src/arch/i386/interface/pcbios/pcibios.c

   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  */
  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  */
  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  */
  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 );