mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-13 06:42:56 +00:00
8b83b53a8d
Update the Kconfig entry to have the correct defaults for i.MX7 platforms, and move the existing large comment from imx7_spl.h to doc/imx/common/imx7.txt so that it's not lost. Signed-off-by: Tom Rini <trini@konsulko.com>
23 lines
1.3 KiB
Text
23 lines
1.3 KiB
Text
U-Boot for Freescale i.MX7
|
|
|
|
SPL Stack size and location notes
|
|
---------------------------------
|
|
See figure 6-22 in i.MX 7Dual/Solo Reference manuals:
|
|
- IMX7D/S OCRAM free area RAM (OCRAM) is from 0x00910000 to
|
|
0x00946C00.
|
|
- Set the stack at the end of the free area section, at 0x00946BB8.
|
|
- The BOOT ROM loads what they consider the firmware image
|
|
which consists of a 4K header in front of us that contains the IVT, DCD
|
|
and some padding. However, the manual also states that the ROM uses the
|
|
OCRAM_EPCD and OCRAM_PXP areas for itself. While the SPL is free to use
|
|
this range for stack and malloc, the SPL itself must fit below 0x920000,
|
|
or the image will be truncated in at least some boot modes like USB SDP.
|
|
Thus our max size is really 0x00920000 - 0x00912000. If necessary,
|
|
CONFIG_SPL_TEXT_BASE could be moved to 0x00911000 to gain 4KB of space
|
|
for the SPL, but 56KB should be more than enough for the SPL.
|
|
- Pad SPL to 68KB (4KB header + 56KB max size + 8KB extra padding)
|
|
The extra padding could be removed, but this value was used historically
|
|
based on an incorrect CONFIG_SPL_MAX_SIZE definition.
|
|
This allows to write the SPL/U-Boot combination generated with
|
|
u-boot-with-spl.imx directly to a boot media (given that boot media specific
|
|
offset is configured properly).
|