linux-kernel - Re: factor out common s2ram wakeup code

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Date:	Fri, 25 Jan 2008 15:36:09 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Pavel Machek <pavel@....cz>
CC:	kernel list <linux-kernel@...r.kernel.org>,
	Linux-pm mailing list <linux-pm@...ts.osdl.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: factor out common s2ram wakeup code

Pavel Machek wrote:
> diff --git a/arch/x86/kernel/acpi/rm/wakemain.c b/arch/x86/kernel/acpi/rm/wakemain.c
> new file mode 100644
> index 0000000..d3173cc
> --- /dev/null
> +++ b/arch/x86/kernel/acpi/rm/wakemain.c
> @@ -0,0 +1,18 @@
> +#include "wakeup.h"
> +#include "boot.h"
> +
> +extern struct wakeup_header wakeup_header;
> +
> +void main(void)
> +{
> +	asm volatile("lcallw   $0xc000,$3;	movw    %cs, %ax;	movw    %ax, %ds;	movw	%ax, %es; movw    %ax, %ss");
> +
> +//	asm volatile("inb	$97, %al; 		outb	%al, $0x80; 		movb	$3, %al; 		outb	%al, $97; 		outb	%al, $0x80; 		movb	$-74, %al; 		outb	%al, $67; 		outb	%al, $0x80; 		movb	$-119, %al; 		outb	%al, $66; 		outb	%al, $0x80; 		movb	$15, %al; 		outb	%al, $66");
> +
> +	/* Need to call BIOS */
> +	probe_cards(0);
> +//	set_mode(wakeup_header.video_mode);
> +	set_mode(6);
> +
> +	/* Set up GDT and IDT here, possibly CR4 and EFER */
> +}

Surely this needs some cleaning up?  ;)

> diff --git a/arch/x86/kernel/acpi/rm/wakeup.S b/arch/x86/kernel/acpi/rm/wakeup.S
> new file mode 100644
> index 0000000..bfa348c
> --- /dev/null
> +++ b/arch/x86/kernel/acpi/rm/wakeup.S
> @@ -0,0 +1,129 @@
> +/*
> + * ACPI wakeup real mode startup stub
> + */
> +#include <asm/segment.h>
> +#include <asm/msr-index.h>
> +
> +	
> +#define BEEP \
> +	inb	$97, %al; 	\
> +	outb	%al, $0x80; 	\
> +	movb	$3, %al; 	\
> +	outb	%al, $97; 	\
> +	outb	%al, $0x80; 	\
> +	movb	$-74, %al; 	\
> +	outb	%al, $67; 	\
> +	outb	%al, $0x80; 	\
> +	movb	$-119, %al; 	\
> +	outb	%al, $66; 	\
> +	outb	%al, $0x80; 	\
> +	movb	$15, %al; 	\
> +	outb	%al, $66;
> +

BEEP isn't actually used here and should probably be a C function if 
needed.  Note: in real mode you can also produce a beep by calling
int $0x10 with %ax = 0x0e07.  Please note that some int $0x10 
implementations clobber certain registers... see the INT10 macro in the 
bootup code.

Seriously cool, though, that you're getting this far.

	-hpa
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