On Mon, Mar 22, 2010 at 20:36:13, Vladimir Pantelic wrote: > Ben Gardiner wrote: > > On Mon, Mar 22, 2010 at 10:20 AM, Vladimir Pantelic > > <[email protected]> wrote: > >> Ben Gardiner wrote: > > >>> We noticed in the recent post by Sudhakar that it is somehow > >>> 'supported' to handle DMA events on the DSP side. This makes a lot of > >>> sense in retrospect and it spurs us to reconsider whether we can or > >>> cannot access HW in general from the DSP side. > >> > >> Are you really really sure you need to have that? > > > > So I guess you agree with our current standing that all HW access > > should be on the linux side then? > > no, but it much easier to do in on the side where all the infrastructure > exists for it. I you must do it on the DSP, then do it, just think hard > whether you really need that.
If you do decide to access peripherals from DSP side, OMAP-L1 SDK provides a DSP side drivers package as well. http://software-dl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/omap_l138/1_00/latest/index_FDS.html > > >> So, the SPI data ends up in linux user space anyway. So are you really > >> sure you cannot achieve your latencies with linux only? > > > > That's a good question. It is a bit of a hypothetical situation so I > > can't say for sure in this case. I guess what I'm trying to get across > > is that we would prefer to not write linux driver code since having > > alot of custom Linux driver code has burned us in the past. We would > > prefer to use existing code bases and drivers and work to make those > > existing drivers stable with patches (that we post back upstream). > > err, but aren't linux spi drivers "existing" and/or "stable"? > > > This 'proxy driver' would be one that grabs the platform resources and > > does nothing else then? Are there existing examples of proxy drivers > > like this? > > no idea. > AFAIK, there are no such proxy drivers. IMHO, it is much easier to statically partition resources between the two cores rather than create proxy drivers for resource sharing. So, if you want to control a particular SPI instance from DSP, just don't register the platform device for that SPI instance in your Linux board file. Thanks, Sekhar _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
