On 5/17/23 02:17, Bo Gan wrote:
@Heinrich Some background information I discovered by experimenting with
my vf2 board:
The only reasonable place to load SPL is the L2 LIM, which is 2M in size
mapped at
0x8000000. This region consists of 16 0x20000 sized regions, each one
can be used as
either L2 cache way or SRAM (not both). From top to bottom, you have way
0-15. When
ways are enabled, they can't be disabled without reset. Effectively, as
you enabling
more and more L2 cache, this SRAM region shrinks. The way 0 is always
enabled, so SPL
can only use at most 0x1e0000 bytes of memory.
On 5/16/23 12:56 PM, Heinrich Schuchardt wrote:
https://github.com/starfive-tech/Tools/commit/8c5acc4e5eb7e4ad012463b05a5e3dbbfed1c38d
seems to have changed the limit in the tooling.
I don't know how they derive the number 180048, but my guess is they
just pick some
number that fits their u-boot build. For correctness, it really depends
on how ROM is
loading SPL, and where does ROM allocate its data/stack during loading,
so it won't
collide with the SPL being loaded. It might also be that ROM uses S7
DTIM to load SPL,
and doesn't touch L2 LIM at all. The ROM is close-sourced, thus, not
very easy to know
without reverse-engineering it. The defconfig already defines
https://github.com/u-boot/u-boot/blob/6e1852c/configs/starfive_visionfive2_defconfig#L37
CONFIG_SPL_MAX_SIZE=0x40000
CONFIG_SPL_BSS_START_ADDR=0x8040000
256KiB of SPL sounds like a reasonable number to me. 128KiB might be a
little bit small
when you have max loglevels enabled, and -DDEBUG. I think we can
probably just change
CONFIG_SPL_MAX_SIZE to CONFIG_SPL_SIZE_LIMIT, and be done with it.
128 KiB is exceeded when adding the not yet merged patch series for
updating the DTB based on EEPROM data. This is why I hit the old limit
in spl_tool.
I would prefer if we could add the functionality of spl_tool into
U-Boot's mkimage and let binman handle invoking it.
CONFIG_SPL_SIZE_LIMIT would be without the 1 KiB header added by
spl_tool. So should CONFIG_SPL_MAX_SIZE and CONFIG_SPL_SIZE_LIMIT be set
to 0x3FC00?
Best regards
Heinrich
