Merge branch 'master' of git://github.com/illumos/illumos-gate

[unleashed.git] / usr / src / grub / grub-0.97 / netboot / undi.c

/**************************************************************************
Etherboot -  BOOTP/TFTP Bootstrap Program
UNDI NIC driver for Etherboot

This file Copyright (C) 2003 Michael Brown <mbrown@fensystems.co.uk>
of Fen Systems Ltd. (http://www.fensystems.co.uk/).  All rights
reserved.

$Id: undi.c,v 1.8 2003/10/25 13:54:53 mcb30 Exp $
***************************************************************************/

/*
 * 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, or (at
 * your option) any later version.
 */

/* to get some global routines like printf */
#include "etherboot.h"
/* to get the interface to the body of the program */
#include "nic.h"
/* to get the PCI support functions, if this is a PCI NIC */
#include "pci.h"
/* UNDI and PXE defines.  Includes pxe.h. */
#include "undi.h"
/* 8259 PIC defines */
#include "pic8259.h"
#include "bootp.h"
#include "tftp.h"
#include "shared.h"

/* NIC specific static variables go here */
static undi_t undi = { NULL, NULL, NULL, NULL, NULL, NULL, NULL,
                       NULL, NULL, 0, NULL, 0, NULL,
                       0, 0, 0, 0,
                       { 0, 0, 0, NULL, 0, 0, 0, 0, 0, 0, 0, NULL },
                       IRQ_NONE };
static undi_base_mem_data_t undi_base_mem_data;

#define UNDI_HEAP (void *)(512 << 10)

/* Function prototypes */
int allocate_base_mem_data ( void );
int free_base_mem_data ( void );
int eb_pxenv_undi_shutdown ( void );
int eb_pxenv_stop_undi ( void );
int undi_unload_base_code ( void );
int undi_full_shutdown ( void );
int eb_pxenv_get_cached_info (uint8_t, void **info);

/**************************************************************************
 * Utility functions
 **************************************************************************/

/* Checksum a block.
 */

uint8_t checksum ( void *block, size_t size ) {
        uint8_t sum = 0;
        uint16_t i = 0;
        for ( i = 0; i < size; i++ ) {
                sum += ( ( uint8_t * ) block )[i];
        }
        return sum;
}

/* Print the status of a !PXE structure
 */

void pxe_dump ( void ) {
#ifdef TRACE_UNDI
        printf ( "API %hx:%hx St %hx:%hx UD %hx:%hx UC %hx:%hx "
                 "BD %hx:%hx BC %hx:%hx\n",
                 undi.pxe->EntryPointSP.segment, undi.pxe->EntryPointSP.offset,
                 undi.pxe->Stack.Seg_Addr, undi.pxe->Stack.Seg_Size,
                 undi.pxe->UNDIData.Seg_Addr, undi.pxe->UNDIData.Seg_Size,
                 undi.pxe->UNDICode.Seg_Addr, undi.pxe->UNDICode.Seg_Size,
                 undi.pxe->BC_Data.Seg_Addr, undi.pxe->BC_Data.Seg_Size,
                 undi.pxe->BC_Code.Seg_Addr, undi.pxe->BC_Code.Seg_Size );
#endif
}

/* Allocate/free space for structures that must reside in base memory
 */

int allocate_base_mem_data ( void ) {
        /* In GRUB, anything is in base address, so we do not need
         * allocate anything */
        undi.base_mem_data = &undi_base_mem_data;
        memset ( undi.base_mem_data, 0, sizeof(undi_base_mem_data_t) );
        undi.undi_call_info = &undi.base_mem_data->undi_call_info;
        undi.pxs = &undi.base_mem_data->pxs;
        undi.xmit_data = &undi.base_mem_data->xmit_data;
        undi.xmit_buffer = undi.base_mem_data->xmit_buffer;
#if 0                           /* Etherboot Code */
        /* Allocate space in base memory.
         * Initialise pointers to base memory structures.
         */
        if ( undi.base_mem_data == NULL ) {
                undi.base_mem_data =
                        allot_base_memory ( sizeof(undi_base_mem_data_t) +
                                            TRIVIAL_IRQ_HANDLER_SIZE );
                if ( undi.base_mem_data == NULL ) {
                        printf ( "Failed to allocate base memory\n" );
                        free_base_mem_data();
                        return 0;
                }
                memset ( undi.base_mem_data, 0, sizeof(undi_base_mem_data_t) );
                undi.undi_call_info = &undi.base_mem_data->undi_call_info;
                undi.pxs = &undi.base_mem_data->pxs;
                undi.xmit_data = &undi.base_mem_data->xmit_data;
                undi.xmit_buffer = undi.base_mem_data->xmit_buffer;
                copy_trivial_irq_handler ( undi.base_mem_data->irq_handler,
                                           TRIVIAL_IRQ_HANDLER_SIZE );
        }
#endif  /* Etherboot Code */
        return 1;
}

int free_base_mem_data ( void ) {
        /* Just pretend to free something :-) */
        undi.base_mem_data = NULL;
        undi.undi_call_info = NULL;
        undi.pxs = NULL;
        undi.xmit_data = NULL;
        undi.xmit_buffer = NULL;
#if 0                           /* Etherboot Code */
        if ( undi.base_mem_data != NULL ) {
                forget_base_memory ( undi.base_mem_data,
                                     sizeof(undi_base_mem_data_t) +
                                     TRIVIAL_IRQ_HANDLER_SIZE );
                undi.base_mem_data = NULL;
                undi.undi_call_info = NULL;
                undi.pxs = NULL;
                undi.xmit_data = NULL;
                undi.xmit_buffer = NULL;
                copy_trivial_irq_handler ( NULL, 0 );
        }
#endif  /* Etherboot Code */
        return 1;
}

void assemble_firing_squad ( firing_squad_lineup_t *lineup,
                             void *start, size_t size,
                             firing_squad_shoot_t shoot ) {
        int target;
        int index;
        int bit;
        int start_kb = virt_to_phys(start) >> 10;
        int end_kb = ( virt_to_phys(start+size) + (1<<10) - 1 ) >> 10;
        
        for ( target = start_kb; target <= end_kb; target++ ) {
                index = FIRING_SQUAD_TARGET_INDEX ( target );
                bit = FIRING_SQUAD_TARGET_BIT ( target );
                lineup->targets[index] = ( shoot << bit ) |
                        ( lineup->targets[index] & ~( 1 << bit ) );
        }
}

void shoot_targets ( firing_squad_lineup_t *lineup ) {
        int shoot_this_target = 0;
        int shoot_last_target = 0;
        int start_target = 0;
        int target;

        for ( target = 0; target <= 640; target++ ) {
                shoot_this_target = ( target == 640 ? 0 : 
                      ( 1 << FIRING_SQUAD_TARGET_BIT(target) ) &
                      lineup->targets[FIRING_SQUAD_TARGET_INDEX(target)] );
                if ( shoot_this_target && !shoot_last_target ) {
                        start_target = target;
                } else if ( shoot_last_target && !shoot_this_target ) {
                        size_t range_size = ( target - start_target ) << 10;
                        forget_base_memory ( phys_to_virt( start_target<<10 ),
                                             range_size );
                }
                shoot_last_target = shoot_this_target;
        }
}

