libfdt queries

[Varun Wadekar <vwadekar-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

Hi,

I am using libfdt v1.3.0 for modifying the dtb file from the bootloader
(not U-Boot). I have a .dtb file whose bootargs have to be modified
before passing over to the kernel. This is the sequence that I am following:

<snip>

newlen = fdt_totalsize(blob) + 512;
fdt_open_into(blob, blob, newlen)

node = fdt_path_offset(blob, "/chosen");
if (node < 0)
    <error handling code>

fdt_setprop_string(blob, node, "bootargs", cmdline)

<snip>

Now with the above code the serial console on my board does not come up
with the default bootargs that are present in the .dts file. If I
manipulate the bootargs string in the .dts file with some additional
garbage characters and then run the above code then I see that the
serial console comes up. I suspect that the dtb is not getting updated
properly with the above apis. Somehow the dtb contents are getting
overwritten and the serial console info is getting overwritten I think.

If I add a partial command line to my dts, then modifying the bootargs
from fastboot does not corrupt the dtb file and I can see the kernel
console come up.

Any pointers or ideas where I might have screwed up?



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