[PORT] Help Porting U-BOOT master branch to GT90X V4 sun7i a20 tablet board
hello to the u-boot community, last week i wanted to do some hardware hacking and came across one of my nameless chinese brand sun7i a20 tablets poked around in adb shell, mounted the NANDA partition and to my surprise it was running u-boot v2011 , so i wanted to put a linux kernel on there to see if it would boot unfortunately the u-boot was outdated and couldn't boot it, tl dr; i am trying to write a device tree file so i can successfully port U-BOOT v2021.07-rc2-00238-geb53b943be-dirty. So far I have "successfully" compiled a u-boot.bin although binman gives an error of "cant find u-boot.dtb" the u-boot.bin works fine on the device. Sorry for my rambling. I just wanna give the most information in one post. so far I was able to write a simple .dts file for my board to get the debug uart ports working. luckily I discovered some test points on the board that were for uart tx rx. I got the uart interface working. I don't have an ftdi at the moment so i'm using an arduino as an usb to serial passthrough long story short i was able to get the u boot shell working and I was able to interface with the device. since its my first time cross compiling, u-boot and also device tree files i need some guidance to where should i look, one question that i have is Is there any pre-made building environments that I can just run on a virtual machine, im currently using my laptop which has debian 10 on it to compile and i'm not sure if I did everything right to get my build environment working. I have access to the stock rom of my device so i cant brick it and also i have access to the source code of the u-boot 2011 version that was on the board from the factory. unfortunately this device has android 4.2.2 installed on it and i couldn't find any device tree files on it, i have the sysconfig.fex file that has the pinouts and config data on it So basically I'm trying to convert the sysconfig.fex to a dts file.
my objectives right now are: setup ram correctly get nand working get sd/mmc working get usb working get 24bit lvds panel working get touchscreen working get audio working and finally get some sensors working that the board has
I'm having no luck getting the nand and lvds panel working. I haven't tried sd/mmc , audio and touchscreen but i had usb working with some settings, i disabled it when i was debugging for other stuff. This gt90x v4 board is found in many nameless chinese tablets so I'm hoping this little project of mine can help others. also i see an unpopulated place that could take another nand chip , i'll have to try to see if it would work if any of you are interested in this or want to look at everything i got i can for the u-boot repository and commit my changes there and if any of you want to help you are more than welcome since this is my first time doing embedded stuff im learning as i go along so feel free to correct me. I can provide the source code of the 2011 u-boot that had everything working on the device and I can provide everything I have mentioned earlier (file wise).
Let's get to the board details.
ALLWINNER A20 SUN7I DUAL CORE CPU 2x NANYA MTT 256X16DDR3 V 1330 RAM CHIPS (device supposedly has 1gb of ram) TOSHIBA JP5415 TAIWAN 13359 A E / TC58TEG6DCJTA00 (8GB NAND) AXP209 0448CB 66K1 GSL3680 64A0D4281N REALTEK RTL8188ETV D700331 GD27 E203460 9INCH 1024X600 24BIT LVDS PANEL
Thats all of the major components on the board that i can see, i'll have an image of the board down below. https://drive.google.com/drive/folders/17zZTsgPHKktV4VARHAxR8tpHS4P04U7x?usp...
I would be super happy if anyone is able to point me in the right direction or help me.
-Koray
Hi,
You may find some help on the linux-sunxi Wiki: https://linux-sunxi.org/. Consider adding a page for your device as well.
Best of luck!
i got some more progress, i got the lvds panel and backlight working with u-boot, i also switched to u-boot 2021.07-rc3-dirty, i have an mmc driver enabled but so far it wasnt able to detect any sdcards that i plugged in maybe the pin configs are wrong, i still havent tried configuring nand , i migrated my build enviroment to a fresh install of debian 10 on a vm and my build errors that i have encountered are gone so far. heres an image of the working lvds panel : https://drive.google.com/file/d/19-p3G8RATX2tDcESXd6cOlq55flDeED4/view?usp=s...
Koray Bilir koray509@gmail.com, 25 May 2021 Sal, 14:29 tarihinde şunu yazdı:
hello to the u-boot community, last week i wanted to do some hardware hacking and came across one of my nameless chinese brand sun7i a20 tablets poked around in adb shell, mounted the NANDA partition and to my surprise it was running u-boot v2011 , so i wanted to put a linux kernel on there to see if it would boot unfortunately the u-boot was outdated and couldn't boot it, tl dr; i am trying to write a device tree file so i can successfully port U-BOOT v2021.07-rc2-00238-geb53b943be-dirty. So far I have "successfully" compiled a u-boot.bin although binman gives an error of "cant find u-boot.dtb" the u-boot.bin works fine on the device. Sorry for my rambling. I just wanna give the most information in one post. so far I was able to write a simple .dts file for my board to get the debug uart ports working. luckily I discovered some test points on the board that were for uart tx rx. I got the uart interface working. I don't have an ftdi at the moment so i'm using an arduino as an usb to serial passthrough long story short i was able to get the u boot shell working and I was able to interface with the device. since its my first time cross compiling, u-boot and also device tree files i need some guidance to where should i look, one question that i have is Is there any pre-made building environments that I can just run on a virtual machine, im currently using my laptop which has debian 10 on it to compile and i'm not sure if I did everything right to get my build environment working. I have access to the stock rom of my device so i cant brick it and also i have access to the source code of the u-boot 2011 version that was on the board from the factory. unfortunately this device has android 4.2.2 installed on it and i couldn't find any device tree files on it, i have the sysconfig.fex file that has the pinouts and config data on it So basically I'm trying to convert the sysconfig.fex to a dts file.
my objectives right now are: setup ram correctly get nand working get sd/mmc working get usb working get 24bit lvds panel working get touchscreen working get audio working and finally get some sensors working that the board has
I'm having no luck getting the nand and lvds panel working. I haven't tried sd/mmc , audio and touchscreen but i had usb working with some settings, i disabled it when i was debugging for other stuff. This gt90x v4 board is found in many nameless chinese tablets so I'm hoping this little project of mine can help others. also i see an unpopulated place that could take another nand chip , i'll have to try to see if it would work if any of you are interested in this or want to look at everything i got i can for the u-boot repository and commit my changes there and if any of you want to help you are more than welcome since this is my first time doing embedded stuff im learning as i go along so feel free to correct me. I can provide the source code of the 2011 u-boot that had everything working on the device and I can provide everything I have mentioned earlier (file wise).
Let's get to the board details.
ALLWINNER A20 SUN7I DUAL CORE CPU 2x NANYA MTT 256X16DDR3 V 1330 RAM CHIPS (device supposedly has 1gb of ram) TOSHIBA JP5415 TAIWAN 13359 A E / TC58TEG6DCJTA00 (8GB NAND) AXP209 0448CB 66K1 GSL3680 64A0D4281N REALTEK RTL8188ETV D700331 GD27 E203460 9INCH 1024X600 24BIT LVDS PANEL
Thats all of the major components on the board that i can see, i'll have an image of the board down below.
https://drive.google.com/drive/folders/17zZTsgPHKktV4VARHAxR8tpHS4P04U7x?usp...
I would be super happy if anyone is able to point me in the right direction or help me.
-Koray
participants (2)
-
Grzegorz Szymaszek -
Koray Bilir