On Thursday 24 May 2007, Haavard Skinnemoen wrote: > On Wed, 23 May 2007 09:06:12 -0700 > David Brownell <[EMAIL PROTECTED]> wrote: > > On Wednesday 23 May 2007, Ivan Kuten wrote: > > > > > > .chip_select = 0, > > > > Chipselect zero ... I've had one report that this driver has some issues > > on that chipselect. There seem to be two errata in conflict here: > > ... > > Neither of these should cause any problems for the atmel_spi driver > since it manages chip selects using gpio and sets the MODFDIS bit in MR > to disable mode fault detection (I actually ran into both erratas myself > while developing the driver.)
Yet, I got the report (at91rm9200 specific). Bill? (I remember MODFDIS acting oddly, non-rm9200, but forget the details.) And in any case there seem to be other folk reporting rm9200 + dataflash issues ... while mtd_dataflash doesn't seem to be at fault. So maybe that combination of errata isn't the issue, but something else is making the problem. > > I've CC'd the relevant folk from Atmel. Seems that maybe rm9200 > > needs to have a special case whereby chipselect zero is managed > > by the hardware despite the first erratum. And maybe that because > > of that erratum, the DMA chaining needs to be made to work... else > > root-on-dataflash won't behave. (Or some other workaround.) > > Hmm...I don't think I understand why DMA chaining will help in this > case. Could you explain a bit more? It *might* help -- by keeping the transfer buffer busy enough that the "auto-deselect" erratum needn't kick in with some basic request and response protocol operations. - Dave ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ spi-devel-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spi-devel-general
