The Allwinner A64 SoC starts execution in AArch32 mode, and both
the boot ROM and Allwinner's boot0 keep running in this mode.
So U-Boot gets entered in 32-bit, although we want it to run in AArch64.
By using a "magic" instruction, which happens to be an almost-NOP in
AArch64 and a branch in AArch32, we differentiate between being
entered in 64-bit or 32-bit mode.
If in 64-bit mode, we proceed with the branch to reset, but in 32-bit
mode we trigger an RMR write to bring the core into AArch64/EL3 and
re-enter U-Boot at CONFIG_SYS_TEXT_BASE.
This allows a 64-bit U-Boot to be both entered in 32 and 64-bit mode,
so we can use the same start code for the SPL and the U-Boot proper.
We use the existing custom header (boot0.h) functionality, but restrict
the existing boot0 header reservation to the non-SPL build now. A SPL
wouldn't need such header anyway. This allows to have both options
defined and lets us use one for the SPL and the other for U-Boot proper.
Also add arch/arm/mach-sunxi/rmr_switch.S, which contains the original
ARM assembly code and instructions how to re-generate the encoded
version.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
For prepending some board specific header area to U-Boot images we
were so far including a header file with a macro definition containing
the actual header specification.
This works fine if there are just a few statements and if there is only
one alternative.
However adding more complex code quickly gets messy with this approach,
so let's just drop that intermediate macro and let the #include actually
insert the code directly.
This converts the callers and the callees, but doesn't change anything
at this point.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Steve Rae <steve.rae@raedomain.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
The boot0 hook we have so far is applied _after_ the initial branch
to the "reset" entry point. An upcoming change requires even this
branch to be changed, so we apply the hook macro at the earliest
point, and have the branch in the hook file as well.
This is no functional change at this point, just refactoring to simplify
upcoming patches.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Some SPL loaders (like Allwinner's boot0, and Broadcom's boot0)
require a header before the actual U-Boot binary to both check its
validity and to find other data to load. Sometimes this header may
only be a few bytes of information, and sometimes this might simply
be space that needs to be reserved for a post-processing tool.
Introduce a config option to allow assembler preprocessor commands
to be inserted into the code at the appropriate location; typical
assembler preprocessor commands might be:
.space 1000
.word 0x12345678
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Steve Rae <srae@broadcom.com>
Commit Notes:
Please note that the current code:
start.S (arm64) and
vectors.S (arm)
already jumps over some portion of data already, so this option basically
just increases the size of this region (and the resulting binary).
For use with Allwinner's boot0 blob there is a tool called boot0img[1],
which fills the header to allow booting A64 based boards.
For the Pine64 we need a 1536 byte header (including the branch
instruction) at the moment, so we add this to the defconfig.
[1] https://github.com/apritzel/pine64/tree/master/tools
END
Reviewed-by: Tom Rini <trini@konsulko.com>
