irqdomain: Refactor irq_domain_associate_many()

Originally, irq_domain_associate_many() was designed to unwind the
mapped irqs on a failure of any individual association. However, that
proved to be a problem with certain IRQ controllers. Some of them only
support a subset of irqs, and will fail when attempting to map a
reserved IRQ. In those cases we want to map as many IRQs as possible, so
instead it is better for irq_domain_associate_many() to make a
best-effort attempt to map irqs, but not fail if any or all of them
don't succeed. If a caller really cares about how many irqs got
associated, then it should instead go back and check that all of the
irqs is cares about were mapped.

The original design open-coded the individual association code into the
body of irq_domain_associate_many(), but with no longer needing to
unwind associations, the code becomes simpler to split out
irq_domain_associate() to contain the bulk of the logic, and
irq_domain_associate_many() to be a simple loop wrapper.

This patch also adds a new error check to the associate path to make
sure it isn't called for an irq larger than the controller can handle,
and adds locking so that the irq_domain_mutex is held while setting up a
new association.

v3: Fixup missing change to irq_domain_add_tree()
v2: Fixup x86 warning. irq_domain_associate_many() no longer returns an
    error code, but reports errors to the printk log directly. In the
    majority of cases we don't actually want to fail if there is a
    problem, but rather log it and still try to boot the system.

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

irqdomain: Fix flubbed irq_domain_associate_many refactoring

commit d39046ec72, "irqdomain: Refactor irq_domain_associate_many()" was
missing the following hunk which causes a boot failure on anything using
irq_domain_add_tree() to allocate an irq domain.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Cc: Thomas Gleixner <tglx@linutronix.de>,
Cc: Stephen Rothwell <sfr@canb.auug.org.au>

1 files changed, 11 insertions, 13 deletions

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index fd4b26f8f44c..208d1352c40a 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -103,6 +103,7 @@ struct irq_domain {
         struct irq_domain_chip_generic *gc;
 
         /* reverse map data. The linear map gets appended to the irq_domain */
+        irq_hw_number_t hwirq_max;
         unsigned int revmap_direct_max_irq;
         unsigned int revmap_size;
         struct radix_tree_root revmap_tree;
@@ -110,8 +111,8 @@ struct irq_domain {
 };
 
 #ifdef CONFIG_IRQ_DOMAIN
-struct irq_domain *__irq_domain_add(struct device_node *of_node,
-                                    int size, int direct_max,
+struct irq_domain *__irq_domain_add(struct device_node *of_node, int size,
+                                    irq_hw_number_t hwirq_max, int direct_max,
                                     const struct irq_domain_ops *ops,
                                     void *host_data);
 struct irq_domain *irq_domain_add_simple(struct device_node *of_node,
@@ -140,14 +141,14 @@ static inline struct irq_domain *irq_domain_add_linear(struct device_node *of_no
                                          const struct irq_domain_ops *ops,
                                          void *host_data)
 {
-        return __irq_domain_add(of_node, size, 0, ops, host_data);
+        return __irq_domain_add(of_node, size, size, 0, ops, host_data);
 }
 static inline struct irq_domain *irq_domain_add_nomap(struct device_node *of_node,
                                          unsigned int max_irq,
                                          const struct irq_domain_ops *ops,
                                          void *host_data)
 {
-        return __irq_domain_add(of_node, 0, max_irq, ops, host_data);
+        return __irq_domain_add(of_node, 0, max_irq, max_irq, ops, host_data);
 }
 static inline struct irq_domain *irq_domain_add_legacy_isa(
                                 struct device_node *of_node,
@@ -161,19 +162,16 @@ static inline struct irq_domain *irq_domain_add_tree(struct device_node *of_node
                                          const struct irq_domain_ops *ops,
                                          void *host_data)
 {
-        return irq_domain_add_linear(of_node, 0, ops, host_data);
+        return __irq_domain_add(of_node, 0, ~0, 0, ops, host_data);
 }
 
 extern void irq_domain_remove(struct irq_domain *host);
 
-extern int irq_domain_associate_many(struct irq_domain *domain,
-                                     unsigned int irq_base,
-                                     irq_hw_number_t hwirq_base, int count);
-static inline int irq_domain_associate(struct irq_domain *domain, unsigned int irq,
-                                        irq_hw_number_t hwirq)
-{
-        return irq_domain_associate_many(domain, irq, hwirq, 1);
-}
+extern int irq_domain_associate(struct irq_domain *domain, unsigned int irq,
+                                        irq_hw_number_t hwirq);
+extern void irq_domain_associate_many(struct irq_domain *domain,
+                                      unsigned int irq_base,
+                                      irq_hw_number_t hwirq_base, int count);
 
 extern unsigned int irq_create_mapping(struct irq_domain *host,
                                        irq_hw_number_t hwirq);