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author | Tom Rini <trini@konsulko.com> | 2022-05-26 20:46:32 +0300 |
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committer | Tom Rini <trini@konsulko.com> | 2022-06-06 19:09:28 +0300 |
commit | 8b83b53a8d5fa3c2a6ab6a979399b1c285af9bea (patch) | |
tree | cd1658c8d8b324c5ca16ff4c5719f8f54424bba8 /doc/imx | |
parent | 23780398b587ac8bc912971c60cd816bd1afeb12 (diff) | |
download | u-boot-8b83b53a8d5fa3c2a6ab6a979399b1c285af9bea.tar.xz |
imx7: Update CONFIG_SPL_STACK defaults in Kconfig
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>
Diffstat (limited to 'doc/imx')
-rw-r--r-- | doc/imx/common/imx7.txt | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/doc/imx/common/imx7.txt b/doc/imx/common/imx7.txt new file mode 100644 index 0000000000..b9db10341a --- /dev/null +++ b/doc/imx/common/imx7.txt @@ -0,0 +1,23 @@ +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). |