Beagleboard BSP Framebuffer

[Gedare Bloom]

On Tue, Mar 12, 2019 at 6:59 AM Christian Mauderer <
christian.mauderer at embedded-brains.de> wrote:

> Am 12.03.19 um 11:35 schrieb Vijay Kumar Banerjee:
> >
> >
> >
> > On Tue, 12 Mar 2019 at 15:27, Christian Mauderer
> > <christian.mauderer at embedded-brains.de
> > <mailto:christian.mauderer at embedded-brains.de>> wrote:
> >
> >     Am 12.03.19 um 10:52 schrieb Vijay Kumar Banerjee:
> >     >
> >     >
> >     > On Mon, 11 Mar 2019 at 19:21, Gedare Bloom <gedare at rtems.org
> >     <mailto:gedare at rtems.org>
> >     > <mailto:gedare at rtems.org <mailto:gedare at rtems.org>>> wrote:
> >     >
> >     >
> >     >
> >     >     On Sun, Mar 10, 2019 at 7:31 PM Joel Sherrill <joel at rtems.org
> >     <mailto:joel at rtems.org>
> >     >     <mailto:joel at rtems.org <mailto:joel at rtems.org>>> wrote:
> >     >
> >     >         The MINIX license is BSD with advertising clause as I read
> it.
> >     >         That is less preferable to a 2-paragraph BSD license that
> you
> >     >         are likely to find in Freebase. Try there.
> >     >
> >     >     The license is fine if you find nothing else. I assume Joel
> meant
> >     >     FreeBSD.
> >     >
> >     >     Study the framebuffers in i386 and raspberrypi code bases.
> >     >
> >     >
> >     > Hello,
> >     >
> >     > Thanks for the reference, I found the tda19988 driver in
> >     freebsd source.
> >     > Following the raspberrypi framebuffer, I have made a header file
> >     with the
> >     > basic functions to implement. The implementation will be using the
> >     > driver code from the freebsd.
> >     >
> >     > What needs to be figured out next is how to use the driver code
> >     with rtems,
> >     > since the file uses a lot of header files from the freebsd source,
> >     how do we
> >     > go about integrating it with rtems? Is there any guide on using
> >     codes from
> >     > different projects into RTEMS?
> >     >
> >     >
> >
> >     Hello Vijay,
> >
> >     for FreeBSD we have the libbsd as an easy way to integrate sources
> and
> >     keep them up to date. Although I don't think that we have a
> framebuffer
> >     driver there yet I would expect that it is a good method for that
> too.
> >
> >     Best regards
> >
> >     Christian
> >
> > Hi
> >
> > I cloned the rtems-libbsd and the framer driver is not there. I wonder
> > if adding
> > this drivers to libbsd is itself a meaty task. Do we need a ticket for
> > this ?
>
> The files are copied between FreeBSD and libbsd using a script.
> Basically you have to add the files you need to a (new) module in
> libbsd.py. After that you can copy files with the freebsd-to-rtems.py.
> Please take a look at CONTRIBUTING.md in the rtems-libbsd repo on how to
> use the script.
>
>
Bringing the framebuffer codebase into libbsd from FreeBSD, and then
demonstrating it on a target (e.g., BBB), would make a solid GSoC.

>
> > Also, the driver uses i2c bus driver from FreeBSD source, I see that the
> > i2c driver
> > is nicely supported in the rtems beagle bsp, how to use the i2c module
> > in the bsp,
> > with the hdmi framer driver in libbsd ? (I'm a bit confused here :) )
> >
>
> Most likely there will be adaptions necessary here. Either you have to
> replace the BSPs driver with the one from FreeBSD or (the method that I
> would suggest) you have to isolate the calls in the FreeBSD framebuffer
> driver and replace them with RTEMS calls. With some luck, you can just
> overwrite some functions for that. But that is one of the points that
> would need a more thorough look.
>
> Besides I2C you should have a look at which other subsystems are used.
> Every subsystem that isn't ported yet can be more or less work depending
> on the interface. Some might can be ported together with the driver
> others might have to be replaced by RTEMS versions.
>
>
+1

And reach out to others who have done some similar work in the past. We
have got at least a few students in recent history who added more mud to
libbsd. :)
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