/* Debug macros
 */

#ifdef TRACE_UNDI
#define DBG(...) printf ( __VA_ARGS__ )
#else
#define DBG(...)
#endif

#define UNDI_STATUS(pxs) ( (pxs)->Status == PXENV_EXIT_SUCCESS ? \
                              "SUCCESS" : \
                              ( (pxs)->Status == PXENV_EXIT_FAILURE ? \
                                "FAILURE" : "UNKNOWN" ) )

/**************************************************************************
 * Base memory scanning functions
 **************************************************************************/

/* Locate the $PnP structure indicating a PnP BIOS.
 */

int hunt_pnp_bios ( void ) {
        uint32_t off = 0x10000;

        DBG ( "Hunting for PnP BIOS..." );
        while ( off > 0 ) {
                off -= 16;
                undi.pnp_bios = (pnp_bios_t *) phys_to_virt ( 0xf0000 + off );
                if ( undi.pnp_bios->signature == PNP_BIOS_SIGNATURE ) {
                        DBG ( "found $PnP at f000:%hx...", off );
                        if ( checksum(undi.pnp_bios,sizeof(pnp_bios_t)) !=0) {
                                DBG ( "invalid checksum\n..." );
                                continue;
                        }
                        DBG ( "ok\n" );
                        return 1;
                }
        }
        DBG ( "none found\n" );
        undi.pnp_bios = NULL;
        return 0;
}

/* Locate the !PXE structure indicating a loaded UNDI driver.
 */

int hunt_pixie ( void ) {
        static uint32_t ptr = 0;
        pxe_t *pxe = NULL;

        DBG ( "Hunting for pixies..." );
        if ( ptr == 0 ) ptr = 0xa0000;
        while ( ptr > 0x10000 ) {
                ptr -= 16;
                pxe = (pxe_t *) phys_to_virt ( ptr );
                if ( memcmp ( pxe->Signature, "!PXE", 4 ) == 0 ) {
                        DBG ( "found !PXE at %x...", ptr );
                        if ( checksum ( pxe, sizeof(pxe_t) ) != 0 ) {
                                DBG ( "invalid checksum\n..." );
                                continue;
                        }
                        if ( ptr < get_free_base_memory() ) {
                                DBG ( "in free base memory!\n\n"
                                         "WARNING: a valid !PXE structure was "
                                         "found in an area of memory marked "
                                         "as free!\n\n" );
                                undi.pxe = pxe;
                                pxe_dump();
                                undi.pxe = NULL;
                                DBG ( "\nIgnoring and continuing, but this "
                                         "may cause problems later!\n\n" );
                                continue;
                        }
                        DBG ( "ok\n" );
                        undi.pxe = pxe;
                        pxe_dump();
                        DBG ( "Resetting pixie...\n" );
                        undi_unload_base_code();
                        eb_pxenv_stop_undi();
                        pxe_dump();
                        return 1;
                }
        }
        DBG ( "none found\n" );
        ptr = 0;
        return 0;
}

/* Locate PCI PnP ROMs.
 */

int hunt_rom ( void ) {
        static uint32_t ptr = 0;

        DBG ( "Hunting for ROMs..." );
        if ( ptr == 0 ) ptr = 0x100000;
        while ( ptr > 0x0c0000 ) {
                ptr -= 0x800;
                undi.rom = ( rom_t * ) phys_to_virt ( ptr );
                if ( undi.rom->signature == ROM_SIGNATURE ) {
                        pcir_header_t *pcir_header = NULL;
                        pnp_header_t *pnp_header = NULL;

                        DBG ( "found 55AA at %x...", ptr );
                        if ( undi.rom->pcir_off == 0 ) {
                                DBG ( "not a PCI ROM\n..." );
                                continue;
                        }
                        pcir_header = (pcir_header_t*)( ( void * ) undi.rom +
                                                        undi.rom->pcir_off );
                        if ( pcir_header->signature != PCIR_SIGNATURE ) {
                                DBG ( "invalid PCI signature\n..." );
                                continue;
                        }
                        DBG ( "PCI:%hx:%hx...", pcir_header->vendor_id,
                                 pcir_header->device_id );
                        if ( ( pcir_header->vendor_id != undi.pci.vendor ) ||
                             ( pcir_header->device_id != undi.pci.dev_id ) ) {
                                DBG ( "not me (%hx:%hx)\n...",
                                         undi.pci.vendor,
                                         undi.pci.dev_id );
                                continue;
                        }
                        if ( undi.rom->pnp_off == 0 ) {
                                DBG ( "not a PnP ROM\n..." );
                                continue;
                        }
                        pnp_header = (pnp_header_t*)( ( void * ) undi.rom +
                                                         undi.rom->pnp_off );
                        if ( pnp_header->signature != PNP_SIGNATURE ) {
                                DBG ( "invalid $PnP signature\n..." );
                                continue;
                        }
                        if ( checksum(pnp_header,sizeof(pnp_header_t)) != 0 ) {
                                DBG ( "invalid PnP checksum\n..." );
                                continue;
                        }
                        DBG ( "ok\n");
                        printf ("ROM %s by %s\n",
                                 pnp_header->product_str_off==0 ? "(unknown)" :
                                 (void*)undi.rom+pnp_header->product_str_off,
                                 pnp_header->manuf_str_off==0 ? "(unknown)" :
                                 (void*)undi.rom+pnp_header->manuf_str_off );
                        return 1;
                }
        }
        DBG ( "none found\n" );
        ptr = 0;
        undi.rom = NULL;
        return 0;
}

/* Locate ROMs containing UNDI drivers.
 */

int hunt_undi_rom ( void ) {
        while ( hunt_rom() ) {
                if ( undi.rom->undi_rom_id_off == 0 ) {
                        DBG ( "Not a PXE ROM\n" );
                        continue;
                }
                undi.undi_rom_id = (undi_rom_id_t *)
                        ( (void *)undi.rom + undi.rom->undi_rom_id_off );
                if ( undi.undi_rom_id->signature != UNDI_SIGNATURE ) {
                        DBG ( "Invalid UNDI signature\n" );
                        continue;
                }
                printf ( "Revision %d.%d.%d",
                         undi.undi_rom_id->undi_rev[2],
                         undi.undi_rom_id->undi_rev[1],
                         undi.undi_rom_id->undi_rev[0] );
                return 1;
        }
        return 0;
}

/**************************************************************************
 * Low-level UNDI API call wrappers
 **************************************************************************/

