Re: [PATCH] ARM: mach-qcom: fix support for ipq806x

[Linus Walleij]

On Thu, Jan 18, 2024 at 12:04 AM Christian Marangi <ansuelsmth@xxxxxxxxx> wrote:

> Some followup on this... I manage to enable DEBUG_LL and can have debug
> output from the decompressor...

Yeah that is helpful!

> From what I can see fdt_check_mem_start is not called at all...
>
> What I'm using with kernel config are:
> CONFIG_ARM_APPENDED_DTB=y
> CONFIG_ARM_ATAG_DTB_COMPAT=y
> And a downstream patch that mangle all the atags and takes only the
> cmdline one.
>
> The load and entry point is:
> 0x42208000
>
> With the current setup I have this (I also added some debug log that
> print what is actually passed to do decompress
>
> DTB:0x42AED270 (0x00008BA7)
> Uncompressing Linux...
> 40208000
> 4220F10C done, booting the kernel.
>
> Where 40208000 is the value of output_start and 4220F10C is input_data.
>
> And I think this confirm that it's getting loaded in the wrong position
> actually in reserved memory... But how this is possible??? Hope can
> someone help me in this since I wasted the entire day with this and
> didn't manage to make any progress... aside from having fun with the
> head.S assembly code.

I have no idea how this happens, but when I boot images I do
it using fastboot like this:

fastboot --base 40200000 --cmdline "console=ttyMSM0,115200,n8" boot zImage

So I definitely hammer it to boot from 0x40200000 (+0x8000).

Yours,
Linus Walleij