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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Rob Herring <robherring2@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>,
	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: Fri, 30 Jan 2015 02:24:51 +0200	[thread overview]
Message-ID: <1612981.2C6LXFqAIA@avalon> (raw)
In-Reply-To: <CAL_Jsq+rzwk0Rw5RRKf9oLqXNFFgnJb4UQ_AzpJLxN1Z0rJWMQ@mail.gmail.com>

Hi Rob,

On Thursday 29 January 2015 10:49:38 Rob Herring wrote:
> On Wed, Jan 28, 2015 at 5:32 PM, Laurent Pinchart wrote:
> > On Wednesday 28 January 2015 13:32:19 Will Deacon wrote:
> >> On Wed, Jan 28, 2015 at 01:15:10PM +0000, Laurent Pinchart wrote:
> >>> On Wednesday 28 January 2015 12:29:42 Will Deacon wrote:
> >>>> On Wed, Jan 28, 2015 at 12:23:03PM +0000, Laurent Pinchart wrote:
> >>>>> 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.
> 
> [...]
> 
> >>> If I understand Murali's patch set right (please correct me if that's
> >>> not the case) the PCI code walks up the DT nodes hierarchy to the
> >>> parent node that contains the iommus attribute and passes a pointer to
> >>> that node to this function. It's thus a PCI-specific solution. As a
> >>> temporary hack that's OK I suppose, but if implementing it right
> >>> straight away isn't difficult that would be better.
> >> 
> >> It looks to me like the code walks the PCI topology to get the DT node
> >> for the host controller, and passes *that* to of_dma_configure. That
> >> sounds like the right thing to do to me, especially since the PCI
> >> topology is likely not encoded in the device-tree. So actually, it is
> >> passing the first parent node afaict.
> > 
> > Indeed, that's right. I forgot for a moment that we have non-DT devices
> > ;-)
> > 
> > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > Murali, nitpicking a bit, shouldn't the iommu_np parameter be renamed ? It
> > points to the node containing the iommus parameter, not to the iommu node,
> > so the current name is slightly confusing. A brief kerneldoc above the
> > function would also help. This can be the subject of a separate patch.
> 
> It was more confusing having np and node within the function.

Agreed.

How about master_np or iommu_master_np ? The latter might be a bit long.

-- 
Regards,

Laurent Pinchart


  reply	other threads:[~2015-01-30  0:24 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
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 [this message]
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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