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Participant
Participant
1,557 Views
Registered: ‎05-20-2018

mapping linux /dev/fb0 to DDR for displaying

hello.

I want to display linux desktop environment on booting my MYiR MYS-7Z020-C-S board.

I designed my PL by VDMA and axi4-lite Video out.

In linux that is booting from ext4 partition of SD card, I want to map fb0 to DDR in order to linux show desktop environment displaying data that exists on fb0 by running server X. Mapping DDR and fb0, can display what I want, because VDMA have access to DDR and can show it to my display hardware.

how can I do this? should I write driver for linux or device tree? how to do it?

can I get help from xylon logicvc driver for this design?

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Voyager
Voyager
1,524 Views
Registered: ‎10-21-2015

Re: mapping linux /dev/fb0 to DDR for displaying

Hi,

 

You need drm(Direct Rendering Manager) driver.

It is not easy to write drm driver for your custom hw with vdma.

It's better to use xylon driver with xylon hw ip

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Mentor
Mentor
1,499 Views
Registered: ‎06-16-2013

Re: mapping linux /dev/fb0 to DDR for displaying

Hi @mojtaba.ahmadi

 

I'm not sure. But I think that the following URLs are helpful for you.

It's not direct answer...

Would you refer them ?

 

http://www.wiki.xilinx.com/Zc702+Base+TRD

http://www.wiki.xilinx.com/Zynq+Base+TRD+14.5

 

Best regards,

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Participant
Participant
1,485 Views
Registered: ‎05-20-2018

Re: mapping linux /dev/fb0 to DDR for displaying

@hokim thanks for your attention. 

because of xylon IP (logicvc) time limitation, it is not applicable for me but I want something like that. as you said I need a driver to work with vdma through linux. 

you mean I can not do that with frame buffer driver? just a drm driver should be written?

do you have any manual to help me for that?

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Participant
Participant
1,481 Views
Registered: ‎05-20-2018

Re: mapping linux /dev/fb0 to DDR for displaying

@watari thanks for your respone.

TRD project has used xylon IP that I do not want to use that because of its time limitation and I am looking for an alternative way to do the same operation (displaying linux desktop environment)

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Voyager
Voyager
1,465 Views
Registered: ‎10-21-2015

Re: mapping linux /dev/fb0 to DDR for displaying

Hi,

You can try to use xilinx_drm driver with digilent encoder.

https://github.com/Digilent/linux-digilent/tree/master/drivers/gpu/drm/xilinx

 

This is related devictree(line55-87)

https://github.com/Digilent/Petalinux-Zybo-Z7-20/blob/master/Zybo-Z7-20/project-spec/meta-user/recipes-bsp/device-tree/files/system-user.dtsi

 

Hardware design should be like this 

https://github.com/Digilent/Zybo-Z7-20-base-linux

 

xilinx_drm support only hdmi and dp(The above is for hdmi)

 

For hdmi using adv7511, refer https://forums.xilinx.com/t5/Embedded-Linux/ZC706-enabling-ADV7511-with-Yocto/m-p/881370#M27959

 

For drm driver for lcd,  you should write for yourself

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