Re: [PATCH v10 1/3] of: Add convenience wrappers for of_map_id()

[Vijayanand Jitta <vijayanand.jitta@xxxxxxxxxxxxxxxx>]

On 3/10/2026 2:46 AM, Dmitry Baryshkov wrote:
> On Mon, Mar 09, 2026 at 01:03:37AM +0530, Vijayanand Jitta wrote:
>> From: Robin Murphy <robin.murphy@xxxxxxx>
>>
>> Since we now have quite a few users parsing "iommu-map" and "msi-map"
>> properties, give them some wrappers to conveniently encapsulate the
>> appropriate sets of property names. This will also make it easier to
>> then change of_map_id() to correctly account for specifier cells.
>>
>> Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
>> Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
>> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
>> Signed-off-by: Vijayanand Jitta <vijayanand.jitta@xxxxxxxxxxxxxxxx>
>> ---
>>  drivers/cdx/cdx_msi.c                    |  3 +--
>>  drivers/iommu/of_iommu.c                 |  4 +---
>>  drivers/irqchip/irq-gic-its-msi-parent.c |  2 +-
>>  drivers/of/base.c                        | 36 
>> ++++++++++++++++++++++++++++++++
>>  drivers/of/irq.c                         |  3 +--
>>  drivers/pci/controller/dwc/pci-imx6.c    |  6 ++----
>>  drivers/pci/controller/pcie-apple.c      |  3 +--
>>  drivers/xen/grant-dma-ops.c              |  3 +--
>>  include/linux/of.h                       | 18 ++++++++++++++++
>>  9 files changed, 62 insertions(+), 16 deletions(-)
>>
>> +
>> +/**
>> + * of_map_msi_id - Translate an ID using "msi-map" bindings.
> 
> Which ID are we talking about wrt. MSI interrupts?
> 

id refers to the device’s requester ID (RID/BDF or platform stream ID),
not an MSI interrupt number; it is the key used in msi-map to obtain
the translated MSI device ID (id_out).

I'll update the kernel doc as below to clarify.


* @id: Requester ID of the device (e.g. PCI RID/BDF or a platform
*      stream/device ID) used as the lookup key in the msi-map table.

Thanks,
Vijay

>> + * @np: root complex device node.
>> + * @id: device ID to map.
>> + * @target: optional pointer to a target device node.
>> + * @id_out: optional pointer to receive the translated ID.
>> + *
>> + * Convenience wrapper around of_map_id() using "msi-map" and 
>> "msi-map-mask".
>> + *
>> + * Return: 0 on success or a standard error code on failure.
>> + */
>> +int of_map_msi_id(const struct device_node *np, u32 id,
>> +              struct device_node **target, u32 *id_out)
>> +{
>> +    return of_map_id(np, id, "msi-map", "msi-map-mask", target, id_out);
>> +}
>> +EXPORT_SYMBOL_GPL(of_map_msi_id);
>