Development Resources

[crashoverride]

The following are provided for developers targeting the GO Advance hardware:

U-Boot
https://github.com/hardkernel/u-boot/tr ... A-v2017.09

Linux Kernel (4.4)
https://github.com/hardkernel/linux/tre ... dgoA-4.4.y

Libgo2
https://github.com/OtherCrashOverride/libgo2

EmulationStation (go2 fork)
https://github.com/OtherCrashOverride/e ... tation-go2

RetroRun
https://github.com/OtherCrashOverride/retrorun-go2

RetroArch
https://github.com/OtherCrashOverride/retroarch-go2

[mad_ady]

Well hello... What's that? Sounds nifty!

[pmprog]

Is libgo2 going to be the library for accessing display, inputs, gpio etc? Or will libraries like SDL work?

[crashoverride]

libgo2 provides simplified access to the hardware. It is similar in concept to the "odroid-go-common" provided for the original GO:
https://github.com/OtherCrashOverride/g ... nts/odroid

The library handles display (including hardware bitblit and backlight), input (gamepad), audio (including path and volume), and battery status.

SDL will work assuming the target dependencies are met (KMS, X11, Wayland).

[pmprog]

Thanks. Will libgo2 be open source too?

[crashoverride]

Will libgo2 be open source too?

Yes! The github link will be posted in the first post of this thread when its released.

[crashoverride]

Updated first post with links to libgo2, emulationstation-go2, and retrorun-go2.

[SlappyMcPhee]

thanks for the resources!

[maker_gamer]

Crash, will any of the "frontends" have bindings for scripting languages? I suspect Lua would be the easiest to bind out the gate given there's ton's of info on it ( https://www.google.com/search?q=how+to+ ... to+c%2B%2B )

Given this is on aarch64, a scripted language performance should be a non-impact for this machine.

Plus, having scripting bindings would be inviting for more folks to extend this platform. Personally, I've not done any C++ in 25yrs. Anymore I've to hammer things out in Bash, Python, Perl, Lua (and if necessary JavaScript) for my SysAdmin work.

Thanks for all your hard work. Looking forward to my Go Advance and seeing what I can do with it beyond just playing games.

Cheers, MG

[pmprog]

Libgo2
https://github.com/OtherCrashOverride/libgo2

I was expecting to see some GPIO functions in here, but there don't seem to be any, will there be? or are there other references for that?

Also, am I correct in thinking that the go2_presenter_post is what pushes the screen buffer to the LCD?

[crashoverride]

will any of the "frontends" have bindings for scripting languages?

I can only speak for the RetroRun frontend (since I wrote it). It is a command line program that can be called from a script language like BASH. It does not host any script engines.

I was expecting to see some GPIO functions in here, but there don't seem to be any, will there be?

There are not currently any GPIO functions. While they can certainly be added at a later date, I anticipated that developers would rather use a port of WIRING(PI).

[crashoverride]

Also, am I correct in thinking that the go2_presenter_post is what pushes the screen buffer to the LCD?

Yes.

A "display" and "presenter" are created:
https://github.com/OtherCrashOverride/r ... pp#L70-L71

Then a "surface" is created to draw on:
https://github.com/OtherCrashOverride/r ... eo.cpp#L92

After a "surface" is drawn on, it is given to the "presenter" to display with optional rotation:
https://github.com/OtherCrashOverride/r ... #L193-L197

The presenter makes a copy of the surface so that it can immediately be re-used without "tearing". The copy is then queued for display at the next VSYNC.

[mad_ady]

@crashoverride am I correct to assume the code is rockchip specific and can't be used to rotate the framebuffer on C2, right?

[pmprog]

I anticipated that developers would rather use a port of WIRING(PI).

Thanks. I'll be happy to use whatever, just want sure what was available.

After a "surface" is drawn on, it is given to the "presenter" to display with optional rotation:

The presenter makes a copy of the surface so that it can immediately be re-used without "tearing". The copy is then queued for display at the next VSYNC.

Forgive me then, but what's the "display" for? Why is it separate from the presenter?

[crashoverride]

what's the "display" for? Why is it separate from the presenter?

