On Mon, Feb 08, 2010 at 11:03:14AM +0100, Andy Green wrote: > On 02/08/10 10:51, Somebody in the thread at some point said: > >> We could of course flush the caches every time we get a page fault but >> that's far from optimal, especially since DMA-capable drivers to do not >> pollute the D-cache and don't need this extra flushing. Note that the >> recent ARM processors have PIPT caches but separate for I and D and it's >> the PIO drivers that pollute the D-cache. > > Just noting that AFAIK iMX31 USB and MMC drivers both are PIO at the > moment, for lack of any platform DMA support of its unusual DMA engine. The EHCI module has its own DMA engine and has nothing to do with the SDMA engine. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
