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107 lines
2.8 KiB
C
107 lines
2.8 KiB
C
/*
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* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdint.h>
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#include <gpxe/pci.h>
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#include <pcibios.h>
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#include <realmode.h>
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/** @file
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*
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* PCI configuration space access via PCI BIOS
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*
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*/
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/**
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* Determine maximum PCI bus number within system
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*
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* @ret max_bus Maximum bus number
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*/
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int pcibios_max_bus ( void ) {
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int discard_a, discard_D;
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uint8_t max_bus;
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__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
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"int $0x1a\n\t"
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"jnc 1f\n\t"
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"xorw %%cx, %%cx\n\t"
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"\n1:\n\t" )
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: "=c" ( max_bus ), "=a" ( discard_a ),
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"=D" ( discard_D )
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: "a" ( PCIBIOS_INSTALLATION_CHECK >> 16 ),
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"D" ( 0 )
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: "ebx", "edx" );
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return max_bus;
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}
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/**
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* Read configuration space via PCI BIOS
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*
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* @v pci PCI device
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* @v command PCI BIOS command
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* @v value Value read
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* @ret rc Return status code
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*/
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int pcibios_read ( struct pci_device *pci, uint32_t command, uint32_t *value ){
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int discard_b, discard_D;
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int status;
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__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
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"int $0x1a\n\t"
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"jnc 1f\n\t"
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"xorl %%eax, %%eax\n\t"
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"decl %%eax\n\t"
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"movl %%eax, %%ecx\n\t"
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"\n1:\n\t" )
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: "=a" ( status ), "=b" ( discard_b ),
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"=c" ( *value ), "=D" ( discard_D )
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: "a" ( command >> 16 ), "D" ( command ),
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"b" ( PCI_BUSDEVFN ( pci->bus, pci->devfn ) )
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: "edx" );
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return ( ( status >> 8 ) & 0xff );
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}
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/**
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* Write configuration space via PCI BIOS
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*
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* @v pci PCI device
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* @v command PCI BIOS command
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* @v value Value to be written
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* @ret rc Return status code
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*/
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int pcibios_write ( struct pci_device *pci, uint32_t command, uint32_t value ){
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int discard_b, discard_c, discard_D;
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int status;
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__asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
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"int $0x1a\n\t"
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"jnc 1f\n\t"
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"movb $0xff, %%ah\n\t"
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"\n1:\n\t" )
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: "=a" ( status ), "=b" ( discard_b ),
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"=c" ( discard_c ), "=D" ( discard_D )
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: "a" ( command >> 16 ), "D" ( command ),
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"b" ( PCI_BUSDEVFN ( pci->bus, pci->devfn ) ),
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"c" ( value )
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: "edx" );
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return ( ( status >> 8 ) & 0xff );
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}
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