ath79: move 8/32 boards to tiny subtarget

[Adrian Schmutzler]

> Indeed "LOW_MEMORY_FOOTPRINT" seems only to affedt 3 general options
> and one option of OpenSSL.
> 
> So it might be an option to :
> * set LOW_MEM for 8/32 MB devies
> * set LOW_MEM and SMALL_FLASH for 4/32 MB devices
> * check the CONFIG-options for usefull defaults So the tiny aubtarget can be
> defined as "boards with 32MB or less of RAM; some boards also with only
> 4MB of flash". This definition would essentially match the "4/32 warning" [1].

Actually, this narrows down to a question that struck me several times already:

Now, that 4 MB flash devices are not "supported" anymore, how should we deal with the "tiny" subtargets:

1. We keep the tiny subtargets configured for low flash, so people still trying to build 4 MB flash devices still can use this. (This will also benefit a few devices with kernel size restrictions; however, this is a much smaller set than in earlier times; most of these devices have dual-stage bootloaders now or died anyway).

2. We convert the tiny targets to low-memory targets; this will improve the situation for a few devices (like you mentioned), but will make it much harder to still build the 4M flash devices without major changes. Apart from ath79, I don't know whether this would make sense for other targets like the old subtargets on ramips. This poses the risk of having some targets low-mem and some small-flash, which I'd like to avoid. Additionally, we will have to change back from low-mem to small-flash again when we start to hit limits with the 8M devices.

3. Though not intended by this conversation, the third option is obviously to just ignore all 4M or 32M devices from now on (as actually announced by the 4/32 warning), and design the tiny targets based on the requirements of the 8M devices that will start to become a "problem" soon (either due to kernel size restrictions or because of small rootfs). Actually, we already went into this direction by using wpad-basic-wolfssl on tiny targets as well.

Best

Adrian

> 
> [1] - https://openwrt.org/supported_devices/432_warning
> 
> Sven
> 
> > [0] https://github.com/freifunk-gluon/gluon/issues/2032
> > [1]
> > https://github.com/freifunk-
> gluon/gluon/commit/7e8af99cf504ca1dc389f28
> > 2a0c9
> > 4f4a911571be
> >
> 
> 
> 
> 
> 
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