cxl: Split out host bridge access coordinates

The difference between access class 0 and access class 1 for 'struct
access_coordinate', if any, is that class 0 is for the distance from
the target to the closest initiator and that class 1 is for the distance
from the target to the closest CPU. For CXL memory, the nearest initiator
may not necessarily be a CPU node. The performance path from the CXL
endpoint to the host bridge should remain the same. However, the numbers
extracted and stored from HMAT is the difference for the two access
classes. Split out the performance numbers for the host bridge (generic
target) from the calculation of the entire path in order to allow
calculation of both access classes for a CXL region.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20240308220055.2172956-7-dave.jiang@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 22 insertions, 6 deletions

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index c1ede0ef9185..04dfda9d1f1b 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -162,15 +162,22 @@ static int cxl_cdat_endpoint_process(struct cxl_port *port,
 static int cxl_port_perf_data_calculate(struct cxl_port *port,
 					struct xarray *dsmas_xa)
 {
-	struct access_coordinate c;
+	struct access_coordinate ep_c;
+	struct access_coordinate coord[ACCESS_COORDINATE_MAX];
 	struct dsmas_entry *dent;
 	int valid_entries = 0;
 	unsigned long index;
 	int rc;
 
-	rc = cxl_endpoint_get_perf_coordinates(port, &c);
+	rc = cxl_endpoint_get_perf_coordinates(port, &ep_c);
 	if (rc) {
-		dev_dbg(&port->dev, "Failed to retrieve perf coordinates.\n");
+		dev_dbg(&port->dev, "Failed to retrieve ep perf coordinates.\n");
+		return rc;
+	}
+
+	rc = cxl_hb_get_perf_coordinates(port, coord);
+	if (rc)  {
+		dev_dbg(&port->dev, "Failed to retrieve hb perf coordinates.\n");
 		return rc;
 	}
 
@@ -185,10 +192,19 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
 	xa_for_each(dsmas_xa, index, dent) {
 		int qos_class;
 
-		cxl_coordinates_combine(&dent->coord, &dent->coord, &c);
+		cxl_coordinates_combine(&dent->coord, &dent->coord, &ep_c);
+		/*
+		 * Keeping the host bridge coordinates separate from the dsmas
+		 * coordinates in order to allow calculation of access class
+		 * 0 and 1 for region later.
+		 */
+		cxl_coordinates_combine(&coord[ACCESS_COORDINATE_LOCAL],
+					&coord[ACCESS_COORDINATE_LOCAL],
+					&dent->coord);
 		dent->entries = 1;
-		rc = cxl_root->ops->qos_class(cxl_root, &dent->coord, 1,
-					      &qos_class);
+		rc = cxl_root->ops->qos_class(cxl_root,
+					      &coord[ACCESS_COORDINATE_LOCAL],
+					      1, &qos_class);
 		if (rc != 1)
 			continue;