[PATCH v2] mkimage: fit_image: Make fit header and data align to 512

[Kever Yang]

The image is usually stored in block device like emmc, SD card, make the
offset of image data aligned to block(512 byte) can avoid data copy
during boot process.
eg. SPL boot from FIT image with external data:
- SPL read the first block of FIT image, and then parse the header;
- SPL read image data separately;
- The first image offset is the base_offset which is the header size;
- The second image offset is just after the first image;
- If the offset of imge does not aligned, SPL will do memcpy;
The header size is a ramdon number, which is very possible not aligned, so
add '-B' to specify the align size in hex for better performance.

example usage:
  ./tools/mkimage -E -f u-boot.its -B 200 u-boot.itb

Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
---

Changes in v2:
- use '-B' to take a argument as a align block lenth;
- address commens from Heinrich, Rasmus, Tom, Punit;

 doc/uImage.FIT/source_file_format.txt |  5 +++++
 tools/fit_image.c                     | 26 ++++++++++++++++++++------
 tools/imagetool.h                     |  1 +
 tools/mkimage.c                       | 14 ++++++++++++--
 4 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/doc/uImage.FIT/source_file_format.txt b/doc/uImage.FIT/source_file_format.txt
index 18d2aedcb7..50679c4b24 100644
--- a/doc/uImage.FIT/source_file_format.txt
+++ b/doc/uImage.FIT/source_file_format.txt
@@ -304,6 +304,11 @@ Normal kernel FIT image has data embedded within FIT structure. U-Boot image
 for SPL boot has external data. Existence of 'data-offset' can be used to
 identify which format is used.
 
+For FIT image with external data, it would be better to align each blob of data
+to block(512 byte) for block device, so that we don't need to do the copy when
+read the image data in SPL. Pass '-B' to mkimage to align the FIT structure and
+data to 512 byte.
+
 9) Examples
 -----------
 
diff --git a/tools/fit_image.c b/tools/fit_image.c
index 6aa4b1c733..6fa2ce328a 100644
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -23,6 +23,11 @@
 
 static image_header_t header;
 
+static int get_aligned_size(int size, int aligned_size)
+{
+	return ((size + aligned_size - 1) & ~(aligned_size - 1));
+}
+
 static int fit_add_file_data(struct image_tool_params *params, size_t size_inc,
 			     const char *tmpfile)
 {
@@ -430,8 +435,11 @@ static int fit_extract_data(struct image_tool_params *params, const char *fname)
 		return -EIO;
 	fit_size = fdt_totalsize(fdt);
 
-	/* Allocate space to hold the image data we will extract */
-	buf = malloc(fit_size);
+	/*
+	 * Allocate space to hold the image data we will extract,
+	 * 4096 byte extral space allocate for image alignment.
+	 */
+	buf = malloc(fit_size + 4096);
 	if (!buf) {
 		ret = -ENOMEM;
 		goto err_munmap;
@@ -471,17 +479,23 @@ static int fit_extract_data(struct image_tool_params *params, const char *fname)
 					buf_ptr);
 		}
 		fdt_setprop_u32(fdt, node, FIT_DATA_SIZE_PROP, len);
-
-		buf_ptr += (len + 3) & ~3;
+		if (params->bl_len > 0)
+			buf_ptr += get_aligned_size(len, params->bl_len);
+		else
+			buf_ptr += get_aligned_size(len, 4);
 	}
 
 	/* Pack the FDT and place the data after it */
 	fdt_pack(fdt);
 
+	new_size = fdt_totalsize(fdt);
+	if (params->bl_len > 0)
+		new_size = get_aligned_size(new_size, params->bl_len);
+	else
+		new_size = get_aligned_size(new_size, 4);
+	fdt_set_totalsize(fdt, new_size);
 	debug("Size reduced from %x to %x\n", fit_size, fdt_totalsize(fdt));
 	debug("External data size %x\n", buf_ptr);
-	new_size = fdt_totalsize(fdt);
-	new_size = (new_size + 3) & ~3;
 	munmap(fdt, sbuf.st_size);
 
 	if (ftruncate(fd, new_size)) {
diff --git a/tools/imagetool.h b/tools/imagetool.h
index e1c778b0df..fd5e4b246c 100644
--- a/tools/imagetool.h
+++ b/tools/imagetool.h
@@ -76,6 +76,7 @@ struct image_tool_params {
 	bool external_data;	/* Store data outside the FIT */
 	bool quiet;		/* Don't output text in normal operation */
 	unsigned int external_offset;	/* Add padding to external data */
+	int bl_len;		/* Block length in byte for external data */
 	const char *engine_id;	/* Engine to use for signing */
 };
 
diff --git a/tools/mkimage.c b/tools/mkimage.c
index 5f51d2cc89..584aeff907 100644
--- a/tools/mkimage.c
+++ b/tools/mkimage.c
@@ -97,8 +97,9 @@ static void usage(const char *msg)
 		"          -i => input filename for ramdisk file\n");
 #ifdef CONFIG_FIT_SIGNATURE
 	fprintf(stderr,
-		"Signing / verified boot options: [-E] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
+		"Signing / verified boot options: [-E] [-B] [-k keydir] [-K dtb] [ -c <comment>] [-p addr] [-r] [-N engine]\n"
 		"          -E => place data outside of the FIT structure\n"
+		"          -B => align FIT structure and header to block\n"
 		"          -k => set directory containing private keys\n"
 		"          -K => write public keys to this .dtb file\n"
 		"          -c => add comment in signature node\n"
@@ -143,7 +144,7 @@ static void process_args(int argc, char **argv)
 	int opt;
 
 	while ((opt = getopt(argc, argv,
-			     "a:A:b:c:C:d:D:e:Ef:Fk:i:K:ln:N:p:O:rR:qsT:vVx")) != -1) {
+			     "a:A:b:B:c:C:d:D:e:Ef:Fk:i:K:ln:N:p:O:rR:qsT:vVx")) != -1) {
 		switch (opt) {
 		case 'a':
 			params.addr = strtoull(optarg, &ptr, 16);
@@ -167,6 +168,15 @@ static void process_args(int argc, char **argv)
 					params.cmdname, optarg);
 				exit(EXIT_FAILURE);
 			}
+			break;
+		case 'B':
+			params.bl_len = strtoull(optarg, &ptr, 16);
+			if (*ptr) {
+				fprintf(stderr, "%s: invalid block length %s\n",
+					params.cmdname, optarg);
+				exit(EXIT_FAILURE);
+			}
+
 			break;
 		case 'c':
 			params.comment = optarg;
-- 
2.17.1