pnpbios.c File Reference

PnP BIOS. More...

#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <realmode.h>
#include <pnpbios.h>

Go to the source code of this file.

Data Structures
struct	pnp_bios
	PnP BIOS structure. More...

Macros
#define	PNP_BIOS_SIGNATURE    ( ( '$' << 0 ) + ( 'P' << 8 ) + ( 'n' << 16 ) + ( 'P' << 24 ) )
	Signature for a PnP BIOS structure.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
struct pnp_bios	__attribute__ ((packed))
static int	is_pnp_bios (unsigned int offset)
	Test address for PnP BIOS structure.
int	find_pnp_bios (void)
	Locate Plug-and-Play BIOS.

Variables
uint32_t	signature
	Signature.
uint8_t	version
	Version as BCD (e.g.
uint8_t	length
	Length of this structure.
uint16_t	control
	System capabilities.
uint8_t	checksum
	Checksum.

Detailed Description

PnP BIOS.

Definition in file pnpbios.c.

Macro Definition Documentation

PNP_BIOS_SIGNATURE

#define PNP_BIOS_SIGNATURE    ( ( '$' << 0 ) + ( 'P' << 8 ) + ( 'n' << 16 ) + ( 'P' << 24 ) )

Signature for a PnP BIOS structure.

Definition at line 56 of file pnpbios.c.

#define PNP_BIOS_SIGNATURE \
        ( ( '$' << 0 ) + ( 'P' << 8 ) + ( 'n' << 16 ) + ( 'P' << 24 ) )

Referenced by is_pnp_bios().

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

is_pnp_bios()

int is_pnp_bios ( unsigned int offset )

static

Test address for PnP BIOS structure.

Parameters

offset

Offset within BIOS segment to test

Return values

rc	Return status code

Definition at line 65 of file pnpbios.c.

                                               {
        union {
                struct pnp_bios pnp_bios;
                uint8_t bytes[256]; /* 256 is maximum length possible */
        } u;
        size_t len;
        unsigned int i;
        uint8_t sum = 0;
 
        /* Read start of header and verify signature */
        copy_from_real ( &u.pnp_bios, BIOS_SEG, offset, sizeof ( u.pnp_bios ));
        if ( u.pnp_bios.signature != PNP_BIOS_SIGNATURE )
                return -EINVAL;
 
        /* Read whole header and verify checksum */
        len = u.pnp_bios.length;
        copy_from_real ( &u.bytes, BIOS_SEG, offset, len );
        for ( i = 0 ; i < len ; i++ ) {
                sum += u.bytes[i];
        }
        if ( sum != 0 )
                return -EINVAL;
 
        DBG ( "Found PnP BIOS at %04x:%04x\n", BIOS_SEG, offset );
 
        return 0;
}

References BIOS_SEG, bytes, copy_from_real, DBG, EINVAL, len, offset, PNP_BIOS_SIGNATURE, and u.

Referenced by find_pnp_bios().

find_pnp_bios()

int find_pnp_bios

(

void

)

Locate Plug-and-Play BIOS.

Return values

pnp_offset

Offset of PnP BIOS structure within BIOS segment

The PnP BIOS structure will be at BIOS_SEG:pnp_offset. If no PnP BIOS is found, -1 is returned.

Definition at line 101 of file pnpbios.c.

                           {
        static int pnp_offset = 0;
 
        if ( pnp_offset )
                return pnp_offset;
 
        for ( pnp_offset = 0 ; pnp_offset < 0x10000 ; pnp_offset += 0x10 ) {
                if ( is_pnp_bios ( pnp_offset ) == 0 )
                        return pnp_offset;
        }
 
        pnp_offset = -1;
        return pnp_offset;
}

References is_pnp_bios().

Referenced by undi_load(), and undinet_probe().

Variable Documentation

signature

uint32_t signature

Signature.

Must be equal to PNP_BIOS_SIGNATURE

Definition at line 4 of file pnpbios.c.

version

uint8_t version

Version as BCD (e.g.

1.0 is 0x10)

Definition at line 6 of file pnpbios.c.

length

uint8_t length

Length of this structure.

Definition at line 8 of file pnpbios.c.

control

uint16_t control

System capabilities.

Definition at line 10 of file pnpbios.c.

checksum

uint8_t checksum

Checksum.

Extended checksum.

Definition at line 12 of file pnpbios.c.

Referenced by ar9003_calc_ptr_chksum(), ar9300_comp_cksum(), ar9300_eeprom_restore_internal(), corkscrew_probe1(), fnrec_dump(), multiboot_find_header(), nvo_save(), and ucode_verify().