Hi Lorenzo,
>[+hanjun, tomasz, sinan]
>
>It is quite a key patchset, I would be glad if they can test on their
>respective platforms with IORT.
>
>On Mon, Jan 23, 2017 at 09:48:10PM +0530, Sricharan R wrote:
>> This is an equivalent to the DT's handling of the iommu master's probe
>> with deferred probing when the corrsponding iommu is not probed yet.
>> 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 firmware 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: Sricharan R <sricharan@xxxxxxxxxxxxxx>
>> ---
>> drivers/acpi/arm64/iort.c | 25 ++++++++++++++++++++++++-
>> drivers/acpi/scan.c | 7 +++++--
>> drivers/base/dma-mapping.c | 2 +-
>> include/acpi/acpi_bus.h | 2 +-
>> include/linux/acpi.h | 7 +++++--
>> 5 files changed, 36 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>> index bf0ed09..d01bae8 100644
>> --- a/drivers/acpi/arm64/iort.c
>> +++ b/drivers/acpi/arm64/iort.c
>> @@ -550,8 +550,17 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
>> return NULL;
>>
>> ops = iommu_get_instance(iort_fwnode);
>> + /*
>> + * If the ops look-up fails, this means that either
>> + * the SMMU drivers have not been probed yet or that
>> + * the SMMU drivers are not built in the kernel;
>> + * Depending on whether the SMMU drivers are built-in
>> + * in the kernel or not, defer the IOMMU configuration
>> + * or just abort it.
>> + */
>> if (!ops)
>> - return NULL;
>> + return iort_iommu_driver_enabled(node->type) ?
>> + ERR_PTR(-EPROBE_DEFER) : NULL;
>>
>> ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops);
>> }
>> @@ -625,12 +634,26 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
>>
>> while (parent) {
>> ops = iort_iommu_xlate(dev, parent, streamid);
>> + if (IS_ERR_OR_NULL(ops))
>> + return ops;
>>
>> parent = iort_node_get_id(node, &streamid,
>> IORT_IOMMU_TYPE, i++);
>> }
>> }
>>
>> + /*
>> + * If we have reason to believe the IOMMU driver missed the initial
>> + * add_device callback for dev, replay it to get things in order.
>> + */
>> + if (!IS_ERR_OR_NULL(ops) && ops->add_device &&
>> + dev->bus && !dev->iommu_group) {
>> + int err = ops->add_device(dev);
>> +
>> + if (err)
>> + ops = ERR_PTR(err);
>> + }
>
>I think there is nothing ACPI specific in this add_device() replay
>path, so there is room for further DT/ACPI consolidation here.
>
ok, the only way is keep this in a function and call it for both DT and ACPI
cases.
>Without any further ado:
>
>Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Thanks for that.
Regards,
Sricharan
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