irqdomain: Add support for generic irq chips creation before publishing a domain

The current API functions create an irq_domain and also publish this
newly created to domain. Once an irq_domain is published, consumers can
request IRQ in order to use them.

Some interrupt controller drivers have to perform some more operations
with the created irq_domain in order to have it ready to be used.
For instance:
   - Allocate generic irq chips with irq_alloc_domain_generic_chips()
   - Retrieve the generic irq chips with irq_get_domain_generic_chip()
   - Initialize retrieved chips: set register base address and offsets,
     set several hooks such as irq_mask, irq_unmask, ...

With the newly introduced irq_domain_alloc_generic_chips(), an interrupt
controller driver can use the irq_domain_chip_generic_info structure and
set the init() hook to perform its generic chips initialization.

In order to avoid a window where the domain is published but not yet
ready to be used, handle the generic chip creation (i.e the
irq_domain_alloc_generic_chips() call) before the domain is published.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240614173232.1184015-16-herve.codina@bootlin.com

1 files changed, 13 insertions, 1 deletions

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index a0324d8e6dab..4d2a40359eb2 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -292,16 +292,25 @@ struct irq_domain *irq_domain_instantiate(const struct irq_domain_info *info)
 	}
 #endif
 
+	if (info->dgc_info) {
+		err = irq_domain_alloc_generic_chips(domain, info->dgc_info);
+		if (err)
+			goto err_domain_free;
+	}
+
 	if (info->init) {
 		err = info->init(domain);
 		if (err)
-			goto err_domain_free;
+			goto err_domain_gc_remove;
 	}
 
 	__irq_domain_publish(domain);
 
 	return domain;
 
+err_domain_gc_remove:
+	if (info->dgc_info)
+		irq_domain_remove_generic_chips(domain);
 err_domain_free:
 	irq_domain_free(domain);
 	return ERR_PTR(err);
@@ -369,6 +378,9 @@ void irq_domain_remove(struct irq_domain *domain)
 
 	mutex_unlock(&irq_domain_mutex);
 
+	if (domain->flags & IRQ_DOMAIN_FLAG_DESTROY_GC)
+		irq_domain_remove_generic_chips(domain);
+
 	pr_debug("Removed domain %s\n", domain->name);
 	irq_domain_free(domain);
 }