1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
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.
8 *
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.
13 *
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., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <stdint.h>
22 #include <gpxe/pci.h>
23 #include <realmode.h>
24
25 /** @file
26 *
27 * PCI configuration space access via PCI BIOS
28 *
29 */
30
31 /**
32 * Determine maximum PCI bus number within system
33 *
34 * @ret max_bus Maximum bus number
35 */
pcibios_max_bus(void)36 static int pcibios_max_bus ( void ) {
37 int discard_a, discard_D;
38 uint8_t max_bus;
39
40 __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
41 "int $0x1a\n\t"
42 "jnc 1f\n\t"
43 "xorw %%cx, %%cx\n\t"
44 "\n1:\n\t" )
45 : "=c" ( max_bus ), "=a" ( discard_a ),
46 "=D" ( discard_D )
47 : "a" ( PCIBIOS_INSTALLATION_CHECK >> 16 ),
48 "D" ( 0 )
49 : "ebx", "edx" );
50
51 return max_bus;
52 }
53
54 /**
55 * Read configuration space via PCI BIOS
56 *
57 * @v pci PCI device
58 * @v command PCI BIOS command
59 * @v value Value read
60 * @ret rc Return status code
61 */
pcibios_read(struct pci_device * pci,uint32_t command,uint32_t * value)62 int pcibios_read ( struct pci_device *pci, uint32_t command, uint32_t *value ){
63 int discard_b, discard_D;
64 int status;
65
66 __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
67 "int $0x1a\n\t"
68 "jnc 1f\n\t"
69 "xorl %%eax, %%eax\n\t"
70 "decl %%eax\n\t"
71 "movl %%eax, %%ecx\n\t"
72 "\n1:\n\t" )
73 : "=a" ( status ), "=b" ( discard_b ),
74 "=c" ( *value ), "=D" ( discard_D )
75 : "a" ( command >> 16 ), "D" ( command ),
76 "b" ( PCI_BUSDEVFN ( pci->bus, pci->devfn ) )
77 : "edx" );
78
79 return ( ( status >> 8 ) & 0xff );
80 }
81
82 /**
83 * Write configuration space via PCI BIOS
84 *
85 * @v pci PCI device
86 * @v command PCI BIOS command
87 * @v value Value to be written
88 * @ret rc Return status code
89 */
pcibios_write(struct pci_device * pci,uint32_t command,uint32_t value)90 int pcibios_write ( struct pci_device *pci, uint32_t command, uint32_t value ){
91 int discard_b, discard_c, discard_D;
92 int status;
93
94 __asm__ __volatile__ ( REAL_CODE ( "stc\n\t"
95 "int $0x1a\n\t"
96 "jnc 1f\n\t"
97 "movb $0xff, %%ah\n\t"
98 "\n1:\n\t" )
99 : "=a" ( status ), "=b" ( discard_b ),
100 "=c" ( discard_c ), "=D" ( discard_D )
101 : "a" ( command >> 16 ), "D" ( command ),
102 "b" ( PCI_BUSDEVFN ( pci->bus, pci->devfn ) ),
103 "c" ( value )
104 : "edx" );
105
106 return ( ( status >> 8 ) & 0xff );
107 }
108
109 PROVIDE_PCIAPI ( pcbios, pci_max_bus, pcibios_max_bus );
110 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_byte );
111 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_word );
112 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_dword );
113 PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_byte );
114 PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_word );
115 PROVIDE_PCIAPI_INLINE ( pcbios, pci_write_config_dword );
116