mkimage: sunxi_egon: Allow overriding the padding size

Due to a bug in the H3 SoC, where the CPU 0 hotplug flag cannot be
written, resuming CPU 0 requires using the "Super Standby" code path in
the BROM instead of the hotplug path. This path requires jumping to an
eGON image in SRAM.

This resume image, whose single purpose is to jump back to the secure
monitor, only needs to contain a single instruction. Padding the image
to 8 KiB would be wasteful of SRAM. Hook up the -B (block size) option
so users can set the block/padding size.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/tools/sunxi_egon.c b/tools/sunxi_egon.c
index a5299eb..d1398c0 100644
--- a/tools/sunxi_egon.c
+++ b/tools/sunxi_egon.c
@@ -10,9 +10,10 @@
 
 /*
  * NAND requires 8K padding. SD/eMMC gets away with 512 bytes,
- * but let's use the larger padding to cover both.
+ * but let's use the larger padding by default to cover both.
  */
 #define PAD_SIZE			8192
+#define PAD_SIZE_MIN			512
 
 static int egon_check_params(struct image_tool_params *params)
 {
@@ -114,10 +115,12 @@
 static int egon_vrec_header(struct image_tool_params *params,
 			    struct image_type_params *tparams)
 {
+	int pad_size = ALIGN(params->bl_len ?: PAD_SIZE, PAD_SIZE_MIN);
+
 	tparams->hdr = calloc(sizeof(struct boot_file_head), 1);
 
-	/* Return padding to 8K blocks. */
-	return ALIGN(params->file_size, PAD_SIZE) - params->file_size;
+	/* Return padding to complete blocks. */
+	return ALIGN(params->file_size, pad_size) - params->file_size;
 }
 
 U_BOOT_IMAGE_TYPE(