mlxsw: core_thermal: Use the .should_bind() thermal zone callback

Make the mlxsw core_thermal driver use the .should_bind() thermal zone
callback to provide the thermal core with the information on whether or
not to bind the given cooling device to the given trip point in the
given thermal zone.  If it returns 'true', the thermal core will bind
the cooling device to the trip and the corresponding unbinding will be
taken care of automatically by the core on the removal of the involved
thermal zone or cooling device.

It replaces the .bind() and .unbind() thermal zone callbacks (in 3
places) which assumed the same trip points ordering in the driver
and in the thermal core (that may not be true any more in the
future).  The .bind() callbacks used loops over trip point indices
to call thermal_zone_bind_cooling_device() for the same cdev (once
it had been verified) and all of the trip points, but they passed
different 'upper' and 'lower' values to it for each trip.

To retain the original functionality, the .should_bind() callbacks
need to use the same 'upper' and 'lower' values that would be used
by the corresponding .bind() callbacks when they are about to return
'true'.  To that end, the 'priv' field of each trip is set during the
thermal zone initialization to point to the corresponding 'state'
object containing the maximum and minimum cooling states of the
cooling device.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/2216931.Icojqenx9y@rjwysocki.net

drivers/net/ethernet/mellanox/mlxsw/core_thermal.c

@@ -165,52 +165,22 @@ static int mlxsw_get_cooling_device_idx(struct mlxsw_thermal *thermal,
 	return -ENODEV;
 }
 
-static int mlxsw_thermal_bind(struct thermal_zone_device *tzdev,
-			      struct thermal_cooling_device *cdev)
+static bool mlxsw_thermal_should_bind(struct thermal_zone_device *tzdev,
+				      const struct thermal_trip *trip,
+				      struct thermal_cooling_device *cdev,
+				      struct cooling_spec *c)
 {
 	struct mlxsw_thermal *thermal = thermal_zone_device_priv(tzdev);
-	struct device *dev = thermal->bus_info->dev;
-	int i, err;
+	const struct mlxsw_cooling_states *state = trip->priv;
 
 	/* If the cooling device is one of ours bind it */
 	if (mlxsw_get_cooling_device_idx(thermal, cdev) < 0)
-		return 0;
+		return false;
 
-	for (i = 0; i < MLXSW_THERMAL_NUM_TRIPS; i++) {
-		const struct mlxsw_cooling_states *state = &thermal->cooling_states[i];
+	c->upper = state->max_state;
+	c->lower = state->min_state;
 
-		err = thermal_zone_bind_cooling_device(tzdev, i, cdev,
-						       state->max_state,
-						       state->min_state,
-						       THERMAL_WEIGHT_DEFAULT);
-		if (err < 0) {
-			dev_err(dev, "Failed to bind cooling device to trip %d\n", i);
-			return err;
-		}
-	}
-	return 0;
-}
-
-static int mlxsw_thermal_unbind(struct thermal_zone_device *tzdev,
-				struct thermal_cooling_device *cdev)
-{
-	struct mlxsw_thermal *thermal = thermal_zone_device_priv(tzdev);
-	struct device *dev = thermal->bus_info->dev;
-	int i;
-	int err;
-
-	/* If the cooling device is our one unbind it */
-	if (mlxsw_get_cooling_device_idx(thermal, cdev) < 0)
-		return 0;
-
-	for (i = 0; i < MLXSW_THERMAL_NUM_TRIPS; i++) {
-		err = thermal_zone_unbind_cooling_device(tzdev, i, cdev);
-		if (err < 0) {
-			dev_err(dev, "Failed to unbind cooling device\n");
-			return err;
-		}
-	}
-	return 0;
+	return true;
 }
 
 static int mlxsw_thermal_get_temp(struct thermal_zone_device *tzdev,
@@ -240,57 +210,27 @@ static struct thermal_zone_params mlxsw_thermal_params = {
 };
 
 static struct thermal_zone_device_ops mlxsw_thermal_ops = {
-	.bind = mlxsw_thermal_bind,
-	.unbind = mlxsw_thermal_unbind,
+	.should_bind = mlxsw_thermal_should_bind,
 	.get_temp = mlxsw_thermal_get_temp,
 };
 
-static int mlxsw_thermal_module_bind(struct thermal_zone_device *tzdev,
-				     struct thermal_cooling_device *cdev)
+static bool mlxsw_thermal_module_should_bind(struct thermal_zone_device *tzdev,
+					     const struct thermal_trip *trip,
+					     struct thermal_cooling_device *cdev,
+					     struct cooling_spec *c)
 {
 	struct mlxsw_thermal_module *tz = thermal_zone_device_priv(tzdev);
+	const struct mlxsw_cooling_states *state = trip->priv;
 	struct mlxsw_thermal *thermal = tz->parent;
-	int i, j, err;
 
 	/* If the cooling device is one of ours bind it */
 	if (mlxsw_get_cooling_device_idx(thermal, cdev) < 0)
-		return 0;
+		return false;
 
-	for (i = 0; i < MLXSW_THERMAL_NUM_TRIPS; i++) {
-		const struct mlxsw_cooling_states *state = &tz->cooling_states[i];
+	c->upper = state->max_state;
+	c->lower = state->min_state;
 
