[PATCH v2] ACPI : Update platform device numa node based on _PXM method

[Shanker Donthineni <shankerd@codeaurora.org>]

The optional _PXM method evaluates to an integer that identifies the
proximity domain of a device object. On ACPI based kernel boot, the
field numa_node in 'struct device' is always set to -1 irrespective
of _PXM value that is specified in the ACPI device object. But in
case of device-tree based kernel boot the numa_node field is populated
and reflects to a DT property that is specified in DTS according to
the below document.

https://www.kernel.org/doc/Documentation/devicetree/bindings/numa.txt
http://lxr.free-electrons.com/source/drivers/of/device.c#L54

Without this patch dev_to_node() always returns a value of -1 for all
platform devices. This patch implements support for ACPI _PXM method
and updates the platform device numa node id using acpi_get_node(),
which provides the PXM to NUMA mapping information. The individual
platform device drivers should be able to use the NUMA aware memory
allocation functions kmalloc_node() and alloc_pages_node() to improve
the performance.

Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
---
Changes since v1: Edited commit text.

Not all the platform devices are attached to NUMA node 0 on Qualcomm
Datacenter Technologies server chips. Platform device drivers needs
to be aware of NUMA information to improve performance.

 drivers/acpi/acpi_platform.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
index b4c1a6a..83d953e 100644
--- a/drivers/acpi/acpi_platform.c
+++ b/drivers/acpi/acpi_platform.c
@@ -119,11 +119,14 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
 	if (IS_ERR(pdev))
 		dev_err(&adev->dev, "platform device creation failed: %ld\n",
 			PTR_ERR(pdev));
-	else
+	else {
+		set_dev_node(&pdev->dev, acpi_get_node(adev->handle));
 		dev_dbg(&adev->dev, "created platform device %s\n",
 			dev_name(&pdev->dev));
+	}
 
 	kfree(resources);
+
 	return pdev;
 }
 EXPORT_SYMBOL_GPL(acpi_create_platform_device);
-- 
Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.