> > awesome! Thank you! Do you know where I can find a good example of using > shared memory? I am wondering if I might be better off using shared memory > instead. Does shared memory work both ways so that ARM can access the PRU > memory and PRU access the ARM memory? >
There is a DDR example here: https://github.com/beagleboard/am335x_pru_package/tree/master/pru_sw/example_apps/PRU_memAccess_DDR_PRUsharedRAM Then if you need a better explanation of the code( Like I would ). You can read this: http://www.embedded-things.com/bbb/understanding-bbb-pru-shared-memory-access/ On Fri, Oct 14, 2016 at 4:36 AM, Jay Doobie <doobi...@gmail.com> wrote: > awesome! Thank you! Do you know where I can find a good example of using > shared memory? I am wondering if I might be better off using shared memory > instead. Does shared memory work both ways so that ARM can access the PRU > memory and PRU access the ARM memory? > > > On Thursday, October 13, 2016 at 10:59:26 PM UTC-4, Charles Steinkuehler > wrote: > >> On 10/13/2016 5:48 PM, Jay Doobie wrote: >> > Hi, >> > >> > I'm trying to send some data from ARM to the PRU for the PRU to execute >> upon it, >> > but I'm having some issues where it tends to miss some of the data on >> the PRU, >> > so I assume I am not synchronizing the interrupts properly, here is >> basically >> > what I am doing: >> > >> > C code: >> > >> > for (i = 0; i < 10; i++) { >> > prussdrv_pru_write_memory(PRUSS0_PRU0_DATARAM, SHARED_MEMORY, >> (unsigned >> > int*)pkts[i], memSize); >> > //if I put a sleep here it generally works: usleep(500000); >> >> The ARM has a weak memory model. You need a memory fence instruction >> here to insure that all writes before the fence (your write to the PRU >> memory, above) have completed before any writes after the fence >> (generating the PRU interrupt) take effect. >> >> It's a bit ham-fisted, but you can use a __sync_synchronize() here >> (assuming you're using gcc...it's a full memory barrier). Or you can >> use the C++11 memory fence semantics (more complicated). Either is >> way better than the "old school" full cache flush and invalidate! :) >> >> > //printf("sending intc...\n"); >> > // here are the packets! >> > prussdrv_pru_send_event(ARM_PRU0_INTERRUPT); >> > // wait for PRU response >> > //printf("waiting intc...\n"); >> > prussdrv_pru_wait_event (PRU_EVTOUT_0); >> > // clear PRU response >> > //printf("clr intc from PRU0...\n"); >> > prussdrv_pru_clear_event (PRU_EVTOUT_0, PRU0_ARM_INTERRUPT); >> > >> > } >> > >> > PRU: >> > >> > HANDLE_DATA: >> > // wait for interrupt >> > WBS r31, #30 >> > // reset interrupt >> > LBCO r20, CONST_IEP, 0x44, 4 // Load CMP_STATUS >> register >> > sbco rResetInterrupt, CONST_PRUSSINTC, SICR_OFFSET, 4 >> > // handle data >> > MOV R31.b0, PRU0_R31_VEC_VALID | PRU_EVTOUT_0 >> > sub rCounter, rCounter, rCounter >> > qbne HANDLE_DATA, rCounter, 0 >> > >> > >> > Kernel: Linux beaglebone 3.8.13-bone79 #1 SMP Tue Oct 13 20:44:55 UTC >> 2015 >> > armv7l GNU/Linux >> > >> > Thanks! >> >> >> >> -- >> Charles Steinkuehler >> cha...@steinkuehler.net >> > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/beagleboard/ec5b24bc-3b9e-4aba-a262-f79355ce0eb4%40googlegroups.com > <https://groups.google.com/d/msgid/beagleboard/ec5b24bc-3b9e-4aba-a262-f79355ce0eb4%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORpvPkLLZwm0qE_dT0Y%2B-HKFnEXaYH2s3wsHohJZpXYcQg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
