[PATCH 4/4] acpi: numa: Add helper function to retrieve the performance attributes

[Dave Jiang <dave.jiang@xxxxxxxxx>]

Add helper to retrieve the performance attributes based on the device
handle.  The helper function is exported so the CXL driver can use that
to acquire the performance data between the CPU and the CXL host bridge.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
 drivers/acpi/numa/hmat.c |   35 +++++++++++++++++++++++++++++++++++
 include/linux/acpi.h     |    9 +++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c
index 951579e903cf..73d716e6096e 100644
--- a/drivers/acpi/numa/hmat.c
+++ b/drivers/acpi/numa/hmat.c
@@ -107,6 +107,41 @@ static struct memory_target *find_mem_target(unsigned int mem_pxm)
 	return NULL;
 }
 
+static struct memory_target *acpi_find_genport_target(u8 *device_handle)
+{
+	struct memory_target *target;
+
+	list_for_each_entry(target, &targets, node) {
+		if (!strncmp(target->device_handle, device_handle,
+			     ACPI_SRAT_DEVICE_HANDLE_SIZE))
+			return target;
+	}
+
+	return NULL;
+}
+
+/**
+ * acpi_get_genport_coordinates - Retrieve the access coordinates for a generic port
+ * @device_handle: Device handle string (ACPI or PCI) to match up to the gen port
+ * @coord: The access coordinates written back out for the generic port
+ *
+ * Return: 0 on success. Errno on failure.
+ */
+int acpi_get_genport_coordinates(u8 *device_handle,
+				 struct access_coordinate *coord)
+{
+	struct memory_target *target;
+
+	target = acpi_find_genport_target(device_handle);
+	if (!target)
+		return -ENOENT;
+
+	*coord = target->coord[NODE_ACCESS_CLASS_GENPORT];
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(acpi_get_genport_coordinates, CXL);
+
 static __init void alloc_memory_initiator(unsigned int cpu_pxm)
 {
 	struct memory_initiator *initiator;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 4c3dfe7587e9..d6a99fa430dd 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -15,6 +15,7 @@
 #include <linux/device.h>
 #include <linux/property.h>
 #include <linux/uuid.h>
+#include <linux/node.h>
 
 #ifndef _LINUX
 #define _LINUX
@@ -455,6 +456,8 @@ extern bool acpi_osi_is_win8(void);
 #ifdef CONFIG_ACPI_NUMA
 int acpi_map_pxm_to_node(int pxm);
 int acpi_get_node(acpi_handle handle);
+int acpi_get_genport_coordinates(u8 *device_handle,
+				 struct access_coordinate *coord);
 
 /**
  * pxm_to_online_node - Map proximity ID to online node
@@ -489,6 +492,12 @@ static inline int acpi_get_node(acpi_handle handle)
 {
 	return 0;
 }
+
+static inline int acpi_get_genport_coordinates(u8 *device_handle,
+					       struct access_coordinate *coord)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 extern int acpi_paddr_to_node(u64 start_addr, u64 size);