/* Make a real-mode UNDI API call to the UNDI routine at
 * routine_seg:routine_off, passing in three uint16 parameters on the
 * real-mode stack.
 * Calls the assembler wrapper routine __undi_call.
 */

static inline PXENV_EXIT_t _undi_call ( uint16_t routine_seg,
                                        uint16_t routine_off, uint16_t st0,
                                        uint16_t st1, uint16_t st2 ) {
        PXENV_EXIT_t ret = PXENV_EXIT_FAILURE;

        undi.undi_call_info->routine.segment = routine_seg;
        undi.undi_call_info->routine.offset = routine_off;
        undi.undi_call_info->stack[0] = st0;
        undi.undi_call_info->stack[1] = st1;
        undi.undi_call_info->stack[2] = st2;
        ret = __undi_call ( SEGMENT( undi.undi_call_info ),
                            OFFSET( undi.undi_call_info ) );

        /* UNDI API calls may rudely change the status of A20 and not
         * bother to restore it afterwards.  Intel is known to be
         * guilty of this.
         *
         * Note that we will return to this point even if A20 gets
         * screwed up by the UNDI driver, because Etherboot always
         * resides in an even megabyte of RAM.
         */
        gateA20_set();

        return ret;
}

/* Make a real-mode call to the UNDI loader routine at
 * routine_seg:routine_off, passing in the seg:off address of a
 * pxenv_structure on the real-mode stack.
 */

int undi_call_loader ( void ) {
        PXENV_EXIT_t pxenv_exit = PXENV_EXIT_FAILURE;
        
        pxenv_exit = _undi_call ( SEGMENT( undi.rom ),
                                  undi.undi_rom_id->undi_loader_off,
                                  OFFSET( undi.pxs ),
                                  SEGMENT( undi.pxs ),
                                  0 /* Unused for UNDI loader API */ );
        /* Return 1 for success, to be consistent with other routines */
        if ( pxenv_exit == PXENV_EXIT_SUCCESS ) return 1;
        DBG ( "UNDI loader call failed with status %#hx\n",
                 undi.pxs->Status );
        return 0;
}

/* Make a real-mode UNDI API call, passing in the opcode and the
 * seg:off address of a pxenv_structure on the real-mode stack.
 *
 * Two versions: undi_call() will automatically report any failure
 * codes, undi_call_silent() will not.
 */

int undi_call_silent ( uint16_t opcode ) {
        PXENV_EXIT_t pxenv_exit = PXENV_EXIT_FAILURE;

        pxenv_exit = _undi_call ( undi.pxe->EntryPointSP.segment,
                                  undi.pxe->EntryPointSP.offset,
                                  opcode,
                                  OFFSET( undi.pxs ),
                                  SEGMENT( undi.pxs ) );
        /* Return 1 for success, to be consistent with other routines */
        return pxenv_exit == PXENV_EXIT_SUCCESS ? 1 : 0;
}

int undi_call ( uint16_t opcode ) {
        if ( undi_call_silent ( opcode ) ) return 1;
        DBG ( "UNDI API call %#hx failed with status %#hx\n",
                 opcode, undi.pxs->Status );
        return 0;
}

/**************************************************************************
 * High-level UNDI API call wrappers
 **************************************************************************/

/* Install the UNDI driver from a located UNDI ROM.
 */

int undi_loader ( void ) {
        pxe_t *pxe = NULL;

        /* AX contains PCI bus:devfn (PCI specification) */
        undi.pxs->loader.ax = ( undi.pci.bus << 8 ) | undi.pci.devfn;
        /* BX and DX set to 0xffff for non-ISAPnP devices
         * (BIOS boot specification)
         */
        undi.pxs->loader.bx = 0xffff;
        undi.pxs->loader.dx = 0xffff;
        /* ES:DI points to PnP BIOS' $PnP structure
         * (BIOS boot specification)
         */
        undi.pxs->loader.es = 0xf000;
        undi.pxs->loader.di = virt_to_phys ( undi.pnp_bios ) - 0xf0000;

        /* Allocate space for UNDI driver's code and data segments */
        undi.driver_code_size = undi.undi_rom_id->code_size;
        undi.driver_code = UNDI_HEAP;
        if ( undi.driver_code == NULL ) {
                printf ( "Could not allocate %d bytes for UNDI code segment\n",
                         undi.driver_code_size );
                return 0;
        }
        undi.pxs->loader.undi_cs = SEGMENT( undi.driver_code );

        undi.driver_data_size = undi.undi_rom_id->data_size;
        undi.driver_data = (void *)((((unsigned long)UNDI_HEAP + undi.undi_rom_id->code_size) | (1024 -1)) + 1);
        if ( undi.driver_data == NULL ) {
                printf ( "Could not allocate %d bytes for UNDI code segment\n",
                         undi.driver_data_size );
                return 0;
        }
        undi.pxs->loader.undi_ds = SEGMENT( undi.driver_data );

        DBG ( "Installing UNDI driver code to %hx:0000, data at %hx:0000\n",
                undi.pxs->loader.undi_cs, undi.pxs->loader.undi_ds );

        /* Do the API call to install the loader */
        if ( ! undi_call_loader () ) return 0;

        pxe = VIRTUAL( undi.pxs->loader.undi_cs, undi.pxs->loader.pxe_off );
        DBG ( "UNDI driver created a pixie at %hx:%hx...",
                 undi.pxs->loader.undi_cs, undi.pxs->loader.pxe_off );
        if ( memcmp ( pxe->Signature, "!PXE", 4 ) != 0 ) {
                DBG ( "invalid signature\n" );
                return 0;
        }
        if ( checksum ( pxe, sizeof(pxe_t) ) != 0 ) {
                DBG ( "invalid checksum\n" );
                return 0;
        }
        DBG ( "ok\n" );
        undi.pxe = pxe;
        pxe_dump();
        return 1;
}

/* Start the UNDI driver.
 */

int eb_pxenv_start_undi ( void ) {
        int success = 0;

        /* AX contains PCI bus:devfn (PCI specification) */
        undi.pxs->start_undi.ax = ( undi.pci.bus << 8 ) | undi.pci.devfn;
        /* BX and DX set to 0xffff for non-ISAPnP devices
         * (BIOS boot specification)
         */
        undi.pxs->start_undi.bx = 0xffff;
        undi.pxs->start_undi.dx = 0xffff;
        /* ES:DI points to PnP BIOS' $PnP structure
         * (BIOS boot specification)
         */
        undi.pxs->start_undi.es = 0xf000;
        undi.pxs->start_undi.di = virt_to_phys ( undi.pnp_bios ) - 0xf0000;

