undiload.c

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/*
 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <pxe.h>
#include <realmode.h>
#include <bios.h>
#include <pnpbios.h>
#include <basemem.h>
#include <gpxe/pci.h>
#include <undi.h>
#include <undirom.h>
#include <undiload.h>

/** @file
 *
 * UNDI load/unload
 *
 */

/** Parameter block for calling UNDI loader */
static struct s_UNDI_LOADER __bss16 ( undi_loader );
#define undi_loader __use_data16 ( undi_loader )

/** UNDI loader entry point */
static SEGOFF16_t __bss16 ( undi_loader_entry );
#define undi_loader_entry __use_data16 ( undi_loader_entry )

/**
 * Call UNDI loader to create a pixie
 *
 * @v undi              UNDI device
 * @v undirom           UNDI ROM
 * @ret rc              Return status code
 */
int undi_load ( struct undi_device *undi, struct undi_rom *undirom ) {
        struct s_PXE ppxe;
        unsigned int fbms_seg;
        uint16_t exit;
        int rc;

        /* Only one UNDI instance may be loaded at any given time */
        if ( undi_loader_entry.segment ) {
                DBG ( "UNDI %p cannot load multiple instances\n", undi );
                return -EBUSY;
        }

        /* Set up START_UNDI parameters */
        memset ( &undi_loader, 0, sizeof ( undi_loader ) );
        undi_loader.AX = undi->pci_busdevfn;
        undi_loader.BX = undi->isapnp_csn;
        undi_loader.DX = undi->isapnp_read_port;
        undi_loader.ES = BIOS_SEG;
        undi_loader.DI = find_pnp_bios();

        /* Allocate base memory for PXE stack */
        undi->restore_fbms = get_fbms();
        fbms_seg = ( undi->restore_fbms << 6 );
        fbms_seg -= ( ( undirom->code_size + 0x0f ) >> 4 );
        undi_loader.UNDI_CS = fbms_seg;
        fbms_seg -= ( ( undirom->data_size + 0x0f ) >> 4 );
        undi_loader.UNDI_DS = fbms_seg;

        /* Debug info */
        DBGC ( undi, "UNDI %p loading UNDI ROM %p to CS %04x DS %04x for ",
               undi, undirom, undi_loader.UNDI_CS, undi_loader.UNDI_DS );
        if ( undi->pci_busdevfn != UNDI_NO_PCI_BUSDEVFN ) {
                unsigned int bus = ( undi->pci_busdevfn >> 8 );
                unsigned int devfn = ( undi->pci_busdevfn & 0xff );
                DBGC ( undi, "PCI %02x:%02x.%x\n",
                       bus, PCI_SLOT ( devfn ), PCI_FUNC ( devfn ) );
        }
        if ( undi->isapnp_csn != UNDI_NO_ISAPNP_CSN ) {
                DBGC ( undi, "ISAPnP(%04x) CSN %04x\n",
                       undi->isapnp_read_port, undi->isapnp_csn );
        }

        /* Call loader */
        undi_loader_entry = undirom->loader_entry;
        __asm__ __volatile__ ( REAL_CODE ( "pushw %%ds\n\t"
                                           "pushw %%ax\n\t"
                                           "lcall *undi_loader_entry\n\t"
                                           "addw $4, %%sp\n\t" )
                               : "=a" ( exit )
                               : "a" ( __from_data16 ( &undi_loader ) )
                               : "ebx", "ecx", "edx", "esi", "edi", "ebp" );

        /* 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();

        if ( exit != PXENV_EXIT_SUCCESS ) {
                /* Clear entry point */
                memset ( &undi_loader_entry, 0, sizeof ( undi_loader_entry ) );

                rc = -undi_loader.Status;
                if ( rc == 0 ) /* Paranoia */
                        rc = -EIO;
                DBGC ( undi, "UNDI %p loader failed: %s\n",
                       undi, strerror ( rc ) );
                return rc;
        }

        /* Populate PXE device structure */
        undi->pxenv = undi_loader.PXENVptr;
        undi->ppxe = undi_loader.PXEptr;
        copy_from_real ( &ppxe, undi->ppxe.segment, undi->ppxe.offset,
                         sizeof ( ppxe ) );
        undi->entry = ppxe.EntryPointSP;
        DBGC ( undi, "UNDI %p loaded PXENV+ %04x:%04x !PXE %04x:%04x "
               "entry %04x:%04x\n", undi, undi->pxenv.segment,
               undi->pxenv.offset, undi->ppxe.segment, undi->ppxe.offset,
               undi->entry.segment, undi->entry.offset );

        /* Update free base memory counter */
        undi->fbms = ( fbms_seg >> 6 );
        set_fbms ( undi->fbms );
        DBGC ( undi, "UNDI %p using [%d,%d) kB of base memory\n",
               undi, undi->fbms, undi->restore_fbms );

        return 0;
}

/**
 * Unload a pixie
 *
 * @v undi              UNDI device
 * @ret rc              Return status code
 *
 * Erases the PXENV+ and !PXE signatures, and frees the used base
 * memory (if possible).
 */
int undi_unload ( struct undi_device *undi ) {
        static uint32_t dead = 0xdeaddead;

        DBGC ( undi, "UNDI %p unloading\n", undi );

        /* Clear entry point */
        memset ( &undi_loader_entry, 0, sizeof ( undi_loader_entry ) );

        /* Erase signatures */
        if ( undi->pxenv.segment )
                put_real ( dead, undi->pxenv.segment, undi->pxenv.offset );
        if ( undi->ppxe.segment )
                put_real ( dead, undi->ppxe.segment, undi->ppxe.offset );

        /* Free base memory, if possible */
        if ( undi->fbms == get_fbms() ) {
                DBGC ( undi, "UNDI %p freeing [%d,%d) kB of base memory\n",
                       undi, undi->fbms, undi->restore_fbms );
                set_fbms ( undi->restore_fbms );
                return 0;
        } else {
                DBGC ( undi, "UNDI %p leaking [%d,%d) kB of base memory\n",
                       undi, undi->fbms, undi->restore_fbms );
                return -EBUSY;
        }
}