[PATCH V7 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error

[sricharan@codeaurora.org (Sricharan)]

Hi Bjorn,

>-----Original Message-----
>From: Bjorn Helgaas [mailto:helgaas at kernel.org]
>Sent: Sunday, January 29, 2017 2:34 AM
>To: Sricharan R <sricharan@codeaurora.org>
>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:
>> 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 <sricharan@codeaurora.org>
>> ...
>
>> 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