firmware: arm_scmi: Add SCMI v3.1 powercap protocol basic support

Add support for SCMI v3.1 powercap protocol, with the exception of powercap
fast channels, exposing all the new related powercap protocol operations as
usual in include/linux/scmi_protocol.h.

Link: https://lore.kernel.org/r/20220704102241.2988447-3-cristian.marussi@arm.comSigned-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/Makefile

@@ -7,7 +7,7 @@ scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_SMC) += smc.o
 scmi-transport-$(CONFIG_ARM_SCMI_HAVE_MSG) += msg.o
 scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_VIRTIO) += virtio.o
 scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_OPTEE) += optee.o
-scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o
+scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o powercap.o
 scmi-module-objs := $(scmi-bus-y) $(scmi-driver-y) $(scmi-protocols-y) \
 		    $(scmi-transport-y)
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o

drivers/firmware/arm_scmi/driver.c

@@ -2485,6 +2485,7 @@ static int __init scmi_driver_init(void)
 	scmi_sensors_register();
 	scmi_voltage_register();
 	scmi_system_register();
+	scmi_powercap_register();
 
 	return platform_driver_register(&scmi_driver);
 }
@@ -2501,6 +2502,7 @@ static void __exit scmi_driver_exit(void)
 	scmi_sensors_unregister();
 	scmi_voltage_unregister();
 	scmi_system_unregister();
+	scmi_powercap_unregister();
 
 	scmi_bus_exit();
 

drivers/firmware/arm_scmi/protocols.h

@@ -315,5 +315,6 @@ DECLARE_SCMI_REGISTER_UNREGISTER(reset);
 DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
 DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
 DECLARE_SCMI_REGISTER_UNREGISTER(system);
+DECLARE_SCMI_REGISTER_UNREGISTER(powercap);
 
 #endif /* _SCMI_PROTOCOLS_H */

include/linux/scmi_protocol.h

@@ -560,6 +560,114 @@ struct scmi_voltage_proto_ops {
 			 s32 *volt_uV);
 };
 
