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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Will Deacon <will.deacon@arm.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	Russell King <linux@arm.linux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>, Joerg Roedel <joro@8bytes.org>,
	Rob Herring <robh+dt@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
	"grant.likely@linaro.org" <grant.likely@linaro.org>
Subject: Re: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure()
Date: Wed, 28 Jan 2015 14:23:03 +0200	[thread overview]
Message-ID: <3953539.m9NpxSWcJ5@avalon> (raw)
In-Reply-To: <20150128113300.GF1569@arm.com>

Hi Will,

On Wednesday 28 January 2015 11:33:00 Will Deacon wrote:
> On Mon, Jan 26, 2015 at 06:49:01PM +0000, Murali Karicheri wrote:
> > On 01/25/2015 08:32 AM, Laurent Pinchart wrote:
> >> On Friday 23 January 2015 17:32:34 Murali Karicheri wrote:
> >>> Function of_iommu_configure() is called from of_dma_configure() to
> >>> setup iommu ops using DT property. This API is currently used for
> >>> platform devices for which DMA configuration (including iommu ops)
> >>> may come from device's parent. To extend this functionality for PCI
> >>> devices, this API need to take a parent node ptr as an argument
> >>> instead of assuming device's parent. This is needed since for PCI, the
> >>> dma configuration may be defined in the DT node of the root bus
> >>> bridge's parent device. Currently only dma-range is used for PCI and
> >>> iommu is not supported. So return error if the device is PCI.
> >>> 
> >>> Cc: Joerg Roedel<joro@8bytes.org>
> >>> Cc: Grant Likely<grant.likely@linaro.org>
> >>> Cc: Rob Herring<robh+dt@kernel.org>
> >>> Cc: Bjorn Helgaas<bhelgaas@google.com>
> >>> Cc: Will Deacon<will.deacon@arm.com>
> >>> Cc: Russell King<linux@arm.linux.org.uk>
> >>> Cc: Arnd Bergmann<arnd@arndb.de>
> >>> Cc: Suravee Suthikulpanit<Suravee.Suthikulpanit@amd.com>
> >>> 
> >>> Signed-off-by: Murali Karicheri<m-karicheri2@ti.com>
> >>> ---
> >>> 
> >>>   drivers/iommu/of_iommu.c |   10 ++++++++--
> >>>   drivers/of/platform.c    |    2 +-
> >>>   include/linux/of_iommu.h |    6 ++++--
> >>>   3 files changed, 13 insertions(+), 5 deletions(-)
> >>> 
> >>> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> >>> index af1dc6a..439235b 100644
> >>> --- a/drivers/iommu/of_iommu.c
> >>> +++ b/drivers/iommu/of_iommu.c
> >>> @@ -133,19 +133,25 @@ struct iommu_ops *of_iommu_get_ops(struct
> >>> device_node *np)
> >>>   	return ops;
> >>>  }
> >>> 
> >>> -struct iommu_ops *of_iommu_configure(struct device *dev)
> >>> +struct iommu_ops *of_iommu_configure(struct device *dev,
> >>> +				     struct device_node *iommu_np)
> >>>  {
> >>>   	struct of_phandle_args iommu_spec;
> >>>   	struct device_node *np;
> >>>   	struct iommu_ops *ops = NULL;
> >>>   	int idx = 0;
> >>> 
> >>> +	if (dev_is_pci(dev)) {
> >>> +		dev_err(dev, "iommu is currently not supported for PCI\n");
> >>> +		return NULL;
> >>> +	}
> >>> +
> >>>   	/*
> >>>   	 * We don't currently walk up the tree looking for a parent IOMMU.
> >>>   	 * See the `Notes:' section of
> >>>   	 * Documentation/devicetree/bindings/iommu/iommu.txt
> >>>   	 */
> >> 
> >> Wouldn't it be better to fix this rather than passing the device node
> >> pointer to the function ? The solution would be more generic.
> > 
> > Laurent,
> > 
> > Will Deacon (Copied here) is working on this as we alteady discussed in
> > this thread. So it will be addressed by him in another series.
> 
> Well, "working on this" equates to "has it somewhere near the bottom of
> a very long list" :)

What's your opinion on this patch then, do you think adding the iommu_np 
argument makes sense as a temporary hack, or should we instead walk up the 
tree looking for an iommus attribute in parent nodes ? I don't expect that to 
be insanely difficult to code.

-- 
Regards,

Laurent Pinchart


  reply	other threads:[~2015-01-28 20:38 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-23 22:32 [PATCH v4 0/6] PCI: get DMA configuration from parent device Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() Murali Karicheri
2015-01-25 13:32   ` Laurent Pinchart
2015-01-26 18:49     ` Murali Karicheri
2015-01-28 11:33       ` Will Deacon
2015-01-28 12:23         ` Laurent Pinchart [this message]
2015-01-28 12:29           ` Will Deacon
2015-01-28 13:15             ` Laurent Pinchart
2015-01-28 13:32               ` Will Deacon
2015-01-28 15:21                 ` Murali Karicheri
2015-01-28 23:32                 ` Laurent Pinchart
2015-01-29 14:59                   ` Murali Karicheri
2015-01-29 16:49                   ` Rob Herring
2015-01-30  0:24                     ` Laurent Pinchart
2015-01-30 15:23                       ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 2/6] of: move of_dma_configure() to device.c to help re-use Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 3/6] of: fix size when dma-range is not used Murali Karicheri
2015-01-27 11:27   ` Robin Murphy
2015-01-27 15:44     ` Murali Karicheri
2015-01-27 18:55     ` Murali Karicheri
2015-01-28 11:05       ` Catalin Marinas
2015-01-28 15:45         ` Rob Herring
2015-01-28 17:23           ` Catalin Marinas
2015-01-28 17:34           ` Murali Karicheri
2015-01-28 15:55         ` Robin Murphy
2015-01-28 17:30           ` Catalin Marinas
2015-01-30 18:06             ` Murali Karicheri
2015-02-02 12:18               ` Catalin Marinas
2015-02-02 16:10                 ` Murali Karicheri
2015-02-05 21:42                 ` Murali Karicheri
2015-02-05 22:44                   ` Catalin Marinas
2015-01-23 22:32 ` [PATCH v4 4/6] of/pci: add of_pci_dma_configure() update dma configuration Murali Karicheri
2015-01-23 23:41   ` Bjorn Helgaas
2015-01-26 23:25     ` Murali Karicheri
2015-01-26 23:59       ` Bjorn Helgaas
2015-01-27 18:14         ` Murali Karicheri
2015-01-27 18:42           ` Bjorn Helgaas
2015-01-27 18:45             ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 5/6] PCI: update dma configuration from DT Murali Karicheri
2015-01-23 23:27   ` Bjorn Helgaas
2015-01-26 23:28     ` Murali Karicheri
2015-01-23 22:32 ` [PATCH v4 6/6] arm: dma-mapping: updates to limit dma_mask and iommu mapping size Murali Karicheri
2015-01-27 11:12   ` Robin Murphy
2015-01-27 11:34     ` Catalin Marinas
2015-01-27 15:19       ` Murali Karicheri

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