RE: [PATCH 0/5] cramfs refresh for embedded usage

On Wednesday, August 16, 2017 1, Nicolas Pitre wrote:

quoted

Just FYI,
I'm running an xipImage with all the RZ/A1 upstream drivers enabled and
only using about 4.5MB of total system RAM.
That's pretty good. Of course for a real application, you would trim off
the drivers and subsystems you don't plan on using, thus lowering your
RAM usage.

On my MMU-less test target I'm going under the 1MB mark now.

Show off  ;)

Given that I also applied the device table patch to mkcramfs (that
allows for the creation of device nodes and arbitrary
user/group/permission without being root) it would be possible to extend
this mechanism to implement other XIP patterns such as for
uncompressible media files for example.

Good, I was going to ask about that.

I made an example once were all the graphics were RAW and uncompressed 
and marked as XIP in AXFS. The result was a large saving of RAM because 
as the graphics framework (DirectFB) would copy directly from Flash 
whenever it needed to do a background erase or image re-draw (button press 
animations).

Same went for playing MP3 files. The MP3 files were XIP in flash, so 
mpg123 pulled from flash directly.


Chris