[RFC PATCH v2 0/4] Core device subsystem

When several interrupt controllers are initialized, it is
necessary to probe them in the order described by their
cascading interrupts (or interrupt-parent in OF parlance).

This patch introduces a method that can be passed to
core_driver_init_class() at runtime and that will
reorder the device list according to the OF properties.

Signed-off-by: Marc Zyngier

drivers/base/core_device.c | 109 +++++++++++++++++++++++++++++++++++++++++++
include/linux/core_device.h | 2 +
2 files changed, 111 insertions(+), 0 deletions(-)

diff --git a/drivers/base/core_device.c b/drivers/base/core_device.c
index 9262145..a8df59d 100644
a/drivers/base/core_device.c
+++ b/drivers/base/core_device.c
@@ -10,7 +10,9 @@
*/
#include <linux/core_device.h>
#include <linux/of_platform.h>
+#include <linux/of_irq.h>
#include <linux/slab.h>
+#include <linux/sort.h>

static struct list_head anchors[CORE_DEV_CLASS_MAX] __initdata = {
[CORE_DEV_CLASS_IRQ] = LIST_HEAD_INIT(anchors[CORE_DEV_CLASS_IRQ]),
@@ -105,4 +107,111 @@ void __init of_core_device_populate(enum core_device_class class,
core_device_register(class, dev);
}
}
+
+struct intc_desc {
+ struct core_device *dev;
+ struct intc_desc *parent;
+ int order;
+};
+
+static struct intc_desc * __init irq_find_parent(struct core_device *dev,
+ struct intc_desc *intcs,
+ int nr)
+{
+ struct device_node *np;
+ int i;
+
+ if (!dev->of_node)
+ return NULL;
+
+ np = of_irq_find_parent(dev->of_node);
+ if (!np || dev->of_node == np) {
+ pr_debug("%s has no interrupt-parent",
+ dev->of_node->full_name);
+ return NULL;
+ }
+
+ of_node_put(np);
+ for (i = 0; i < nr; i++)
+ if (intcs[i].dev->of_node == np) {
+ pr_debug("%s interrupt-parent %s found in probe list",
+ dev->of_node->full_name, np->full_name);
+ return &intcs[i];
+ }
+
+ pr_warning("%s interrupt-parent %s not in probe list",
+ dev->of_node->full_name, np->full_name);
+ return NULL;
+}
+
+static int __init irq_cmp_intc_desc(const void *x1, const void *x2)
+{
+ const struct intc_desc *d1 = x1, *d2 = x2;
+ return d1->order - d2->order;
+}
+
+void __init core_device_irq_sort(struct list_head *head)
+{
+ struct intc_desc *intcs;
+ struct core_device *dev, *tmp;
+ int count = 0, i = 0, inc, max_order = 0;
+
+ if (list_empty(head))
+ return;
+
+ /* Count the number of interrupt controllers */
+ list_for_each_entry(dev, head, entry)
+ count++;
+
+ if (count == 1)
+ return;
+
+ /* Allocate a big enough array */
+ intcs = kmalloc(sizeof(*intcs) * count, GFP_KERNEL);
+ if (!intcs) {
+ pr_err("irq_core_device_sort: allocation failed");
+ return;
+ }
+
+ /* Populate the array */
+ i = 0;
+ list_for_each_entry(dev, head, entry) {
+ intcs[i].dev = dev;
+ intcs[i].parent = NULL;
+ intcs[i].order = 0;
+ i++;
+ }
+
+ /* Find out the interrupt-parents */
+ for (i = 0; i < count; i++)
+ intcs[i].parent = irq_find_parent(intcs[i].dev, intcs, count);
+
+ /* Compute the orders */
+ do {
+ inc = 0;
+ for (i = 0; i < count; i++)
+ if (intcs[i].parent &&
+ intcs[i].order <= intcs[i].parent->order) {
+ intcs[i].order = intcs[i].parent->order + 1;
+ if (max_order < intcs[i].order)
+ max_order = intcs[i].order;
+ inc = 1;
+ }
+ } while (inc);
+
+ if (max_order) {
+ /* Sort the array according to the order, if necessary */
+ sort(intcs, count, sizeof(*intcs), irq_cmp_intc_desc, NULL);
+
+ /* Empty the list... */
+ list_for_each_entry_safe(dev, tmp, head, entry)
+ list_del(&dev->entry);
+
+ /* ... and populate the list back, preserving the ordering */
+ for (i = 0; i < count; i++)
+ list_add_tail(&intcs[i].dev->entry, head);
+ }
+ /* Free the array */
+ kfree(intcs);
+}
#endif
diff --git a/include/linux/core_device.h b/include/linux/core_device.h
index ca67e5e..e632868 100644
a/include/linux/core_device.h
+++ b/include/linux/core_device.h
@@ -48,11 +48,13 @@ void core_driver_init_class(enum core_device_class class,
#ifdef CONFIG_OF
void of_core_device_populate(enum core_device_class class,
struct of_device_id *matches);
+void core_device_irq_sort(struct list_head *head);
#else
static inline void of_core_device_populate(enum core_device_class class,
struct of_device_id *matches)
{
}
+#define core_device_irq_sort NULL
#endif

struct core_driver_setup_block {
1.7.0.4


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