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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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdint.h>
#include <gpxe/pci.h>
#include <pcibios.h>
#include <realmode.h>
/** @file
*
* PCI configuration space access via PCI BIOS
*
*/
/**
* Determine maximum PCI bus number within system
*
* @ret max_bus Maximum bus number
*/
int pcibios_max_bus ( void ) {
int discard_a;
uint8_t max_bus;
REAL_EXEC ( rm_pcibios_check,
"stc\n\t"
"int $0x1a\n\t"
"jnc 1f\n\t"
"xorw %%cx, %%cx\n\t"
"\n1:\n\t",
2,
OUT_CONSTRAINTS ( "=a" ( discard_a ), "=c" ( max_bus ) ),
IN_CONSTRAINTS ( "a" ( PCIBIOS_INSTALLATION_CHECK >> 16 )),
CLOBBER ( "ebx", "edx", "edi" ) );
return max_bus;
}
/**
* 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;
int status;
REAL_EXEC ( rm_pcibios_read,
"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",
4,
OUT_CONSTRAINTS ( "=a" ( status ), "=b" ( discard_b ),
"=c" ( *value ), "=D" ( discard_D ) ),
IN_CONSTRAINTS ( "a" ( command >> 16 ),
"b" ( ( pci->bus << 8 ) | pci->devfn ),
"D" ( command ) ),
CLOBBER ( "edx" ) );
return ( ( status >> 8 ) & 0xff );
}
/**
* 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;
int status;
REAL_EXEC ( rm_pcibios_write,
"stc\n\t"
"int $0x1a\n\t"
"jnc 1f\n\t"
"movb $0xff, %%ah\n\t"
"\n1:\n\t",
4,
OUT_CONSTRAINTS ( "=a" ( status ), "=b" ( discard_b ),
"=c" ( discard_c ), "=D" ( discard_D ) ),
IN_CONSTRAINTS ( "a" ( command >> 16 ),
"b" ( ( pci->bus << 8 ) | pci->devfn ),
"c" ( value ), "D" ( command ) ),
CLOBBER ( "edx" ) );
return ( ( status >> 8 ) & 0xff );
}
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