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/* $Id: udelay.c 844 2007-10-01 15:49:21Z michael $
* $URL: https://ssl.bulix.org/svn/lcd4linux/trunk/udelay.c $
*
* short delays
*
* Copyright (C) 1999, 2000 Michael Reinelt <michael@reinelt.co.at>
* Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
*
* This file is part of LCD4Linux.
*
* LCD4Linux is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* LCD4Linux is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
/*
*
* exported fuctions:
*
* void udelay_init (void)
* selects delay method (gettimeofday() ord rdtsc() according
* to processor features
*
* unsigned long timing (const char *driver, const char *section, const char *name, const int defval, const char *unit);
* returns a timing value from config or the default value
*
* void udelay (unsigned long usec)
* delays program execution for usec microseconds
* uses global variable 'loops_per_usec', which has to be set before.
* This function does busy-waiting! so use only for delays smaller
* than 10 msec
*
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/time.h>
#include "debug.h"
#include "cfg.h"
#include "qprintf.h"
#include "udelay.h"
void udelay_init(void)
{
info("udelay: using gettimeofday() delay loop");
}
unsigned long timing(const char *driver, const char *section, const char *name, const int defval, const char *unit)
{
char sec[256];
int fuzz, val;
qprintf(sec, sizeof(sec), "%s.Timing", section);
/* fuzz all timings by given factor */
cfg_number(sec, "fuzz", 100, 1, -1, &fuzz);
cfg_number(sec, name, defval, 0, -1, &val);
val = val * fuzz / 100;
if (val != defval) {
if (fuzz != 100) {
info("%s: timing: %6s = %5d %s (default %d %s, fuzz %d)", driver, name, val, unit, defval, unit, fuzz);
} else {
info("%s: timing: %6s = %5d %s (default %d %s)", driver, name, val, unit, defval, unit);
}
} else {
info("%s: timing: %6s = %5d %s (default)", driver, name, defval, unit);
}
return val;
}
void ndelay(const unsigned long nsec)
{
struct timeval now, end;
gettimeofday(&end, NULL);
end.tv_usec += (nsec + 999) / 1000;
while (end.tv_usec > 1000000) {
end.tv_usec -= 1000000;
end.tv_sec++;
}
do {
rep_nop();
gettimeofday(&now, NULL);
} while (now.tv_sec == end.tv_sec ? now.tv_usec < end.tv_usec : now.tv_sec < end.tv_sec);
}
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