Dear Arnd, In message <201207241319.45101.a...@arndb.de> you wrote: > > > I'm trying to implement a driver that can do both DMA and PIO, and it would > > be > > nice if the user was able to select the mode (on a per-bus basis) using the > > DT. > > The PIO mode can reduce the overhead in some cases and therefore be better > > choice than the DMA (for example when most transfers move only very few > > data, or > > when board-specific hardware properties kick in). > > > > I was thinking about using some "manf,use-pio" DT property, but I haven't > > found > > any such example yet, so I wonder if this is a good idea. > > > > What kind of device is this? We are currently working on the dmaengine > binding, so an easy way to do this would be (one that binding is complete) > to either provide or not provide the channel description depending on > what you want to do with the device. This is clearly a hack but might > fit your use case without adding any ugly code to the kernel. > > Another option would be to make it a runtime configuration option, > e.g. through sysfs, but that again depends a lot on what device you > are talking about.
At least in my example of the x86 system a sysfs interface would not help, as the kernel would crash during bootup before I can run user space code. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de Mirrors should reflect a little before throwing back images. - Jean Cocteau _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss
