firmware: arm_scmi: Add voltage domain management protocol support

SCMI v3.0 introduces voltage domain protocol which provides commands to:
 - Discover the voltage levels supported by a domain
 - Get the configuration and voltage level of a domain
 - Set the configuration and voltage level of a domain

Let us add support for the same.

Link: https://lore.kernel.org/r/20201119191051.46363-2-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 9cd312a1ff92..b11ca01e2393 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -210,6 +210,64 @@ struct scmi_reset_ops {
 };
 
 /**
+ * struct scmi_voltage_info - describe one available SCMI Voltage Domain
+ *
+ * @id: the domain ID as advertised by the platform
+ * @segmented: defines the layout of the entries of array @levels_uv.
+ *	       - when True the entries are to be interpreted as triplets,
+ *	         each defining a segment representing a range of equally
+ *	         space voltages: <lowest_volts>, <highest_volt>, <step_uV>
+ *	       - when False the entries simply represent a single discrete
+ *	         supported voltage level
+ * @negative_volts_allowed: True if any of the entries of @levels_uv represent
+ *			    a negative voltage.
+ * @attributes: represents Voltage Domain advertised attributes
+ * @name: name assigned to the Voltage Domain by platform
+ * @num_levels: number of total entries in @levels_uv.
+ * @levels_uv: array of entries describing the available voltage levels for
+ *	       this domain.
+ */
+struct scmi_voltage_info {
+	unsigned int id;
+	bool segmented;
+	bool negative_volts_allowed;
+	unsigned int attributes;
+	char name[SCMI_MAX_STR_SIZE];
+	unsigned int num_levels;
+#define SCMI_VOLTAGE_SEGMENT_LOW	0
+#define SCMI_VOLTAGE_SEGMENT_HIGH	1
+#define SCMI_VOLTAGE_SEGMENT_STEP	2
+	int *levels_uv;
+};
+
+/**
+ * struct scmi_voltage_ops - represents the various operations provided
+ * by SCMI Voltage Protocol
+ *
+ * @num_domains_get: get the count of voltage domains provided by SCMI
+ * @info_get: get the information of the specified domain
+ * @config_set: set the config for the specified domain
+ * @config_get: get the config of the specified domain
+ * @level_set: set the voltage level for the specified domain
+ * @level_get: get the voltage level of the specified domain
+ */
+struct scmi_voltage_ops {
+	int (*num_domains_get)(const struct scmi_handle *handle);
+	const struct scmi_voltage_info __must_check *(*info_get)
+		(const struct scmi_handle *handle, u32 domain_id);
+	int (*config_set)(const struct scmi_handle *handle, u32 domain_id,
+			  u32 config);
+#define	SCMI_VOLTAGE_ARCH_STATE_OFF		0x0
+#define	SCMI_VOLTAGE_ARCH_STATE_ON		0x7
+	int (*config_get)(const struct scmi_handle *handle, u32 domain_id,
+			  u32 *config);
+	int (*level_set)(const struct scmi_handle *handle, u32 domain_id,
+			 u32 flags, s32 volt_uV);
+	int (*level_get)(const struct scmi_handle *handle, u32 domain_id,
+			 s32 *volt_uV);
+};
+
+/**
  * struct scmi_notify_ops  - represents notifications' operations provided by
  * SCMI core
  * @register_event_notifier: Register a notifier_block for the requested event
@@ -262,6 +320,7 @@ struct scmi_notify_ops {
  * @clk_ops: pointer to set of clock protocol operations
  * @sensor_ops: pointer to set of sensor protocol operations
  * @reset_ops: pointer to set of reset protocol operations
+ * @voltage_ops: pointer to set of voltage protocol operations
  * @notify_ops: pointer to set of notifications related operations
  * @perf_priv: pointer to private data structure specific to performance
  *	protocol(for internal use only)
@@ -273,6 +332,8 @@ struct scmi_notify_ops {
  *	protocol(for internal use only)
  * @reset_priv: pointer to private data structure specific to reset
  *	protocol(for internal use only)
+ * @voltage_priv: pointer to private data structure specific to voltage
+ *	protocol(for internal use only)
  * @notify_priv: pointer to private data structure specific to notifications
  *	(for internal use only)
  */
@@ -284,6 +345,7 @@ struct scmi_handle {
 	const struct scmi_power_ops *power_ops;
 	const struct scmi_sensor_ops *sensor_ops;
 	const struct scmi_reset_ops *reset_ops;
+	const struct scmi_voltage_ops *voltage_ops;
 	const struct scmi_notify_ops *notify_ops;
 	/* for protocol internal use */
 	void *perf_priv;
@@ -291,6 +353,7 @@ struct scmi_handle {
 	void *power_priv;
 	void *sensor_priv;
 	void *reset_priv;
+	void *voltage_priv;
 	void *notify_priv;
 	void *system_priv;
 };
@@ -303,6 +366,7 @@ enum scmi_std_protocol {
 	SCMI_PROTOCOL_CLOCK = 0x14,
 	SCMI_PROTOCOL_SENSOR = 0x15,
 	SCMI_PROTOCOL_RESET = 0x16,
+	SCMI_PROTOCOL_VOLTAGE = 0x17,
 };
 
 enum scmi_system_events {