Hi,
I've got an Appro dev kit, DM355 based net camera. AFAICT, it has 128 MB of DRAM, 80 MB for Linux, and 48 MB for CMEM. The CMEM layout seems quite complex, as reported by cat /proc/cmem.
I found http://wiki.davincidsp.com/index.php?title=Changing_the_DVEVM_memory_map , but this is aimed at the 6446. Is there a similar doc for the 355?
Our own design will have 256 MB of DRAM, and I need to increase the encoded MPEG-4 stream buffer, to about 50 MB. How do I do this?
Regards,
James.
Two things that you need to consider come to mind
1) You can redefine cmem memory range and buffer by editing loadmodules.sh file
2) You will need to rebuild codec server used in demos (or your application) to make it aware of this new memory map, in a similar fashion to what is done in DM6446 article, except that the source tree may be a bit different for DM355. The challenge would be tracking down the files where the memory layout is defined and modify them. Unfortunately, there is no similar article for DM355, but it would make a great addition to the wiki once we figure this out.
After digging a bit more into this, it appears there is no memory set aside for codec severs and hence step 2 in my previous e-mail is not necessary. If you consider the DM355 EVM has 128MB of DDR2 and by default 116 MB is assigned to Linux (see u-boot bootargs) and 12 MB to cmem (see loadmodules.sh), all the DDR2 memory is either Linux or cmem. This means that you probably only need to change loadmodules.sh to redefine cmem memory map and bootargs to set Linux memory map. Codec engine for this platform is likely ARM/Linux and will allocate all memory resources it needs to load codecs from Linux portion of memory.
As Juan mentions this should be simpler than the Wiki page for the DM644x describes, for defining the over all memory map you only change settings in U-Boot and in the loadmodules.sh script file that inserts the CMEM module.
Though I am not sure if we are entirely clear on your question, aside from these configurations most any other memory management would be done within your appliation. To try to answer your question directly, I believe you would change the buffer of the compressed MPEG data from the codec in your application (malloc a larger buffer), which could be quite large considering your memory map adjustments. In this case the memory would be taken from Linux which you initially allocated for it in U-Boot.
Hopefully these responses resolve your issue, if not please let us know.
James,
Is the increased 50MB buffer used to pass video frames to codec (in which case it should come from CMEM), or is it contained and used by your Linux side application (no codec involvement), in which case it would come from Linux portion of memory?
I think that by knowing that bootargs define Linux memory map, and loadmodules.sh defines CMEM memory map, you can probably figure out the rest, but do not hesitate to ask more questions if you require further assistance.
Thanks to all for answering my question.
The 50 MB buffer is to store encoded mpeg from the codec, just prior to bundling them and audio into an avi file. It is implmented at the moment in CMEM, so I shall leave it that way.
Cheers.