[PATCH 2/6] of/pci: Add of_pci_parse_bus_range() function

[Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

From: Thierry Reding <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org>

This function can be used to parse a bus-range property as specified by
device nodes representing PCI bridges.

Signed-off-by: Thierry Reding <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org>
Signed-off-by: Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 drivers/of/of_pci.c    |   25 +++++++++++++++++++++++++
 include/linux/of_pci.h |    1 +
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 13e37e2..4ca7837 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -40,3 +40,28 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(of_pci_find_child_device);
+
+/**
+ * of_pci_parse_bus_range() - parse the bus-range property of a PCI device
+ * @node: device node
+ * @res: address to a struct resource to return the bus-range
+ *
+ * Returns 0 on success or a negative error-code on failure.
+ */
+int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
+{
+	const __be32 *values;
+	int len;
+
+	values = of_get_property(node, "bus-range", &len);
+	if (!values || len < sizeof(*values) * 2)
+		return -EINVAL;
+
+	res->name = node->name;
+	res->start = be32_to_cpup(values++);
+	res->end = be32_to_cpup(values);
+	res->flags = IORESOURCE_BUS;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index bb115de..178a5cc 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -10,5 +10,6 @@ int of_irq_map_pci(const struct pci_dev *pdev, struct of_irq *out_irq);
 struct device_node;
 struct device_node *of_pci_find_child_device(struct device_node *parent,
 					     unsigned int devfn);
+int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
 
 #endif
-- 
1.7.2.5