From: Peter Ujfalusi Subject: Re: [PATCH 02/13] dmaengine: Introduce dma_request_slave_channel_compat_reason() Date: Wed, 18 Nov 2015 16:41:35 +0200 Message-ID: <564C8E1F.8010501@ti.com> References: <1432646768-12532-1-git-send-email-peter.ujfalusi@ti.com> <20150624162401.GP19530@localhost> <564C8966.9080406@ti.com> <6347063.Gd6coh6hX8@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Vinod Koul , Geert Uytterhoeven , Tony Lindgren , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Dan Williams , , "linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linux MMC List , , linux-spi , Linux Media Mailing List , ALSA Development Mailing List To: Arnd Bergmann Return-path: In-Reply-To: <6347063.Gd6coh6hX8@wuerfel> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-crypto.vger.kernel.org On 11/18/2015 04:29 PM, Arnd Bergmann wrote: > On Wednesday 18 November 2015 16:21:26 Peter Ujfalusi wrote: >> 2. non slave channel requests, where only the functionality matters,= like >> memcpy, interleaved, memset, etc. >> We could have a simple: >> dma_request_channel(mask); >> >> But looking at the drivers using dmaengine legacy dma_request_channe= l() API: >> Some sets DMA_INTERRUPT or DMA_PRIVATE or DMA_SG along with DMA_SLAV= E: >> drivers/misc/carma/carma-fpga.c DMA_INTERRUPT|DMA_SL= AVE|DMA_SG >> drivers/misc/carma/carma-fpga-program.c DMA_MEMCPY|DMA_SLAVE= |DMA_SG >> drivers/media/platform/soc_camera/mx3_camera.c DMA_SLAVE|DMA_PRIVAT= E >> sound/soc/intel/common/sst-firmware.c DMA_SLAVE|DMA_MEMCPY >> >> as examples. >> Not sure how valid are these... >=20 > It's usually not much harder to separate out the legacy case from > the normal dma_request_slave_channel_reason(), so those drivers don't > really need to use the unified compat API. The current dma_request_slave_channel()/_reason() is not the 'legacy' A= PI. Currently there is no way to get the reason why the dma channel request= fails when using the _compat() version of the API, which is used by drivers w= hich can be used in DT or in legacy mode as well. Sure, they all could have = local if(){}else{} for handling this, but it is not a nice thing. As it was discussed instead of adding the _reason() version for the _co= mpat call, we should simplify the dmaengine API for getting the channel and = at the same time we will have ERR_PTR returned instead of NULL. --=20 P=E9ter -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html