From 75b930f39633282acf5c5692e8f6df25b4c3e97a Mon Sep 17 00:00:00 2001
From: Magnus Eriksson <packetlss@gmail.com>
Date: Wed, 10 Mar 2010 18:29:38 +0100
Subject: [PATCH] added erase_flash, utility to erase mtd partition

primarily for platforms without engineering SPL or native fastboot support
---
 mtdutils/Android.mk    |  9 +++++
 mtdutils/erase_flash.c | 82 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 mtdutils/erase_flash.c

diff --git a/mtdutils/Android.mk b/mtdutils/Android.mk
index 06ba854..e83cbf3 100644
--- a/mtdutils/Android.mk
+++ b/mtdutils/Android.mk
@@ -28,6 +28,14 @@ LOCAL_STATIC_LIBRARIES := libmtdutils
 LOCAL_SHARED_LIBRARIES := libcutils libc
 include $(BUILD_EXECUTABLE)
 
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := erase_flash.c
+LOCAL_MODULE := erase_flash
+LOCAL_MODULE_TAGS := eng
+LOCAL_STATIC_LIBRARIES := libmtdutils
+LOCAL_SHARED_LIBRARIES := libcutils libc
+include $(BUILD_EXECUTABLE)
+
 include $(CLEAR_VARS)
 LOCAL_SRC_FILES := flash_image.c
 LOCAL_MODULE := libflash_image
@@ -46,6 +54,7 @@ LOCAL_MODULE_PATH := $(TARGET_OUT)/utilities
 LOCAL_STATIC_LIBRARIES := libmtdutils libcutils libc 
 include $(BUILD_EXECUTABLE)
 
+
 include $(CLEAR_VARS)
 LOCAL_SRC_FILES := dump_image.c
 LOCAL_MODULE := libdump_image
diff --git a/mtdutils/erase_flash.c b/mtdutils/erase_flash.c
new file mode 100644
index 0000000..111e637
--- /dev/null
+++ b/mtdutils/erase_flash.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * Portions Copyright (C) 2010 Magnus Eriksson <packetlss@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <fcntl.h>
+#include <mtd/mtd-user.h>
+
+#include "cutils/log.h"
+#include "mtdutils.h"
+
+#ifdef LOG_TAG
+#undef LOG_TAG
+#endif
+
+#define LOG_TAG "erase_flash"
+
+void die(const char *msg, ...) {
+    int err = errno;
+    va_list args;
+    va_start(args, msg);
+    char buf[1024];
+    vsnprintf(buf, sizeof(buf), msg, args);
+    va_end(args);
+
+    if (err != 0) {
+        strlcat(buf, ": ", sizeof(buf));
+        strlcat(buf, strerror(err), sizeof(buf));
+    }
+
+    fprintf(stderr, "%s\n", buf);
+    LOGE("%s\n", buf);
+    exit(1);
+}
+
+/* Erase a mtd partition */
+
+int main(int argc, char **argv) {
+    MtdWriteContext *out;
+    size_t erased;
+    size_t total_size;
+    size_t erase_size;
+
+    if (argc != 2) {
+        fprintf(stderr, "usage: %s <partition>\n", argv[0]);
+        return 2;
+    }
+
+    if (mtd_scan_partitions() <= 0) die("error scanning partitions");
+    const MtdPartition *partition = mtd_find_partition_by_name(argv[1]);
+    if (partition == NULL) die("can't find %s partition", argv[1]);
+
+    out = mtd_write_partition(partition);
+    if (out == NULL) die("could not estabilish write context for %s", argv[1]);
+
+    // do the actual erase, -1 = full partition erase
+    erased = mtd_erase_blocks(out, -1);
+
+    // erased = bytes erased, if zero, something borked
+    if (!erased) die("error erasing %s", argv[1]);
+
+    return 0;
+}