Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753169AbdIDAMM convert rfc822-to-8bit (ORCPT ); Sun, 3 Sep 2017 20:12:12 -0400 Received: from mail-out-1.itc.rwth-aachen.de ([134.130.5.46]:62337 "EHLO mail-out-1.itc.rwth-aachen.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753036AbdIDAML (ORCPT ); Sun, 3 Sep 2017 20:12:11 -0400 X-IronPort-AV: E=Sophos;i="5.41,472,1498514400"; d="scan'208";a="11607973" From: Stefan Bruens To: =?ISO-8859-1?Q?Andr=E9?= Przywara CC: , , , Vinod Koul , , , Maxime Ripard , Chen-Yu Tsai , Rob Herring , Code Kipper Subject: Re: [PATCH 07/10] dmaengine: sun6i: Retrieve channel count/max request from devicetree Date: Mon, 4 Sep 2017 02:12:07 +0200 Message-ID: <2286861.ip18xhFNEq@pebbles.site> In-Reply-To: References: <20170903224100.17893-1-stefan.bruens@rwth-aachen.de> <20170903224100.17893-8-stefan.bruens@rwth-aachen.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" X-Originating-IP: [92.225.242.208] X-ClientProxiedBy: rwthex-w1-a.rwth-ad.de (2002:8682:1a9c::8682:1a9c) To rwthex-w2-b.rwth-ad.de (2002:8682:1a9f::8682:1a9f) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2874 Lines: 94 On Montag, 4. September 2017 01:44:54 CEST Andr? Przywara wrote: > Hi, > > On 03/09/17 23:40, Stefan Br?ns wrote: > > To avoid introduction of a new compatible for each small SoC/DMA > > controller > > variation, move the definition of the channel count to the devicetree. > > > > The number of vchans is no longer explicit, but limited by the highest > > port/DMA request number. The result is a slight overallocation for SoCs > > with a sparse port mapping. > > > > Signed-off-by: Stefan Br?ns > > --- > > > > drivers/dma/sun6i-dma.c | 35 ++++++++++++++++++++++++++++++++++- > > 1 file changed, 34 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c > > index c69dadb853d2..bd4c2e4a759b 100644 > > --- a/drivers/dma/sun6i-dma.c > > +++ b/drivers/dma/sun6i-dma.c > > @@ -42,6 +42,9 @@ > > > > #define DMA_STAT 0x30 > > > > +/* Offset between DMA_IRQ_EN and DMA_IRQ_STAT limits number of channels > > */ > > +#define DMA_MAX_CHANNELS (DMA_IRQ_CHAN_NR * 0x10 / 4) > > + > > > > /* > > > > * sun8i specific registers > > */ > > > > @@ -65,7 +68,8 @@ > > > > #define DMA_CHAN_LLI_ADDR 0x08 > > > > #define DMA_CHAN_CUR_CFG 0x0c > > > > -#define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & 0x1f) > > +#define DMA_CHAN_MAX_DRQ 0x1f > > +#define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & DMA_CHAN_MAX_DRQ) > > > > #define DMA_CHAN_CFG_SRC_IO_MODE BIT(5) > > #define DMA_CHAN_CFG_SRC_LINEAR_MODE (0 << 5) > > #define DMA_CHAN_CFG_SRC_BURST_A31(x) (((x) & 0x3) << 7) > > > > @@ -1173,6 +1177,35 @@ static int sun6i_dma_probe(struct platform_device > > *pdev)> > > sdc->num_vchans = sdc->cfg->nr_max_vchans; > > sdc->max_request = sdc->cfg->nr_max_requests; > > > > + ret = of_property_read_u32(np, "dma-channels", &sdc->num_pchans); > > + if (ret && !sdc->num_pchans) { > > + dev_err(&pdev->dev, "Can't get dma-channels.\n"); > > + return ret; > > + } > > + > > + if (sdc->num_pchans > DMA_MAX_CHANNELS) { > > + dev_err(&pdev->dev, "Number of dma-channels out of range.\n"); > > + return -EINVAL; > > + } > > + > > + ret = of_property_read_u32(np, "dma-requests", &sdc->max_request); > > + if (ret && !sdc->max_request) { > > + dev_info(&pdev->dev, "Missing dma-requests, using %u.\n", > > + DMA_CHAN_MAX_DRQ); > > Mmmh, is this mapping of "!sdc->max_request" -> DMA_CHAN_MAX_DRQ > implemented somewhere else? Or is it just missing here: > sdc->max_request = DMA_CHAN_MAX_DRQ; Well spotted, that assignment is actually missing. With this line added, your comment for patch 8/10 should also be addressed (regarding the default value). > Otherwise this is looking good, thanks for picking up the DT property > approach! > > Cheers, > Andre. > Kind regards, Stefan -- Stefan Br?ns / Bergstra?e 21 / 52062 Aachen home: +49 241 53809034 mobile: +49 151 50412019