Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755521AbbESKjY (ORCPT ); Tue, 19 May 2015 06:39:24 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([207.82.80.143]:12901 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752367AbbESKjW convert rfc822-to-8bit (ORCPT ); Tue, 19 May 2015 06:39:22 -0400 Message-ID: <555B12D5.5080608@arm.com> Date: Tue, 19 May 2015 11:39:17 +0100 From: Robin Murphy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Laurent Pinchart , "linux-kernel@vger.kernel.org" CC: "linux-arm-kernel@lists.infradead.org" , "iommu@lists.linux-foundation.org" , Laura Abbott , Arnd Bergmann , Mitchel Humpherys , Joreg Roedel , Will Deacon , "grant.likely@linaro.org" , Marek Szyprowski , Thierry Reding , Greg Kroah-Hartman Subject: Re: [RFC/PATCH 6/9] drivers: platform: Configure dma operations at probe time References: <1431644410-2997-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> <1431644410-2997-7-git-send-email-laurent.pinchart+renesas@ideasonboard.com> In-Reply-To: <1431644410-2997-7-git-send-email-laurent.pinchart+renesas@ideasonboard.com> X-OriginalArrivalTime: 19 May 2015 10:39:18.0363 (UTC) FILETIME=[0F18B2B0:01D09220] X-MC-Unique: IpHIjbKuTYixnTyxmABDRA-1 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3699 Lines: 100 Hi Laurent, On 15/05/15 00:00, Laurent Pinchart wrote: > Configuring DMA ops at probe time will allow deferring device probe when > the IOMMU isn't available yet. This is great, as I think it also subtly solves the ordering problem the current domain allocation has with platform devices. WRT to your comment on the other thread, this actually makes things slightly saner for IOMMU groups - the group assignment has to happen after device creation or else some sysfs stuff blows up, so of_xlate is far too early and the add_device callback is a reasonable place for it to be (until we can move it out of every driver and into bus code). However, we're currently attaching the device to the automatic domain long before that, so things happen logically backwards and drivers like the ARM SMMU which actually use the group to store relevant data get all confused. With this change, the existing attach_device call in arch_setup_dma_ops will actually work far more reliably, and I might be able to revive my attempt to port the ARM SMMU driver over to of_xlate :D Robin. > Signed-off-by: Laurent Pinchart > --- > drivers/base/platform.c | 9 +++++++++ > drivers/of/platform.c | 7 +++---- > 2 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index ebf034b97278..508a866859dc 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -516,6 +516,10 @@ static int platform_drv_probe(struct device *_dev) > if (ret < 0) > return ret; > > + ret = of_dma_configure_ops(_dev, _dev->of_node); > + if (ret < 0) > + goto done; > + > ret = dev_pm_domain_attach(_dev, true); > if (ret != -EPROBE_DEFER) { > ret = drv->probe(dev); > @@ -523,6 +527,10 @@ static int platform_drv_probe(struct device *_dev) > dev_pm_domain_detach(_dev, true); > } > > + if (ret) > + of_dma_deconfigure(_dev); > + > +done: > if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { > dev_warn(_dev, "probe deferral not supported\n"); > ret = -ENXIO; > @@ -544,6 +552,7 @@ static int platform_drv_remove(struct device *_dev) > > ret = drv->remove(dev); > dev_pm_domain_detach(_dev, true); > + of_dma_deconfigure(_dev); > > return ret; > } > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 9a29f09b7723..fc939bec799e 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -178,10 +178,8 @@ static struct platform_device *of_platform_device_create_pdata( > dev->dev.bus = &platform_bus_type; > dev->dev.platform_data = platform_data; > of_dma_configure_masks(&dev->dev, dev->dev.of_node); > - of_dma_configure_ops(&dev->dev, dev->dev.of_node); > > if (of_device_add(dev) != 0) { > - of_dma_deconfigure(&dev->dev); > platform_device_put(dev); > goto err_clear_flag; > } > @@ -465,11 +463,12 @@ static int of_platform_device_destroy(struct device *dev, void *data) > if (dev->bus == &platform_bus_type) > platform_device_unregister(to_platform_device(dev)); > #ifdef CONFIG_ARM_AMBA > - else if (dev->bus == &amba_bustype) > + else if (dev->bus == &amba_bustype) { > amba_device_unregister(to_amba_device(dev)); > + of_dma_deconfigure(dev); > + } > #endif > > - of_dma_deconfigure(dev); > of_node_clear_flag(dev->of_node, OF_POPULATED); > of_node_clear_flag(dev->of_node, OF_POPULATED_BUS); > return 0; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/