Re: [PATCH v2 5/7] of: overlay: Add export_symbols_name in of_overlay_fdt_apply() parameters

[Ayush Singh <ayush@beagleboard.org>]

On 4/30/25 18:21, Herve Codina wrote:

> In order to prepare the introduction of the export symbols node
> handling, add a export_symbols_name parameter in of_overlay_fdt_apply().
>
> The export_symbols_name is the name of the export symbols subnode
> available in the base node that will be used by the resolver to handle
> export symbols resolution.
>
> Having the name of the subnode in parameters instead of the subnode
> itself avoids the use of an export symbol node that is not directly
> related to the base node.
>
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> Tested-by: Ayush Singh <ayush@beagleboard.org>
> ---
>   drivers/misc/lan966x_pci.c    | 3 ++-
>   drivers/of/of_kunit_helpers.c | 2 +-
>   drivers/of/overlay.c          | 7 ++++++-
>   drivers/of/unittest.c         | 4 ++--
>   include/linux/of.h            | 6 ++++--
>   5 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/misc/lan966x_pci.c b/drivers/misc/lan966x_pci.c
> index 9c79b58137e5..f05cb040ec69 100644
> --- a/drivers/misc/lan966x_pci.c
> +++ b/drivers/misc/lan966x_pci.c
> @@ -128,7 +128,8 @@ static int lan966x_pci_load_overlay(struct lan966x_pci *data)
>   	u32 dtbo_size = __dtbo_lan966x_pci_end - __dtbo_lan966x_pci_begin;
>   	void *dtbo_start = __dtbo_lan966x_pci_begin;
>   
> -	return of_overlay_fdt_apply(dtbo_start, dtbo_size, &data->ovcs_id, dev_of_node(data->dev));
> +	return of_overlay_fdt_apply(dtbo_start, dtbo_size, &data->ovcs_id,
> +				    dev_of_node(data->dev), NULL);
>   }
>   
>   static void lan966x_pci_unload_overlay(struct lan966x_pci *data)
> diff --git a/drivers/of/of_kunit_helpers.c b/drivers/of/of_kunit_helpers.c
> index 7b3ed5a382aa..476b43474168 100644
> --- a/drivers/of/of_kunit_helpers.c
> +++ b/drivers/of/of_kunit_helpers.c
> @@ -56,7 +56,7 @@ int of_overlay_fdt_apply_kunit(struct kunit *test, void *overlay_fdt,
>   		return -ENOMEM;
>   
>   	ret = of_overlay_fdt_apply(overlay_fdt, overlay_fdt_size,
> -				   ovcs_id, NULL);
> +				   ovcs_id, NULL, NULL);
>   	if (ret)
>   		return ret;
>   
> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> index aa1b97e634aa..73ff38c41de2 100644
> --- a/drivers/of/overlay.c
> +++ b/drivers/of/overlay.c
> @@ -968,6 +968,10 @@ static int of_overlay_apply(struct overlay_changeset *ovcs,
>    * @overlay_fdt_size:	number of bytes in @overlay_fdt
>    * @ret_ovcs_id:	pointer for returning created changeset id
>    * @base:		pointer for the target node to apply overlay
> + * @export_symbols_name:
> + *			Name of the export symbol subnode of the @base node to
> + *			provide extra symbols. Those extra symbols are used in
> + *			the overlay symbols resolution.
>    *
>    * Creates and applies an overlay changeset.
>    *
> @@ -983,7 +987,8 @@ static int of_overlay_apply(struct overlay_changeset *ovcs,
>    */
>   
>   int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
> -			 int *ret_ovcs_id, const struct device_node *base)
> +			 int *ret_ovcs_id, const struct device_node *base,
> +			 const char *export_symbols_name)

Do we really need the export-symbols node name to be configurable?


>   {
>   	void *new_fdt;
>   	void *new_fdt_align;
> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
> index 658690fd6980..11091b0176e0 100644
> --- a/drivers/of/unittest.c
> +++ b/drivers/of/unittest.c
> @@ -3858,7 +3858,7 @@ static int __init overlay_data_apply(const char *overlay_name, int *ovcs_id)
>   		pr_err("no overlay data for %s\n", overlay_name);
>   
>   	ret = of_overlay_fdt_apply(info->dtbo_begin, size, &info->ovcs_id,
> -				   NULL);
> +				   NULL, NULL);
>   	if (ovcs_id)
>   		*ovcs_id = info->ovcs_id;
>   	if (ret < 0)
> @@ -4198,7 +4198,7 @@ static int testdrv_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>   	}
>   
>   	size = info->dtbo_end - info->dtbo_begin;
> -	ret = of_overlay_fdt_apply(info->dtbo_begin, size, &ovcs_id, dn);
> +	ret = of_overlay_fdt_apply(info->dtbo_begin, size, &ovcs_id, dn, NULL);
>   	of_node_put(dn);
>   	if (ret)
>   		return ret;
> diff --git a/include/linux/of.h b/include/linux/of.h
> index a62154aeda1b..d8e0dd210e09 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -1749,7 +1749,8 @@ struct of_overlay_notify_data {
>   #ifdef CONFIG_OF_OVERLAY
>   
>   int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
> -			 int *ovcs_id, const struct device_node *target_base);
> +			 int *ovcs_id, const struct device_node *target_base,
> +			 const char *export_symbols_name);
>   int of_overlay_remove(int *ovcs_id);
>   int of_overlay_remove_all(void);
>   
> @@ -1759,7 +1760,8 @@ int of_overlay_notifier_unregister(struct notifier_block *nb);
>   #else
>   
>   static inline int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
> -				       int *ovcs_id, const struct device_node *target_base)
> +				       int *ovcs_id, const struct device_node *target_base,
> +				       const char *export_symbols_name)
>   {
>   	return -ENOTSUPP;
>   }


Ayush Singh