A "display" object wraps a Linux DRI display device (/dev/dri/card0). All surface allocations are made from this device per Linux KMS/DRM API. This API requires that a "surface" (GEM buffer) be attached to a "framebuffer" which can then be shown by a "display":
https://github.com/OtherCrashOverride/l ... play.h#L69
https://github.com/OtherCrashOverride/l ... play.h#L84
https://github.com/OtherCrashOverride/l ... play.h#L61

The "presenter" is effectively a mini-compositor that provides a simple way to drive the display. This eliminates the need for each program to have its own display management code. In addition to maintaining surface/framebuffer mappings, it also provides triple buffering (threaded operation) and rotation transparently. Applications may still directly drive the display using the above mentioned APIs. These are the same APIs used by the "presenter" itself.

[crashoverride]

am I correct to assume the code is rockchip specific and can't be used to rotate the framebuffer on C2, right?

libgo2 uses Linux DRI/KMS/DRM APIs. These are not available on the C2 (or N2) currently. It also uses Rockchip's librga for rotation.

The libgo2 API could theoretically be adapted to C2/N2 in the future. However, at the moment, it is Rockchip specific.

[crashoverride]

I posted a port of GO1's prosystem (Atari 7800) to GO2. This example serves to illustrate the use of libgo2:
https://github.com/OtherCrashOverride/prosystem-go2

1) A display and presenter are created:
https://github.com/OtherCrashOverride/p ... #L307-L308

2) A surface is created and memory mapped for the emulator to draw on:
https://github.com/OtherCrashOverride/p ... #L310-L311

3) Audio and input (gamepad) are initialized:
https://github.com/OtherCrashOverride/p ... main.c#L74
https://github.com/OtherCrashOverride/p ... main.c#L84

4) The render loop is then entered. The gamepad is sampled. The simulator is then stepped a single frame. This produces both audio and video:
https://github.com/OtherCrashOverride/p ... main.c#L89
https://github.com/OtherCrashOverride/p ... ain.c#L342

5) The audio is submitted and buffered by libgo2:
https://github.com/OtherCrashOverride/p ... main.c#L79

6) The surface is submitted and buffered+rotated by libgo2:
https://github.com/OtherCrashOverride/p ... #L344-L348

7) The render loop then repeats at step #4.

[mad_ady]

This would be the shortest but most complex Odroid Magazine article ever

[shanti]

For libgo2, other than to compile, is Lua needed after that? any possibility for alternative compile method?

[crashoverride]

For libgo2, other than to compile, is Lua needed after that?

Premake generates 'make' files or project files for IDEs such as Visual Studio and XCode. Lua is only used in the construction of these files.
https://premake.github.io/

Install premake4:

Code: Select all

sudo apt install premake4

Generate makefile in the libgo2 repo:

Code: Select all

premake4 gmake
make

[crashoverride]

any possibility for alternative compile method?

The compile uses standard 'make' and GCC (sudo apt install build-essential). I do not currently have any plans to change it.

[shanti]

Thanks I was not aware of Premake

[shanti]

Trying to cross-compile, first error:

Code: Select all

../../src/display.c:42:10: fatal error: rga/RgaApi.h: No such file or directory
 #include <rga/RgaApi.h>

compiled librga from here https://github.com/rockchip-linux/librga and it seems at least on my build (with default settings) librga is installed to "include/rk_rga" so I manually edit the display.c from <rga/RgaApi.h> to <rk_rga/RgaApi.h>

Second error:

Code: Select all

../../src/display.c: In function 'go2_surface_blit':
../../src/display.c:632:8: error: 'rga_info_t' {aka 'struct rga_info'} has no member named 'scale_mode'
     src.scale_mode = 2;
        ^
../../src/display.c: In function 'go2_presenter_post':
../../src/display.c:1003:15: warning: implicit declaration of function 'c_RkRgaColorFill'; did you mean 'c_RkRgaBlit'? [-Wimplicit-function-declaration]
     int ret = c_RkRgaColorFill(&dst);
               ^~~~~~~~~~~~~~~~
               c_RkRgaBlit
make[1]: *** [Makefile:133: obj/Debug/display.o] Error 1
make: *** [Makefile:17: go2] Error 2

any ideas?

