Add time measurement command to u-boot

The command "time" takes a command as its argument, executes the command, and reports how much time the command has used.

Example usage:
------------------------------------------------------------
CrOS> time sleep 1

time: 1.000 seconds, 1000 ticks
CrOS> time sleep 10

time: 10.000 seconds, 10000 ticks
------------------------------------------------------------

R=robotboy@chromium.org,sjg@chromium.org
BUG=none
TEST=see above

Review URL: http://codereview.chromium.org/6670118

Change-Id: I97cb234c68f29e5db1f5a66abbe32ec6e575b847
diff --git a/common/Makefile b/common/Makefile
index 13f50fe..4c5cde4 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -146,6 +146,7 @@
 COBJS-$(CONFIG_CMD_SPIBOOTLDR) += cmd_spibootldr.o
 COBJS-$(CONFIG_CMD_STRINGS) += cmd_strings.o
 COBJS-$(CONFIG_CMD_TERMINAL) += cmd_terminal.o
+COBJS-$(CONFIG_CMD_TIME) += cmd_time.o
 COBJS-$(CONFIG_SYS_HUSH_PARSER) += cmd_test.o
 COBJS-$(CONFIG_CMD_TSI148) += cmd_tsi148.o
 COBJS-$(CONFIG_CMD_UBI) += cmd_ubi.o
diff --git a/common/cmd_time.c b/common/cmd_time.c
new file mode 100644
index 0000000..98c1993
--- /dev/null
+++ b/common/cmd_time.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ */
+
+/* time - run a command and report its run time */
+
+#include <common.h>
+#include <command.h>
+
+static void report_time(unsigned long int cycles)
+{
+#ifdef CONFIG_SYS_HZ
+	unsigned long int minutes, seconds, milliseconds;
+	unsigned long int total_seconds, remainder;
+
+	total_seconds = cycles / CONFIG_SYS_HZ;
+	remainder = cycles % CONFIG_SYS_HZ;
+	minutes = total_seconds / 60;
+	seconds = total_seconds % 60;
+	/* approximate millisecond value */
+	milliseconds = (remainder * 1000 + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ;
+
+	printf("time:");
+	if (minutes)
+		printf(" %lu minutes,", minutes);
+	printf(" %lu.%03lu seconds,", seconds, milliseconds);
+	printf(" %lu ticks\n", cycles);
+#else
+	printf("CONFIG_SYS_HZ not defined\n");
+	printf("time: %lu ticks\n", cycles);
+#endif
+}
+
+int do_time(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	const int target_argc = argc - 1;
+	int retval = 0;
+	unsigned long int cycles = 0;
+	cmd_tbl_t *target_cmdtp = NULL;
+
+	if (argc == 1) {
+		printf("no command provided\n");
+		return 1;
+	}
+
+	/* parse command */
+	target_cmdtp = find_cmd(argv[1]);
+	if (!target_cmdtp) {
+		printf("command not found: %s\n", argv[1]);
+		return 1;
+	}
+
+	if (target_argc > target_cmdtp->maxargs) {
+		printf("maxarags exceeded: %d > %d\n", target_argc,
+				target_cmdtp->maxargs);
+		return 1;
+	}
+
+	/* run the command and report run time */
+	cycles = get_timer_masked();
+	retval = target_cmdtp->cmd(target_cmdtp, 0, target_argc, argv + 1);
+	cycles = get_timer_masked() - cycles;
+
+	putc('\n');
+	report_time(cycles);
+
+	return retval;
+}
+
+U_BOOT_CMD(time, CONFIG_SYS_MAXARGS, 0, do_time,
+		"run a command and report its run time",
+		"command [args...]\n"
+		"the return value of time is the return value of "
+		"the command it executed, "
+		"or non-zero if there is an internal error of time.\n");
diff --git a/include/config_cmd_all.h b/include/config_cmd_all.h
index 02a58a5..7ee2e60 100644
--- a/include/config_cmd_all.h
+++ b/include/config_cmd_all.h
@@ -86,6 +86,7 @@
 #define CONFIG_CMD_SOURCE	/* "source" command support	*/
 #define CONFIG_CMD_SPI		/* SPI utility			*/
 #define CONFIG_CMD_TERMINAL	/* built-in Serial Terminal	*/
+#define CONFIG_CMD_TIME		/* Measure run time of a command */
 #define CONFIG_CMD_UBI		/* UBI Support			*/
 #define CONFIG_CMD_UBIFS	/* UBIFS Support		*/
 #define CONFIG_CMD_UNIVERSE	/* Tundra Universe Support	*/