Re: [PATCH v7 5/5] iommu/of: Add support for "iommu-ranges" on a device node

[Krzysztof Kozlowski <krzk@kernel.org>]

On 06/11/2026 18:14, Vikash Garodia wrote:
> Reserving an IOVA address using "iommu-addresses" requires it to be
> placed in the reserved-memory node. But when "iommu-addresses" is the
> only property being described and there is no backing "reg" (i.e. no
> actual reserved system memory), it does not really belong under
> /reserved-memory. A device IOVA range is specific to its own address
> space, and does not describe the system physical memory to make it
> qualify under reserved-memory. Given this, place "iommu-addresses"
> inside reserved-memory only when it is paired with a "reg", otherwise,
> define it within the device own node. It was discussed here:
> https://lore.kernel.org/all/662f7093-fb0a-4564-9ca0-98e03e68ba9a@kernel.org
> 
> Existing "iommu-addresses" property expects a phandle, which does
> not make sense when the property is defined within the device node.
> "iommu-ranges" was introduced to specify the device specific IOVA ranges
> when there is no backing "reg".
> 
> Suggested-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> Co-developed-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
> Signed-off-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
> Signed-off-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
> ---
>  drivers/iommu/of_iommu.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 107 insertions(+)
> 


Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

Best regards,
Krzysztof