Messages in this thread | | | Date | Fri, 30 Jan 2015 10:23:52 -0500 | From | Murali Karicheri <> | Subject | Re: [PATCH v4 1/6] of: iommu: add ptr to OF node arg to of_iommu_configure() |
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On 01/29/2015 07:24 PM, Laurent Pinchart wrote: > 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. > Probabaly master_np suffice as this function is named of_iommu_configure(). I will update it.
-- Murali Karicheri Linux Kernel, Texas Instruments
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