[Pull Request] New Platform: EcoNet EN75xx MIPS

[Caleb James DeLisle]

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On 09/02/2025 22:12, Caleb James DeLisle wrote:
> Hello all,
>
> I've just created a PR on Github to add a new platform, EN75xx MIPS.
> https://github.com/openwrt/openwrt/pull/17928
>
> I made my best effort to explain the design decisions in the commit
> message itself, so I'll use this message to explain on a higher level
> the platform and my objectives for it.
>
> As I noted in the commit message, this is my first contribution so I
> would most appreciate any help I can get in moving it down the road
> toward being merge-able.
>
> The SmartFiber XP8421-B is a sub-$20 device available from Alibaba and
> it has a 900Mhz 34Kc Big Endian MIPS processor, 512M memory, 256M SPI
> NAND flash, 2x USB 2.0, 4x Gb Ethernet, Wifi MT7603 + MT7662E, XPON,
> and VoIP DSP.
>
> EcoNet used to be a subsidiary of MediaTek which produced telecom
> focused products before merging with Airoha, another subsidiary with-whom
> EcoNet shared a lot of IP. While they share a number of drivers,
> Airoha focused on the ARM(el) architecture while EcoNet focused on
> MIPS(eb).
>
> The airoha target on OpenWRT is an ARM target which is supporting
> their current flagship AN7581, my goal with introducing the en75
> target is to support the EcoNet MIPS devices which will allow
> up-cycling of telecom e-waste and the use of bargain-bin devices based
> on EOL'd silicon.
>
> There are two sub-targets of the en75 target, those are EN751221 and

EN751627 (these are the names used in vender firmware).

The EN751221 is based on the 34Kc processor with a custom interrupt
controller and consists of the EN7512, EN7513, EN7521 and EN7526.
The EN751627 is based on the 1004Kc and uses an IRQ-GIC compatible
controller. This sub-platform consists of the EN7516, EN7527 and EN7561.
EN7528, EN7565 and EN7580 are *probably* similar to the EN751627
group, but the GPL dumps I have don't mention them.

EN7523, EN7529, EN7562, EN7563, and EN7581 are ARM based and
should better be referred to as ANxxxx because they were more the focus
of Airoha than EcoNet.

My immediate goals are to land this patch and get the confirmation that
this is indeed a fit for OpenWRT, then to try to develop a few more drivers.
Of particular interest to me is USB since it can be used both for additional
disk space and for ethernet. The native ethernet on this SoC is a bit of a
nightmare. It may be that the ethernet driver from the airoha target
will Just Work, but if not this may be a lot of work.

I was able to get MT SMP working on the device, but I dropped it because it
automatically enables EI/VI which makes the interrupt controller a mess
that I wouldn't ask anyone to merge. I may contribute a generalized EI/VI
interrupt handler which takes the place of the CPU interrupt controller,
allowing any 34Kc SoC to switch on MT SMP without changing their own
interrupt controller driver.

Lastly, I have an EN7528 in my closet which I might try to port, though I
would rather have a 12, 13 or 21 so I can confirm that the EN751221
sub-target works on all of them.


Thanks,
Caleb