From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [RFC PATCH 2/3] mmc: host: omap_hsmmc: Enable ADMA2 Date: Thu, 19 May 2016 11:02:43 +0300 Message-ID: <2d328902-d59e-4497-38fa-5bc3ec98180f@ti.com> References: <1463561115-31798-1-git-send-email-kishon@ti.com> <1463561115-31798-3-git-send-email-kishon@ti.com> <573D57DA.20900@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <573D57DA.20900@ti.com> Sender: linux-mmc-owner@vger.kernel.org To: Kishon Vijay Abraham I , linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org, afenkart@gmail.com, ulf.hansson@linaro.org, linux@armlinux.org.uk, tony@atomide.com Cc: rogerq@ti.com, bcousson@baylibre.com, galak@codeaurora.org, ijc+devicetree@hellion.org.uk, mark.rutland@arm.com, pawel.moll@arm.com, robh+dt@kernel.org, nsekhar@ti.com List-Id: linux-omap@vger.kernel.org On 05/19/2016 09:06 AM, Kishon Vijay Abraham I wrote: > Hi Peter, >=20 > On Wednesday 18 May 2016 03:54 PM, Peter Ujfalusi wrote: >> On 05/18/16 11:45, Kishon Vijay Abraham I wrote: >>> omap hsmmc host controller has ADMA2 feature. Enable it here >>> for better read and write throughput. Add a new dt binding >>> "ti,use_adma" to enable ADMA2. >>> >>> Signed-off-by: Kishon Vijay Abraham I >>> --- >>> .../devicetree/bindings/mmc/ti-omap-hsmmc.txt | 1 + >>> drivers/mmc/host/omap_hsmmc.c | 320 ++++++++= ++++++++---- >>> include/linux/platform_data/hsmmc-omap.h | 1 + >>> 3 files changed, 256 insertions(+), 66 deletions(-) >>> >>> diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.tx= t b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt >>> index 74166a0..eb5ceec2 100644 >>> --- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt >>> +++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt >>> @@ -28,6 +28,7 @@ specifier is required. >>> dma-names: List of DMA request names. These strings correspond >>> 1:1 with the DMA specifiers listed in dmas. The string naming is >>> to be "rx" and "tx" for RX and TX DMA requests, respectively. >>> +ti,use_adma: enable adma2 feature >> >> Do we have use case when you want to fall back to generic DMA instea= d of aDMA2? >> IMHO if the driver supports aDMA2, it is going to use it instead of = the >> generic s/eDMA. >> What I mean is: >> the driver implements the aDMA2 support. >> if the IP has support for aDMA2, then it is going to use it, otherwi= se it will >> use the generic DMA. >=20 > hmm.. how will the driver know if the IP has support for aDMA2. Using= dt > binding is one way. Using MMCHS_HL_HWINFO is another way but then the= register > offsets in omap_hsmmc driver has to be modified for omap4+. I remember Felipe saying that MMCHS_HL_HWINFO is not reliable for some = reason? But in any case it would be better IMHO if we query the HW for Master D= MA support and if it is available we will use it. If it is really the case that MMCHS_HL_HWINFO is not reliable, then pro= bably have a flag for the MMC/SD phandle saying that ti,master_dma_supported = to indicate that it is capable has ADMA support also. --=20 P=E9ter