[PATCH 07/18] cxl: Add callback to parse the DSLBIS subtable from CDAT

[Dave Jiang <dave.jiang@xxxxxxxxx>]

Provide a callback to parse the Device Scoped Latency and Bandwidth
Information Structure (DSLBIS) in the CDAT structures. The DSLBIS
contains the bandwidth and latency information that's tied to a DSMAS
handle. The driver will retrieve the read and write latency and
bandwidth associated with the DSMAS which is tied to a DPA range.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
 drivers/cxl/core/cdat.c |   34 ++++++++++++++++++++++++++++++++++
 drivers/cxl/cxl.h       |    2 ++
 drivers/cxl/port.c      |    9 ++++++++-
 include/acpi/actbl1.h   |    5 +++++
 4 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index f9a64a0f1ee4..3c8f3956487e 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -121,3 +121,37 @@ int cxl_dsmas_parse_entry(struct acpi_cdat_header *header, void *arg)
 	return 0;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_dsmas_parse_entry, CXL);
+
+int cxl_dslbis_parse_entry(struct acpi_cdat_header *header, void *arg)
+{
+	struct cxl_port *port = (struct cxl_port *)arg;
+	struct dsmas_entry *dent;
+	struct acpi_cdat_dslbis *dslbis;
+	u64 val;
+
+	if (header->type != ACPI_CDAT_TYPE_DSLBIS)
+		return -EINVAL;
+
+	dslbis = (struct acpi_cdat_dslbis *)((unsigned long)header + sizeof(*header));
+	if ((dslbis->flags & ACPI_CEDT_DSLBIS_MEM_MASK) !=
+	     ACPI_CEDT_DSLBIS_MEM_MEMORY)
+		return 0;
+
+	if (dslbis->data_type > ACPI_HMAT_WRITE_BANDWIDTH)
+		return -ENXIO;
+
+	/* Value calculation with base_unit, see ACPI Spec 6.5 5.2.28.4 */
+	val = dslbis->entry[0] * dslbis->entry_base_unit;
+
+	mutex_lock(&port->cdat.dsmas_lock);
+	list_for_each_entry(dent, &port->cdat.dsmas_list, list) {
+		if (dslbis->handle == dent->handle) {
+			dent->qos[dslbis->data_type] = val;
+			break;
+		}
+	}
+	mutex_unlock(&port->cdat.dsmas_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_dslbis_parse_entry, CXL);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 1e5e69f08480..849b22236f1d 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -705,6 +705,7 @@ struct dsmas_entry {
 	struct list_head list;
 	struct range dpa_range;
 	u16 handle;
+	u64 qos[ACPI_HMAT_WRITE_BANDWIDTH + 1];
 };
 
 typedef int (*cdat_tbl_entry_handler)(struct acpi_cdat_header *header, void *arg);
@@ -716,6 +717,7 @@ int cdat_table_parse_dslbis(void *table, cdat_tbl_entry_handler handler,
 			    void *arg);
 
 int cxl_dsmas_parse_entry(struct acpi_cdat_header *header, void *arg);
+int cxl_dslbis_parse_entry(struct acpi_cdat_header *header, void *arg);
 
 /*
  * Unit test builds overrides this to __weak, find the 'strong' version
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
index b1da73e99bab..8de311208b37 100644
--- a/drivers/cxl/port.c
+++ b/drivers/cxl/port.c
@@ -65,8 +65,15 @@ static int cxl_port_probe(struct device *dev)
 			rc = cdat_table_parse_dsmas(port->cdat.table,
 						    cxl_dsmas_parse_entry,
 						    (void *)port);
-			if (rc < 0)
+			if (rc > 0) {
+				rc = cdat_table_parse_dslbis(port->cdat.table,
+							     cxl_dslbis_parse_entry,
+							     (void *)port);
+				if (rc <= 0)
+					dev_dbg(dev, "Failed to parse DSLBIS: %d\n", rc);
+			} else {
 				dev_dbg(dev, "Failed to parse DSMAS: %d\n", rc);
+			}
 		}
 
 		rc = cxl_hdm_decode_init(cxlds, cxlhdm);
diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h
index e8297cefde09..ff6092e45196 100644
--- a/include/acpi/actbl1.h
+++ b/include/acpi/actbl1.h
@@ -369,6 +369,11 @@ struct acpi_cdat_dslbis {
 	u16 reserved2;
 };
 
+/* Flags for subtable above */
+
+#define ACPI_CEDT_DSLBIS_MEM_MASK	GENMASK(3, 0)
+#define ACPI_CEDT_DSLBIS_MEM_MEMORY	0
+
 /* Subtable 2: Device Scoped Memory Side Cache Information Structure (DSMSCIS) */
 
 struct acpi_cdat_dsmscis {