On Mon, Jan 23, 2017 at 09:48:09PM +0530, Sricharan R wrote:
> From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxxxx>
> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
> ...
> 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?
> #include <linux/slab.h>
>
> static const struct of_device_id __iommu_of_table_sentinel
> @@ -223,7 +224,7 @@ const struct iommu_ops *of_iommu_configure(struct device *dev,
> ops = ERR_PTR(err);
> }
>
> - return IS_ERR(ops) ? NULL : ops;
> + return ops;
> }
>
> static int __init of_iommu_init(void)
> @@ -234,7 +235,7 @@ static int __init of_iommu_init(void)
> for_each_matching_node_and_match(np, matches, &match) {
> const of_iommu_init_fn init_fn = match->data;
>
> - if (init_fn(np))
> + if (init_fn && init_fn(np))
> pr_err("Failed to initialise IOMMU %s\n",
> of_node_full_name(np));
> }
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