irqdomain: Eliminate revmap type

The NOMAP irq_domain type is only used by a handful of interrupt
controllers and it unnecessarily complicates the code by adding special
cases on how to look up mappings and different revmap functions are used
for each type which need to validate the correct type is passed to it
before performing the reverse map. Eliminating the revmap_type and
making a single reverse mapping function simplifies the code. It also
shouldn't be any slower than having separate revmap functions because
the type of the revmap needed to be checked anyway.

The linear and tree revmap types were already merged in a previous
patch. This patch rolls the NOMAP or direct mapping behaviour into the
same domain code making is possible for an irq domain to do any mapping
type; linear, tree or direct; and that the mapping will be transparent
to the interrupt controller driver.

With this change, direct mappings will get stored in the linear or tree
mapping for consistency. Reverse mapping from the hwirq to virq will go
through the normal lookup process. However, any controller using a
direct mapping can take advantage of knowing that hwirq==virq for any
mapped interrupts skip doing a revmap lookup when handling IRQs.

Signed-off-by: Grant Likely <grant.likely@linaro.org>

2 files changed, 23 insertions, 37 deletions

diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index ca98cc5d6308..4b011064e146 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -270,10 +270,7 @@ int irq_alloc_domain_generic_chips(struct irq_domain *d, int irqs_per_chip,
 	if (d->gc)
 		return -EBUSY;
 
-	if (d->revmap_type != IRQ_DOMAIN_MAP_LINEAR)
-		return -EINVAL;
-
-	numchips = d->revmap_data.linear.size / irqs_per_chip;
+	numchips = d->revmap_size / irqs_per_chip;
 	if (!numchips)
 		return -EINVAL;
 
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 5a1d8ec8509e..c38be78fceb4 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -25,7 +25,6 @@ static struct irq_domain *irq_default_domain;
 /**
  * irq_domain_alloc() - Allocate a new irq_domain data structure
  * @of_node: optional device-tree node of the interrupt controller
- * @revmap_type: type of reverse mapping to use
  * @ops: map/unmap domain callbacks
  * @host_data: Controller private data pointer
  *
@@ -34,7 +33,7 @@ static struct irq_domain *irq_default_domain;
  * to IRQ domain, or NULL on failure.
  */
 static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
-					   unsigned int revmap_type, int size,
+					   int size,
 					   const struct irq_domain_ops *ops,
 					   void *host_data)
 {
@@ -46,12 +45,11 @@ static struct irq_domain *irq_domain_alloc(struct device_node *of_node,
 		return NULL;
 
 	/* Fill structure */
-	INIT_RADIX_TREE(&domain->revmap_data.tree, GFP_KERNEL);
-	domain->revmap_type = revmap_type;
+	INIT_RADIX_TREE(&domain->revmap_tree, GFP_KERNEL);
 	domain->ops = ops;
 	domain->host_data = host_data;
 	domain->of_node = of_node_get(of_node);
-	domain->revmap_data.linear.size = size;
+	domain->revmap_size = size;
 
 	return domain;
 }
@@ -67,8 +65,7 @@ static void irq_domain_add(struct irq_domain *domain)
 	mutex_lock(&irq_domain_mutex);
 	list_add(&domain->link, &irq_domain_list);
 	mutex_unlock(&irq_domain_mutex);
-	pr_debug("Allocated domain of type %d @0x%p\n",
-		 domain->revmap_type, domain);
+	pr_debug("Added domain %s\n", domain->name);
 }
 
 /**
@@ -88,7 +85,7 @@ void irq_domain_remove(struct irq_domain *domain)
 	 * node when all entries are removed. Shout if there are
 	 * any mappings left.
 	 */
-	WARN_ON(domain->revmap_data.tree.height);
+	WARN_ON(domain->revmap_tree.height);
 
 	list_del(&domain->link);
 
@@ -100,8 +97,7 @@ void irq_domain_remove(struct irq_domain *domain)
 
 	mutex_unlock(&irq_domain_mutex);
 
-	pr_debug("Removed domain of type %d @0x%p\n",
-		 domain->revmap_type, domain);
+	pr_debug("Removed domain %s\n", domain->name);
 
 	irq_domain_free(domain);
 }
@@ -216,7 +212,7 @@ struct irq_domain *irq_domain_add_linear(struct device_node *of_node,
 {
 	struct irq_domain *domain;
 
-	domain = irq_domain_alloc(of_node, IRQ_DOMAIN_MAP_LINEAR, size, ops, host_data);
+	domain = irq_domain_alloc(of_node, size, ops, host_data);
 	if (!domain)
 		return NULL;
 