        DBG ( "PXENV_START_UNDI => AX=%hx BX=%hx DX=%hx ES:DI=%hx:%hx\n",
              undi.pxs->start_undi.ax,
              undi.pxs->start_undi.bx, undi.pxs->start_undi.dx,
              undi.pxs->start_undi.es, undi.pxs->start_undi.di );
        success = undi_call ( PXENV_START_UNDI );
        DBG ( "PXENV_START_UNDI <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) undi.prestarted = 1;
        return success;
}

int eb_pxenv_undi_startup ( void )      {
        int success = 0;

        DBG ( "PXENV_UNDI_STARTUP => (void)\n" );
        success = undi_call ( PXENV_UNDI_STARTUP );
        DBG ( "PXENV_UNDI_STARTUP <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) undi.started = 1;
        return success;
}

int eb_pxenv_undi_cleanup ( void ) {
        int success = 0;

        DBG ( "PXENV_UNDI_CLEANUP => (void)\n" );
        success = undi_call ( PXENV_UNDI_CLEANUP );
        DBG ( "PXENV_UNDI_CLEANUP <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        return success;
}

int eb_pxenv_undi_initialize ( void ) {
        int success = 0;

        undi.pxs->undi_initialize.ProtocolIni = 0;
        memset ( &undi.pxs->undi_initialize.reserved, 0,
                 sizeof ( undi.pxs->undi_initialize.reserved ) );
        DBG ( "PXENV_UNDI_INITIALIZE => ProtocolIni=%x\n" );
        success = undi_call ( PXENV_UNDI_INITIALIZE );
        DBG ( "PXENV_UNDI_INITIALIZE <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) undi.initialized = 1;
        return success;
}

int eb_pxenv_undi_shutdown ( void ) {
        int success = 0;

        DBG ( "PXENV_UNDI_SHUTDOWN => (void)\n" );
        success = undi_call ( PXENV_UNDI_SHUTDOWN );
        DBG ( "PXENV_UNDI_SHUTDOWN <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) {
                undi.initialized = 0;
                undi.started = 0;
        }
        return success;
}

int eb_pxenv_undi_open ( void ) {
        int success = 0;

        undi.pxs->undi_open.OpenFlag = 0;
        undi.pxs->undi_open.PktFilter = FLTR_DIRECTED | FLTR_BRDCST;
        
        /* Multicast support not yet implemented */
        undi.pxs->undi_open.R_Mcast_Buf.MCastAddrCount = 0;
        DBG ( "PXENV_UNDI_OPEN => OpenFlag=%hx PktFilter=%hx "
              "MCastAddrCount=%hx\n",
              undi.pxs->undi_open.OpenFlag, undi.pxs->undi_open.PktFilter,
              undi.pxs->undi_open.R_Mcast_Buf.MCastAddrCount );
        success = undi_call ( PXENV_UNDI_OPEN );
        DBG ( "PXENV_UNDI_OPEN <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) undi.opened = 1;
        return success; 
}

int eb_pxenv_undi_close ( void ) {
        int success = 0;

        DBG ( "PXENV_UNDI_CLOSE => (void)\n" );
        success = undi_call ( PXENV_UNDI_CLOSE );
        DBG ( "PXENV_UNDI_CLOSE <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) undi.opened = 0;
        return success;
}

int eb_pxenv_undi_transmit_packet ( void ) {
        int success = 0;
        static const uint8_t broadcast[] = { 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF };

        /* XMitFlag selects unicast / broadcast */
        if ( memcmp ( undi.xmit_data->destaddr, broadcast,
                      sizeof(broadcast) ) == 0 ) {
                undi.pxs->undi_transmit.XmitFlag = XMT_BROADCAST;
        } else {
                undi.pxs->undi_transmit.XmitFlag = XMT_DESTADDR;
        }

        /* Zero reserved dwords */
        undi.pxs->undi_transmit.Reserved[0] = 0;
        undi.pxs->undi_transmit.Reserved[1] = 0;

        /* Segment:offset pointer to DestAddr in base memory */
        undi.pxs->undi_transmit.DestAddr.segment =
                SEGMENT( undi.xmit_data->destaddr );
        undi.pxs->undi_transmit.DestAddr.offset =
                OFFSET( undi.xmit_data->destaddr );

        /* Segment:offset pointer to TBD in base memory */
        undi.pxs->undi_transmit.TBD.segment = SEGMENT( &undi.xmit_data->tbd );
        undi.pxs->undi_transmit.TBD.offset = OFFSET( &undi.xmit_data->tbd );

        /* Use only the "immediate" part of the TBD */
        undi.xmit_data->tbd.DataBlkCount = 0;
        
        DBG ( "PXENV_UNDI_TRANSMIT_PACKET => Protocol=%hx XmitFlag=%hx ...\n"
              "... DestAddr=%hx:%hx TBD=%hx:%hx ...\n",
              undi.pxs->undi_transmit.Protocol,
              undi.pxs->undi_transmit.XmitFlag,
              undi.pxs->undi_transmit.DestAddr.segment,
              undi.pxs->undi_transmit.DestAddr.offset,
              undi.pxs->undi_transmit.TBD.segment,
              undi.pxs->undi_transmit.TBD.offset );
        DBG ( "... TBD { ImmedLength=%hx Xmit=%hx:%hx DataBlkCount=%hx }\n",
              undi.xmit_data->tbd.ImmedLength,
              undi.xmit_data->tbd.Xmit.segment,
              undi.xmit_data->tbd.Xmit.offset,
              undi.xmit_data->tbd.DataBlkCount );
        success = undi_call ( PXENV_UNDI_TRANSMIT );
        DBG ( "PXENV_UNDI_TRANSMIT_PACKET <= Status=%s\n",
              UNDI_STATUS(undi.pxs) );
        return success;
}

int eb_pxenv_undi_set_station_address ( void ) {
        /* This will spuriously fail on some cards.  Ignore failures.
         * We only ever use it to set the MAC address to the card's
         * permanent value anyway, so it's a useless call (although we
         * make it because PXE spec says we should).
         */
        DBG ( "PXENV_UNDI_SET_STATION_ADDRESS => "
              "StationAddress=%!\n",
              undi.pxs->undi_set_station_address.StationAddress );
        undi_call_silent ( PXENV_UNDI_SET_STATION_ADDRESS );
        DBG ( "PXENV_UNDI_SET_STATION_ADDRESS <= Status=%s\n",
              UNDI_STATUS(undi.pxs) );
        return 1;
}

int eb_pxenv_undi_get_information ( void ) {
        int success = 0;
        memset ( undi.pxs, 0, sizeof ( undi.pxs ) );
        DBG ( "PXENV_UNDI_GET_INFORMATION => (void)\n" );
        success = undi_call ( PXENV_UNDI_GET_INFORMATION );
        DBG ( "PXENV_UNDI_GET_INFORMATION <= Status=%s "
              "BaseIO=%hx IntNumber=%hx ...\n"
              "... MaxTranUnit=%hx HwType=%hx HwAddrlen=%hx ...\n"
              "... CurrentNodeAddress=%! PermNodeAddress=%! ...\n"
              "... ROMAddress=%hx RxBufCt=%hx TxBufCt=%hx\n",
              UNDI_STATUS(undi.pxs),
              undi.pxs->undi_get_information.BaseIo,
              undi.pxs->undi_get_information.IntNumber,
              undi.pxs->undi_get_information.MaxTranUnit,
              undi.pxs->undi_get_information.HwType,
              undi.pxs->undi_get_information.HwAddrLen,
              undi.pxs->undi_get_information.CurrentNodeAddress,
              undi.pxs->undi_get_information.PermNodeAddress,
              undi.pxs->undi_get_information.ROMAddress,
              undi.pxs->undi_get_information.RxBufCt,
              undi.pxs->undi_get_information.TxBufCt );
        return success;
}

int eb_pxenv_undi_get_iface_info ( void ) {
        int success = 0;

        DBG ( "PXENV_UNDI_GET_IFACE_INFO => (void)\n" );
        success = undi_call ( PXENV_UNDI_GET_IFACE_INFO );
        DBG ( "PXENV_UNDI_GET_IFACE_INFO <= Status=%s IfaceType=%s ...\n"
              "... LinkSpeed=%x ServiceFlags=%x\n",
              UNDI_STATUS(undi.pxs),
              undi.pxs->undi_get_iface_info.IfaceType,
              undi.pxs->undi_get_iface_info.LinkSpeed,
              undi.pxs->undi_get_iface_info.ServiceFlags );
        return success;
}

int eb_pxenv_undi_isr ( void ) {
        int success = 0;

        DBG ( "PXENV_UNDI_ISR => FuncFlag=%hx\n",
              undi.pxs->undi_isr.FuncFlag );    
        success = undi_call ( PXENV_UNDI_ISR );
        DBG ( "PXENV_UNDI_ISR <= Status=%s FuncFlag=%hx BufferLength=%hx ...\n"
              "... FrameLength=%hx FrameHeaderLength=%hx Frame=%hx:%hx "
              "ProtType=%hhx ...\n... PktType=%hhx\n",
              UNDI_STATUS(undi.pxs), undi.pxs->undi_isr.FuncFlag,
              undi.pxs->undi_isr.BufferLength,
              undi.pxs->undi_isr.FrameLength,
              undi.pxs->undi_isr.FrameHeaderLength,
              undi.pxs->undi_isr.Frame.segment,
              undi.pxs->undi_isr.Frame.offset,
              undi.pxs->undi_isr.ProtType,
              undi.pxs->undi_isr.PktType );
        return success;
}

int eb_pxenv_stop_undi ( void ) {
        int success = 0;

        DBG ( "PXENV_STOP_UNDI => (void)\n" );
        success = undi_call ( PXENV_STOP_UNDI );
        DBG ( "PXENV_STOP_UNDI <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        if ( success ) undi.prestarted = 0;
        return success;
}

int eb_pxenv_unload_stack ( void ) {
        int success = 0;

        memset ( undi.pxs, 0, sizeof ( undi.pxs ) );
        DBG ( "PXENV_UNLOAD_STACK => (void)\n" );
        success = undi_call_silent ( PXENV_UNLOAD_STACK );
        DBG ( "PXENV_UNLOAD_STACK <= Status=%s ...\n... (%s)\n",
              UNDI_STATUS(undi.pxs),
              ( undi.pxs->Status == PXENV_STATUS_SUCCESS ?
                "base-code is ready to be removed" :
                ( undi.pxs->Status == PXENV_STATUS_FAILURE ?
                  "the size of free base memory has been changed" :
                  ( undi.pxs->Status == PXENV_STATUS_KEEP_ALL ?
                    "the NIC interrupt vector has been changed" :
                    "UNEXPECTED STATUS CODE" ) ) ) );
        return success;
}

int eb_pxenv_stop_base ( void ) {
        int success = 0;

        DBG ( "PXENV_STOP_BASE => (void)\n" );
        success = undi_call ( PXENV_STOP_BASE );
        DBG ( "PXENV_STOP_BASE <= Status=%s\n", UNDI_STATUS(undi.pxs) );
        return success;
}

/* Unload UNDI base code (if any present) and free memory.
 */
int undi_unload_base_code ( void ) {
        /* In GRUB, we do not allocate anything, but we still can call
         * to free the base space */
        void *bc_code = VIRTUAL( undi.pxe->BC_Code.Seg_Addr, 0 );
        size_t bc_code_size = undi.pxe->BC_Code.Seg_Size;
        void *bc_data = VIRTUAL( undi.pxe->BC_Data.Seg_Addr, 0 );
        size_t bc_data_size = undi.pxe->BC_Data.Seg_Size;
        void *bc_stck = VIRTUAL( undi.pxe->Stack.Seg_Addr, 0 );
        size_t bc_stck_size = undi.pxe->Stack.Seg_Size;
        firing_squad_lineup_t lineup;

        /* Don't unload if there is no base code present */
        if ( undi.pxe->BC_Code.Seg_Addr == 0 ) return 1;

        /* Since we never start the base code, the only time we should
         * reach this is if we were loaded via PXE.  There are many
         * different and conflicting versions of the "correct" way to
         * unload the PXE base code, several of which appear within
         * the PXE specification itself.  This one seems to work for
         * our purposes.
         */
        eb_pxenv_stop_base();
        //eb_pxenv_unload_stack();
/*      if ( ( undi.pxs->unload_stack.Status != PXENV_STATUS_SUCCESS ) &&
             ( undi.pxs->unload_stack.Status != PXENV_STATUS_FAILURE ) ) {
                printf ( "Could not free memory allocated to PXE base code: "
                         "possible memory leak\n" );
                return 0;
                }*/
        /* Free data structures.  Forget what the PXE specification
         * says about how to calculate the new size of base memory;
         * basemem.c takes care of all that for us.  Note that we also
         * have to free the stack (even though PXE spec doesn't say
         * anything about it) because nothing else is going to do so.
         *
         * Structures will almost certainly not be kB-aligned and
         * there's a reasonable chance that the UNDI code or data
         * portions will lie in the same kB as the base code.  Since
         * forget_base_memory works only in 1kB increments, this means
         * we have to do some arcane trickery.
         */
        memset ( &lineup, 0, sizeof(lineup) );
        if ( SEGMENT(bc_code) != 0 )
                assemble_firing_squad( &lineup, bc_code, bc_code_size, SHOOT );
        if ( SEGMENT(bc_data) != 0 )
                assemble_firing_squad( &lineup, bc_data, bc_data_size, SHOOT );
        if ( SEGMENT(bc_stck) != 0 )
                assemble_firing_squad( &lineup, bc_stck, bc_stck_size, SHOOT );
        /* Don't shoot any bits of the UNDI driver code or data */
        assemble_firing_squad ( &lineup,
                                VIRTUAL(undi.pxe->UNDICode.Seg_Addr, 0),
                                undi.pxe->UNDICode.Seg_Size, DONTSHOOT );
        assemble_firing_squad ( &lineup,
                                VIRTUAL(undi.pxe->UNDIData.Seg_Addr, 0),
                                undi.pxe->UNDIData.Seg_Size, DONTSHOOT );
        //shoot_targets ( &lineup );
        //undi.pxe->BC_Code.Seg_Addr = 0;
        //undi.pxe->BC_Data.Seg_Addr = 0;
        //undi.pxe->Stack.Seg_Addr = 0;

