IRQ data */

        data[0] = virt_to_bus ( &priv->dma->irq_data );
        data[1] = 0;
        data[2] = sizeof ( priv->dma->irq_data );
        TRY ( CMD_SET_, STATS_DMA_V2, );

        /* Post receives. */

        while ( priv->receives_posted <= MYRI10GE_RECEIVE_WRAP ) {

                /* Reserve 2 extra bytes at the start of packets, since
                   the firmware always skips the first 2 bytes of the buffer
                   so TCP headers will be aligned. */

                iob = alloc_iob ( MXGEFW_PAD + ETH_FRAME_LEN );
                if ( !iob ) {
                        rc = -ENOMEM;
                        dbg = "alloc_iob";
                        goto abort_with_receives_posted;
                }
                iob_reserve ( iob, MXGEFW_PAD );
                myri10ge_post_receive ( priv, iob );
        }

        /* Bring up the link. */

        TRY ( CMD_, ETHERNET_UP, );

        DBG2_RINGS ( priv );
        return 0;

abort_with_receives_posted:
        while ( priv->receives_posted-- )
                free_iob ( priv->receive_iob[priv->receives_posted] );
abort_with_dma:
        /* Because the link is not up, we don't have to reset the NIC here. */
        free_dma ( priv->dma, sizeof ( *priv->dma ) );
abort_with_nothing:
        /* Erase all signs of the failed open. */
        memset ( priv, 0, sizeof ( *priv ) );
        DBG ( "%s: %s\n", dbg, strerror ( rc ) );
        return ( rc );
}

/*
 * This function allows a driver to process events during operation.
 *
 * @v netdev            Device being polled.
 *
 * This is called periodically by gPXE to let the driver check the status of
 * transmitted packets and to allow the driver to check for received packets.
 * This is a gPXE Network Device Driver API function.
 */
static void myri10ge_net_poll ( struct net_device *netdev )
{
        struct io_buffer                *iob;
        struct io_buffer                *replacement;
        struct myri10ge_dma_buffers     *dma;
        struct myri10ge_private         *priv;
        unsigned int                     length;
        unsigned int                     orig_receives_posted;

        DBGP ( "myri10ge_net_poll\n" );
        priv = myri10ge_priv ( netdev );
        dma  = priv->dma;

        /* Process any pending interrupt. */

        myri10ge_interrupt_handler ( netdev );

        /* Pass up received frames, but limit ourselves to receives posted
           before this function was called, so we cannot livelock if
           receives are arriving faster than we process them. */

        orig_receives_posted = priv->receives_posted;
        while ( priv->receives_done != orig_receives_posted ) {

                /* Stop if there is no pending receive. */

                length = ntohs ( dma->receive_completion
                                 [priv->receives_done
                                  & MYRI10GE_RECEIVE_COMPLETION_WRAP]
                                 .length );
                if ( length == 0 )
                        break;

                /* Allocate a replacement buffer.  If none is available,
                   stop passing up packets until a buffer is available.

                   Reserve 2 extra bytes at the start of packets, since
                   the firmware always skips the first 2 bytes of the buffer
                   so TCP headers will be aligned. */

                replacement = alloc_iob ( MXGEFW_PAD + ETH_FRAME_LEN );
                if ( !replacement ) {
                        DBG ( "NO RX BUF\n" );
                        break;
                }
                iob_reserve ( replacement, MXGEFW_PAD );

                /* Pass up the received frame. */

                iob = priv->receive_iob[priv->receives_done
                                        & MYRI10GE_RECEIVE_WRAP];
                iob_put ( iob, length );
                netdev_rx ( netdev, iob );

                /* We have consumed the packet, so clear the receive
                   notification. */

                dma->receive_completion [priv->receives_done
                                         & MYRI10GE_RECEIVE_COMPLETION_WRAP]
                        .length = 0;
                wmb();

                /* Replace the passed-up I/O buffer. */

                myri10ge_post_receive ( priv, replacement );
                ++priv->receives_done;
                DBG2_RINGS ( priv );
        }
}

/*
 * This transmits a packet.
 *
 * @v netdev            Device to transmit from.
 * @v iobuf             Data to transmit.
 * @ret rc              Non-zero if failed to transmit.
 *
 * This is a gPXE Network Driver API function.
 */
static int myri10ge_net_transmit ( struct net_device *netdev,
                                   struct io_buffer *iobuf )
{
        mcp_kreq_ether_send_t   *kreq;
        size_t                   len;
        struct myri10ge_private *priv;
        uint32                   transmits_posted;

        DBGP ( "myri10ge_net_transmit\n" );
        priv = myri10ge_priv ( netdev );

        /* Confirm space in the send ring. */

        transmits_posted = priv->transmits_posted;
        if ( transmits_posted - priv->transmits_done
             > MYRI10GE_TRANSMIT_WRAP ) {
                DBG ( "TX ring full\n" );
                return -ENOBUFS;
        }

        DBG2 ( "TX %p+%d ", iobuf->data, iob_len ( iobuf ) );
        DBG2_HD ( iobuf->data, 14 );

        /* Record the packet being transmitted, so we can later report
           send completion. */

        priv->transmit_iob[transmits_posted & MYRI10GE_TRANSMIT_WRAP] = iobuf;

        /* Copy and pad undersized frames, because the NIC does not pad,
           and we would rather copy small frames than do a gather. */

        len = iob_len ( iobuf );
        if ( len < ETH_ZLEN ) {
                iob_pad ( iobuf, ETH_ZLEN );
                len = ETH_ZLEN;
        }

        /* Enqueue the packet by writing a descriptor to the NIC.
           This is a bit tricky because the HW requires 32-bit writes,
           but the structure has smaller fields. */

        kreq = &priv->transmit_ring[transmits_posted
                                    & priv->transmit_ring_wrap];
        kreq->addr_high = 0;
        kreq->addr_low = htonl ( virt_to_bus ( iobuf->data ) );
        ( ( uint32 * ) kreq ) [2] = htonl (
                0x0000 << 16     /* pseudo_header_offset */
                | ( len & 0xFFFF ) /* length */
                );
        wmb();
        ( ( uint32 * ) kreq ) [3] = htonl (
                0x00 << 24      /* pad */
                | 0x01 << 16    /* rdma_count */
                | 0x00 << 8     /* cksum_offset */
                | ( MXGEFW_FLAGS_SMALL
                    | MXGEFW_FLAGS_FIRST
                    | MXGEFW_FLAGS_NO_TSO ) /* flags */
                );
        wmb();

        /* Mark the slot as consumed and return. */

        priv->transmits_posted = ++transmits_posted;
        DBG2_RINGS ( priv );
        return 0;
}

static struct pci_device_id myri10ge_nics[] = {
        /* Each of these macros must be a single line to satisfy a script. */
        PCI_ROM ( 0x14c1, 0x0008, "myri10ge", "Myricom 10Gb Ethernet Adapter", 0 ) ,
};

struct pci_driver myri10ge_driver __pci_driver = {
        .ids      = myri10ge_nics,
        .id_count = ( sizeof ( myri10ge_nics ) / sizeof ( myri10ge_nics[0] ) ) ,
        .probe    = myri10ge_pci_probe,
        .remove   = myri10ge_pci_remove
};

/*
 * Local variables:
 *  c-basic-offset: 8
 *  c-indent-level: 8
 *  tab-width: 8
 * End:
 */