From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [RFC 5/9] drivers: platform: Configure dma operations at probe time Date: Tue, 24 May 2016 16:45:17 +0100 Message-ID: <5744770D.9090303@arm.com> References: <1461599894-1969-1-git-send-email-sricharan@codeaurora.org> <1461599894-1969-6-git-send-email-sricharan@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1461599894-1969-6-git-send-email-sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Sricharan R , will.deacon-5wv7dgnIgG8@public.gmane.org, joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org List-Id: iommu@lists.linux-foundation.org On 25/04/16 16:58, Sricharan R wrote: > From: Laurent Pinchart > > Configuring DMA ops at probe time will allow deferring device probe when > the IOMMU isn't available yet. > > Signed-off-by: Laurent Pinchart > --- > drivers/base/platform.c | 13 +++++++++++++ > drivers/of/platform.c | 7 +++---- > 2 files changed, 16 insertions(+), 4 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index f437afa..17e64a4 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -557,6 +557,12 @@ static int platform_drv_probe(struct device *_dev) > if (ret < 0) > return ret; > > + if (of_have_populated_dt()) { > + 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) { > if (drv->probe) { > @@ -569,6 +575,11 @@ static int platform_drv_probe(struct device *_dev) > } > } > > + if (of_have_populated_dt()) { > + 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; > @@ -591,6 +602,8 @@ static int platform_drv_remove(struct device *_dev) > if (drv->remove) > ret = drv->remove(dev); > dev_pm_domain_detach(_dev, true); > + if (of_have_populated_dt()) > + of_dma_deconfigure(_dev); > > return ret; > } > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 17ee8d5..12bbc8e1 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -180,11 +180,9 @@ 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); > of_msi_configure(&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; > } > @@ -481,11 +479,12 @@ 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); > + } Note that we definitely need this to happen properly on other buses, too. I had something for the AMBA bus back when I last looked at this[0], but since then we now have PCI devices going through the of_dma_configure() path as well (hence 226d89cbb242). There's also now some initial ACPI code in flight[1], so it's probably about time to take another closer look at how this can be properly generalised, but I'm not necessarily averse to starting with a DT-focused solution that gets at least half way, then building on top of that. Robin. [0]:http://www.linux-arm.org/git?p=linux-rm.git;a=commitdiff;h=1f38b62b05e17ccbfcc68e4229c69fee74922e2a [1]:http://thread.gmane.org/gmane.linux.kernel.iommu/13046 > #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; >