        /* Free and reallocate our own base memory data structures, to
         * allow the freed base-code blocks to be fully released.
         */
        free_base_mem_data();
        if ( ! allocate_base_mem_data() ) {
                printf ( "FATAL: memory unaccountably lost\n" );
                while ( 1 ) {};
        }

        return 1;
}

/* UNDI full initialization
 *
 * This calls all the various UNDI initialization routines in sequence.
 */

int undi_full_startup ( void ) {
        if ( ! eb_pxenv_start_undi() ) return 0;
        if ( ! eb_pxenv_undi_startup() ) return 0;
        if ( ! eb_pxenv_undi_initialize() ) return 0;
        if ( ! eb_pxenv_undi_get_information() ) return 0;
        undi.irq = undi.pxs->undi_get_information.IntNumber;
        if ( ! install_undi_irq_handler ( undi.irq, undi.pxe->EntryPointSP ) ) {
                undi.irq = IRQ_NONE;
                return 0;
        }
        memmove ( &undi.pxs->undi_set_station_address.StationAddress,
                  &undi.pxs->undi_get_information.PermNodeAddress,
                  sizeof (undi.pxs->undi_set_station_address.StationAddress) );
        if ( ! eb_pxenv_undi_set_station_address() ) return 0;
        if ( ! eb_pxenv_undi_open() ) return 0;
        /* install_undi_irq_handler leaves irq disabled */
        enable_irq ( undi.irq );
        return 1;
}

/* UNDI full shutdown
 *
 * This calls all the various UNDI shutdown routines in sequence and
 * also frees any memory that it can.
 */

int undi_full_shutdown ( void ) {
        if ( undi.pxe != NULL ) {
                /* In case we didn't allocate the driver's memory in the first
                 * place, try to grab the code and data segments and sizes
                 * from the !PXE structure.
                 */
                if ( undi.driver_code == NULL ) {
                        undi.driver_code = VIRTUAL(undi.pxe->UNDICode.Seg_Addr,
                                                   0 );
                        undi.driver_code_size = undi.pxe->UNDICode.Seg_Size;
                }
                if ( undi.driver_data == NULL ) {
                        undi.driver_data = VIRTUAL(undi.pxe->UNDIData.Seg_Addr,
                                                   0 );
                        undi.driver_data_size = undi.pxe->UNDIData.Seg_Size;
                }
                
                /* Ignore errors and continue in the hope of shutting
                 * down anyway
                 */
                if ( undi.opened ) eb_pxenv_undi_close();
                if ( undi.started ) {
                        eb_pxenv_undi_cleanup();
                        /* We may get spurious UNDI API errors at this
                         * point.  If startup() succeeded but
                         * initialize() failed then according to the
                         * spec, we should call shutdown().  However,
                         * some NICS will fail with a status code
                         * 0x006a (INVALID_STATE).
                         */
                        eb_pxenv_undi_shutdown();
                }
                if ( undi.irq != IRQ_NONE ) {
                        remove_undi_irq_handler ( undi.irq );
                        undi.irq = IRQ_NONE;
                }
                undi_unload_base_code();
                if ( undi.prestarted ) {
                        eb_pxenv_stop_undi();
                        /* Success OR Failure indicates that memory
                         * can be freed.  Any other status code means
                         * that it can't.
                         */
                        if (( undi.pxs->Status == PXENV_STATUS_KEEP_UNDI ) ||
                            ( undi.pxs->Status == PXENV_STATUS_KEEP_ALL ) ) {
                                printf ("Could not free memory allocated to "
                                        "UNDI driver: possible memory leak\n");
                                return 0;
                        }
                }
        }
        /* Free memory allocated to UNDI driver */
        if ( undi.driver_code != NULL ) {
                /* Clear contents in order to eliminate !PXE and PXENV
                 * signatures to prevent spurious detection via base
                 * memory scan.
                 */
                memset ( undi.driver_code, 0, undi.driver_code_size );
                /* forget_base_memory ( undi.driver_code, undi.driver_code_size ); */
                undi.driver_code = NULL;
                undi.driver_code_size = 0;
        }
        if ( undi.driver_data != NULL ) {
                /* forget_base_memory ( undi.driver_data, undi.driver_data_size ); */
                undi.driver_data = NULL;
                undi.driver_data_size = 0;
        }
        /* !PXE structure now gone; memory freed */
        undi.pxe = NULL;
        return 1;
}

/**************************************************************************
POLL - Wait for a frame
***************************************************************************/
static int undi_poll(struct nic *nic, int retrieve)
{
        /* Fun, fun, fun.  UNDI drivers don't use polling; they use
         * interrupts.  We therefore cheat and pretend that an
         * interrupt has occurred every time undi_poll() is called.
         * This isn't too much of a hack; PCI devices share IRQs and
         * so the first thing that a proper ISR should do is call
         * PXENV_UNDI_ISR to determine whether or not the UNDI NIC
         * generated the interrupt; there is no harm done by spurious
         * calls to PXENV_UNDI_ISR.  Similarly, we wouldn't be
         * handling them any more rapidly than the usual rate of
         * undi_poll() being called even if we did implement a full
         * ISR.  So it should work.  Ha!
         *
         * Addendum (21/10/03).  Some cards don't play nicely with
         * this trick, so instead of doing it the easy way we have to
         * go to all the hassle of installing a genuine interrupt
         * service routine and dealing with the wonderful 8259
         * Programmable Interrupt Controller.  Joy.
         *
         * (02/01/2005). A real UNDI ISR is now implemented in,
         * following Figure 3-4 in PXE spec 2.0.  The interrupt
         * handler, undi_irq_handler, issues PXENV_UNDI_ISR_IN_START.
         * If the interrupt is ours, the handler sends EOI and bumps the
         * undi_irq_trigger_count. This polled routine is equivalent
         * to the "driver strategy routine".
         *
         * Another issue is that upper layer await_*() does not handle
         * coalesced packets. The UNDI implementation on broadcom chips
         * appear to combine interrupts. If we loop through GET_NEXT,
         * we may hand up coalesced packets, resulting in drops, and
         * severe time delay. As a temperary hack, we return as soon as
         * we get something, remembering where we were (IN_PROCESS
         * or GET_NEXT). This assume packets are never broken up.
         * XXX Need to fix upper layer to handle coalesced data.
         */

        static int undi_opcode = PXENV_UNDI_ISR_IN_PROCESS;

