Re: [PATCH v5 04/13] iommu: of_iommu: Add support for "iommu-ranges" on a device node

[Bryan O'Donoghue]

On 26/10/2026 12:31, Bryan O'Donoghue wrote:
> On 26/10/2026 12:08, Vikash Garodia wrote:
>>> https://github.com/devicetree-org/dt-schema/pull/207
>>>
>>> Perhaps splitting this into two patches as an iommu-series would be 
>>> best.
>> Intention was to keep the patch to add iommu-ranges property as part of
>> iris driver patches to show the usage of this new property.
>>
>> I am fine either ways, whatever it takes for the maintainers of this
>> file to review.
>>
>> Regards,
>> Vikash
>>
>>>>            end = maps + size / sizeof(__be32);
>>>> @@ -258,6 +367,9 @@ void of_iommu_get_resv_regions(struct device *dev,
>>>> struct list_head *list)
>>>>                    }
>>>>                    type = iommu_resv_region_get_type(dev, &phys, iova,
>>>> length);
>>>> +                if (type != IOMMU_RESV_DIRECT)
>>>> +                    continue;
>>>> +
>>> If you look in iommu_resv_region_get_type() you can emit
>>>
>>>           dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap- 
>>> %pap]
>>> as reservation\n", phys,
>>>                    &start, &end);
>>>           return IOMMU_RESV_RESERVED;
>>>
>>> on a mismatch - which is not what the code will do now. Mismatch will
>>> warn and then not map.
>>>
>>> So maybe dev_err() saying you won't map - in the new patch for reg.
>>> Either way this isn't a change specific to iommu-ranges.
> 
> Sure the above needs to be addressed though because its not a straight 
> change.
> 
> Before if there was a mismatch it would sill be mapped - now we print a 
> warning and _don't_ map.
> 
> I'm not sure that's really what you meant to do here but if it is it 
> should be stated in the git log and IMO it should be a follow on change 
> _after_ the initial addition (or before it) stating why mismatched will 
> no longer be mapped.
> 
> Because add iommu-ranges != don't map mismatched, basically.
> 
> ---
> bod

sic - "before it was reserved, now we will print a warning stating 
something we don't do and won't reserve it"

---
bod