From: Hiroshi DOYU <hiroshi.d...@nokia.com> Subject: Re: [RFC] Inter-processor Mailboxes Drivers Date: Mon, 14 Feb 2011 10:55:53 +0200 (EET)
> From: ext Linus Walleij <linus.wall...@linaro.org> > Subject: Re: [RFC] Inter-processor Mailboxes Drivers > Date: Mon, 14 Feb 2011 09:39:32 +0100 > >> On Mon, Feb 14, 2011 at 8:32 AM, Hiroshi DOYU <hiroshi.d...@nokia.com> wrote: >> >>> OMAP mailbox is the interrupt driven 32bit unit H/W FIFO to other >>> cores. >> >> How is it used? Is it a low-traffic (like single 32bit words etc) signal >> control-path link while the actual high-throughput data-path is done >> with shared memory? (That is how the db5500 mbox works anyways.) > > Yes, maybe quite similar. > > maibox is not single 32 bit but is 32 bit x 4(or 8?) slots fifo, IIRC, > and mainly it is used as notification between cores. And big amount of > data is transftered with sahred memory, which has been mapped onto the > virtual address space of the other side of core, in advance. > > For example, typical usage of DSP, mp3 decoding, > > 1, ARM maps 2 shared memory area(input/output) onto DSP virtual > address space. > 2, ARM fills mp3 data in input buffer. > 3, ARM notifies DSP that data is ready in input buffer. > 4, DSP decodes input data and put output data on output buffer. > 5, DSP notifies that output buffer is ready. > > Roughly something like the above. DSP S/W is multi-tasking, though. Here, ARM side process talks to DSP site process in their own way, and also there are another cores, talking with their own protocols. So I think that at least, protocol part should be pluggable anyway although it doesn't have to be always in userland. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