+/**
+ * struct scmi_powercap_info  - Describe one available Powercap domain
+ *
+ * @id: Domain ID as advertised by the platform.
+ * @notify_powercap_cap_change: CAP change notification support.
+ * @notify_powercap_measurement_change: MEASUREMENTS change notifications
+ *				       support.
+ * @async_powercap_cap_set: Asynchronous CAP set support.
+ * @powercap_cap_config: CAP configuration support.
+ * @powercap_monitoring: Monitoring (measurements) support.
+ * @powercap_pai_config: PAI configuration support.
+ * @powercap_scale_mw: Domain reports power data in milliwatt units.
+ * @powercap_scale_uw: Domain reports power data in microwatt units.
+ *		       Note that, when both @powercap_scale_mw and
+ *		       @powercap_scale_uw are set to false, the domain
+ *		       reports power data on an abstract linear scale.
+ * @name: name assigned to the Powercap Domain by platform.
+ * @min_pai: Minimum configurable PAI.
+ * @max_pai: Maximum configurable PAI.
+ * @pai_step: Step size between two consecutive PAI values.
+ * @min_power_cap: Minimum configurable CAP.
+ * @max_power_cap: Maximum configurable CAP.
+ * @power_cap_step: Step size between two consecutive CAP values.
+ * @sustainable_power: Maximum sustainable power consumption for this domain
+ *		       under normal conditions.
+ * @accuracy: The accuracy with which the power is measured and reported in
+ *	      integral multiples of 0.001 percent.
+ * @parent_id: Identifier of the containing parent power capping domain, or the
+ *	       value 0xFFFFFFFF if this powercap domain is a root domain not
+ *	       contained in any other domain.
+ */
+struct scmi_powercap_info {
+	unsigned int id;
+	bool notify_powercap_cap_change;
+	bool notify_powercap_measurement_change;
+	bool async_powercap_cap_set;
+	bool powercap_cap_config;
+	bool powercap_monitoring;
+	bool powercap_pai_config;
+	bool powercap_scale_mw;
+	bool powercap_scale_uw;
+	char name[SCMI_MAX_STR_SIZE];
+	unsigned int min_pai;
+	unsigned int max_pai;
+	unsigned int pai_step;
+	unsigned int min_power_cap;
+	unsigned int max_power_cap;
+	unsigned int power_cap_step;
+	unsigned int sustainable_power;
+	unsigned int accuracy;
+#define SCMI_POWERCAP_ROOT_ZONE_ID     0xFFFFFFFFUL
+	unsigned int parent_id;
+};
+
+/**
+ * struct scmi_powercap_proto_ops - represents the various operations provided
+ * by SCMI Powercap Protocol
+ *
+ * @num_domains_get: get the count of powercap domains provided by SCMI.
+ * @info_get: get the information for the specified domain.
+ * @cap_get: get the current CAP value for the specified domain.
+ * @cap_set: set the CAP value for the specified domain to the provided value;
+ *	     if the domain supports setting the CAP with an asynchronous command
+ *	     this request will finally trigger an asynchronous transfer, but, if
+ *	     @ignore_dresp here is set to true, this call will anyway return
+ *	     immediately without waiting for the related delayed response.
+ * @pai_get: get the current PAI value for the specified domain.
+ * @pai_set: set the PAI value for the specified domain to the provided value.
+ * @measurements_get: retrieve the current average power measurements for the
+ *		      specified domain and the related PAI upon which is
+ *		      calculated.
+ * @measurements_threshold_set: set the desired low and high power thresholds
+ *				to be used when registering for notification
+ *				of type POWERCAP_MEASUREMENTS_NOTIFY with this
+ *				powercap domain.
+ *				Note that this must be called at least once
+ *				before registering any callback with the usual
+ *				@scmi_notify_ops; moreover, in case this method
+ *				is called with measurement notifications already
+ *				enabled it will also trigger, transparently, a
+ *				proper update of the power thresholds configured
+ *				in the SCMI backend server.
+ * @measurements_threshold_get: get the currently configured low and high power
+ *				thresholds used when registering callbacks for
+ *				notification POWERCAP_MEASUREMENTS_NOTIFY.
+ */
+struct scmi_powercap_proto_ops {
+	int (*num_domains_get)(const struct scmi_protocol_handle *ph);
+	const struct scmi_powercap_info __must_check *(*info_get)
+		(const struct scmi_protocol_handle *ph, u32 domain_id);
+	int (*cap_get)(const struct scmi_protocol_handle *ph, u32 domain_id,
+		       u32 *power_cap);
+	int (*cap_set)(const struct scmi_protocol_handle *ph, u32 domain_id,
+		       u32 power_cap, bool ignore_dresp);
+	int (*pai_get)(const struct scmi_protocol_handle *ph, u32 domain_id,
+		       u32 *pai);
+	int (*pai_set)(const struct scmi_protocol_handle *ph, u32 domain_id,
+		       u32 pai);
+	int (*measurements_get)(const struct scmi_protocol_handle *ph,
+				u32 domain_id, u32 *average_power, u32 *pai);
+	int (*measurements_threshold_set)(const struct scmi_protocol_handle *ph,
+					  u32 domain_id, u32 power_thresh_low,
+					  u32 power_thresh_high);
+	int (*measurements_threshold_get)(const struct scmi_protocol_handle *ph,
+					  u32 domain_id, u32 *power_thresh_low,
+					  u32 *power_thresh_high);
+};
+
 /**
  * struct scmi_notify_ops  - represents notifications' operations provided by
  * SCMI core
@@ -666,6 +774,7 @@ enum scmi_std_protocol {
 	SCMI_PROTOCOL_SENSOR = 0x15,
 	SCMI_PROTOCOL_RESET = 0x16,
 	SCMI_PROTOCOL_VOLTAGE = 0x17,
+	SCMI_PROTOCOL_POWERCAP = 0x18,
 };
 
 enum scmi_system_events {
@@ -767,6 +876,8 @@ enum scmi_notification_events {
 	SCMI_EVENT_RESET_ISSUED = 0x0,
 	SCMI_EVENT_BASE_ERROR_EVENT = 0x0,
 	SCMI_EVENT_SYSTEM_POWER_STATE_NOTIFIER = 0x0,
+	SCMI_EVENT_POWERCAP_CAP_CHANGED = 0x0,
+	SCMI_EVENT_POWERCAP_MEASUREMENTS_CHANGED = 0x1,
 };
 
 struct scmi_power_state_changed_report {
@@ -837,4 +948,18 @@ struct scmi_base_error_report {
 	unsigned long long	reports[];
 };
 
+struct scmi_powercap_cap_changed_report {
+	ktime_t		timestamp;
+	unsigned int	agent_id;
+	unsigned int	domain_id;
+	unsigned int	power_cap;
+	unsigned int	pai;
+};
+
+struct scmi_powercap_meas_changed_report {
+	ktime_t		timestamp;
+	unsigned int	agent_id;
+	unsigned int	domain_id;
+	unsigned int	power;
+};
 #endif /* _LINUX_SCMI_PROTOCOL_H */