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To find the coreboot tables, the payload has historically searched for their
signature in a predefined region of memory. This is a little clumsy on x86,
but it works because you can assume certain regions are RAM. Also, there are
areas which are set aside for the firmware by convention. On x86 there's a
forwarding entry which goes in one of those fairly small conventional areas
and which points to the CBMEM area at the end of memory.
On ARM there aren't areas like that, so we've left out the forwarding entry and
gone directly to CBMEM. RAM may not start at the beginning of the address space
or go to its end, and that means there isn't really anywhere fixed you can put
the coreboot tables. That's meant that libpayload has to be configured on a
per board basis to know where to look for CBMEM.
Now that we have boards that don't have fixed amounts of memory, the location
of the end of RAM isn't fixed even on a per board level which means even that
workaround will no longer cut it.
This change makes coreboot pass the location of the coreboot tables to
libpayload using r0, the first argument register. That means we'll be able to
find them no matter where CBMEM is, and we can get rid of the per board search
ranges.
We can extend this mechanism to x86 as well, but there may be more
complications and it's less necessary there. It would be a good thing to do
eventually though.
BUG=None
TEST=Built and booted on nyan. Changed the size of memory and saw that the
payload could still find the coreboot tables where before it couldn't. Built
for pit, snow, and big.
BRANCH=None
Original-Change-Id: I7218afd999da1662b0db8172fd8125670ceac471
Original-Signed-off-by: Gabe Black <gabeblack@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/185572
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Commit-Queue: Gabe Black <gabeblack@chromium.org>
Original-Tested-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit ca88f39c21158b59abe3001f986207a292359cf5)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Change-Id: Iab14e9502b6ce7a55f0a72e190fa582f89f11a1e
Reviewed-on: http://review.coreboot.org/7655
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
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There are ARM systems which are essentially heterogeneous multicores where
some cores implement a different ARM architecture version than other cores. A
specific example is the tegra124 which boots on an ARMv4 coprocessor while
most code, including most of the firmware, runs on the main ARMv7 core. To
support SOCs like this, the plan is to generalize the ARM architecture so that
all versions are available, and an SOC/CPU can then select what architecture
variant should be used for each component of the firmware; bootblock,
romstage, and ramstage.
Old-Change-Id: I22e048c3bc72bd56371e14200942e436c1e312c2
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://chromium-review.googlesource.com/171338
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 8423a41529da0ff67fb9873be1e2beb30b09ae2d)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
ARM: Split out ARMv7 code and make it possible to have other arch versions.
We don't always want to use ARMv7 code when building for ARM, so we should
separate out the ARMv7 code so it can be excluded, and also make it possible
to include code for some other version of the architecture instead, all per
build component for cases where we need more than one architecture version
at a time.
The tegra124 bootblock will ultimately need to be ARMv4, but until we have
some ARMv4 code to switch over to we can leave it set to ARMv7.
Old-Change-Id: Ia982c91057fac9c252397b7c866224f103761cc7
Reviewed-on: https://chromium-review.googlesource.com/171400
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
(cherry picked from commit 799514e6060aa97acdcf081b5c48f965be134483)
Squashed two related patches for splitting ARM support into general
ARM support and ARMv7 specific pieces.
Change-Id: Ic6511507953a2223c87c55f90252c4a4e1dd6010
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6782
Tested-by: build bot (Jenkins)
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