        /* See if a hardware interrupt has occurred since the last poll().
         */
        switch ( undi_opcode ) {
        case PXENV_UNDI_ISR_IN_PROCESS:
                if ( ! undi_irq_triggered ( undi.irq ) )
                        return 0;
        default:
                break;
        }

        /* We have an interrupt or there is something left from
         * last poll. Either way, we need to call UNDI ISR.
         */
        nic->packetlen = 0;
        undi.pxs->undi_isr.FuncFlag = undi_opcode;
        /* there is no good way to handle this error */
        if ( ! eb_pxenv_undi_isr() ) {
                printf ("undi isr call failed: opcode = %d\n", undi_opcode);
                return 0;
        }
        switch ( undi.pxs->undi_isr.FuncFlag ) {
        case PXENV_UNDI_ISR_OUT_DONE:
                /* Set opcode back to IN_PROCESS and wait for next intr */
                undi_opcode = PXENV_UNDI_ISR_IN_PROCESS;
                return 0;
        case PXENV_UNDI_ISR_OUT_TRANSMIT:
                /* We really don't care about transmission complete
                 * interrupts. Move on to next frame.
                 */
                undi_opcode = PXENV_UNDI_ISR_IN_GET_NEXT;
                return 0;
        case PXENV_UNDI_ISR_OUT_BUSY:
                /* This should never happen.
                 */
                undi_opcode = PXENV_UNDI_ISR_IN_GET_NEXT;
                printf ( "UNDI ISR thinks it's being re-entered!\n"
                         "Aborting receive\n" );
                return 0;
        case PXENV_UNDI_ISR_OUT_RECEIVE:
                /* Copy data to receive buffer and move on to next frame */
                undi_opcode = PXENV_UNDI_ISR_IN_GET_NEXT;
                memcpy ( nic->packet + nic->packetlen,
                         VIRTUAL( undi.pxs->undi_isr.Frame.segment,
                                  undi.pxs->undi_isr.Frame.offset ),
                         undi.pxs->undi_isr.BufferLength );
                nic->packetlen += undi.pxs->undi_isr.BufferLength;
                break;
        default:
                undi_opcode = PXENV_UNDI_ISR_IN_PROCESS;
                printf ( "UNDI ISR returned bizzare status code %d\n",
                         undi.pxs->undi_isr.FuncFlag );
        }

        return nic->packetlen > 0 ? 1 : 0;
}

/**************************************************************************
TRANSMIT - Transmit a frame
***************************************************************************/
static void undi_transmit(
        struct nic *nic,
        const char *d,                  /* Destination */
        unsigned int t,                 /* Type */
        unsigned int s,                 /* size */
        const char *p)                  /* Packet */
{
        /* Inhibit compiler warning about unused parameter nic */
        if ( nic == NULL ) {};

        /* Copy destination to buffer in base memory */
        memcpy ( undi.xmit_data->destaddr, d, sizeof(MAC_ADDR) );

        /* Translate packet type to UNDI packet type */
        switch ( t ) {
        case IP :  undi.pxs->undi_transmit.Protocol = P_IP;   break;
        case ARP:  undi.pxs->undi_transmit.Protocol = P_ARP;  break;
        case RARP: undi.pxs->undi_transmit.Protocol = P_RARP; break;
        default: undi.pxs->undi_transmit.Protocol = P_UNKNOWN; break;
        }

        /* Store packet length in TBD */
        undi.xmit_data->tbd.ImmedLength = s;

        /* Check to see if data to be transmitted is currently in base
         * memory.  If not, allocate temporary storage in base memory
         * and copy it there.
         */
        if ( SEGMENT( p ) <= 0xffff ) {
                undi.xmit_data->tbd.Xmit.segment = SEGMENT( p );
                undi.xmit_data->tbd.Xmit.offset = OFFSET( p );
        } else {
                memcpy ( undi.xmit_buffer, p, s );
                undi.xmit_data->tbd.Xmit.segment = SEGMENT( undi.xmit_buffer );
                undi.xmit_data->tbd.Xmit.offset = OFFSET( undi.xmit_buffer );
        }

        eb_pxenv_undi_transmit_packet();
}

/**************************************************************************
DISABLE - Turn off ethernet interface
***************************************************************************/
static void undi_disable(struct dev *dev)
{
        /* Inhibit compiler warning about unused parameter dev */
        if ( dev == NULL ) {};
        undi_full_shutdown();
        free_base_mem_data();
}

/**************************************************************************
PROBE - Look for an adapter, this routine's visible to the outside
***************************************************************************/

/* Locate an UNDI driver by first scanning through base memory for an
 * installed driver and then by scanning for UNDI ROMs and attempting
 * to install their drivers.
 */

int hunt_pixies_and_undi_roms ( void ) {
        static uint8_t hunt_type = HUNT_FOR_PIXIES;
        
        if ( hunt_type == HUNT_FOR_PIXIES ) {
                if ( hunt_pixie() ) {
                        return 1;
                }
        }
        hunt_type = HUNT_FOR_UNDI_ROMS;
        while ( hunt_undi_rom() ) {
                if ( undi_loader() ) {
                        return 1;
                }
                undi_full_shutdown(); /* Free any allocated memory */
        }
        hunt_type = HUNT_FOR_PIXIES;
        return 0;
}

/* The actual Etherboot probe routine.
 */

static int undi_probe(struct dev *dev, struct pci_device *pci)
{
        struct nic *nic = (struct nic *)dev;

        /* Zero out global undi structure */
        memset ( &undi, 0, sizeof(undi) );

        /* Store PCI parameters; we will need them to initialize the UNDI
         * driver later.
         */
        memcpy ( &undi.pci, pci, sizeof(undi.pci) );

        /* Find the BIOS' $PnP structure */
        if ( ! hunt_pnp_bios() ) {
                printf ( "No PnP BIOS found; aborting\n" );
                return 0;
        }

        /* Allocate base memory data structures */
        if ( ! allocate_base_mem_data() ) return 0;

