Since devices that can't DMA above 4GiB will misbehave with this option enabled add a warning on the documentation.
Signed-off-by: Ilias Apalodimas <[email protected]> --- doc/develop/memory.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/doc/develop/memory.rst b/doc/develop/memory.rst index 5177229630d1..ffee06c1530c 100644 --- a/doc/develop/memory.rst +++ b/doc/develop/memory.rst @@ -110,6 +110,12 @@ U-Boot Proper Flow This follows the same as in SPL flow. In board_init_f(), a part of memory is reserved at the end of RAM (see reserve_* functions in init_sequence_f) + #. Relocation address + By default U-Boot will try to relocate below the 4GiB boundary. If + RELOC_ADDR_TOP is enabled U-Boot will look into the dram bank config of + gd->dram[] and try to relocate to the highest available bank. Use this + with caution as devices that can only DMA below 4GiB will misbehave + since their buffers may be allocated above the 32-bit boundary. #. Code Relocation -- 2.53.0
