On Mon, Jul 25, 2016 at 10:21:10AM -0500, Rob Herring wrote:

On Mon, Jul 25, 2016 at 10:09 AM, Robin Murphy [off-list ref] wrote:

quoted

Hi Lorenzo,

On 20/07/16 12:23, Lorenzo Pieralisi wrote:

quoted

The iommu_fwspec structure, used to hold per device iommu configuration
data is not OF specific and therefore can be moved to a generic
and OF independent compilation unit.

In particular, the iommu_fwspec handling hinges on the device_node
pointer to identify the IOMMU device associated with the iommu_fwspec
structure, that is easily converted to a more generic fwnode_handle
pointer that can cater for OF and non-OF (ie ACPI) systems.

Create the files and related Kconfig entry to decouple iommu_fwspec
structure from the OF iommu kernel layer.

Given that the current iommu_fwspec implementation relies on
the arch specific struct device.archdata.iommu field in its
implementation, by making the code standalone and independent
of the OF layer this patch makes sure that the iommu_fwspec
kernel code can be selected only on arches implementing the
struct device.archdata.iommu field by adding an explicit
arch dependency in its config entry.

Current drivers using the iommu_fwspec for streamid translation
are converted to the new iommu_fwspec API by simply converting
the device_node to its fwnode_handle pointer.

Signed-off-by: Lorenzo Pieralisi <redacted>
Cc: Will Deacon <redacted>
Cc: Hanjun Guo <redacted>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
---
 drivers/iommu/Kconfig        |   4 ++
 drivers/iommu/Makefile       |   1 +
 drivers/iommu/arm-smmu-v3.c  |  13 +++--
 drivers/iommu/iommu-fwspec.c | 114 +++++++++++++++++++++++++++++++++++++++++++
 drivers/iommu/of_iommu.c     |  52 --------------------
 include/linux/iommu-fwspec.h |  60 +++++++++++++++++++++++
 include/linux/of_iommu.h     |  24 +++------
 7 files changed, 196 insertions(+), 72 deletions(-)
 create mode 100644 drivers/iommu/iommu-fwspec.c
 create mode 100644 include/linux/iommu-fwspec.h

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index d1c66af..2b26bfb 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig

@@ -67,6 +67,10 @@ config OF_IOMMU
        def_bool y
        depends on OF && IOMMU_API

+config IOMMU_FWSPEC
+       def_bool y
+       depends on ARM64 && IOMMU_API

I think that could be at least (ARM || ARM64).

Why any arch dependency?

Seems like OF_IOMMU (and ACPI?) should select this.

Absolutely, that's the end goal. Current issue is that the iommu_fwspec
mechanism relies on dev_archdata.iommu pointer internally to work and
since that's arch specific I can't select it on arches that do not have
that field, it would break the compilation.

I will follow up with Robin to make sure we will be able to
implement what you request above.

Thanks !
Lorenzo