Re: [UPDATE PATCH V10 1/8] ACPI: I/O Remapping Table (IORT) initial support

From: Tomasz Nowicki
Date: Mon Sep 12 2016 - 08:37:16 EST


Hi Rafael,

On 09.09.2016 11:20, Lorenzo Pieralisi wrote:
Hi Rafael,

On Wed, Sep 07, 2016 at 01:56:52PM +0200, Tomasz Nowicki wrote:
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 iort_table_detect() 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@xxxxxxxxxxxx>
Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
---

Apart from the minor commit logs oversights we consider these two
patches ready to go, please let us know if there is something you want
changed since we are at risk of missing yet another merge window.

It is ARM64 specific code, we created and moved the code to its
ARM64 specific directory and we are happy to maintain it as such,
we need your ACK to get this done so if there is something you
want changed please let us know otherwise I would ask your ACK
on these two patches to give Marc a go-ahead for -next and
hopefully 4.9.

Kindly reminder. Is there anything we need to do more about these patches? Please let us know. Note this is the major thing for incoming IORT more advance feature.

Thanks,
Tomasz