ACCESS ARM MEMORY THROUGH PRU

Hello Prial,

I assume you are talking about DDR accesses from the PRU?

All you need to do is enable the OCP port, as we discussed in your previous thread: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1239243/use-gpio-pins-via-ocp/4685262#4685262

Then you can read & write directly to the DDR addresses (which I would expect to be 0x8000_0000 to 0xA000_0000 if you have 512 MB).

Regards,

Nick

Hello Prial,

Please reference the PRU Getting Started Labs, section Debugging from Linux: https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/08_06_00_42/exports/docs/common/PRU-ICSS/PRU-Getting-Started-Labs_Lab5.html#debugging-the-pru-from-linux-core

Let's say you want to write to DDR memory address 0x8A00_0000. Then I would modify the PRU example code from the labs like this:

/* breakpoint1 is at DDR, address 0x8A00_0000 */
#define breakpoint1  (*((volatile unsigned int *)0x8a000000))

...

breakpoint1 = 0;
while( breakpoint1 != 1 ) {}

Please keep in mind that you should reserve any region of DDR memory where you do not want Linux to overwrite that memory. For more in depth examples, reference TIDA-01555:

https://git.ti.com/cgit/apps/tida01555/tree/dts/am335x-boneblack-pruadc.dts

https://www.ti.com/tool/TIDA-01555

Regards,

Nick