From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH 3/4] dmaengine: fsl-edma: support little endian for edma driver Date: Tue, 21 May 2019 10:08:07 +0530 Message-ID: <20190521043807.GN15118@vkoul-mobl> References: <20190506090344.37784-1-peng.ma@nxp.com> <20190506090344.37784-3-peng.ma@nxp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190506090344.37784-3-peng.ma@nxp.com> Sender: linux-kernel-owner@vger.kernel.org To: Peng Ma Cc: robh+dt@kernel.org, shawnguo@kernel.org, mark.rutland@arm.com, leoyang.li@nxp.com, dan.j.williams@intel.com, dmaengine@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On 06-05-19, 09:03, Peng Ma wrote: > improve edma driver to support little endian. Can you explain a bit more how adding the below lines adds little endian support... > > Signed-off-by: Peng Ma > --- > drivers/dma/fsl-edma-common.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c > index 680b2a0..6bf238e 100644 > --- a/drivers/dma/fsl-edma-common.c > +++ b/drivers/dma/fsl-edma-common.c > @@ -83,9 +83,14 @@ void fsl_edma_chan_mux(struct fsl_edma_chan *fsl_chan, > u32 ch = fsl_chan->vchan.chan.chan_id; > void __iomem *muxaddr; > unsigned int chans_per_mux, ch_off; > + int endian_diff[4] = {3, 1, -1, -3}; > > chans_per_mux = fsl_chan->edma->n_chans / DMAMUX_NR; > ch_off = fsl_chan->vchan.chan.chan_id % chans_per_mux; > + > + if (!fsl_chan->edma->big_endian) > + ch_off += endian_diff[ch_off % 4]; > + > muxaddr = fsl_chan->edma->muxbase[ch / chans_per_mux]; > slot = EDMAMUX_CHCFG_SOURCE(slot); > > -- > 1.7.1 -- ~Vinod