init_qtime_mx21.c

来自「QNX ADS BSP code for i.MX27 chips」· C语言 代码 · 共 98 行

/*
 * $QNXLicenseC: 
 * Copyright 2007, QNX Software Systems.  
 *  
 * Licensed under the Apache License, Version 2.0 (the "License"). You  
 * may not reproduce, modify or distribute this software except in  
 * compliance with the License. You may obtain a copy of the License  
 * at: http://www.apache.org/licenses/LICENSE-2.0  
 *  
 * Unless required by applicable law or agreed to in writing, software  
 * distributed under the License is distributed on an "AS IS" basis,  
 * WITHOUT WARRANTIES OF ANY KIND, either express or implied. 
 * 
 * This file may contain contributions from others, either as  
 * contributors under the License or as licensors under other terms.   
 * Please review this entire file for other proprietary rights or license  
 * notices, as well as the QNX Development Suite License Guide at  
 * http://licensing.qnx.com/license-guide/ for other information. 
 * $
 */


/*
 * MC9328MX21 specific timer support.
 *
 * This should be usable by any board that uses an MC9328MX21
 */

#include "startup.h"
#include <arm/mx1.h>
#include <arm/mx21.h>

extern struct callout_rtn	timer_load_mx21;
extern struct callout_rtn	timer_value_mx21;
extern struct callout_rtn	timer_reload_mx21;

static uintptr_t	mx21_timer_base;


static const struct callout_slot	timer_callouts[] = {
	{ CALLOUT_SLOT(timer_load, _mx21) },
	{ CALLOUT_SLOT(timer_value, _mx21) },
	{ CALLOUT_SLOT(timer_reload, _mx21) },
};

static unsigned
timer_start_mx21()
{
	return in32(mx21_timer_base + MX1_TIMER_CN);
}

static unsigned
timer_diff_mx21(unsigned start)
{
	unsigned now = in32(mx21_timer_base + MX1_TIMER_CN);

	return (unsigned)((int)now - (int)start);
}

void
init_qtime_mx21()
{
	struct qtime_entry	*qtime = alloc_qtime();

	/*
	 * Map the timer registers
	 */
	mx21_timer_base = startup_io_map(MX1_TIMER_SIZE, MX21_GPT1_BASE);

	/*
	 * Clear match status and interrupt enable, and disable watchdog reset
	 */
	out32(mx21_timer_base + MX1_TIMER_CTL, 2);

	/*
	 * Prescaler = 2
	 */
	out32(mx21_timer_base + MX1_TIMER_PRER, 1);

	timer_start = timer_start_mx21;
	timer_diff = timer_diff_mx21;

	/* 
	 * IRQ number for Timer 1 is 26
	 */
	qtime->intr = 26;

#define MX21_CLOCK_FREQ		22166667UL
#define MX21_CLOCK_RATE		45112781UL
#define MX21_CLOCK_SCALE	-15

	qtime->timer_rate  = MX21_CLOCK_RATE;
	qtime->timer_scale = MX21_CLOCK_SCALE;
	qtime->cycles_per_sec = (uint64_t)MX21_CLOCK_FREQ;

	add_callout_array(timer_callouts, sizeof(timer_callouts));
}