On Fri, May 8, 2020 at 4:49 AM Samuel Holland samuel@sholland.org wrote:
Some boards, specifically 64-bit Allwinner boards (sun50i), are extremely limited on SPL size. One strategy that was used to make space was to remove the FIT "os" property parsing code, because it uses a rather large lookup table.
However, this forces the legacy FIT parsing code path, which requires the "firmware" entry in the FIT to reference the U-Boot binary, even if U-Boot is not the next binary in the boot sequence (for example, on sun50i boards, ATF is run first).
This prevents the same FIT image from being used with a SPL with CONFIG_SPL_FIT_IMAGE_TINY=n and CONFIG_SPL_ATF=y, because the boot method selection code looks at `spl_image.os`, which is only set from the "firmware" entry's "os" property.
To be able to use CONFIG_SPL_ATF=y, the "firmware" entry in the FIT must be ATF, and U-Boot must be a loadable. For this to work, we need to parse the "os" property just enough to tell U-Boot from other images, so we can find it in the loadables list to append the FDT, and so we don't try to append the FDT to ATF (which could clobber adjacent firmware).
So add the minimal code necessary to distinguish U-Boot/non-U-Boot loadables with CONFIG_SPL_FIT_IMAGE_TINY=y. This adds about 300 bytes, much less than the 7400 bytes added by CONFIG_SPL_FIT_IMAGE_TINY=n.
Signed-off-by: Samuel Holland samuel@sholland.org
+ Andre