-		err = thermal_zone_bind_cooling_device(tzdev, i, cdev,
-						       state->max_state,
-						       state->min_state,
-						       THERMAL_WEIGHT_DEFAULT);
-		if (err < 0)
-			goto err_thermal_zone_bind_cooling_device;
-	}
-	return 0;
-
-err_thermal_zone_bind_cooling_device:
-	for (j = i - 1; j >= 0; j--)
-		thermal_zone_unbind_cooling_device(tzdev, j, cdev);
-	return err;
-}
-
-static int mlxsw_thermal_module_unbind(struct thermal_zone_device *tzdev,
-				       struct thermal_cooling_device *cdev)
-{
-	struct mlxsw_thermal_module *tz = thermal_zone_device_priv(tzdev);
-	struct mlxsw_thermal *thermal = tz->parent;
-	int i;
-	int err;
-
-	/* If the cooling device is one of ours unbind it */
-	if (mlxsw_get_cooling_device_idx(thermal, cdev) < 0)
-		return 0;
-
-	for (i = 0; i < MLXSW_THERMAL_NUM_TRIPS; i++) {
-		err = thermal_zone_unbind_cooling_device(tzdev, i, cdev);
-		WARN_ON(err);
-	}
-	return err;
+	return true;
 }
 
 static int mlxsw_thermal_module_temp_get(struct thermal_zone_device *tzdev,
@@ -313,8 +253,7 @@ static int mlxsw_thermal_module_temp_get(struct thermal_zone_device *tzdev,
 }
 
 static struct thermal_zone_device_ops mlxsw_thermal_module_ops = {
-	.bind		= mlxsw_thermal_module_bind,
-	.unbind		= mlxsw_thermal_module_unbind,
+	.should_bind	= mlxsw_thermal_module_should_bind,
 	.get_temp	= mlxsw_thermal_module_temp_get,
 };
 
@@ -342,8 +281,7 @@ static int mlxsw_thermal_gearbox_temp_get(struct thermal_zone_device *tzdev,
 }
 
 static struct thermal_zone_device_ops mlxsw_thermal_gearbox_ops = {
-	.bind		= mlxsw_thermal_module_bind,
-	.unbind		= mlxsw_thermal_module_unbind,
+	.should_bind	= mlxsw_thermal_module_should_bind,
 	.get_temp	= mlxsw_thermal_gearbox_temp_get,
 };
 
@@ -451,6 +389,7 @@ mlxsw_thermal_module_init(struct device *dev, struct mlxsw_core *core,
 			  struct mlxsw_thermal_area *area, u8 module)
 {
 	struct mlxsw_thermal_module *module_tz;
+	int i;
 
 	module_tz = &area->tz_module_arr[module];
 	/* Skip if parent is already set (case of port split). */
@@ -465,6 +404,8 @@ mlxsw_thermal_module_init(struct device *dev, struct mlxsw_core *core,
 	       sizeof(thermal->trips));
 	memcpy(module_tz->cooling_states, default_cooling_states,
 	       sizeof(thermal->cooling_states));
+	for (i = 0; i < MLXSW_THERMAL_NUM_TRIPS; i++)
+		module_tz->trips[i].priv = &module_tz->cooling_states[i];
 }
 
 static void mlxsw_thermal_module_fini(struct mlxsw_thermal_module *module_tz)
@@ -579,7 +520,7 @@ mlxsw_thermal_gearboxes_init(struct device *dev, struct mlxsw_core *core,
 	struct mlxsw_thermal_module *gearbox_tz;
 	char mgpir_pl[MLXSW_REG_MGPIR_LEN];
 	u8 gbox_num;
-	int i;
+	int i, j;
 	int err;
 
 	mlxsw_reg_mgpir_pack(mgpir_pl, area->slot_index);
@@ -606,6 +547,9 @@ mlxsw_thermal_gearboxes_init(struct device *dev, struct mlxsw_core *core,
 		       sizeof(thermal->trips));
 		memcpy(gearbox_tz->cooling_states, default_cooling_states,
 		       sizeof(thermal->cooling_states));
+		for (j = 0; j < MLXSW_THERMAL_NUM_TRIPS; j++)
+			gearbox_tz->trips[j].priv = &gearbox_tz->cooling_states[j];
+
 		gearbox_tz->module = i;
 		gearbox_tz->parent = thermal;
 		gearbox_tz->slot_index = area->slot_index;
@@ -722,6 +666,9 @@ int mlxsw_thermal_init(struct mlxsw_core *core,
 	thermal->bus_info = bus_info;
 	memcpy(thermal->trips, default_thermal_trips, sizeof(thermal->trips));
 	memcpy(thermal->cooling_states, default_cooling_states, sizeof(thermal->cooling_states));
+	for (i = 0; i < MLXSW_THERMAL_NUM_TRIPS; i++)
+		thermal->trips[i].priv = &thermal->cooling_states[i];
+
 	thermal->line_cards[0].slot_index = 0;
 
 	err = mlxsw_reg_query(thermal->core, MLXSW_REG(mfcr), mfcr_pl);