        /* Search thoroughly for UNDI drivers */
        for ( ; hunt_pixies_and_undi_roms(); undi_full_shutdown() ) {
                /* Try to initialise UNDI driver */
                DBG ( "Initializing UNDI driver.  Please wait...\n" );
                if ( ! undi_full_startup() ) {
                        if ( undi.pxs->Status ==
                             PXENV_STATUS_UNDI_MEDIATEST_FAILED ) {
                                DBG ( "Cable not connected (code %#hx)\n",
                                         PXENV_STATUS_UNDI_MEDIATEST_FAILED );
                        }
                        continue;
                }
                /* Basic information: MAC, IO addr, IRQ */
                if ( ! eb_pxenv_undi_get_information() ) continue;
                DBG ( "Initialized UNDI NIC with IO %#hx, IRQ %d, MAC %!\n",
                         undi.pxs->undi_get_information.BaseIo,
                         undi.pxs->undi_get_information.IntNumber,
                         undi.pxs->undi_get_information.CurrentNodeAddress );
                /* Fill out MAC address in nic structure */
                memcpy ( nic->node_addr,
                         undi.pxs->undi_get_information.CurrentNodeAddress,
                         ETH_ALEN );
                /* More diagnostic information including link speed */
                if ( ! eb_pxenv_undi_get_iface_info() ) continue;
                printf ( "  NDIS type %s interface at %d Mbps\n",
                         undi.pxs->undi_get_iface_info.IfaceType,
                         undi.pxs->undi_get_iface_info.LinkSpeed / 1000000 );
                DBG ("UNDI Stack at %#hx:%#hx",UNDI_STACK_SEG, UNDI_STACK_OFF);
                dev->disable  = undi_disable;
                nic->poll     = undi_poll;
                nic->transmit = undi_transmit;
                return 1;
        }
        undi_disable ( dev ); /* To free base memory structures */
        return 0;
}

/* UNDI driver states that it is suitable for any PCI NIC (i.e. any
 * PCI device of class PCI_CLASS_NETWORK_ETHERNET).  If there are any
 * obscure UNDI NICs that have the incorrect PCI class, add them to
 * this list.
 */
static struct pci_id undi_nics[] = {
        PCI_ROM(0x10de, 0x0057, "ck804", "nVidia Corporation CK804 Ethernet"),
        PCI_ROM(0x10de, 0x0373, "mcp55", "nVidia Corporation MCP55 Ethernet")
};

struct pci_driver undi_driver = {
        .type     = NIC_DRIVER,
        .name     = "UNDI",
        .probe    = undi_probe,
        .ids      = undi_nics,
        .id_count = sizeof(undi_nics)/sizeof(undi_nics[0]),
        .class    = PCI_CLASS_NETWORK_ETHERNET,
};

/************************************************
 * Code for reusing the BIOS provided pxe stack
 */

/* Verify !PXE structure saved by pxeloader. */
int undi_bios_pxe(void **dhcpreply)
{
        pxe_t *pxe;
        uint16_t *ptr = (uint16_t *)0x7C80;

        pxe = (pxe_t *) VIRTUAL(ptr[0], ptr[1]);
        if (memcmp(pxe->Signature, "!PXE", 4) != 0) {
                DBG ("invalid !PXE signature at %x:%x\n", ptr[0], ptr[1]);
                return 0;
        }

        if (checksum(pxe, sizeof(pxe_t)) != 0) {
                DBG ("invalid checksum\n");
                return 0;
        }

        /* Zero out global undi structure */
        memset (&undi, 0, sizeof(undi));

        /* Allocate base memory data structures */
        if (! allocate_base_mem_data()) return 0;

        undi.pxe = pxe;
        pxe_dump();

        if (!eb_pxenv_get_cached_info(PXENV_PACKET_TYPE_DHCP_ACK, dhcpreply)) {
                DBG ("failed to get cached DHCP reply\n");
                return 0;
        }
        return 1;
}

void undi_pxe_disable(void)
{
        /* full shutdown is problematic for some machines */
        (void) eb_pxenv_undi_shutdown();
}

/*
 * Various helper functions for dhcp and tftp
 */
int eb_pxenv_get_cached_info (uint8_t type, void **info)
{
        int success;

        memset(undi.pxs, 0, sizeof (undi.pxs));
        /* Segment:offset pointer to DestAddr in base memory */
        undi.pxs->get_cached_info.PacketType = type;
        undi.pxs->get_cached_info.BufferSize = 0;
        undi.pxs->get_cached_info.Buffer.segment = 0;
        undi.pxs->get_cached_info.Buffer.offset = 0;

        success = undi_call(PXENV_GET_CACHED_INFO);
        DBG ("PXENV_GET_CACHED_INFO <= Status=%s\n", UNDI_STATUS(undi.pxs));

        *info = (void *)VIRTUAL(undi.pxs->get_cached_info.Buffer.segment,
            undi.pxs->get_cached_info.Buffer.offset);
        return success;
}

/* tftp help routines */
int eb_pxenv_tftp_open(char *file, IP4_t serverip, IP4_t gatewayip,
    uint16_t *pktlen)
{
        int success;
        memset(undi.pxs, 0, sizeof (undi.pxs));
        undi.pxs->tftp_open.ServerIPAddress = serverip;
        undi.pxs->tftp_open.GatewayIPAddress = gatewayip;
        undi.pxs->tftp_open.TFTPPort = htons(TFTP_PORT);
        undi.pxs->tftp_open.PacketSize = TFTP_MAX_PACKET;
        (void) sprintf(undi.pxs->tftp_open.FileName, "%s", file);
        success = undi_call(PXENV_TFTP_OPEN);
        DBG ("PXENV_TFTP_OPEN <= Status=%s\n", UNDI_STATUS(undi.pxs));
        *pktlen = undi.pxs->tftp_open.PacketSize;
        return success;
}

int eb_pxenv_tftp_read(uint8_t *buf, uint16_t *len)
{
        static int tftp_count = 0;

        int success;
        memset(undi.pxs, 0, sizeof (undi.pxs));
        undi.pxs->tftp_read.Buffer.segment = SEGMENT(buf);
        undi.pxs->tftp_read.Buffer.offset = OFFSET(buf);
        success = undi_call(PXENV_TFTP_READ);
        DBG ("PXENV_TFTP_READ <= Status=%s\n", UNDI_STATUS(undi.pxs));
        *len = undi.pxs->tftp_read.BufferSize;
        tftp_count++;
        if ((tftp_count % 1000) == 0)
                noisy_printf(".");
        return success;
}

int eb_pxenv_tftp_close(void)
{
        int success;
        memset(undi.pxs, 0, sizeof (undi.pxs));
        success = undi_call(PXENV_TFTP_CLOSE);
        DBG ("PXENV_TFTP_CLOSE <= Status=%s\n", UNDI_STATUS(undi.pxs));
        return success;
}

int eb_pxenv_tftp_get_fsize(char *file, IP4_t serverip, IP4_t gatewayip,
    uint32_t *fsize)
{
        int success;
        memset(undi.pxs, 0, sizeof (undi.pxs));
        undi.pxs->tftp_open.ServerIPAddress = serverip;
        undi.pxs->tftp_open.GatewayIPAddress = gatewayip;
        (void) sprintf(undi.pxs->tftp_open.FileName, "%s", file);
        success = undi_call(PXENV_TFTP_GET_FSIZE);
        DBG ("PXENV_TFTP_GET_FSIZE <= Status=%s\n", UNDI_STATUS(undi.pxs));
        *fsize = undi.pxs->tftp_get_fsize.FileSize;
        return success;
}