Exynos5250: add a microsecond timer

Add a microsecond timer, its declaration, the function to start it,
and its usage.  To start it, one calls timer_start().  From that point
on, one can call timer_us() to find microseconds since the timer was
started.

We show its use in the bootblock. You want it started very early.

Finally, the delay.h change having been (ironically) delayed, we
create time.h and have it hold one declaration, for the timer_us() and
timer_start() prototype.

We feel that these two functions should become the hardware specific
functions, allowing us to finally move udelay() into src/lib where it
belongs.

Change-Id: I19cbc2bb0089a3de88cfb94276266af38b9363c5
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/3073
Tested-by: build bot (Jenkins)

1 files changed, 26 insertions, 0 deletions

diff --git a/src/include/time.h b/src/include/time.h
new file mode 100644
index 0000000000..2cfcb356c4
--- /dev/null
+++ b/src/include/time.h
@@ -0,0 +1,26 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013 Google, Inc.
+ *
+ * This program 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; version 2 of the License.
+ *
+ * This program 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., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#ifndef TIME_H
+#define TIME_H
+
+void timer_start(void);
+u32 timer_us(void);
+
+#endif /* TIME_H */