Why does Linux stop the DSP application?

Francesco Danilo De Vita

Other Parts Discussed in Thread: OMAP-L137

I'm working with an EVM OMAP-L137.
My goal is to start at first the DSP application, then the application ARM with the sequence UBL-uboot-Linux, without resetting the DSP.
I don't want to use DSPlink to load and run the DSP application because I want that, after the board reset, the DSP application starts as rapidly as possible.

That's the matter.
After reset, the rom bootloader loads my DSP application and runs it. Then I would start the ARM applications launching the ARM UBL.

The first problem was that my application were stopped by UBL with "DEVICE_disable_DSP()" instruction. To solve this first problem I had simply commented this line: DSP application e UBL ARM work fine indipendently.

There was a second problem: when UBL ARM load and run Uboot, Uboot cleared and configured the same timer used by DSP stopping the DSP application. I solved this second problem by assigning the timer 1 to DSP and timer 0 to Uboot: DSP application e Uboot work fine indipendently.

There was a third problem by which I'm been stopped: Linux kernel, during its launching, resets and reconfigures both timers.
Is there a way to set the kernel to use only the timer 0 without affecting in any way the timer used by the DSP?

Thanks

Danilo

over 15 years ago

0 Sekhar Nori over 15 years ago

TI__Expert 6385 points

Hello,

Francesco Danilo De Vita said:
There was a third problem by which I'm been stopped: Linux kernel, during its launching, resets and reconfigures both timers.
Is there a way to set the kernel to use only the timer 0 without affecting in any way the timer used by the DSP?

Can you try modifying the for loop in timer_init() to only touch timer0?

http://arago-project.org/git/people/?p=sekhar/linux-omapl1.git;a=blob;f=arch/arm/mach-davinci/time.c;h=42d985beece512bcccdf6d02e53b156d60b5bc9b;hb=2acf935c01b9adb50164d421c40cdc5862b9e143#l202

Thanks,

Sekhar

0 Francesco Danilo De Vita over 15 years ago in reply to Sekhar Nori

Intellectual 255 points

Hello Sekhar, thanks for your answer.

I tried to change the for instruction but it doesn't fix the problem.
I explain you what happens.
I see that DSP is running because the DSP application turns on and off a LED.
Before the modification, the DSP is blocked just after starting the kernel.
After modification, during the launch of the Linux, the DSP is running. It blocks itself only when I introduce the first character in Linux shell (to write "root").
I assume that the interrupts, related to the serial port, are still connected to timer 1.
I also tried to configure Linux in different way (for example enabling/disabling high resolution timer support) but no change yet.

Any idea?

Danilo

0 Sekhar Nori over 15 years ago in reply to Francesco Danilo De Vita

TI__Expert 6385 points

Hi Danilo,

The serial port interrupts are not related to timer1. I think the issue you are facing now is different from what you faced initially.

Do you have serial driver enabled on BIOS side as well? May be a serial interrupt from Linux is causing the BIOS driver to try and handle it?

Thanks,

Sekhar

0 Francesco Danilo De Vita over 15 years ago in reply to Sekhar Nori

Intellectual 255 points

Ok, Sekhar. Thanks a lot.

I disabled the serial driver in DSP BIOS and now either DSP application and Linux run indipendently.

My question, now, is: Is there a way to use the same peripheral? Or must we disable in Linux (if it is possible) all peripherals that we want use with DSP?

Thanks.

Danilo

0 Sekhar Nori over 15 years ago in reply to Francesco Danilo De Vita

TI__Expert 6385 points

Hi Danilo,

You need to avoid using the same UART from both ARM and DSP. Doing this will lead to race conditions between the two cores.

Thanks,

Sekhar

Processors

Processors forum

Why does Linux stop the DSP application?