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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>
zero-sugar-mainline-defconfig
Barry Song 2020-06-19 15:00:45 +12:00 committed by Greg Kroah-Hartman
parent 079ad2fb4b
commit 4a60406d35
2 changed files with 35 additions and 1 deletions
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10
Documentation/ABI/testing/sysfs-bus-platform
View File

@ -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.

26
drivers/base/platform.c
View File

@ -1076,13 +1076,37 @@ static ssize_t driver_override_show(struct device *dev,
}
static DEVICE_ATTR_RW(driver_override);
static ssize_t numa_node_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", dev_to_node(dev));
}
static DEVICE_ATTR_RO(numa_node);
static umode_t platform_dev_attrs_visible(struct kobject *kobj, struct attribute *a,
int n)
{
struct device *dev = container_of(kobj, typeof(*dev), kobj);
if (a == &dev_attr_numa_node.attr &&
dev_to_node(dev) == NUMA_NO_NODE)
return 0;
return a->mode;
}
static struct attribute *platform_dev_attrs[] = {
&dev_attr_modalias.attr,
&dev_attr_numa_node.attr,
&dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(platform_dev);
static struct attribute_group platform_dev_group = {
.attrs = platform_dev_attrs,
.is_visible = platform_dev_attrs_visible,
};
__ATTRIBUTE_GROUPS(platform_dev);
static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
{