On Mon, 29 Jun 2026 17:42:24 +0200, Andy Shevchenko
<[email protected]> said:
> +Cc: Herve, to just ask the situation with one series that adds nice helper.
>
> On Mon, Jun 29, 2026 at 12:52:07PM +0200, Bartosz Golaszewski wrote:
>> Software nodes can be used to describe supplier-consumer relationships
>> between devices they represent using reference property entries. Unlike
>> for OF-nodes, driver core cannot yet use these references to create a
>> probe order that avoids needless probe deferrals on missing providers.
>>
>> Implement software_node_add_links() modelled on of_fwnode_add_links().
>> For every DEV_PROP_REF property we resolve each referenced supplier and
>> create an fwnode link from the node to it. The driver core later promotes
>> these to device links and defers the consumer until the suppliers are
>> ready.
>>
>> There's no allowlist like the one DT needs - devicetree phandles appear
>> in plenty of non-supplier contexts, but a software node only carries a
>> reference property when its author explicitly points at another node, so
>> we treat every reference as an intentional supplier dependency and link
>> all of them. Graph "remote-endpoint" references are skipped for now: they
>> go 2-ways between endpoint nodes and would create graph cycles without
>> the port-parent lifting DT does via get_con_dev(). References to
>> suppliers that aren't registered yet and self-references are ignored.
>>
>> fw_devlink resolves the supplier device through fwnode->dev but the core
>> only records the owning device on the primary fwnode. When the software
>> node is a device's secondary fwnode, mirror the device pointer onto it in
>> software_node_notify() so the consumer can actually find the supplier
>> instead of deferring forever.
>>
>> While at it: purge the fwnode links in software_node_release() now that
>> software nodes can own them.
>
> ...
>
>> +static int software_node_add_links(struct fwnode_handle *fwnode)
>> +{
>> + const struct software_node_ref_args *ref, *ref_array;
>> + struct swnode *swnode = to_swnode(fwnode);
>> + const struct property_entry *prop;
>> + struct fwnode_handle *refnode;
>> + unsigned int count, i;
>
> 'i' is local to the loop.
>
>> + if (!swnode || !swnode->node->properties)
>> + return 0;
>> +
>> + /*
>> + * Unlike Device Tree, where phandles appear in many non-supplier
>> + * contexts and a curated allowlist is required, a software node only
>> + * carries a DEV_PROP_REF property when the author explicitly describes
>> + * a reference to another node. Every such reference is therefore an
>> + * intentional supplier dependency, so we create fwnode links for all
>> + * of them.
>> + */
>> + for (prop = swnode->node->properties; prop->name; prop++) {
>> + if (prop->type != DEV_PROP_REF || prop->is_inline)
>> + continue;
>> +
>> + /*
>> + * TODO: Graph "remote-endpoint" references go both ways
>> + * between endpoint child nodes and would create endpoint
>> + * cycles. Let's leave it out for now until we have potential
>> + * users.
>> + */
>> + if (!strcmp(prop->name, "remote-endpoint"))
>> + continue;
>> +
>> + ref_array = prop->pointer;
>> + count = prop->length / sizeof(*ref_array);
>
> Seems we are going to have more of a such, perhaps make a helper for counting
> (which will do that division beneath).
>
Let's cross that bridge when we get there? I don't want to burden the series
with more changes than necessary.
>> + for (i = 0; i < count; i++) {
>
> for (unsigned int i = 0; i < count; i++) {
>
>> +
>
> Redundant blank line?
I think it's fine for readability.
I fixed the rest in v2.
Bart
