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OMAP L138 notify priority in Linux

Other Parts Discussed in Thread: OMAPL138

I have a quick question regarding setting Notify priority.

Basically my system consist of some algorithms running on the DSP which then notifies the ARM processor using the Notify mechanism. Once the ARM processor receives this Notification it copies some data from shared memory between the DSP and ARM and prints in to the screen. This happens at 50Hz.

What seems to happen from time to time is that the ARM processor is not processing the Notification and so two 50Hz notification has been received before the ARM processor is giving time to process the interrupts. This causes it to output two samples straight after each other. So I do not get a steady stream of 50Hz samples but instead once in a while I get two 50Hz samples straight after each other.

I'm not sure what is causing this behaviour. Could it be that Linux is prioritising other processes which causes the notification interrupt to be delayed more than 1 50Hz period and thus it suddenly processes the two notification interrupts that waiting? If so how can I increase the priority for the notification interrupt?

Cheers Rolf

  • Hello Rolf,

    Please direct your question to the appropriate OMAP-L13x, AM1x and C674x Processors Forum (http://e2e.ti.com/support/dsp/omap_applications_processors/f/42.aspx) .

    Best Regards,

    Yordan

  • Hello Rolf,

    I am also trying to access SHRAM from ARM of OMAPL138.

    Can you please help me with some of my issues? [These may seem very basic issues , but i am a novice in LINUX, and will appreciate help]

    1. Have you done any changes in linux kernel to access SHRAM? Like Ioremapping to SHRAM address or something like that?

    2. How did you access SHRAM in your application code? Did you use 'mmap' or some other function?

    Thanks.