Draft email to genode list about framebuffer

Edward Sandberg ed.sandberg at adventiumlabs.com
Mon Sep 17 19:21:46 CEST 2018


I am attempting to add framebuffer support for the Wandboard Quad using
the imx53 code as a base and modifying it as necessary.  At this point I
can build run/framebuffer with the seL4 kernel and I see no errors when
I run the uImage on the wandboard Quad but I also don't get any HDMI ouput.

I resolved the problem of the bootloader not providing the framebuffer
information by hardcoding the framebuffer address, width, height, bpp,
and pitch in the framebuffer.cc file.  I have tracked down almost all of
the addresses that needed to be modified but I am stuck on a couple things.

In /os/src/drivers/platform/spec/imx53/ccm.h lines 82 and 83, what are
these addresses?  I can't find them anywhere in the imx53 device tree.
write<Cscmr2>(0xa2b32f0b);
write<Cdcdr>(0x14370092);

In:
./os/src/drivers/platform/spec/imx53/iim.h line 27,
./os/src/drivers/framebuffer/spec/imx53/pwm.h line 22, and
./os/src/drivers/platform/spec/imx53/src.h line 30
I am unclear on the significance of the chosen register/bitfields and if
they needs to be changed to match the imx6:
struct Fuse_bank0_gp6 : Register<0x878, 32> {};
struct Ctrl_reg : Register<0x0, 32>
struct Ipu_rst : Bitfield<3, 1> { };

Can anyone help with these?

Also I have added all of my changes in a branch of the genode code:
https://github.com/sand7000/genode/commit/bb7ad099bed584d31542ac237f127798aa0e032c
In case anyone is interested or is familiar with the imx53/imx6 and has
insight into what else I might need to modify.

-- 
Edward Sandberg
Adventium Labs
111 3rd Avenue S. Suite #100
Minneapolis, MN 55401
ed.sandberg at adventiumlabs.com





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