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x86: Initialize i8254 timer counter 1

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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.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Bin Meng 2015-10-22 19:13:29 -07:00
parent 0a2ea02068
commit bffeed0158
1 changed files with 10 additions and 0 deletions
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10
arch/x86/lib/pcat_timer.c
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@ -9,10 +9,20 @@
#include <asm/io.h>
#include <asm/i8254.h>
#define TIMER1_VALUE 18 /* 15.6us */
#define TIMER2_VALUE 0x0a8e /* 440Hz */
int pcat_timer_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.