[PATCH v7 1/6] pci: Introduce pci_register_io_range() helper function.

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

Some architectures do not share x86 simple view of the PCI I/O space
and instead use a range of addresses that map to bus addresses. For
some architectures these ranges will be expressed by OF bindings
in a device tree file.

Introduce a pci_register_io_range() helper function that can be used
by the architecture code to keep track of the I/O ranges described by the
PCI bindings. If the PCI_IOBASE macro is not defined that signals
lack of support for PCI and we return an error.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tanmay Inamdar <tinamdar@apm.com>
---
 drivers/of/address.c       | 9 +++++++++
 include/linux/of_address.h | 1 +
 2 files changed, 10 insertions(+)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 1a54f1f..be958ed 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -619,6 +619,15 @@ const __be32 *of_get_address(struct device_node *dev, int index, u64 *size,
 }
 EXPORT_SYMBOL(of_get_address);
 
+int __weak pci_register_io_range(phys_addr_t addr, resource_size_t size)
+{
+#ifndef PCI_IOBASE
+	return -EINVAL;
+#else
+	return 0;
+#endif
+}
+
 unsigned long __weak pci_address_to_pio(phys_addr_t address)
 {
 	if (address > IO_SPACE_LIMIT)
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 5f6ed6b..40c418d 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -56,6 +56,7 @@ extern void __iomem *of_iomap(struct device_node *device, int index);
 extern const __be32 *of_get_address(struct device_node *dev, int index,
 			   u64 *size, unsigned int *flags);
 
+extern int pci_register_io_range(phys_addr_t addr, resource_size_t size);
 extern unsigned long pci_address_to_pio(phys_addr_t addr);
 
 extern int of_pci_range_parser_init(struct of_pci_range_parser *parser,
-- 
1.9.0