ACPI: I/O Remapping Table (IORT) initial support
authorTomasz Nowicki <tn@semihalf.com>
Mon, 12 Sep 2016 18:54:20 +0000 (20:54 +0200)
committerMarc Zyngier <marc.zyngier@arm.com>
Mon, 12 Sep 2016 19:32:30 +0000 (20:32 +0100)
commit88ef16d888a094587b2ac77de60927df5da5d56d
treea15c57a32a81fd41efa2b0be1ea9492035dcc74f
parent89c59cca48f04ede7e63944418af1794a8e31da6
ACPI: I/O Remapping Table (IORT) initial support

IORT shows representation of IO topology for ARM based systems.
It describes how various components are connected together on
parent-child basis e.g. PCI RC -> SMMU -> ITS. Also see IORT spec.
http://infocenter.arm.com/help/topic/com.arm.doc.den0049b/DEN0049B_IO_Remapping_Table.pdf

Initial support allows to detect IORT table presence and save its
root pointer obtained through acpi_get_table(). The pointer validity
depends on acpi_gbl_permanent_mmap because if acpi_gbl_permanent_mmap
is not set while using IORT nodes we would dereference unmapped pointers.

For the aforementioned reason call acpi_iort_init() from acpi_init()
which guarantees acpi_gbl_permanent_mmap to be set at that point.

Add generic helpers which are helpful for scanning and retrieving
information from IORT table content. List of the most important helpers:
- iort_find_dev_node() finds IORT node for a given device
- iort_node_map_rid() maps device RID and returns IORT node which provides
  final translation

IORT support is placed under drivers/acpi/arm64/ new directory due to its
ARM64 specific nature. The code there is considered only for ARM64.
The long term plan is to keep all ARM64 specific tables support
in this place e.g. GTDT table.

Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
drivers/acpi/Kconfig
drivers/acpi/Makefile
drivers/acpi/arm64/Kconfig [new file with mode: 0644]
drivers/acpi/arm64/Makefile [new file with mode: 0644]
drivers/acpi/arm64/iort.c [new file with mode: 0644]
drivers/acpi/bus.c
include/linux/acpi_iort.h [new file with mode: 0644]