@@ -230,10 +226,9 @@ struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
 					 const struct irq_domain_ops *ops,
 					 void *host_data)
 {
-	struct irq_domain *domain = irq_domain_alloc(of_node,
-					IRQ_DOMAIN_MAP_NOMAP, 0, ops, host_data);
+	struct irq_domain *domain = irq_domain_alloc(of_node, 0, ops, host_data);
 	if (domain) {
-		domain->revmap_data.nomap.max_irq = max_irq ? max_irq : ~0;
+		domain->revmap_direct_max_irq = max_irq ? max_irq : ~0;
 		irq_domain_add(domain);
 	}
 	return domain;
@@ -321,11 +316,11 @@ static void irq_domain_disassociate_many(struct irq_domain *domain,
 		irq_data->hwirq = 0;
 
 		/* Clear reverse map for this hwirq */
-		if (hwirq < domain->revmap_data.linear.size) {
+		if (hwirq < domain->revmap_size) {
 			domain->linear_revmap[hwirq] = 0;
 		} else {
 			mutex_lock(&revmap_trees_mutex);
-			radix_tree_delete(&domain->revmap_data.tree, hwirq);
+			radix_tree_delete(&domain->revmap_tree, hwirq);
 			mutex_unlock(&revmap_trees_mutex);
 		}
 	}
@@ -378,11 +373,11 @@ int irq_domain_associate_many(struct irq_domain *domain, unsigned int irq_base,
 				domain->name = irq_data->chip->name;
 		}
 
-		if (hwirq < domain->revmap_data.linear.size) {
+		if (hwirq < domain->revmap_size) {
 			domain->linear_revmap[hwirq] = virq;
 		} else {
 			mutex_lock(&revmap_trees_mutex);
-			radix_tree_insert(&domain->revmap_data.tree, hwirq, irq_data);
+			radix_tree_insert(&domain->revmap_tree, hwirq, irq_data);
 			mutex_unlock(&revmap_trees_mutex);
 		}
 
@@ -399,7 +394,9 @@ EXPORT_SYMBOL_GPL(irq_domain_associate_many);
  *
  * This routine is used for irq controllers which can choose the hardware
  * interrupt numbers they generate. In such a case it's simplest to use
- * the linux irq as the hardware interrupt number.
+ * the linux irq as the hardware interrupt number. It still uses the linear
+ * or radix tree to store the mapping, but the irq controller can optimize
+ * the revmap path by using the hwirq directly.
  */
 unsigned int irq_create_direct_mapping(struct irq_domain *domain)
 {
@@ -408,17 +405,14 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain)
 	if (domain == NULL)
 		domain = irq_default_domain;
 
-	if (WARN_ON(!domain || domain->revmap_type != IRQ_DOMAIN_MAP_NOMAP))
-		return 0;
-
 	virq = irq_alloc_desc_from(1, of_node_to_nid(domain->of_node));
 	if (!virq) {
 		pr_debug("create_direct virq allocation failed\n");
 		return 0;
 	}
-	if (virq >= domain->revmap_data.nomap.max_irq) {
+	if (virq >= domain->revmap_direct_max_irq) {
 		pr_err("ERROR: no free irqs available below %i maximum\n",
-			domain->revmap_data.nomap.max_irq);
+			domain->revmap_direct_max_irq);
 		irq_free_desc(virq);
 		return 0;
 	}
@@ -617,17 +611,13 @@ unsigned int irq_find_mapping(struct irq_domain *domain,
 	if (domain == NULL)
 		return 0;
 
-	switch (domain->revmap_type) {
-	case IRQ_DOMAIN_MAP_LINEAR:
-		return irq_linear_revmap(domain, hwirq);
-	case IRQ_DOMAIN_MAP_NOMAP:
+	if (hwirq < domain->revmap_direct_max_irq) {
 		data = irq_get_irq_data(hwirq);
 		if (data && (data->domain == domain) && (data->hwirq == hwirq))
 			return hwirq;
-		break;
 	}
 
-	return 0;
+	return irq_linear_revmap(domain, hwirq);
 }
 EXPORT_SYMBOL_GPL(irq_find_mapping);
 
@@ -643,12 +633,11 @@ unsigned int irq_linear_revmap(struct irq_domain *domain,
 			       irq_hw_number_t hwirq)
 {
 	struct irq_data *data;
-	BUG_ON(domain->revmap_type != IRQ_DOMAIN_MAP_LINEAR);
 
 	/* Check revmap bounds; complain if exceeded */
-	if (hwirq >= domain->revmap_data.linear.size) {
+	if (hwirq >= domain->revmap_size) {
 		rcu_read_lock();
-		data = radix_tree_lookup(&domain->revmap_data.tree, hwirq);
+		data = radix_tree_lookup(&domain->revmap_tree, hwirq);
 		rcu_read_unlock();
 		return data ? data->irq : 0;
 	}