1 files changed, 114 insertions, 0 deletions
diff --git a/udelay.c b/udelay.c
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index 0000000..33ffa95
--- /dev/null
+++ b/udelay.c
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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);
+}