CHROMIUM: Add memory wipe library and its test.

The old code is copied from the old recovery firmware implementation:
http://gerrit.chromium.org/gerrit/gitweb?p=chromiumos/third_party/u-boot.git;a=blob;f=common/cmd_cros_rec.c;h=4188ec98d136129e45d9d6c7664f861b279185f8;hb=refs/heads/chromeos-v2010.09

BUG=chromium-os:17950
TEST=run "vboot_test memwipe" success.
Tegra2 # vboot_test memwipe
memory_wipe: clear memory regions:
memory_wipe:    [0x3f760c5c, 0x3f760c5d)
memory_wipe:    [0x3f760c64, 0x3f760c65)
Memory wipe test SUCCESS!

Change-Id: Ieb587dbe001f91a58add6bcd3a1bc505e4227bda
Reviewed-on: http://gerrit.chromium.org/gerrit/4478
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
Reviewed-by: Che-Liang Chiou <clchiou@chromium.org>

2 files changed, 70 insertions, 1 deletions

diff --git a/lib/chromeos/Makefile b/lib/chromeos/Makefile
index 0056259c2f..a004bfba6d 100644
--- a/lib/chromeos/Makefile
+++ b/lib/chromeos/Makefile
@@ -16,8 +16,9 @@ COBJS-$(CONFIG_CHROMEOS) += cmdline_updater.o
 COBJS-$(CONFIG_CHROMEOS) += crossystem_data.o
 COBJS-$(CONFIG_CHROMEOS) += fdt_decode.o
 COBJS-$(CONFIG_CHROMEOS) += firmware_storage_spi.o
-COBJS-$(CONFIG_CHROMEOS) += preboot_fdt_update.o
 COBJS-$(CONFIG_CHROMEOS) += gbb_bmpblk.o
+COBJS-$(CONFIG_CHROMEOS) += memory_wipe.o
+COBJS-$(CONFIG_CHROMEOS) += preboot_fdt_update.o
 
 # TODO(sjg): This MMC code is not needed as yet, and needs slight changes
 # to build now
diff --git a/lib/chromeos/memory_wipe.c b/lib/chromeos/memory_wipe.c
new file mode 100644
index 0000000000..59ea0ef145
--- /dev/null
+++ b/lib/chromeos/memory_wipe.c
@@ -0,0 +1,68 @@
+/*
+ * 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.
+ */
+
+#include <common.h>
+#include <chromeos/common.h>
+#include <chromeos/memory_wipe.h>
+
+#include <vboot_api.h>
+
+#define PREFIX		"memory_wipe: "
+
+void memory_wipe_init(memory_wipe_t *wipe, uintptr_t start, uintptr_t end)
+{
+	wipe->whole.start = start;
+	wipe->whole.end = end;
+	wipe->excluded_count = 0;
+}
+
+int memory_wipe_exclude(memory_wipe_t *wipe, uintptr_t start, uintptr_t end)
+{
+	int i = wipe->excluded_count;
+
+	if (i >= MAX_EXCLUDED_REGIONS) {
+		VBDEBUG(PREFIX "the number of excluded regions reaches"
+				"the maximum: %d\n", MAX_EXCLUDED_REGIONS);
+		return -1;
+	}
+
+	while (i > 0 && wipe->excluded[i - 1].start > start) {
+		wipe->excluded[i].start = wipe->excluded[i - 1].start;
+		wipe->excluded[i].end = wipe->excluded[i - 1].end;
+		i--;
+	}
+	wipe->excluded[i].start = start;
+	wipe->excluded[i].end = end;
+	wipe->excluded_count++;
+
+	return 0;
+}
+
+static void zero_mem(uintptr_t start, uintptr_t end)
+{
+	if (end > start) {
+		VBDEBUG(PREFIX "\t[0x%08x, 0x%08x)\n", start, end);
+		memset((void *)start, '\0', (size_t)(end - start));
+	}
+}
+
+void memory_wipe_execute(memory_wipe_t *wipe)
+{
+	uintptr_t addr = wipe->whole.start;
+	int i;
+
+	VBDEBUG(PREFIX "Wipe memory regions:\n");
+	for (i = 0; i < wipe->excluded_count; i++) {
+		zero_mem(addr, wipe->excluded[i].start);
+		if (wipe->excluded[i].end > addr)
+			addr = wipe->excluded[i].end;
+	}
+	zero_mem(addr, wipe->whole.end);
+}