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Date:   Tue, 13 Mar 2018 08:27:28 +0100
From:   "hch@lst.de" <hch@lst.de>
To:     Nipun Gupta <nipun.gupta@nxp.com>
Cc:     Sinan Kaya <okaya@codeaurora.org>, "hch@lst.de" <hch@lst.de>,
        "robin.murphy@arm.com" <robin.murphy@arm.com>,
        "linux@armlinux.org.uk" <linux@armlinux.org.uk>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
        "bhelgaas@google.com" <bhelgaas@google.com>,
        "dmitry.torokhov@gmail.com" <dmitry.torokhov@gmail.com>,
        "rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
        "jarkko.sakkinen@linux.intel.com" <jarkko.sakkinen@linux.intel.com>,
        "linus.walleij@linaro.org" <linus.walleij@linaro.org>,
        "johan@kernel.org" <johan@kernel.org>,
        "msuchanek@suse.de" <msuchanek@suse.de>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        Bharat Bhushan <bharat.bhushan@nxp.com>,
        Leo Li <leoyang.li@nxp.com>
Subject: Re: [PATCH] dma-mapping: move dma configuration to bus
        infrastructure
Message-ID: <20180313072727.GA32191@lst.de>
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On Tue, Mar 13, 2018 at 04:22:53AM +0000, Nipun Gupta wrote:
> > Isn't this one or the other one but not both?
> > 
> > Something like:
> > 
> > if (dev->of_node)
> > 	of_dma_deconfigure(dev);
> > else
> > 	acpi_dma_deconfigure(dev);
> > 
> > should work.
> 
> I understand your point. Seems reasonable as we should not expect
> the 'of/acpi DMA deconfigure' API to not fail when they are not configured.
> 
> But, here we would also need to get dma_device (just as we get in
> 'pci_dma_configure') and need a check on it as for PCI there 'of_node'
> is present in the dma_dev.

Both of_dma_deconfigure and acpi_dma_deconfigure just end up calling
arch_teardown_dma_ops.  So my preference would be to just remove
of_dma_deconfigure and acpi_dma_deconfigure and call arch_teardown_dma_ops
as a prep patch before this one.