Platforms that have memory mapped IO port (such as ARM64) need special
handling for PCI I/O resources. For host bridge's resource probing case
these resources need to be fixed up with pci_register_io_range/pci_remap_iospace etc.

The same I/O resources need to be released after hotplug
removal so that it can be re-added back by the pci_remap_iospace
function during insertion. As a consequence we unmap I/O resources
with pci_unmap_iospace when we release host bridge resources.

Signed-off-by: Jayachandran C <redacted>
Signed-off-by: Sinan Kaya <redacted>
Signed-off-by: Tomasz Nowicki <redacted>
---
 drivers/acpi/pci_root.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index ae3fe4e..ee3b728 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c

@@ -720,6 +720,40 @@ next:
 	}
 }
 
+#ifdef PCI_IOBASE
+static void acpi_pci_root_remap_iospace(struct resource_entry *entry)
+{
+	struct resource *res = entry->res;
+	resource_size_t cpu_addr = res->start;
+	resource_size_t pci_addr = cpu_addr - entry->offset;
+	resource_size_t length = resource_size(res);
+	unsigned long port;
+
+	if (pci_register_io_range(cpu_addr, length))
+		goto err;
+
+	port = pci_address_to_pio(cpu_addr);
+	if (port == (unsigned long)-1)
+		goto err;
+
+	res->start = port;
+	res->end = port + length - 1;
+	entry->offset = port - pci_addr;
+
+	if (pci_remap_iospace(res, cpu_addr) < 0)
+		goto err;
+
+	pr_info("Remapped I/O %pa to %pR\n", &cpu_addr, res);
+	return;
+err:
+	res->flags |= IORESOURCE_DISABLED;