> > *Ok, as is usual, in hindsight, my error now seems massively idiotic* >
Sounds like you learned something though ! Don't worry however, because you're not alone. On Tue, Oct 20, 2015 at 7:16 PM, Andrew Szymkowiak <[email protected]> wrote: > Ok, as is usual, in hindsight, my error now seems massively idiotic. If > you call prussdrv_map_prumem, one gets a pointer to a region of memory, > whose beginning corresponds to a zero offset from the corresponding > constant table entry on the PRU. So, after having gotten that to work, I > decided by some magical thinking that prussdrv_map_extmem would work the > same same. But no, what it actually does is give you a pointer to a buffer > which the uio_pruss driver has allocated. It is then the user's > responsibility to get the physical address of this buffer, and transmit it > to the PRU, and use that as the starting address for i/o into this buffer. > (I'd been trying to use offsets relative to the extmem entry in the > constants table, which always starts at 0x80000000 (+ offsets from writing > into CTPPR_1), which was corrupting other things in the Linux memory...I > guess I was hoping that the driver would somehow muscle the reserved buffer > area to that address, though I now freely admit I'd have no idea how one > could accomplish that, without having had the Linux VM system skip that > range at boot with the MEMMAP entries...) > > -- > 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 [email protected]. > 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
