u-boot/arch/x86/lib/i8254.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

36 lines
964 B
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
*/
#include <common.h>
#include <asm/io.h>
#include <asm/i8254.h>
#define TIMER1_VALUE 18 /* 15.6us */
#define TIMER2_VALUE 0x0a8e /* 440Hz */
int i8254_init(void)
{
/*
* Initialize counter 1, used to refresh request signal.
* This is required for legacy purpose as some codes like
* vgabios utilizes counter 1 to provide delay functionality.
*/
outb(PIT_CMD_CTR1 | PIT_CMD_LOW | PIT_CMD_MODE2,
PIT_BASE + PIT_COMMAND);
outb(TIMER1_VALUE, PIT_BASE + PIT_T1);
/*
* Initialize counter 2, used to drive the speaker.
* To start a beep, set both bit0 and bit1 of port 0x61.
* To stop it, clear both bit0 and bit1 of port 0x61.
*/
outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
PIT_BASE + PIT_COMMAND);
outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
return 0;
}