2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
32 * PCI configuration space access via PCI BIOS
37 * Determine number of PCI buses within system
39 * @ret num_bus Number of buses
41 static int pcibios_num_bus ( void ) {
42 int discard_a, discard_D;
45 /* We issue this call using flat real mode, to work around a
46 * bug in some HP BIOSes.
48 __asm__ __volatile__ ( REAL_CODE ( "call flatten_real_mode\n\t"
54 : "=c" ( max_bus ), "=a" ( discard_a ),
56 : "a" ( PCIBIOS_INSTALLATION_CHECK >> 16 ),
60 return ( max_bus + 1 );
64 * Read configuration space via PCI BIOS
67 * @v command PCI BIOS command
69 * @ret rc Return status code
71 int pcibios_read ( struct pci_device *pci, uint32_t command, uint32_t *value ){
72 int discard_b, discard_D;
75 __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
78 "xorl %%eax, %%eax\n\t"
80 "movl %%eax, %%ecx\n\t"
82 : "=a" ( status ), "=b" ( discard_b ),
83 "=c" ( *value ), "=D" ( discard_D )
84 : "a" ( command >> 16 ), "D" ( command ),
88 return ( ( status >> 8 ) & 0xff );
92 * Write configuration space via PCI BIOS
95 * @v command PCI BIOS command
96 * @v value Value to be written
97 * @ret rc Return status code
99 int pcibios_write ( struct pci_device *pci, uint32_t command, uint32_t value ){
100 int discard_b, discard_c, discard_D;
103 __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
106 "movb $0xff, %%ah\n\t"
108 : "=a" ( status ), "=b" ( discard_b ),
109 "=c" ( discard_c ), "=D" ( discard_D )
110 : "a" ( command >> 16 ), "D" ( command ),
111 "b" ( pci->busdevfn ), "c" ( value )
114 return ( ( status >> 8 ) & 0xff );
117 PROVIDE_PCIAPI ( pcbios, pci_num_bus, pcibios_num_bus );
118 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_byte );
119 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_word );
120 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_dword );
121 PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_byte );
122 PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_word );
123 PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_dword );