Revert "openfirmware: remove real_time_clock."

This reverts commit 4e134b546a.

It breaks bootloader build on powerpc.

src/system/boot/platform/openfirmware/Jamfile

@@ -21,6 +21,7 @@ local platform_src =
 	menu.cpp
 	mmu.cpp
 	network.cpp
+	real_time_clock.cpp
 	start.cpp
 	support.cpp
 	video.cpp

src/system/boot/platform/openfirmware/real_time_clock.cpp

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2006, Ingo Weinhold <[email protected]>.
+ * Copyright 2010, Andreas Färber <[email protected]>
+ * All rights reserved. Distributed under the terms of the MIT License.
+ */
+
+
+#include "real_time_clock.h"
+
+#include <stdio.h>
+
+#include <boot/kernel_args.h>
+#include <boot/stage2.h>
+#include <platform/openfirmware/devices.h>
+#include <platform/openfirmware/openfirmware.h>
+
+
+static int sHandle = OF_FAILED;
+
+
+status_t
+init_real_time_clock(void)
+{
+	// find RTC
+	intptr_t rtcCookie = 0;
+	if (of_get_next_device(&rtcCookie, 0, "rtc",
+			gKernelArgs.platform_args.rtc_path,
+			sizeof(gKernelArgs.platform_args.rtc_path)) != B_OK) {
+		printf("init_real_time_clock(): Found no RTC device!");
+		return B_ERROR;
+	}
+
+	sHandle = of_open(gKernelArgs.platform_args.rtc_path);
+	if (sHandle == OF_FAILED) {
+		printf("%s(): Could not open RTC device!\n", __func__);
+		return B_ERROR;
+	}
+
+	return B_OK;
+}
+
+
+bigtime_t
+real_time_clock_usecs(void)
+{
+	if (sHandle == OF_FAILED)
+		return OF_FAILED;
+	int second, minute, hour, day, month, year;
+	if (of_call_method(sHandle, "get-time", 0, 6, &year, &month, &day,
+			&hour, &minute, &second) == OF_FAILED)
+		return OF_FAILED;
+	int days = day;
+		// TODO: Apply algorithm from kernel
+		// to assure monotonically increasing date.
+	return (((days * 24 + hour) * 60ULL + minute) * 60ULL + second)
+		* 1000000ULL;
+}

src/system/boot/platform/openfirmware/real_time_clock.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2006, Ingo Weinhold <[email protected]>.
+ * Copyright 2010, Andreas Färber <[email protected]>
+ * All rights reserved. Distributed under the terms of the MIT License.
+ */
+#ifndef OPENFIRMWARE_REAL_TIME_CLOCK_H
+#define OPENFIRMWARE_REAL_TIME_CLOCK_H
+
+
+#include <SupportDefs.h>
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+status_t init_real_time_clock(void);
+bigtime_t real_time_clock_usecs(void);
+
+#ifdef __cplusplus
+}   // extern "C"
+#endif
+
+#endif	/* OPENFIRMWARE_REAL_TIME_CLOCK_H */

src/system/boot/platform/openfirmware/start.cpp

@@ -20,6 +20,7 @@
 
 #include "console.h"
 #include "machine.h"
+#include "real_time_clock.h"
 
 
 #define HEAP_SIZE 65536
@@ -125,6 +126,9 @@ start(void *openFirmwareEntry)
 	if (boot_arch_cpu_init() != B_OK)
 		of_exit();
 
+	if (init_real_time_clock() != B_OK)
+		of_exit();
+
 	// check for key presses once
 	sBootOptions = 0;
 	int key = console_check_for_key();