libpayload: Add gettimeofday() and friends

Add a gettimeofday() implementation - it works pretty well, but it
drifts a little bit so its not very suitable for keeping time.  It
works best to track changes in time over small periods of time.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3272 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

payloads/libpayload/libc/time.c

@@ -0,0 +1,128 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <libpayload.h>
+#include <arch/rdtsc.h>
+
+extern u32 cpu_khz;
+
+static struct {
+	u64 ticks;
+	time_t secs;
+	suseconds_t usecs;
+} clock;
+
+#define TICKS_PER_SEC (cpu_khz * 1000)
+#define TICKS_PER_USEC (cpu_khz / 1000)
+
+static void update_clock(void)
+{
+	u64 delta = rdtsc() - clock.ticks;
+	int secs;
+
+	clock.ticks += delta;
+
+	secs = (int) (delta / TICKS_PER_SEC);
+	clock.secs += secs;
+	delta -= (secs * TICKS_PER_SEC);
+	clock.usecs += (int) (delta / TICKS_PER_USEC);
+
+	if (clock.usecs > 1000000) {
+		clock.usecs -= 1000000;
+		clock.secs++;
+	}
+}
+
+#ifdef CONFIG_NVRAM
+
+static unsigned int day_of_year(int mon, int day, int year)
+{
+	static u8 mdays[12] = { 31, 28, 31, 30, 31, 30,
+				31, 31, 30, 31, 30, 31 };
+
+	int i, ret = 0;
+
+	for(i = 0; i < mon; i++) {
+		ret += mdays[i];
+
+		if (i == 1 && (year % 4))
+			ret++;
+	}
+
+	return (ret + day);
+}
+
+static void gettimeofday_init(void)
+{
+	int days, delta;
+	struct tm tm;
+
+	rtc_read_clock(&tm);
+	clock.ticks = rdtsc();
+
+	/* Calculate the number of days in the year so far */
+	days = day_of_year(tm.tm_mon, tm.tm_mday, tm.tm_year + 1900);
+
+	delta = tm.tm_year - 70;
+
+	days += (delta * 365);
+
+	/* Figure leap years */
+
+	if (delta > 2)
+	  days += (delta - 2) / 4;
+
+	clock.secs = (days * 86400) + (tm.tm_hour * 3600) +
+		(tm.tm_min * 60) + tm.tm_sec;
+}
+#else
+static void gettimeofday_init(void)
+{
+	/* Record the number of ticks */
+	clock.ticks = rdtsc();
+}
+#endif
+
+int gettimeofday(struct timeval *tv, void *tz)
+{
+	/* Call the gtod init when we need it - this keeps
+	   the code from being included in the binary if we don't
+	   need it
+	*/
+
+	if (!clock.ticks)
+		gettimeofday_init();
+
+	update_clock();
+
+	tv->tv_sec = clock.secs;
+	tv->tv_usec = clock.usecs;
+
+	return 0;
+}