Re: [PATCH v9 2/3] of: factor arguments passed to of_map_id() into a struct

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>]

On Sun, Mar 01, 2026 at 02:04:20PM +0530, Vijayanand Jitta wrote:
> From: Charan Teja Kalla <charan.kalla@xxxxxxxxxxxxxxxx>
> 
> Change of_map_id() to take a pointer to struct of_phandle_args
> instead of passing target device node and translated IDs separately.
> Update all callers accordingly.
> 
> Subsequent patch will make use of the args_count field in
> struct of_phandle_args.
> 
> Suggested-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
> Signed-off-by: Charan Teja Kalla <charan.kalla@xxxxxxxxxxxxxxxx>
> Signed-off-by: Vijayanand Jitta <vijayanand.jitta@xxxxxxxxxxxxxxxx>
> ---
>  drivers/iommu/of_iommu.c              |  2 +-
>  drivers/of/base.c                     | 37 
> +++++++++++++++++------------------
>  drivers/pci/controller/dwc/pci-imx6.c |  8 +++++++-
>  drivers/pci/controller/pcie-apple.c   |  4 +++-
>  drivers/xen/grant-dma-ops.c           |  2 +-
>  include/linux/of.h                    | 21 +++++++++++++-------
>  6 files changed, 44 insertions(+), 30 deletions(-)
> 

> @@ -2193,11 +2193,10 @@ int of_map_id(const struct device_node *np, u32 id,
>       }
>  
>       pr_info("%pOF: no %s translation for id 0x%x on %pOF\n", np, map_name,
> -             id, target && *target ? *target : NULL);
> +             id, arg->np ? arg->np : NULL);

Is it just 'args->np' then? If it's NULL, it's NULL anyway.

>  
>       /* Bypasses translation */
> -     if (id_out)
> -             *id_out = id;
> +     arg->args[0] = id;
>       return 0;
>  }
>  EXPORT_SYMBOL_GPL(of_map_id);
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c 
> b/drivers/pci/controller/dwc/pci-imx6.c
> index bff8289f804a..74fc603b3f84 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1139,12 +1139,18 @@ static int imx_pcie_add_lut_by_rid(struct imx_pcie 
> *imx_pcie, u32 rid)
>  {
>       struct device *dev = imx_pcie->pci->dev;
>       struct device_node *target;
> +     struct of_phandle_args iommu_spec = { .args_count = 1 };
>       u32 sid_i, sid_m;
>       int err_i, err_m;
>       u32 sid = 0;
>  
>       target = NULL;
> -     err_i = of_map_iommu_id(dev->of_node, rid, &target, &sid_i);
> +     err_i = of_map_iommu_id(dev->of_node, rid, &iommu_spec);
> +     if (!err_i) {
> +             target = iommu_spec.np;
> +             sid_i = iommu_spec.args[0];
> +     }
> +
>       if (target) {
>               of_node_put(target);
>       } else {
> diff --git a/drivers/pci/controller/pcie-apple.c 
> b/drivers/pci/controller/pcie-apple.c
> index a0937b7b3c4d..e1d4b37d200d 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -755,6 +755,7 @@ static int apple_pcie_enable_device(struct 
> pci_host_bridge *bridge, struct pci_d
>  {
>       u32 sid, rid = pci_dev_id(pdev);
>       struct apple_pcie_port *port;
> +     struct of_phandle_args iommu_spec = { .args_count = 1 };
>       int idx, err;
>  
>       port = apple_pcie_get_port(pdev);
> @@ -764,10 +765,11 @@ static int apple_pcie_enable_device(struct 
> pci_host_bridge *bridge, struct pci_d
>       dev_dbg(&pdev->dev, "added to bus %s, index %d\n",
>               pci_name(pdev->bus->self), port->idx);
>  
> -     err = of_map_iommu_id(port->pcie->dev->of_node, rid, NULL, &sid);
> +     err = of_map_iommu_id(port->pcie->dev->of_node, rid, &iommu_spec);
>       if (err)
>               return err;

of_node_put(iommu_spec.np);

>  
> +     sid = iommu_spec.args[0];
>       mutex_lock(&port->pcie->lock);
>  
>       idx = bitmap_find_free_region(port->sid_map, port->sid_map_sz, 0);
> diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
> index 1b7696b2d762..5f1d6540049a 100644
> --- a/drivers/xen/grant-dma-ops.c
> +++ b/drivers/xen/grant-dma-ops.c
> @@ -325,7 +325,7 @@ static int xen_dt_grant_init_backend_domid(struct device 
> *dev,
>               struct pci_dev *pdev = to_pci_dev(dev);
>               u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn);
>  
> -             if (of_map_iommu_id(np, rid, &iommu_spec.np, iommu_spec.args)) {
> +             if (of_map_iommu_id(np, rid, &iommu_spec)) {
>                       dev_dbg(dev, "Cannot translate ID\n");
>                       return -ESRCH;
>               }
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 824649867810..9d72d76f909d 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -463,7 +463,7 @@ bool of_console_check(const struct device_node *dn, char 
> *name, int index);
>  
>  int of_map_id(const struct device_node *np, u32 id,
>              const char *map_name, const char *map_mask_name,
> -            struct device_node **target, u32 *id_out);
> +            struct of_phandle_args *arg);
>  
>  phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);
>  
> @@ -929,7 +929,7 @@ static inline void of_property_clear_flag(struct property 
> *p, unsigned long flag
>  
>  static inline int of_map_id(const struct device_node *np, u32 id,
>                            const char *map_name, const char *map_mask_name,
> -                          struct device_node **target, u32 *id_out)
> +                          struct of_phandle_args *arg)
>  {
>       return -EINVAL;
>  }
> @@ -1458,17 +1458,24 @@ static inline int of_property_read_s32(const struct 
> device_node *np,
>  }
>  
>  static inline int of_map_iommu_id(const struct device_node *np, u32 id,
> -                               struct device_node **target, u32 *id_out)
> +                               struct of_phandle_args *arg)

Document that it's the caller's responsibility to of_node_put() returned
node. As it can be seen from the previous comment, it's not obvious.

>  {
> -     return of_map_id(np, id, "iommu-map", "iommu-map-mask",
> -                      target, id_out);
> +     return of_map_id(np, id, "iommu-map", "iommu-map-mask", arg);
>  }
>  
>  static inline int of_map_msi_id(const struct device_node *np, u32 id,
>                               struct device_node **target, u32 *id_out)

Is there a reason for chaning the of_map_iommu_id() args but not
of_map_msi_id() args?

>  {
> -     return of_map_id(np, id, "msi-map", "msi-map-mask",
> -                      target, id_out);
> +     struct of_phandle_args msi_spec = { .np = *target, .args_count = 1 };

Which driver passes something being worth of storing in .np?

> +     int ret;
> +
> +     ret = of_map_id(np, id, "msi-map", "msi-map-mask", &msi_spec);
> +     if (!ret) {
> +             *target = msi_spec.np;
> +             *id_out = msi_spec.args[0];
> +     }
> +
> +     return ret;
>  }
>  
>  #define of_for_each_phandle(it, err, np, ln, cn, cc)                 \
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry