[PATCH 2/4] filetype: add fat filesystem support

[Jean-Christophe PLAGNIOL-VILLARD]

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
 common/filetype.c  |   20 ++++++++++++++++++++
 include/filetype.h |    1 +
 2 files changed, 21 insertions(+)

diff --git a/common/filetype.c b/common/filetype.c
index 1a5b82d..e736d43 100644
--- a/common/filetype.c
+++ b/common/filetype.c
@@ -22,6 +22,7 @@
 #include <common.h>
 #include <filetype.h>
 #include <asm/byteorder.h>
+#include <asm/unaligned.h>
 #include <fcntl.h>
 #include <fs.h>
 #include <malloc.h>
@@ -40,6 +41,7 @@ static const char *filetype_str[] = {
 	[filetype_aimage] = "Android boot image",
 	[filetype_sh] = "Bourne Shell",
 	[filetype_mips_barebox] = "MIPS barebox image",
+	[filetype_fat] = "FAT filesytem",
 };
 
 const char *file_type_to_string(enum filetype f)
@@ -50,6 +52,22 @@ const char *file_type_to_string(enum filetype f)
 	return NULL;
 }
 
+static int is_fat(u8 *buf)
+{
+	if (get_unaligned_le16(&buf[510]) != 0xAA55)
+		return 0;
+
+	/* FAT */
+	if ((get_unaligned_le32(&buf[54]) & 0xFFFFFF) == 0x544146)
+		return 1;
+
+	/* FAT32 */
+	if ((get_unaligned_le32(&buf[82]) & 0xFFFFFF) == 0x544146)
+		return 1;
+
+	return 0;
+}
+
 enum filetype file_detect_type(void *_buf)
 {
 	u32 *buf = _buf;
@@ -81,6 +99,8 @@ enum filetype file_detect_type(void *_buf)
 		return filetype_aimage;
 	if (strncmp(buf8 + 0x10, "barebox", 7) == 0)
 		return filetype_mips_barebox;
+	if (is_fat(buf8))
+		return filetype_fat;
 
 	return filetype_unknown;
 }
diff --git a/include/filetype.h b/include/filetype.h
index f5de8ed..179ec0f 100644
--- a/include/filetype.h
+++ b/include/filetype.h
@@ -18,6 +18,7 @@ enum filetype {
 	filetype_aimage,
 	filetype_sh,
 	filetype_mips_barebox,
+	filetype_fat,
 };
 
 const char *file_type_to_string(enum filetype f);
-- 
1.7.10.4