From: John Garry <john.garry@huawei.com>
Date: Thu, 15 Mar 2018 02:15:57 +0800
Subject: ACPI / scan: Do not enumerate Indirect IO host children
Git-commit: dfda4492322ed0a1eb9c4d4715c4b90c9af57352
Patch-mainline: v4.17-rc1
References: fate#325788

Through the logical PIO framework, systems which otherwise have no IO space
access to legacy ISA/LPC devices may access these devices through so-called
"indirect IO" method.  In this, IO space accesses for non-PCI hosts are
redirected to a host LLDD to manually generate the IO space (bus) accesses.
Hosts are able to register a region in logical PIO space to map to its bus
address range.

Indirect IO child devices have an associated host-specific bus address.
Special translation is required to map between a logical PIO address for a
device and its host bus address.

Since in the ACPI tables the child device IO resources would be the
host-specific values, it is required the ACPI scan code should not
enumerate these devices, and that this should be the responsibility of the
host driver so that it can "fixup" the resources so that they map to the
appropriate logical PIO addresses.

To avoid enumerating these child devices, add a check from
acpi_device_enumeration_by_parent() as to whether the parent for a device
is a member of a known list of "indirect IO" hosts.  For now, the HiSilicon
LPC host controller ID is added.

Tested-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
 drivers/acpi/scan.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1448,11 +1448,25 @@ static int acpi_check_serial_bus_slave(s
 	return -1;
 }
 
+static bool acpi_is_indirect_io_slave(struct acpi_device *device)
+{
+	struct acpi_device *parent = device->parent;
+	const struct acpi_device_id indirect_io_hosts[] = {
+		{"HISI0191", 0},
+		{}
+	};
+
+	return parent && !acpi_match_device_ids(parent, indirect_io_hosts);
+}
+
 static bool acpi_device_enumeration_by_parent(struct acpi_device *device)
 {
 	struct list_head resource_list;
 	bool is_serial_bus_slave = false;
 
+	if (acpi_is_indirect_io_slave(device))
+		return true;
+
 	INIT_LIST_HEAD(&resource_list);
 	acpi_dev_get_resources(device, &resource_list,
 			       acpi_check_serial_bus_slave,