of/irq: do irq resolution in platform_get_irq

Currently we get the following kind of errors if we try to use interrupt
phandles to irqchips that have not yet initialized:

irq: no irq domain found for /ocp/pinmux@48002030 !
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/of/platform.c:171 of_device_alloc+0x144/0x184()
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-00038-g42a9708 #1012
(show_stack+0x14/0x1c)
(dump_stack+0x6c/0xa0)
(warn_slowpath_common+0x64/0x84)
(warn_slowpath_null+0x1c/0x24)
(of_device_alloc+0x144/0x184)
(of_platform_device_create_pdata+0x44/0x9c)
(of_platform_bus_create+0xd0/0x170)
(of_platform_bus_create+0x12c/0x170)
(of_platform_populate+0x60/0x98)

This is because we're wrongly trying to populate resources that are not
yet available. It's perfectly valid to create irqchips dynamically, so
let's fix up the issue by resolving the interrupt resources when
platform_get_irq is called.

And then we also need to accept the fact that some irqdomains do not
exist that early on, and only get initialized later on. So we can
make the current WARN_ON into just into a pr_debug().

We still attempt to populate irq resources when we create the devices.
This allows current drivers which don't use platform_get_irq to continue
to function. Once all drivers are fixed, this code can be removed.

Suggested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Grant Likely <grant.likely@linaro.org>

4 files changed, 40 insertions, 2 deletions

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index e714709704e4..5b47210889e0 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -13,6 +13,7 @@
 #include <linux/string.h>
 #include <linux/platform_device.h>
 #include <linux/of_device.h>
+#include <linux/of_irq.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/dma-mapping.h>
@@ -87,7 +88,11 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
                 return -ENXIO;
         return dev->archdata.irqs[num];
 #else
-        struct resource *r = platform_get_resource(dev, IORESOURCE_IRQ, num);
+        struct resource *r;
+        if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node)
+                return of_irq_get(dev->dev.of_node, num);
+
+        r = platform_get_resource(dev, IORESOURCE_IRQ, num);
 
         return r ? r->start : -ENXIO;
 #endif
diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index e2e4c548a42f..5aeb89411350 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -380,6 +380,32 @@ int of_irq_to_resource(struct device_node *dev, int index, struct resource *r)
 EXPORT_SYMBOL_GPL(of_irq_to_resource);
 
 /**
+ * of_irq_get - Decode a node's IRQ and return it as a Linux irq number
+ * @dev: pointer to device tree node
+ * @index: zero-based index of the irq
+ *
+ * Returns Linux irq number on success, or -EPROBE_DEFER if the irq domain
+ * is not yet created.
+ *
+ */
+int of_irq_get(struct device_node *dev, int index)
+{
+        int rc;
+        struct of_phandle_args oirq;
+        struct irq_domain *domain;
+
+        rc = of_irq_parse_one(dev, index, &oirq);
+        if (rc)
+                return rc;
+
+        domain = irq_find_host(oirq.np);
+        if (!domain)
+                return -EPROBE_DEFER;
+
+        return irq_create_of_mapping(&oirq);
+}
+
+/**
  * of_irq_count - Count the number of IRQs a node uses
  * @dev: pointer to device tree node
  */
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 404d1daebefa..bd47fbc53dc9 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -168,7 +168,9 @@ struct platform_device *of_device_alloc(struct device_node *np,
                         rc = of_address_to_resource(np, i, res);
                         WARN_ON(rc);
                 }
-                WARN_ON(of_irq_to_resource_table(np, res, num_irq) != num_irq);
+                if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
+                        pr_debug("not all legacy IRQ resources mapped for %s\n",
+                                 np->name);
         }
 
         dev->dev.of_node = of_node_get(np);
diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
index 3f23b4472c31..6404253d810d 100644
--- a/include/linux/of_irq.h
+++ b/include/linux/of_irq.h
@@ -44,11 +44,16 @@ extern void of_irq_init(const struct of_device_id *matches);
 
 #ifdef CONFIG_OF_IRQ
 extern int of_irq_count(struct device_node *dev);
+extern int of_irq_get(struct device_node *dev, int index);
 #else
 static inline int of_irq_count(struct device_node *dev)
 {
         return 0;
 }
+static inline int of_irq_get(struct device_node *dev, int index)
+{
+        return 0;
+}
 #endif
 
 #if defined(CONFIG_OF)