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Commit 49df18fa authored by H. Peter Anvin's avatar H. Peter Anvin Committed by Linus Torvalds
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APM probing code 



APM probing code for the new x86 setup code.  This implements the
same functionality as the assembly version.

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5a8a8128

arch/i386/boot/apm.c

0 → 100644
+97 −0
Original line number Original line Diff line number Diff line 
/* -*- linux-c -*- ------------------------------------------------------- *

 *

 *   Copyright (C) 1991, 1992 Linus Torvalds

 *   Copyright 2007 rPath, Inc. - All Rights Reserved

 *

 *   Original APM BIOS checking by Stephen Rothwell, May 1994

 *   (sfr@canb.auug.org.au)

 *

 *   This file is part of the Linux kernel, and is made available under

 *   the terms of the GNU General Public License version 2.

 *

 * ----------------------------------------------------------------------- */



/*

 * arch/i386/boot/apm.c

 *

 * Get APM BIOS information

 */



#include "boot.h"



#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)



int query_apm_bios(void)

{

	u16 ax, bx, cx, dx, di;

	u32 ebx, esi;

	u8 err;



	/* APM BIOS installation check */

	ax = 0x5300;

	bx = cx = 0;

	asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0"

		     : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx)

		     : : "esi", "edi");



	if (err)

		return -1;		/* No APM BIOS */



	if (bx != 0x504d)	/* "PM" signature */

		return -1;



	if (cx & 0x02)		/* 32 bits supported? */

		return -1;



	/* Disconnect first, just in case */

	ax = 0x5304;

	asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp"

		     : "+a" (ax)

		     : : "ebx", "ecx", "edx", "esi", "edi");



	/* Paranoia */

	ebx = esi = 0;

	cx = dx = di = 0;



	/* 32-bit connect */

	asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %6"

		     : "=a" (ax), "+b" (ebx), "+c" (cx), "+d" (dx),

		       "+S" (esi), "+D" (di), "=m" (err)

		     : "a" (0x5303));



	boot_params.apm_bios_info.cseg = ax;

	boot_params.apm_bios_info.offset = ebx;

	boot_params.apm_bios_info.cseg_16 = cx;

	boot_params.apm_bios_info.dseg = dx;

	boot_params.apm_bios_info.cseg_len = (u16)esi;

	boot_params.apm_bios_info.cseg_16_len = esi >> 16;

	boot_params.apm_bios_info.dseg_len = di;



	if (err)

		return -1;



	/* Redo the installation check as the 32-bit connect;

	   some BIOSes return different flags this way... */



	ax = 0x5300;

	bx = cx = 0;

	asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0"

		     : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx)

		     : : "esi", "edi");



	if (err || bx != 0x504d) {

		/* Failure with 32-bit connect, try to disconect and ignore */

		ax = 0x5304;

		bx = 0;

		asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp"

			     : "+a" (ax), "+b" (bx)

			     : : "ecx", "edx", "esi", "edi");

		return -1;

	}



	boot_params.apm_bios_info.version = ax;

	boot_params.apm_bios_info.flags = cx;

	return 0;

}



#endif