[PATCH 0/7] lantiq: initial support for x490 Fritzboxes

[Torsten Duwe]

On Sat, 12 Feb 2022 02:05:17 +0100
Mathias Kresin <dev at kresin.me> wrote:

> 
> 2/11/22 23:39, kestrel1974 at t-online.de:
> > Hi,
> > 
> > I have created a new PR:
> > https://github.com/openwrt/openwrt/pull/5074
> > 
> > Which also includes a remote processor framework kernel module,

Cramming it all into one big commit makes it hard to review and test.
LKML is therefore pretty strict to receive minimal changes that do not
break anything (-> bisect); I tried to transform the required changes
accordingly.

The WiFi system has the same architecture, sure, so it can be compiled
by the same toolchain. OTOH, the main system has everything but WiFi,
and the secondary system has nothing but WiFi, so I doubt that
compiling both kernels from one source is a good thing, unless the
kernel code memory can be physically shared (haven't checked), or the
whole kernel can be properly modularised.
This should be discussed first, and in the meantime discrete support
patches for the main system should be acceptable.

[...]

> > Looking at your submitted patches, many fritzbox devices have
> > different NAND manufacturers.

The question is, does their geometry differ across specimen of the same
model? Maybe with different manufacturing runs?

> >  So the best way is to support all.

No contradiction from my side.

> > I created a DTB and image configuration for Micron and non Micron
> > NAND. This is probably the best way and not supporting just one
> > NAND type per device. Unfortunately auto detection was not accepted
> > by the kernel maintainers, so there is no other solution.
> > 
> > I also saw the addition of ubifs. I have not used this so far and I
> > wonder what the advantage is over using squashfs with overlay?
> 
> Let me cite https://en.wikipedia.org/wiki/UBIFS
> 
> - tracking NAND flash bad blocks
> - providing wear leveling
> 
> NAND is a rather unreliable type of flash, hence some special
> treatment has to be done to make it last as long as possible.

Yes, I somehow had gotten the impression that UBI was mandatory for
OpenWRT ports to new devices with NAND, so I went that way.

Is sysupgrade prepared for squashfs+overlay as UBI volumes?

	Torsten