[AreaScout]

@shanti

Use this repo https://github.com/rockchip-linux/linux-rga.git so ->

Code: Select all

git clone https://github.com/rockchip-linux/linux-rga.git
cd linux-rga
sudo mkdir /usr/local/include/rga
sudo cp *.h /usr/local/include/rga/.
make -j3 PROJECT_DIR=/home/odroid/linux-rga/
sudo cp lib/librga.so /usr/local/lib/.
sudo ldconfig

edit: disable debug, by setting DEBUG := y to DEBUG := n inside the Makefile

RG

[crashoverride]

As noted by @AreaScout, the librga.so repo is:
https://github.com/rockchip-linux/linux-rga.git

The compile procedure used is:

Code: Select all

mkdir build
make CFLAGS=-fPIC PROJECT_DIR=build

# Library
cp build/lib/librga.so /usr/local/lib/aarch64-linux-gnu/

# Headers
cp drmrga.h /usr/local/include/rga/
cp rga.h /usr/local/include/rga/
cp RgaApi.h /usr/local/include/rga/
cp RockchipRgaMacro.h /usr/local/include/rga/

[shanti]

Thanks, that did it:)

[crashoverride]

I have added libgo2 support to RetroArch for full rotation (menus and games). I will be posting a link to this resource after further testing.

Compile:

Code: Select all

./configure --enable-alsa --enable-udev --enable-kms --disable-opengl1 --disable-opengl --enable-egl --enable-opengles --enable-opengles3 --disable-wayland --disable-x11
make

The repo can be found here:
https://github.com/OtherCrashOverride/retroarch-go2

This repo servers as an example for anyone wanting to upstream GO Advance platform support. Currently, support is 'hacked' into an existing file:
https://github.com/OtherCrashOverride/r ... /drm_ctx.c

Integration will involve 1) copying the above to a new file name, 2) linking with libgo2, and 3) adding a '--with-libgo2' configure option to use both 1 and 2.
https://github.com/OtherCrashOverride/r ... kefile#L32

Note that the retroarch-go2 repo is unsupported. I have no plans to develop it further.

[valadaa48]

@crashoverride, would you mind pasting the changes to RetroArch? I would like to assist in testing and development. If you're not comfortable posting publicly then feel free to IM me.

Also, what toolchain are you using and are you cross compiling on your linux box or on the odroid go itself? Curious because of the required dependencies (headers, libs).

Thanks!

[crashoverride]

would you mind pasting the changes to RetroArch?

I plan to post the changes tomorrow (my timezone). I needed to validate the changes which meant adding 3D support to RetroRun for comparison.

what toolchain are you using and are you cross compiling on your linux box or on the odroid go itself?

I use an arm64 and armhf rootfs (chroot with qemu) on x86 for compiling the 64bit and 32bit versions respectively. The compiler used is GCC from the Ubuntu apt repo. Standard headers/libs are all install using 'apt install'. The libgo2 library and headers are from the github repo in the first topic of this forum thread.

[valadaa48]

Thanks @crashoverride. My setup is similar.

I'm trying to track down the precise source for the mali drivers so I can slipstream them into my linux build. Does anyone know the location?

[crashoverride]

I'm trying to track down the precise source for the mali drivers so I can slipstream them into my linux build. Does anyone know the location?

https://github.com/rockchip-linux/libmali/tree/master

[valadaa48]

Thanks got it. I setup an Archlinux rootfs but soon learned that Arch doesn't support mixed arm64/arm32 and the pcsx_rearmed I built for arm64 didn't have anywhere near the performance of your 32bit build so I had to abandon it. Looking forward to your retroarch port for me to test and help develop where I can. Thanks!

[crashoverride]

I have added the RetroArch repo link to the first post and edited my previous post on the topic.

[valadaa48]

Thanks, it runs very well!

[kernelspace]

Does anybody have any notes on how to set up a cross compile toolchain and chroot for the odroid go advance?

Also it occurs to me that we could probably write an SDL2 backend on top of libgo2. I was planning to use SDL2 for a game, but I'd really like to target this hardware also.

[maker_gamer]

I'm interested too so I can bring some non-game utils over.

[valadaa48]

Copy the stock image into a qemu aarch64 image and boot it up. apt install all the utilities. You can even just qemu chroot into the image as well.

[hzulla]

Hi. What are the plans for the kernel drivers, do you expect to upstream them to the mainline kernel? I'd love to see a Kernel 5.x on this thing.

[crashoverride]

What are the plans for the kernel drivers, do you expect to upstream them to the mainline kernel?

I can only speak for myself when I say I do not currently have any plans to upstream drivers. HardKernel maintains the kernel, and I do not speak for them.
https://github.com/hardkernel/linux/tre ... dgoA-4.4.y

I'd love to see a Kernel 5.x on this thing.

I do not know the status of RK3326 in Kernel 5.x. The current LTS kernel continues to receive security updates.
https://github.com/rockchip-linux/kernel