[Tinkerphones] Dual personality systems (was Re: ZeroPhone site offline)

H. Nikolaus Schaller hns at goldelico.com
Tue Jan 11 07:26:32 CET 2022


> Am 10.01.2022 um 22:51 schrieb Paul Boddie <paul at boddie.org.uk>:
> 
> On Monday, 10 January 2022 02:27:15 CET Jonas Smedegaard wrote:
>> Quoting Paul Boddie (2022-01-09 23:40:08)
>>> 
>>> The AR100 processor in the Allwinner SoCs appears to be used as a kind
>>> of microcontroller without memory management unit, at least from what
>>> I can understand from that wiki page, so running vanilla Linux would
>>> be out of the question. But there are other things it could presumably
>>> be asked to do.
>> 
>> It was my understanding that the AR100 was unusable for running Linux -
>> until I read that wiki page, which to me seems to explicitly mention
>> running linux on it - in the very section header, ever:
>>> Mainline Kernel Support
>> 
>> I am not knowledgeable in this low-level stuff though, so I take your
>> word for it.
> 
> I wouldn't know without really taking a look at it. However, it sounds like 
> the Linux support would be comparable to what has been done (or attempted) 
> with the Ingenic auxiliary cores (AUX and MCU),

I just want to add that the OMAP processors have similar facilities.
All of them have some sort of DSP and the OMAP5 comes with
"two Cortex-M4 processors for low-power offload and real-time control".

> meaning that the additional 
> core is supported by a Linux driver which allows code to be transferred to the 
> core and then run. This is obviously different from actually running a kernel 
> on such a core: even the driver supporting the core is external to it, merely 
> offering the mechanism to control it.

AFAIR there were attempts (or success) to run uCLinux on the OMAP5
subcores. Since they lack MMU it is a little limited.

But do these nice things solve any real world problem?

If we can't get a nice and working and well accepted stack on the main
processor - how would a SoC specific subcore help? It adds fragmentation
is not available everywhere, difficult to debug etc.

BR,
Nikolaus




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