> -----Original Message----- > From: devicetree-discuss [mailto:devicetree-discuss- > bounces+poonam.aggrwal=freescale....@lists.ozlabs.org] On Behalf Of Marek > Vasut > Sent: Monday, July 23, 2012 2:58 AM > To: devicetree-discuss@lists.ozlabs.org > Cc: pa...@denx.de; Wolfgang Denk > Subject: Forcing PIO mode instead of DMA via DT property > > Hi guys, > > 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. Not sure, but as far as I understand device tree is to publish the hardware capabilities, not the user choice/configuration. One option would be to put a compile time flag in the driver, which prefers PIO than DMA. I believe by default DMA is the first preference.
Regards Poonam > > What is your suggestion how I shoud address such a problem? > > Thanks in advance! > > Best regards, > Marek Vasut > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/devicetree-discuss _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss
