BCM53xx on D-Link DIR-890L - 2MB max problem

[Linus Walleij]

On Sun, Jan 15, 2023 at 9:02 PM Arınç ÜNAL <arinc.unal at arinc9.com> wrote:
> On 15.01.2023 17:54, Linus Walleij wrote:
> > On Fri, Jan 13, 2023 at 11:11 PM Arınç ÜNAL <arinc.unal at arinc9.com> wrote:
> >
> >> Side question, did you risk writing your test builds to the flash or
> >> have you already got the flash in an easily reprogrammable set up?
> >
> > This device has the boot prom in NOR so firmware is only flashed
> > to the NAND flash, no risk of overwriting the boot loader.
>
> Sorry, I don't follow. What's a boot prom?

There are 2 flash chips in the device one NOR flash for the CFE and NVRAM,
and one NAND flash for all other firmware.

> You didn't overwrite CFE when you booted U-Boot?
>I was asking how did you write U-Boot to flash if it
> wasn't clear.

No, I let CFE boot U-boot instead of the kernel.

Flashing is done with the manufacturing method: holding in RESET
and powering on, then a rescue mode web server flash tool appears
(super convenient).

> I've just spotted SYS_BOOTM_LEN in the same menu as CMD_BOOTZ:
>
> This is the maximum size of the buffer that is used to decompress the OS
> image in to, if passing a compressed image to bootm/booti/bootz.
>
> This is set to 0x2000000 (32 MiB) on the U-Boot I was testing the
> compressed kernel images on. The lzma compressed image at 19134142 bytes
> (~18.2477 MiB) must've exceeded 32 MiB when decompressed.
>
> Maybe there's an option like this for CFE. I don't know if you're able
> to compile a custom CFE and boot it somehow.

No need for me, I just leave CFE as it is. Maybe a but clunky but
it works...

> >> Did you try booting a kernel on this Northstar SoC with U-Boot?
> >
> > Haven't gotten there yet, I need to implement SEAMA support
> > (the D-Link preferred NAND image format) first, because it
> > totally scrambles the stuff written to flash.
>
> I guess tftpboot is out of question, no network support yet?

TFTPBOOT actually works with CFE!
ifconfig -addr=192.168.1.35 eth0
boot -raw -addr=0x01097000 -max=0x2000000 -tftp 192.168.1.2:zImage

...so I managed to develop and test the kernel with this. Device tree
is complete and all.

But now I want something that is convenient and easy for OpenWrt
users without UART etc to use. So I need to fix installation into
NAND.

Thanks!
Linus Walleij