Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de> Acked-by: Uwe Hermann <uwe@hermann-uwe.de> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4117 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
		
			
				
	
	
		
			67 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			67 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * This file is part of the flashrom project.
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 *
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 * Copyright (C) 2000 Silicon Integrated System Corporation
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
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 */
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#include <sys/time.h>
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#include <stdio.h>
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#include "flash.h"
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// count to a billion. Time it. If it's < 1 sec, count to 10B, etc.
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unsigned long micro = 1;
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void myusec_delay(int time)
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{
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	volatile unsigned long i;
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	for (i = 0; i < time * micro; i++) ;
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}
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void myusec_calibrate_delay(void)
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{
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	int count = 1000;
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	unsigned long timeusec;
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	struct timeval start, end;
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	int ok = 0;
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	printf("Calibrating delay loop... ");
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	while (!ok) {
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		gettimeofday(&start, 0);
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		myusec_delay(count);
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		gettimeofday(&end, 0);
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		timeusec = 1000000 * (end.tv_sec - start.tv_sec) +
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		    (end.tv_usec - start.tv_usec);
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		count *= 2;
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		if (timeusec < 1000000 / 4)
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			continue;
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		ok = 1;
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	}
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	// compute one microsecond. That will be count / time
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	micro = count / timeusec;
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	gettimeofday(&start, 0);
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	myusec_delay(100);
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	gettimeofday(&end, 0);
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	timeusec = 1000000 * (end.tv_sec - start.tv_sec) +
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	    (end.tv_usec - start.tv_usec);
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	printf_debug("%ldM loops per second, 100 myus = %ld us. ",
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		     (unsigned long)micro, timeusec);
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	printf("OK.\n");
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}
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