dmaengine cyclic transfers
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From: Sascha Hauer on 10 Aug 2010 09:20 Hi All, I'm just looking into implementing the Freescale i.MX SDMA engine in the dmaengine API. One usecase of this dma engine is sound. After some digging I found the following commit: commit d9de451989a88a2003ca06e524aca4665c0c7f06 Author: Hans-Christian Egtvedt <hans-christian.egtvedt(a)atmel.com> Date: Wed Apr 1 15:47:02 2009 +0200 dw_dmac: add cyclic API to DW DMA driver This could be very useful for the SDMA engine aswell. What are the reasons this is not implemented in the generic dmaengine API but as an extension to a specific driver? Should I also implement it like this or isn't it better to extend the dmaengine itself? 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-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Linus Walleij on 10 Aug 2010 17:20
2010/8/10 Sascha Hauer <s.hauer(a)pengutronix.de>: > Author: Hans-Christian Egtvedt <hans-christian.egtvedt(a)atmel.com> > Date: � Wed Apr 1 15:47:02 2009 +0200 > > � �dw_dmac: add cyclic API to DW DMA driver > > This could be very useful for the SDMA engine aswell. What are the > reasons this is not implemented in the generic dmaengine API but as > an extension to a specific driver? No reasons what I know. There was a similar code snippet in Peter Pearse's PL08x driver as well, I just didn't know what to do with it. > Should I also implement it like > this or isn't it better to extend the dmaengine itself? This is going to be generally useful, so please extend the DMAengine if I have my say. I actually miss two functions from the engine: 1) Single buffer slave transfers (without sglist) 2) Cyclic buffers (esp good for audio) The first I have a patch for, will repost. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |