Add information about memory usage when U-Boot is started from coreboot. This is useful when debugging. Also, since coreboot takes a chunk of memory in the middle of SDRAM for use by PCI devices, it can help avoid overwriting this with a loaded kernel by accident.
Signed-off-by: Simon Glass sjg@chromium.org ---
Changes in v2: - Convert table to reST format
doc/board/coreboot/coreboot.rst | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/doc/board/coreboot/coreboot.rst b/doc/board/coreboot/coreboot.rst index 9c44c025a48..3792f9e1c8d 100644 --- a/doc/board/coreboot/coreboot.rst +++ b/doc/board/coreboot/coreboot.rst @@ -50,3 +50,24 @@ works by using a 32-bit SPL binary to switch to 64-bit for running U-Boot. It can be useful for running UEFI applications, for example.
This has only been lightly tested. + + +Memory map +---------- + + ========== ================================================================== + Address Region at that address + ========== ================================================================== + ffffffff Top of ROM (and last byte of 32-bit address space) + 7a9fd000 Typical top of memory available to U-Boot + (use cbsysinfo to see where memory range 'table' starts) + 10000000 Memory reserved by coreboot for mapping PCI devices + (typical size 2151000, includes framebuffer) + 1920000 CONFIG_SYS_CAR_ADDR, fake Cache-as-RAM memory, used during startup + 1110000 CONFIG_SYS_TEXT_BASE (start address of U-Boot code, before reloc) + 110000 CONFIG_BLOBLIST_ADDR (before being relocated) + 100000 CONFIG_PRE_CON_BUF_ADDR + f0000 ACPI tables set up by U-Boot + (typically redirects to 7ab10030 or similar) + 500 Location of coreboot sysinfo table, used during startup + ========== ==================================================================