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parameter meaning of loadmodule.sh on dm355 EVM?

stanlerwang
Intellectual 510 points

hi,all

in the loadmodule.sh:

allocate user space is 12M,in detail as follow:

phys_start=0x87400000 phys_end=0x88000000 pools=1x2097152,2x1529856,7x829440,1x524288,1x108680,1x81920,2x8192,6x4096

I ask you what does per vaule of pools signify? you give me some hint?Thank you! 

  • 0
    TI__Mastermind 37340 points

    the pools define quantity and size of buffers, for example, in the configuration you sated above, it would mean that you have a pool with one buffer of size 2097152, two buffers of size 1529856, seven of size 829440 ...

    This i svery useful when you design your system; for instance if you know you will be supporting NTSC (720x480) 16-bit pixels (2 bytes) and that you will need double buffering (to give one to DSP while ARM works on another), then  you know you will need two buffers of size 720x480x2 and hence you can define these in your memory pool for optimum memory usage.

  • 0 in reply to Juan Gonzales
    Intellectual 510 points

    Thank for Juan Gonzales.

    I know I will be supporting PAL(720x576)16bit pixels(2 bytes);you can go into particulars later on.

    for example:

                    why need allocate one buffer of size 2097152?what is the purpose?

    Thank you!

  • 0 in reply to stanlerwang
    TI__Mastermind 37340 points

    To be nohext, I am not sure why the system designer choose a buffer of 2097152 size;  I am not even sure if this is for audio, video imaging, speech or some other porpuse.  It appears this size would be able to support NTSC

       (720x480)  x (2 bytes per pixel) x triple buffering = 2073600 (slightly smaller than 2097152).

    You can read more about CMEM and how these memory pools work here : http://wiki.davincidsp.com/index.php?title=CMEM_Overview