diff options
| author | Shawn Guo <shawn.guo@linaro.org> | 2012-01-09 21:54:08 +0000 |
|---|---|---|
| committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2012-02-27 21:19:24 +0100 |
| commit | fa34f6b25b3c92f27b245c52378a0d2af24aaa19 (patch) | |
| tree | 633f7e7a58730058e6b77e6800dcf41adc5e1bdb /README | |
| parent | ba901df41b0d77088408c1f6aac65eaadd4d12a0 (diff) | |
common/image.c: align usage of fdt_high with initrd_high
The commit message of a28afca (Add uboot "fdt_high" enviroment variable)
states that fdt_high behaves similarly to the existing initrd_high.
But fdt_high actually has an outstanding difference from initrd_high.
The former specifies the start address, while the later specifies the
end address.
As fdt_high and initrd_high will likely be used together, it'd be nice
to have them behave same. The patch changes the behavior of fdt_high
to have it aligned with initrd_high.
The document of fdt_high in README is updated with an example to
demonstrate the usage of this environment variable.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'README')
| -rw-r--r-- | README | 8 |
1 files changed, 8 insertions, 0 deletions
@@ -3665,6 +3665,14 @@ List of environment variables (most likely not complete): fdt_high - if set this restricts the maximum address that the flattened device tree will be copied into upon boot. + For example, if you have a system with 1 GB memory + at physical address 0x10000000, while Linux kernel + only recognizes the first 704 MB as low memory, you + may need to set fdt_high as 0x3C000000 to have the + device tree blob be copied to the maximum address + of the 704 MB low memory, so that Linux kernel can + access it during the boot procedure. + If this is set to the special value 0xFFFFFFFF then the fdt will not be copied at all on boot. For this to work it must reside in writable memory, have |