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/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright 2022 Oxide Computer Company
*/
#include "payload_common.h"
#include "payload_utils.h"
#include "test_defs.h"
void
timer0_reset(void)
{
/*
* Configure timer 0 for interrupt-on-terminal-count mode, and prepare
* it to be loaded with the high and low bytes.
*/
outb(IOP_ATPIT_CMD, 0x30);
/* Load timer with max value (0xffff) */
outb(IOP_ATPIT_C0, 0xff);
outb(IOP_ATPIT_C0, 0xff);
}
uint16_t
timer0_read(void)
{
uint16_t val;
/* Latch timer0 */
outb(IOP_ATPIT_CMD, 0x00);
/* Read low and high bytes */
val = inb(IOP_ATPIT_C0);
val |= (uint16_t)inb(IOP_ATPIT_C0) << 8;
return (val);
}
void
start(void)
{
/* loop for as long as the host wants */
for (;;) {
uint16_t start, end;
timer0_reset();
start = timer0_read();
outw(IOP_TEST_VALUE, start);
do {
end = timer0_read();
/* wait for enough ticks to pass */
} while (end > (start - ATPIT_TARGET_TICKS));
outw(IOP_TEST_VALUE, end);
}
}
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