On 29/07/15 10:17, Pavel Pisa wrote:
Hello Sebastian,
On Wednesday 29 of July 2015 09:06:47 Sebastian Huber wrote:
On 28/07/15 02:31, Pavel Pisa wrote:
I think it's much closer to what we expected. you may checkout my
github and my dropbox.
https://github.com/yangqiao/rtems/tree/framebuffer
https://www.dropbox.com/sh/95bu6skofkmrlvc/AABXjwvvFhQScJdo_rwj12V6a?dl
=0
The commits log is messy, I'll rebase it afterward until we think it's
acceptable.
I think that Sebastian, Joel or some other core developer opinion
would be nice there.
I don't have time to check out external repositories. I will only look
at information included in e-mails posted to the devel list.
I am not sure why you need additional sections in the MMU table for the
frame buffer. In case it needs non-cachable memory, why don't you put it
into the .bsp_nocache section? You can also use a heap for this
section, see rtems_cache_coherent_allocate().
I am not sure, if there is alternative way with .bsp_nocache section
and some request to reconfigure VideoCore memory placement/division.
Actual/standard way how RPi is used/setup is different.
The VideoCore detect/have specified actual amount of physical
memory then it reads "config.txt" file and reserves end
of memory for framebuffer and internal use. Operating system
has to adapt to that division.
So if RTEMS is intended to run on all RPi 1 boards with at least
two possible different amount of physical memory populated
and do not clash with user setup configs and some sizes
adjustment based (may be) even on VideoCore firmware version/binaries
then it needs to adapt to actual memory amount. Other option is
to use minimum for RTEMS application (i.e. 128 MB) and define rest
to 1 GB as noncacheable, but that is far from beeing ideal.
So the memory layout is mostly unknown at link-time? In this case a
writeable MMU configuration table is indeed an option.
A custom workspace initialization can be done via
bsp_work_area_initialize().
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.hu...@embedded-brains.de
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Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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