sensor: add a family field in the handler

Currently, we are hijacking the last bit of the resource field of the
sensor handler to differentiate the sensor families and route the
opal_sensor_read() call to the appropriate component.

Let's reserve the last 3bits and provide an API to set the sensor
family for current use and future use. This gives us a maximum of 8
families and 32 resource classes. The FSP uses 15, so we should be
fine for a while.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

core/sensor.c

@@ -26,8 +26,10 @@ struct dt_node *sensor_node;
 static int64_t opal_sensor_read(uint32_t sensor_hndl, int token,
 		uint32_t *sensor_data)
 {
-	if (sensor_is_dts(sensor_hndl))
+	switch (sensor_get_family(sensor_hndl)) {
+	case SENSOR_DTS:
 		return dts_sensor_read(sensor_hndl, sensor_data);
+	}
 
 	if (platform.sensor_read)
 		return platform.sensor_read(sensor_hndl, token, sensor_data);

doc/device-tree/ibm,opal/sensors.rst

@@ -24,9 +24,12 @@ Each node has a minimum set of properties describing the sensor :
   OPAL_SENSOR_READ call to be used by Linux to get the value of
   a sensor attribute. A sensor handler has the following encoding : ::
 
-		|  Attr. |  Res.  |   Resource     |
-		| Number | Class  |      Id        |
-		|--------|--------|----------------|
+		|  Attr. |Fam|Res. |   Resource     |
+		| Number |ily|Class|      Id        |
+		|--------|---|-----|----------------|
+
+  The sensor family (FSP, DTS, etc) is used to dispatch the call to
+  the appriopriate skiboot component.
 
 - a "sensor-status" property giving the state of the sensor. The
   status bits have the slightly meanings depending on the resource

hw/dts.c

@@ -290,7 +290,7 @@ int64_t dts_sensor_read(uint32_t sensor_hndl, uint32_t *sensor_data)
 
 	memset(&dts, 0, sizeof(struct dts));
 
-	switch (sensor_get_frc(sensor_hndl) & ~SENSOR_DTS) {
+	switch (sensor_get_frc(sensor_hndl)) {
 	case SENSOR_DTS_CORE_TEMP:
 		rc = dts_read_core_temp(rid, &dts);
 		break;
@@ -326,11 +326,11 @@ int64_t dts_sensor_read(uint32_t sensor_hndl, uint32_t *sensor_data)
 	(((chip_id) & 0x3ff) | ((dimm_id) << 10))
 
 #define core_handler(core_id, attr_id)					\
-	sensor_make_handler(SENSOR_DTS_CORE_TEMP | SENSOR_DTS,		\
+	sensor_make_handler(SENSOR_DTS, SENSOR_DTS_CORE_TEMP,		\
 			    core_id, attr_id)
 
 #define cen_handler(cen_id, attr_id)					\
-	sensor_make_handler(SENSOR_DTS_MEM_TEMP|SENSOR_DTS,		\
+	sensor_make_handler(SENSOR_DTS, SENSOR_DTS_MEM_TEMP,		\
 			    centaur_make_id(chip_id, 0), attr_id)
 
 bool dts_sensor_create_nodes(struct dt_node *sensors)

hw/fsp/fsp-sensor.c

@@ -617,7 +617,7 @@ static struct dt_node *sensor_get_node(struct dt_node *sensors,
 }
 
 #define sensor_handler(header, attr_num) \
-	sensor_make_handler((header).frc, (header).rid, attr_num)
+	sensor_make_handler(SENSOR_FSP, (header).frc, (header).rid, attr_num)
 
 static int add_sensor_prs(struct dt_node *sensors, struct sensor_prs *prs)
 {

include/sensor.h

@@ -22,31 +22,39 @@
  * its resource class (temperature, fans ...), a resource identifier
  * and an attribute number (data, status, ...) :
  *
- *                 Res.
- *     | Attr.  | Class  |   Resource Id  |
- *     |--------|--------|----------------|
- *
+ *                    Res.
+ *     | Attr.  |Fam Class|   Resource Id  |
+ *     |--------|---|-----|----------------|
  *
+ * The last 3bits of the resource class are used to hold the family
+ * number. That leaves 32 differents resource classes. This is enough
+ * for the FSP as it uses 15.
+ */
+
+/*
  * Helper routines to build or use the sensor handler.
  */
-#define sensor_make_handler(sensor_class, sensor_rid, sensor_attr) \
-	(((sensor_attr) << 24) | ((sensor_class) & 0xff) << 16 | \
-	 ((sensor_rid) & 0xffff))
+#define sensor_make_handler(family, class, rid, attr)			\
+	(((attr) << 24) | ((family) & 0x7) << 21 | ((class) & 0x1f) << 16 | \
+	 ((rid) & 0xffff))
 
-#define sensor_get_frc(handler)		(((handler) >> 16) & 0xff)
+#define sensor_get_family(handler)	(((handler) >> 21) & 0x7)
+#define sensor_get_frc(handler)		(((handler) >> 16) & 0x1f)
 #define sensor_get_rid(handler)		((handler) & 0xffff)
 #define sensor_get_attr(handler)	((handler) >> 24)
 
 /*
  * Sensor families
  *
  * This identifier is used to dispatch calls to OPAL_SENSOR_READ to
- * the appropriate component. FSP is the initial family.
+ * the appropriate component. FSP is the initial family and you can
+ * have up to eight, as we are hijacking the last 3bits of the
+ * resource class.
  */
-#define SENSOR_FSP 0x0
-#define SENSOR_DTS 0x80
-
-#define sensor_is_dts(handler)	(sensor_get_frc(handler) & SENSOR_DTS)
+enum {
+	SENSOR_FSP = 0,
+	SENSOR_DTS = 7,
+};
 
 /*
  * root node of all sensors : /ibm,opal/sensors