[PATCH v2 1/3] irqdomain: simplify simple and legacy domain creation

[Matti Vaittinen]

Move a bit more logic in the generic __irq_domain_instantiate() from the
irq_domain_create_simple() and the irq_domain_create_legacy(). This does
simplify the irq_domain_create_simple() and irq_domain_create_legacy().
It will also ease the use of irq_domain_instantiate() instead of the
irq_domain_create_simple() or irq_domain_create_legacy() by allowing the
callers of irq_domain_instantiate() to omit the IRQ association and
irq_desc allocation code.

Reduce code duplication by introducing the hwirq_base and virq_base
members in the irq_domain_info structure, creating helper function
for allocating irq_descs, and moving logic from the .._legacy() and
the .._simple() to the more generic irq_domain_instantiate().

Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
Revision history:
v1 => v2:
 - New patch

Please note that this patch has received only limited testing. Any and
all testing with devices using the legacy domains is greatly appreciated
:)
---
 include/linux/irqdomain.h |  5 +++
 kernel/irq/irqdomain.c    | 73 +++++++++++++++++++++------------------
 2 files changed, 45 insertions(+), 33 deletions(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index de6105f68fec..bfcffa2c7047 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -291,6 +291,9 @@ struct irq_domain_chip_generic_info;
  * @hwirq_max:		Maximum number of interrupts supported by controller
  * @direct_max:		Maximum value of direct maps;
  *			Use ~0 for no limit; 0 for no direct mapping
+ * @hwirq_base:		The first hardware interrupt number (legacy domains only)
+ * @virq_base:		The first Linux interrupt number for legacy domains to
+ *			immediately associate the interrupts after domain creation
  * @bus_token:		Domain bus token
  * @ops:		Domain operation callbacks
  * @host_data:		Controller private data pointer
@@ -307,6 +310,8 @@ struct irq_domain_info {
 	unsigned int				size;
 	irq_hw_number_t				hwirq_max;
 	int					direct_max;
+	unsigned int				hwirq_base;
+	unsigned int				virq_base;
 	enum irq_domain_bus_token		bus_token;
 	const struct irq_domain_ops		*ops;
 	void					*host_data;
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index cea8f6874b1f..5af5e4028de2 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -267,13 +267,20 @@ static void irq_domain_free(struct irq_domain *domain)
 	kfree(domain);
 }
 
-/**
- * irq_domain_instantiate() - Instantiate a new irq domain data structure
- * @info: Domain information pointer pointing to the information for this domain
- *
- * Return: A pointer to the instantiated irq domain or an ERR_PTR value.
- */
-struct irq_domain *irq_domain_instantiate(const struct irq_domain_info *info)
+static void irq_domain_instantiate_descs(const struct irq_domain_info *info)
+{
+	if (!IS_ENABLED(CONFIG_SPARSE_IRQ))
+		return;
+
+	if (irq_alloc_descs(info->virq_base, info->virq_base, info->size,
+			    of_node_to_nid(to_of_node(info->fwnode))) < 0) {
+		pr_info("Cannot allocate irq_descs @ IRQ%d, assuming pre-allocated\n",
+			info->virq_base);
+	}
+}
+
+static struct irq_domain *__irq_domain_instantiate(const struct irq_domain_info *info,
+						   bool cond_alloc_descs)
 {
 	struct irq_domain *domain;
 	int err;
@@ -306,6 +313,14 @@ struct irq_domain *irq_domain_instantiate(const struct irq_domain_info *info)
 
 	__irq_domain_publish(domain);
 
+	if (cond_alloc_descs && info->virq_base > 0)
+		irq_domain_instantiate_descs(info);
+
+	/* Legacy interrupt domains have a fixed Linux interrupt number */
+	if (info->virq_base > 0)
+		irq_domain_associate_many(domain, info->virq_base, info->hwirq_base,
+					  info->size - info->hwirq_base);
+
 	return domain;
 
 err_domain_gc_remove:
@@ -315,6 +330,17 @@ struct irq_domain *irq_domain_instantiate(const struct irq_domain_info *info)
 	irq_domain_free(domain);
 	return ERR_PTR(err);
 }
+
+/**
+ * irq_domain_instantiate() - Instantiate a new irq domain data structure
+ * @info: Domain information pointer pointing to the information for this domain
+ *
+ * Return: A pointer to the instantiated irq domain or an ERR_PTR value.
+ */
+struct irq_domain *irq_domain_instantiate(const struct irq_domain_info *info)
+{
+	return __irq_domain_instantiate(info, false);
+}
 EXPORT_SYMBOL_GPL(irq_domain_instantiate);
 
 /**
@@ -413,28 +439,13 @@ struct irq_domain *irq_domain_create_simple(struct fwnode_handle *fwnode,
 		.fwnode		= fwnode,
 		.size		= size,
 		.hwirq_max	= size,
+		.virq_base	= first_irq,
 		.ops		= ops,
 		.host_data	= host_data,
 	};
-	struct irq_domain *domain;
+	struct irq_domain *domain = __irq_domain_instantiate(&info, true);
 
-	domain = irq_domain_instantiate(&info);
-	if (IS_ERR(domain))
-		return NULL;
-
-	if (first_irq > 0) {
-		if (IS_ENABLED(CONFIG_SPARSE_IRQ)) {
-			/* attempt to allocated irq_descs */
-			int rc = irq_alloc_descs(first_irq, first_irq, size,
-						 of_node_to_nid(to_of_node(fwnode)));
-			if (rc < 0)
-				pr_info("Cannot allocate irq_descs @ IRQ%d, assuming pre-allocated\n",
-					first_irq);
-		}
-		irq_domain_associate_many(domain, first_irq, 0, size);
-	}
-
-	return domain;
+	return IS_ERR(domain) ? NULL : domain;
 }
 EXPORT_SYMBOL_GPL(irq_domain_create_simple);
 
@@ -476,18 +487,14 @@ struct irq_domain *irq_domain_create_legacy(struct fwnode_handle *fwnode,
 		.fwnode		= fwnode,
 		.size		= first_hwirq + size,
 		.hwirq_max	= first_hwirq + size,
+		.hwirq_base	= first_hwirq,
+		.virq_base	= first_irq,
 		.ops		= ops,
 		.host_data	= host_data,
 	};
-	struct irq_domain *domain;
+	struct irq_domain *domain = irq_domain_instantiate(&info);
 
-	domain = irq_domain_instantiate(&info);
-	if (IS_ERR(domain))
-		return NULL;
-
-	irq_domain_associate_many(domain, first_irq, first_hwirq, size);
-
-	return domain;
+	return IS_ERR(domain) ? NULL : domain;
 }
 EXPORT_SYMBOL_GPL(irq_domain_create_legacy);
 
-- 
2.45.2


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

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