From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934945AbbLQPyv (ORCPT ); Thu, 17 Dec 2015 10:54:51 -0500 Received: from mga09.intel.com ([134.134.136.24]:39279 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932952AbbLQPys (ORCPT ); Thu, 17 Dec 2015 10:54:48 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,441,1444719600"; d="scan'208";a="863057905" Message-ID: <1450367702.30729.146.camel@linux.intel.com> Subject: Re: [PATCH 1/3] ata: sata_dwc_460ex: use "dmas" DT property to find dma channel From: Andy Shevchenko To: =?ISO-8859-1?Q?M=E5ns_Rullg=E5rd?= Cc: Tejun Heo , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 17 Dec 2015 17:55:02 +0200 In-Reply-To: References: <1450221935-6034-1-git-send-email-mans@mansr.com> <1450364395.30729.136.camel@linux.intel.com> Organization: Intel Finland Oy Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2015-12-17 at 15:13 +0000, Måns Rullgård wrote: > Andy Shevchenko writes: > > > On Tue, 2015-12-15 at 23:34 +0000, Måns Rullgård wrote: > > > Mans Rullgard writes: > > > > > > > Currently this driver only works with a DesignWare DMA engine > > > > which > > > > it > > > > registers manually using the second "reg" address range and > > > > interrupt > > > > number from the DT node. > > > > > > > > This patch makes the driver instead use the "dmas" property if > > > > present, > > > > otherwise optionally falling back on the old way so existing > > > > device > > > > trees can continue to work. > > > > > > > > With this change, there is no longer any reason to depend on > > > > the > > > > 460EX > > > > machine type so drop that from Kconfig. > > > > > > > > Signed-off-by: Mans Rullgard > > > > --- > > > >  drivers/ata/Kconfig          |  10 ++- > > > >  drivers/ata/sata_dwc_460ex.c | 192 > > > > +++++++++++++++++++++++++++-- > > > > -------------- > > > >  2 files changed, 131 insertions(+), 71 deletions(-) > > > > > > The corresponding patch for the canyonlands devicetree looks > > > something > > > like this.  I don't have any such hardware or even a manual, so I > > > don't > > > know what values to use for the various required DT properties of > > > the > > > DMA controller node, nor can I test it.  The SATA driver works > > > with a > > > different DMA controller on a Sigma Designs chip. > > > > > > diff --git a/arch/powerpc/boot/dts/canyonlands.dts > > > b/arch/powerpc/boot/dts/canyonlands.dts > > > index 3dc75de..959f36e 100644 > > > --- a/arch/powerpc/boot/dts/canyonlands.dts > > > +++ b/arch/powerpc/boot/dts/canyonlands.dts > > > @@ -190,12 +190,22 @@ > > >    /* DMA */ 0x2 &UIC0 0xc > > > 0x4>; > > >   }; > > >   > > > + DMA0: dma@bffd0800 { > > > + compatible = "snps,dma-spear1340"; > > > + reg = <4 0xbffd0800 0x400>; > > > + interrupt-parent = <&UIC3>; > > > + interrupts = <0x5 0x4>; > > > + #dma-cells = <3>; > > > + /* required properties here */ > > > > You have to move the master assignments and other custom dw_dmac > > properties. Maybe at some point I will fix that in dw/platform.c. > > > > > + }; > > The current sata_dwc driver calls dw_dma_probe() with null pdata > which > causes the dw_dma driver to auto-detect most parameters.  It looks > like > simply omitting those properties here results in the same thing, > although in this case dw_dma_parse_dt() leaves a devm-allocated pdata > struct adrift.  Deferring the allocation of that and changing the DT > binding doc to make these properties optional for auto-detect-capable > hardware should just work.   Yeah, I would like to allow autoconfiguration in case of DT as well and translate it to use unified device property API. > Something like this: If it works for you, please, submit as a patch. Thanks. > > diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c > index 68a4815..f90c465 100644 > --- a/drivers/dma/dw/platform.c > +++ b/drivers/dma/dw/platform.c > @@ -103,18 +103,21 @@ dw_dma_parse_dt(struct platform_device *pdev) >   struct device_node *np = pdev->dev.of_node; >   struct dw_dma_platform_data *pdata; >   u32 tmp, arr[DW_DMA_MAX_NR_MASTERS]; > + u32 nr_channels; >   >   if (!np) { >   dev_err(&pdev->dev, "Missing DT data\n"); >   return NULL; >   } >   > + if (of_property_read_u32(np, "dma-channels", nr_channels)) > + return NULL; > + >   pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), > GFP_KERNEL); >   if (!pdata) >   return NULL; >   > - if (of_property_read_u32(np, "dma-channels", &pdata- > >nr_channels)) > - return NULL; > + pdata->nr_channels = nr_channels; >   >   if (of_property_read_bool(np, "is_private")) >   pdata->is_private = true; > > -- Andy Shevchenko Intel Finland Oy