Re: [PATCH 3/7] bus: add bus driver for accessing Allwinner A64 DE2

From: Jagan Teki
Date: Thu Apr 19 2018 - 02:35:49 EST

On Sat, Apr 14, 2018 at 4:16 PM, Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Sat, Apr 14, 2018 at 4:00 PM, Chen-Yu Tsai <wens@xxxxxxxx> wrote:
>> On Sat, Apr 14, 2018 at 6:25 PM, Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote:
>>> On Fri, Mar 16, 2018 at 11:23 PM, Icenowy Zheng <icenowy@xxxxxxx> wrote:
>>>> The "Display Engine 2.0" (usually called DE2) on the Allwinner A64 SoC
>>>> is different from the ones on other Allwinner SoCs. It requires a SRAM
>>>> region to be claimed, otherwise all DE2 subblocks won't be accessible.
>>>> Add a bus driver for the Allwinner A64 DE2 part which claims the SRAM
>>>> region when probing.
>>> Along with this bus driver, we also need
>>> drivers/gpu/drm/sun4i/sun4i_drv.c which can usually drive the
>>> pipelines like mixer0 and 1 are the cases for A64?
>> I imagine that's the next part to be sent out, after the hardware
>> representation in the device tree has been decided on.
> Yeah, this hardware representation along with separate bus driver
> going like in another direction especially if we add pipelines support
> to it, may be we can add sram stuff to platdata of existinf
> sun4i_drv.c

Look like SRAM init during sun4i_drv is unable to claim or map the
memory? do we have any suggestion on adding 'allwinner,pipelines' ? is
it ok to add one more de which is compatible with sun4i_drv.c like

de: display-engine {
compatible = "allwinner,sun8i-a64-display-engine",
allwinner,pipelines = <&mixer0>;


Jagan Teki
Senior Linux Kernel Engineer | Amarula Solutions
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.