Hi Bjorn,

-----Original Message-----
From: Bjorn Helgaas [mailto:helgaas at kernel.org]
Sent: Sunday, January 29, 2017 2:34 AM
To: Sricharan R <redacted>
Cc: robin.murphy at arm.com; will.deacon at arm.com; joro at 8bytes.org; lorenzo.pieralisi at arm.com; iommu at lists.linux-foundation.org;
linux-arm-kernel at lists.infradead.org; linux-arm-msm at vger.kernel.org; m.szyprowski at samsung.com; bhelgaas at google.com; linux-
pci at vger.kernel.org; linux-acpi at vger.kernel.org
Subject: Re: [PATCH V7 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error

On Mon, Jan 23, 2017 at 09:48:09PM +0530, Sricharan R wrote:

quoted

From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Failures to look up an IOMMU when parsing the DT iommus property need to
be handled separately from the .of_xlate() failures to support deferred
probing.

The lack of a registered IOMMU can be caused by the lack of a driver for
the IOMMU, the IOMMU device probe not having been performed yet, having
been deferred, or having failed.

The first case occurs when the device tree describes the bus master and
IOMMU topology correctly but no device driver exists for the IOMMU yet
or the device driver has not been compiled in. Return NULL, the caller
will configure the device without an IOMMU.

The second and third cases are handled by deferring the probe of the bus
master device which will eventually get reprobed after the IOMMU.

The last case is currently handled by deferring the probe of the bus
master device as well. A mechanism to either configure the bus master
device without an IOMMU or to fail the bus master device probe depending
on whether the IOMMU is optional or mandatory would be a good
enhancement.

Signed-off-by: Laurent Pichart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sricharan R <redacted>
...

quoted

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 349bd1d..9529d6c 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c

@@ -23,6 +23,7 @@
 #include <linux/of.h>
 #include <linux/of_iommu.h>
 #include <linux/of_pci.h>
+#include <linux/pci.h>

Why do we need this?

Right, will remove it.

Regards,
 Sricharan