pcibios.c

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/*
 * Copyright (C) 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/pci.h>
#include <realmode.h>

/** @file
 *
 * PCI configuration space access via PCI BIOS
 *
 */

/**
 * Find next PCI bus:dev.fn address range in system
 *
 * @v busdevfn          Starting PCI bus:dev.fn address
 * @v range             PCI bus:dev.fn address range to fill in
 */
static void pcibios_discover ( uint32_t busdevfn __unused,
                               struct pci_range *range ) {
        int discard_a, discard_D;
        uint16_t num_bus;

        /* We issue this call using flat real mode, to work around a
         * bug in some HP BIOSes.
         */
        __asm__ __volatile__ ( REAL_CODE ( "call flatten_real_mode\n\t"
                                           "stc\n\t"
                                           "int $0x1a\n\t"
                                           "movzbw %%cl, %%cx\n\t"
                                           "incw %%cx\n\t"
                                           "jnc 1f\n\t"
                                           "xorw %%cx, %%cx\n\t"
                                           "\n1:\n\t" )
                               : "=c" ( num_bus ), "=a" ( discard_a ),
                                 "=D" ( discard_D )
                               : "a" ( PCIBIOS_INSTALLATION_CHECK >> 16 ),
                                 "D" ( 0 )
                               : "ebx", "edx" );

        /* Populate range */
        range->start = PCI_BUSDEVFN ( 0, 0, 0, 0 );
        range->count = PCI_BUSDEVFN ( 0, num_bus, 0, 0 );
}

/**
 * Read configuration space via PCI BIOS
 *
 * @v pci       PCI device
 * @v command   PCI BIOS command
 * @v value     Value read
 * @ret rc      Return status code
 */
int pcibios_read ( struct pci_device *pci, uint32_t command, uint32_t *value ){
        int discard_b, discard_D;
        uint16_t status;

        __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
                                           "int $0x1a\n\t"
                                           "jnc 1f\n\t"
                                           "xorl %%eax, %%eax\n\t"
                                           "decl %%eax\n\t"
                                           "movl %%eax, %%ecx\n\t"
                                           "\n1:\n\t" )
                               : "=a" ( status ), "=b" ( discard_b ),
                                 "=c" ( *value ), "=D" ( discard_D )
                               : "a" ( command >> 16 ), "D" ( command ),
                                 "b" ( pci->busdevfn )
                               : "edx" );

        return ( status >> 8 );
}

/**
 * Write configuration space via PCI BIOS
 *
 * @v pci       PCI device
 * @v command   PCI BIOS command
 * @v value     Value to be written
 * @ret rc      Return status code
 */
int pcibios_write ( struct pci_device *pci, uint32_t command, uint32_t value ){
        int discard_b, discard_c, discard_D;
        uint16_t status;

        __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
                                           "int $0x1a\n\t"
                                           "jnc 1f\n\t"
                                           "movb $0xff, %%ah\n\t"
                                           "\n1:\n\t" )
                               : "=a" ( status ), "=b" ( discard_b ),
                                 "=c" ( discard_c ), "=D" ( discard_D )
                               : "a" ( command >> 16 ), "D" ( command ),
                                 "b" ( pci->busdevfn ), "c" ( value )
                               : "edx" );
        
        return ( status >> 8 );
}

PROVIDE_PCIAPI_INLINE ( pcbios, pci_can_probe );
PROVIDE_PCIAPI ( pcbios, pci_discover, pcibios_discover );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_byte );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_word );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_dword );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_byte );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_word );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_dword );
PROVIDE_PCIAPI_INLINE ( pcbios, pci_ioremap );

struct pci_api pcibios_api = PCIAPI_RUNTIME ( pcbios );