Duncan Hare
714 931 7952
----- Forwarded Message -----
From: "d...@synoia.com" <d...@synoia.com>
To: "u-boot@lists.denx.de" <u-boot@lists.denx.de>
Cc: Cédric Schieli <cschi...@gmail.com>
Sent: Sunday, November 13, 2016 4:08 PM
Subject: FDT retrived varaibles appear to have different properties fom other
u-boot variables - and are corrupted on get, set, get sequence
Cédric
I move the fdt to 0x100
fdt move ${fdt_addr} 100
fdt addr 100
then
fdt get value bootargs /chosen bootargs
printenv bootargs
bootargs=8250.nr_uarts=1 dma.dmachans=........all the boot args....... (note
the space after "uarts=1)
setenv abc $bootargs fails...as does printenv $bootargs
They I tried
fdt set bootargs /chosen bootargsfdt get value bootargs /chosen
bootargsbootargs=8250.nr_uarts=1
The bootargs parameter list is truncated after the first blank.
Something is not right in the world of fdt code.
Duncan Hare
714 931 7952
From: Cédric Schieli <cschi...@gmail.com>
To: d...@synoia.com
Sent: Sunday, November 13, 2016 2:21 AM
Subject: Re: Fw: [U-Boot] Fw: FDT pointer value, passed by the PI firmware, is
not set in u-boot
Hello Duncan,
2016-11-13 3:04 GMT+01:00 <d...@synoia.com>:
> If appending to "/chosen bootargs" (making it longer), does the fdt command
> automatically relocate the fdt, or does the u-boot script have to do that
> itself?
>
> The fdt doc at http://www.denx.de/wiki/view/ DULG/UBootCmdFDT
> Is quite unclear on how the fdt size is managed, especially when the fdt is
> located close to the end of memory.
I'm not an expert here, but looking at cmd/fdt.c I didn't find any kind of
relocation code. So I guess the safe bet is to move the blob before making any
(growing) change to the tree:
# load the blob from the firmware provided address (at the end of memory)
fdt addr ${fdt_addr}
# move the blob to the (previously) default location (0x100)
fdt move ${fdt_addr_r}
# make needed changes
setenv bootargs "......."
# boot from the new location
bootz ${kernel_addr_r} - ${fdt_addr_r}
Another solution is to force the firmware to load the blob at a fixed location
(as before) by updating config.txt:
device_tree_address=0x100
Regards,
Cédric
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