[PATCH v7 2/6] pci: OF: Fix the conversion of IO ranges into IO resources.

[Liviu Dudau <Liviu.Dudau@arm.com>]

The ranges property for a host bridge controller in DT describes
the mapping between the PCI bus address and the CPU physical address.
The resources framework however expects that the IO resources start
at a pseudo "port" address 0 (zero) and have a maximum size of IO_SPACE_LIMIT.
The conversion from pci ranges to resources failed to take that into account.

In the process move the function into drivers/of/address.c as it now
depends on pci_address_to_pio() code and make it return an error message.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Tested-by: Tanmay Inamdar <tinamdar@apm.com>
---
 drivers/of/address.c       | 40 ++++++++++++++++++++++++++++++++++++
 include/linux/of_address.h | 13 ++----------
 2 files changed, 42 insertions(+), 11 deletions(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index be958ed..4eabd30 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -728,3 +728,43 @@ void __iomem *of_iomap(struct device_node *np, int index)
 	return ioremap(res.start, resource_size(&res));
 }
 EXPORT_SYMBOL(of_iomap);
+
+/**
+ * of_pci_range_to_resource - Create a resource from an of_pci_range
+ * @range:	the PCI range that describes the resource
+ * @np:		device node where the range belongs to
+ * @res:	pointer to a valid resource that will be updated to
+ *              reflect the values contained in the range.
+ *
+ * Returns EINVAL if the range cannot be converted to resource.
+ *
+ * Note that if the range is an IO range, the resource will be converted
+ * using pci_address_to_pio() which can fail if it is called too early or
+ * if the range cannot be matched to any host bridge IO space (our case here).
+ * To guard against that we try to register the IO range first.
+ * If that fails we know that pci_address_to_pio() will do too.
+ */
+int of_pci_range_to_resource(struct of_pci_range *range,
+	struct device_node *np, struct resource *res)
+{
+	res->flags = range->flags;
+	if (res->flags & IORESOURCE_IO) {
+		unsigned long port = -1;
+		int err = pci_register_io_range(range->cpu_addr, range->size);
+		if (err)
+			return err;
+		port = pci_address_to_pio(range->cpu_addr);
+		if (port == (unsigned long)-1) {
+			res->start = (resource_size_t)OF_BAD_ADDR;
+			res->end = (resource_size_t)OF_BAD_ADDR;
+			return -EINVAL;
+		}
+		res->start = port;
+	} else {
+		res->start = range->cpu_addr;
+	}
+	res->end = res->start + range->size - 1;
+	res->parent = res->child = res->sibling = NULL;
+	res->name = np->full_name;
+	return 0;
+}
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 40c418d..a4b400d 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -23,17 +23,8 @@ struct of_pci_range {
 #define for_each_of_pci_range(parser, range) \
 	for (; of_pci_range_parser_one(parser, range);)
 
-static inline void of_pci_range_to_resource(struct of_pci_range *range,
-					    struct device_node *np,
-					    struct resource *res)
-{
-	res->flags = range->flags;
-	res->start = range->cpu_addr;
-	res->end = range->cpu_addr + range->size - 1;
-	res->parent = res->child = res->sibling = NULL;
-	res->name = np->full_name;
-}
-
+extern int of_pci_range_to_resource(struct of_pci_range *range,
+		struct device_node *np, struct resource *res);
 /* Translate a DMA address from device space to CPU space */
 extern u64 of_translate_dma_address(struct device_node *dev,
 				    const __be32 *in_addr);
-- 
1.9.0