rockchip: mkimage: clarify header0 initialisation

This change set adds documentation to the header0 initialisation and
improves readability for the calculations of various offsets/lengths.

As the U-Boot SPL stage doesn't use any payload beyond what is covered
by init_size, we no longer add RK_MAX_BOOT_SIZE to init_boot_size.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/tools/rkcommon.c b/tools/rkcommon.c
index 1880fef5248b9e16ca4054410c5b89f4a1536275..f8260011188e443c4a9d59fd7d43f4eee1cc6863 100644 (file)
--- a/tools/rkcommon.c
+++ b/tools/rkcommon.c
@@ -13,6 +13,8 @@
 #include "mkimage.h"
 #include "rkcommon.h"
 
+#define DIV_ROUND_UP(n, d)     (((n) + (d) - 1) / (d))
+
 enum {
        RK_SIGNATURE            = 0x0ff0aa55,
 };
@@ -160,9 +162,21 @@ static void rkcommon_set_header0(void *buf, uint file_size,
        hdr->disable_rc4 = !rkcommon_need_rc4_spl(params);
        hdr->init_offset = RK_INIT_OFFSET;
 
-       hdr->init_size = (file_size + RK_BLK_SIZE - 1) / RK_BLK_SIZE;
-       hdr->init_size = (hdr->init_size + 3) & ~3;
-       hdr->init_boot_size = hdr->init_size + RK_MAX_BOOT_SIZE / RK_BLK_SIZE;
+       hdr->init_size = DIV_ROUND_UP(file_size, RK_BLK_SIZE);
+       /*
+        * The init_size has to be a multiple of 4 blocks (i.e. of 2K)
+        * or the BootROM will not boot the image.
+        *
+        * Note: To verify that this is not a legacy constraint, we
+        *       rechecked this against the RK3399 BootROM.
+        */
+       hdr->init_size = ROUND(hdr->init_size, 4);
+       /*
+        * The images we create do not contain the stage following the SPL as
+        * part of the SPL image, so the init_boot_size (which might have been
+        * read by Rockchip's miniloder) should be the same as the init_size.
+        */
+       hdr->init_boot_size = hdr->init_size;
 
        rc4_encode(buf, RK_BLK_SIZE, rc4_key);
 }