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authorBarry Song <song.bao.hua@hisilicon.com>2020-06-19 15:00:45 +1200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-07-10 14:14:37 +0200
commit4a60406d3592373b8fd27ddfd010c5e62ad6c674 (patch)
treec222443b64feee47c2db0bb8cedc8b96d3fa1c77 /Documentation/ABI
parent079ad2fb4bf9eba8a0aaab014b49705cd7f07c66 (diff)
downloadlinux-4a60406d3592373b8fd27ddfd010c5e62ad6c674.tar.gz
driver core: platform: expose numa_node to users in sysfs
Some platform devices like ARM SMMU are memory-mapped and populated by ACPI/IORT.
In this case, NUMA topology of those platform devices are exported by firmware as
well. Software might care about the numa_node of those devices in order to achieve
NUMA locality.
This patch will show the numa_node for this kind of devices in sysfs. For those
platform devices without numa, numa_node won't be visible.

Cc: Prime Zeng <prime.zeng@hisilicon.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lore.kernel.org/r/20200619030045.81956-1-song.bao.hua@hisilicon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-platform10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-platform b/Documentation/ABI/testing/sysfs-bus-platform
index 5172a6124b27..194ca700e962 100644
--- a/Documentation/ABI/testing/sysfs-bus-platform
+++ b/Documentation/ABI/testing/sysfs-bus-platform
@@ -18,3 +18,13 @@ Description:
 		devices to opt-out of driver binding using a driver_override
 		name such as "none".  Only a single driver may be specified in
 		the override, there is no support for parsing delimiters.
+
+What:		/sys/bus/platform/devices/.../numa_node
+Date:		June 2020
+Contact:	Barry Song <song.bao.hua@hisilicon.com>
+Description:
+		This file contains the NUMA node to which the platform device
+		is attached. It won't be visible if the node is unknown. The
+		value comes from an ACPI _PXM method or a similar firmware
+		source. Initial users for this file would be devices like
+		arm smmu which are populated by arm64 acpi_iort.