[Arm-netbook] Arm processors

[Siarhei Siamashka]

On Fri, Mar 3, 2017 at 12:48 AM, Paul Boddie <paul at boddie.org.uk> wrote:
> On Thursday 2. March 2017 22.20.27 Siarhei Siamashka wrote:
>> On Thu, Mar 2, 2017 at 6:22 AM, Luke Kenneth Casson Leighton
>>
>> <lkcl at lkcl.net> wrote:
>> > On Thu, Mar 2, 2017 at 12:49 AM, zap <zapper at openmailbox.org> wrote:
>> >  reverse-engineering i have come to the conclusion is a total - and
>> >
>> > criminal - waste of time and effort.  by the time all features are
>> > 100% stable it's several YEARS down the line.  look at how long ago
>> > the A64 was released, and the libdram code STILL HAS NOT BEEN
>> > REVERSE-ENGINEERED.  it's 200 lines of code for fuck's sake.
>>
>> You are just very poorly informed about the status of A64 support.
>> And it's quite funny that there are people who believe you rather
>> than trying to get this information first hand.
>
> Well, I posted the results of some enquiries a few weeks ago in the context of
> the Olimex laptop. Everything sounded very promising until this appeared:
>
> "For the moment the only working Linux Kernel which supports all A64 features
> is the Allwinner Android Kernel. This Kernel is full of binary blobs, but the
> only one which could be used for demo. Beside the binary blobs many other
> things are broken, like the power management, different drivers like the LCD
> backlight PWM, wake up from suspend, eDP converter is not set properly and
> works just in 15 bit color mode etc etc. We have the hardware for 50 laptops
> ready (developer edition), but we do not want to ship before we take care for
> the software. At other hand we do not want to ship TERES I with Android or
> RemixOS also which are complete with binary blobs and will never be Open
> Source."
>
> Source: https://olimex.wordpress.com/2017/02/07/fosdem-and-teres-i-update/
>
> Some of that is specific to their laptop, but some of it seems relevant to any
> A64 device. Maybe you could reconcile what the Olimex people are saying with
> what you are claiming.

I guess, the emphasis was on *all* A64 features. And the mainline kernel
clearly does not support *all* A64 features yet.

Also Olimex people are always saying that they don't do software and
don't have software expertise in-house. The are not the best people
to ask for this information.

> If you have any definitive information to the contrary, particularly about the
> boot0 code that Luke appears to be referring to, please post links to it.

Regarding Luke's claim stated in bold letters, here is the commit in the
mainline U-Boot, which has added the A64 DRAM controller support:

    http://git.denx.de/?p=u-boot.git;a=commitdiff;h=1bc464be1fc559a3f6dc1334297245d5b27b9b57

But the reverse engineered A64 DRAM controller support code existed
in experimental git branches many months before it finally landed
upstream and anyone could try it.

> The linux-sunxi wiki was very vague on such matters last time I checked.
> And yes, I have seen the "mainlining effort" page:
>
> https://linux-sunxi.org/Linux_mainlining_effort#Status_Matrix

It's very good that you have found this page. You can clearly see
many links to the work-in progress branches that are used for
developing various drivers and test them.

If you don't understand something, you can always join the #linux-sunxi
irc channel on freenode and ask around.

-- 
Best regards,
Siarhei Siamashka