Add a dhrystone benchmark command

Drystone provides a convenient sanity check that the CPU is running at full
speed. Add this as a command which can be enabled as needed.

Note: I investigated using Coremark for this but there was a license
agreement and I could not work out if it was GPL-compatible.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/Kconfig

@@ -50,6 +50,8 @@ config LIB_RAND
 	help
 	  This library provides pseudo-random number generator functions.
 
+source lib/dhry/Kconfig
+
 source lib/rsa/Kconfig
 
 menu "Hashing Support"

lib/Makefile

@@ -15,6 +15,8 @@ obj-$(CONFIG_BZIP2) += bzip2/
 obj-$(CONFIG_TIZEN) += tizen/
 obj-$(CONFIG_OF_LIBFDT) += libfdt/
 obj-$(CONFIG_FIT) += libfdt/
+obj-$(CONFIG_FIT) += libfdt/
+obj-$(CONFIG_CMD_DHRYSTONE) += dhry/
 
 obj-$(CONFIG_AES) += aes.o
 obj-$(CONFIG_USB_TTY) += circbuf.o

lib/dhry/Kconfig

@@ -0,0 +1,7 @@
+config CMD_DHRYSTONE
+	bool "Support the 'dhry' command to run the dhrystone benchmark"
+	help
+	  Dhrystone is an old benchmark in the public domain that gives a
+	  rough idea of CPU performance. This enables a 'dhry' command
+	  which runs this benchmark within U-Boot and reports the performance.
+	  The number of 'Dhrystone MIPS' is also reported.

lib/dhry/Makefile

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2015 Google, Inc
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y += cmd_dhry.o dhry_1.o dhry_2.o

lib/dhry/cmd_dhry.c

@@ -0,0 +1,34 @@
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include "dhry.h"
+
+static int do_dhry(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	ulong start, duration, dhry_per_sec, vax_mips;
+	int iterations = 1000000;
+
+	if (argc > 1)
+		iterations = simple_strtoul(argv[1], NULL, 10);
+
+	start = get_timer(0);
+	dhry(iterations);
+	duration = get_timer(start);
+	dhry_per_sec = iterations * 1000 / duration;
+	vax_mips = dhry_per_sec / 1757;
+	printf("%d iterations in %lu ms: %lu/s, %lu DMIPS\n", iterations,
+	       duration, dhry_per_sec, vax_mips);
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	dhry,	2,	1,	do_dhry,
+	"[iterations] - run dhrystone benchmark",
+	"\n    - run the Dhrystone 2.1 benchmark, a rough measure of CPU speed\n"
+);