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b811461abb
Clean up code duplication and measure timing of 10/100/1000/10000 us delays. Corresponding to flashrom svn r986. Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> Acked-by: Maciej Pijanka <maciej.pijanka@gmail.com>
95 lines
2.3 KiB
C
95 lines
2.3 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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* Copyright (C) 2009,2010 Carl-Daniel Hailfinger
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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 <stdlib.h>
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#include <limits.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 usecs)
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{
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volatile unsigned long i;
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for (i = 0; i < usecs * micro; i++) ;
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}
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unsigned long measure_delay(int usecs)
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{
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unsigned long timeusec;
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struct timeval start, end;
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gettimeofday(&start, 0);
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myusec_delay(usecs);
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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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return timeusec;
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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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int ok = 0;
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printf("Calibrating delay loop... ");
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while (!ok) {
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timeusec = measure_delay(count);
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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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msg_pdbg("%ldM loops per second, ", micro);
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/* We're interested in the actual precision. */
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timeusec = measure_delay(10);
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msg_pdbg("10 myus = %ld us, ", timeusec);
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timeusec = measure_delay(100);
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msg_pdbg("100 myus = %ld us, ", timeusec);
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timeusec = measure_delay(1000);
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msg_pdbg("1000 myus = %ld us, ", timeusec);
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timeusec = measure_delay(10000);
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msg_pdbg("10000 myus = %ld us, ", timeusec);
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printf("OK.\n");
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}
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void internal_delay(int usecs)
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{
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/* If the delay is >1 s, use usleep because timing does not need to
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* be so precise.
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*/
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if (usecs > 1000000) {
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usleep(usecs);
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} else {
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myusec_delay(usecs);
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}
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}
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