This patch makes DRAM an explicit region by introducing
DECLARE_OPTIONAL_REGION(dram) and DRAM_END().
Note: many SoC platforms determine DRAM size and layout dynamically
during boot, making a static compile-time value is not feasible always.
Attempting to use REGION_SIZE(dram) in this scenario would result in a
missing symbol `_dram_size` error.
By making dram an optional region, we allow its size and address to be
defined only when available, preventing build failures on platforms
that configure DRAM dynamically.
The old extern u8 _dram[] is removed, as it's now covered by the new
region definition.
This is a preparatory step for future changes that will make use of
the new DRAM_END() macro.
This symbol is necessary for systems that require
the DRAM size to be known and accessible from the linker script or
other parts of the build system.
Additionally, a new macro DRAM_END(addr) is defined in memlayout.h.
This macro provides a consistent way to mark the end of the DRAM
region, similar to how REGION_END and other start/end macros are used
throughout the codebase.
TEST=Able to build and boot google/quenbi.
Change-Id: Ib98ec4b991eed56385c83be6a9ca39ff1380ff1b
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88751
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
b4347f11d9