Re: [PATCH 0/3] add Ebang EBAZ4205 support

From: Michael Walle
Date: Thu Jan 21 2021 - 05:15:29 EST


Am 2021-01-21 10:57, schrieb Michal Simek:

On 1/21/21 10:35 AM, Michael Walle wrote:
Hi Michal,

Am 2021-01-21 10:25, schrieb Michal Simek:
On 1/20/21 8:40 PM, Michael Walle wrote:
Add support for the Ebang EBAZ4205 board. This board was once used as a
control board for a bitcoin mining device. Nowawdays it is sold as a
Zynq-7000 eval board.

Michael Walle (3):
  dt-bindings: add ebang vendor prefix
  dt-bindings: arm: add Ebang EBAZ4205 board
  ARM: dts: add Ebang EBAZ4205 device tree

 .../devicetree/bindings/arm/xilinx.yaml       |   1 +
 .../devicetree/bindings/vendor-prefixes.yaml  |   2 +
 arch/arm/boot/dts/Makefile                    |   1 +
 arch/arm/boot/dts/zynq-ebaz4205.dts           | 109 ++++++++++++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 arch/arm/boot/dts/zynq-ebaz4205.dts

any link with schematics?, looks like these are
reverse engineered (from a layout file?) though.

Interesting but at least something.

I will let dt guys to comment 1/3 but series look good to me.
The board doesn't look interesting from description point of view that's
why all the time thinking if makes sense to add it to kernel.

What do you want to tell me? That for the time being, it didn't
appear to you to add the board yourself - or do you thing it
doesn't make sense at all. If its the latter, what would be
actual reason to have a board in mainline?

I have bad experience with for example Avnet boards which people add and
none is really updating them and they are in the same state for years.

Wouldn't it be better then to pull the plug at some time and remove these

TBH I was a bit disappointed by your statement. It sounded like "nah
this board isn't worth it". Esp. because it is just one (small) file.
But more below.

Long time ago we agreed that doesn't make sense to describe PL in
upstream projects and we only describe PS part. It means you likely miss
several things which are useful and the reason for using these SoCs is PL.

As you likely know Xilinx has Versal device and I didn't push any device
tree to any upstream project and thinking not to add any description for
boards and stay in sort of space that "virtual" description for SoC
should be enough. Maybe just versal.dtsi and one kitchen sink DT should
be added but not description for all boards.

The same is if make sense to push all DTs for all standard xilinx zynqmp
evaluation boards. If there is something interesting/new I thought it
makes sense to add it as pattern to follow. But for boards which looks
very similar from PS point of view I don't think there is real value to
add and invest time for maintaining.

Back to your case. Board is cheap which is not all the time case for any
xilinx board but you have only uart, sd and partially described ethernet
which doesn't work without PL. Is it worth to have this described?

I got your point. But it is at least a jump start for the users if that
board boots out of the box. And yes, its unfortunate, that ethernet
just works if the PL is configured. This is already done by the
bootloader, because there I do have the same problem.

Especially when it is visible that you need to describe custom PL and DT
overlays are not solid yet.