Hi, On 02/05/17 08:25, Pajeet Gurav wrote: > Hello, I'm trying to write a hobby operating system and I would like to > find at what address the A64 framebuffer resides and how to initialize > the graphics engine to perform such a function, I only need to be able > to pixels on the screen, thanks
If you use U-Boot as your boot loader, that's fairly simple, as you can rely on the simple-framebuffer mechanism. Recent patches (which are queued in u-boot-sunxi/master already, see the patches from Jernej [1]) do what you want: The code initialises the Allwinner DE2 display engine and the HDMI controller. The framebuffer is then situated in DRAM and the address of that (which is configurable) is put into the simplefb DT node. Whatever you write into this memory, appears on the screen. The DT node tells you about the colour encoding and the resolution as well. Setting up the DE2 and the HDMI controller is not trivial and I'd recommend against doing that yourself in your OS code. There is quite something to do (complex clock setup, EDID configuration, HDMI output setup) and most of that is not well documented (if at all). Cheers, Andre. [1] http://git.denx.de/?p=u-boot/u-boot-sunxi.git;a=shortlog -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
