ppc400_pit_init_qtime.c

qnx powerpc MPC8245的 BSP源文件

/*
 * $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. 
 * $ 
 */

#include "startup.h"

/*
 * ppc400_pit_init_qtime()
 *	Initialize Neutrino time data structures for use with the PPC400 PIT
 *  unit.
 */

/*
 * Can use the TBLO register for startup interval timing since it's running
 * at the same speed as the PIT.
 */
static unsigned
timer_start_pit_alternate() {
	return(get_spr(PPC400_SPR_TBLO));
}

static unsigned
timer_diff_pit_alternate(unsigned start) {
	return(get_spr(PPC400_SPR_TBLO) - start);
}

static unsigned
timer_start_pit_normal() {
	return(get_spr(PPC_SPR_TBL));
}

static unsigned
timer_diff_pit_normal(unsigned start) {
	return(get_spr(PPC_SPR_TBL) - start);
}

static const struct callout_slot timer_callouts[] = {
	{ CALLOUT_SLOT( timer_load, _400 ) },
	{ CALLOUT_SLOT( timer_value, _400 ) },
	{ CALLOUT_SLOT( timer_reload, _400 ) },
};

void
ppc400_pit_init_qtime() {
	struct qtime_entry *qtime = alloc_qtime();
	unsigned long		freq;

	qtime->intr = PPC400_INTR_PI;

	freq = cycles_freq;
	if(freq == 0) freq = cpu_freq;
	switch(PPC_GET_FAM_MEMBER(get_pvr())) {
	case PPC_403:
		if(get_dcr(PPC403_DCR_IOCR) & PPC403_IOCR_TCS) {
			freq = timer_freq;
		}
		break;
	}
	qtime->cycles_per_sec = freq;
	invert_timer_freq(qtime, freq);

	add_callout_array(timer_callouts, sizeof(timer_callouts));

	if(ppc400_mftb_supported()) {
		timer_start = timer_start_pit_normal;
		timer_diff  = timer_diff_pit_normal;
	} else {
		/*
			401, 403 used different SPRs for timebase (for no
			rational reason as far as I could see - doc says that they
			weren't the same as PPC standard but I can't see how).
		*/
		timer_start = timer_start_pit_alternate;
		timer_diff  = timer_diff_pit_alternate;
	}
}