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<j...@8bytes.org>
> >>> Cc: Grant Likely<grant.lik...@linaro.org>
> >>> Cc: Rob Herring<robh...@kernel.org>
> >>> Cc: Bjorn Helgaas<bhelg...@google.com>
> >>> Cc: Will Deacon<will.dea...@arm.com>
> >>> Cc: Russell King<li...@arm.linux.org.uk>
> >>> Cc: Arnd Bergmann<a...@arndb.de>
> >>> Cc: Suravee Suthikulpanit<suravee.suthikulpa...@amd.com>
> >>>
> >>> Signed-off-by: Murali Karicheri<m-kariche...@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
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