Merge tag 'scmi-updates-4.17' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into next/drivers

Pull "ARM SCMI support for v4.17" from Sudeep Holla:

ARM System Control and Management Interface(SCMI)[1] is more flexible and
easily extensible than any of the existing interfaces.

Few existing as well as future ARM platforms provide micro-controllers
to abstract various power and other system management tasks which have
similar interfaces, both in terms of the functions that are provided by
them, and in terms of how requests are communicated to them.

There are quite a few protocols like ARM SCPI, TI SCI, QCOM RPM, Nvidia Tegra
BPMP, and so on already. This specification is to standardize and avoid any
further fragmentation in the design of such interface by various vendors.

The current SCMI driver implementation is very basic and initial support.
It lacks support for notifications, asynchronous/delayed response, perf/power
statistics region and sensor register region.

Mailbox is the only form of transport supported currently in the driver.
SCMI supports interrupt based mailbox communication, where, on completion
of the processing of a message, the caller receives an interrupt as well as
polling for completion.

SCMI is designed to minimize the dependency on the mailbox/transport
hardware. So in terms of SCMI, each channel in the mailbox includes
memory area, doorbell and completion interrupt.

However the doorbell and completion interrupt is highly mailbox dependent
which was bit of controversial as part of SCMI/mailbox discussions.

Arnd and me discussed about the few aspects of SCMI and the mailbox framework:

1. Use of mailbox framework for doorbell type mailbox controller:
   - Such hardware may not require any data to be sent to signal the remote
     about the presence of a message. The channel will have in-built
     information on how to trigger the signal to the remote.
     There are few mailbox controller drivers which are purely doorbell based.
     e.g.QCOM IPC, STM, Tegra, ACPI PCC,..etc

2. Supporting other mailbox controller:
   - SCMI just needs a mechanism to signal the remote firmware. Such
     controller may need fixed message to be sent to trigger a doorbell.
     In such case we may need to get that data from DT and pass the same
     to the controller. It's not covered in the current DT binding, but
     can be extended as optional property in future.

     However handling notifications may be interesting on such mailbox, but
     again there is no way to interpret what the data field(remote message)
     means, it could be a bit mask or a number or don't-care.

Arnd mentioned that he doesn't like the way the mailbox binding deals
with doorbell-type hardware, but we do have quite a few precedent drivers
already and changing the binding to add a data field would not make it any
better, but could cause other problems. So he is happy with the status quo
of SCMI implementation.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0056a/index.html

* tag 'scmi-updates-4.17' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  cpufreq: scmi: add support for fast frequency switching
  cpufreq: add support for CPU DVFS based on SCMI message protocol
  hwmon: add support for sensors exported via ARM SCMI
  hwmon: (core) Add hwmon_max to hwmon_sensor_types enumeration
  clk: add support for clocks provided by SCMI
  firmware: arm_scmi: add device power domain support using genpd
  firmware: arm_scmi: add per-protocol channels support using idr objects
  firmware: arm_scmi: refactor in preparation to support per-protocol channels
  firmware: arm_scmi: add option for polling based performance domain operations
  firmware: arm_scmi: add support for polling based SCMI transfers
  firmware: arm_scmi: probe and initialise all the supported protocols
  firmware: arm_scmi: add initial support for sensor protocol
  firmware: arm_scmi: add initial support for power protocol
  firmware: arm_scmi: add initial support for clock protocol
  firmware: arm_scmi: add initial support for performance protocol
  firmware: arm_scmi: add scmi protocol bus to enumerate protocol devices
  firmware: arm_scmi: add common infrastructure and support for base protocol
  firmware: arm_scmi: add basic driver infrastructure for SCMI
  dt-bindings: arm: add support for ARM System Control and Management Interface(SCMI) protocol
  dt-bindings: mailbox: add support for mailbox client shared memory

1 files changed, 277 insertions, 0 deletions

diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
new file mode 100644
index 000000000000..b458c87b866c
--- /dev/null
+++ b/include/linux/scmi_protocol.h
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SCMI Message Protocol driver header
+ *
+ * Copyright (C) 2018 ARM Ltd.
+ */
+#include <linux/device.h>
+#include <linux/types.h>
+
+#define SCMI_MAX_STR_SIZE	16
+#define SCMI_MAX_NUM_RATES	16
+
+/**
+ * struct scmi_revision_info - version information structure
+ *
+ * @major_ver: Major ABI version. Change here implies risk of backward
+ *	compatibility break.
+ * @minor_ver: Minor ABI version. Change here implies new feature addition,
+ *	or compatible change in ABI.
+ * @num_protocols: Number of protocols that are implemented, excluding the
+ *	base protocol.
+ * @num_agents: Number of agents in the system.
+ * @impl_ver: A vendor-specific implementation version.
+ * @vendor_id: A vendor identifier(Null terminated ASCII string)
+ * @sub_vendor_id: A sub-vendor identifier(Null terminated ASCII string)
+ */
+struct scmi_revision_info {
+	u16 major_ver;
+	u16 minor_ver;
+	u8 num_protocols;
+	u8 num_agents;
+	u32 impl_ver;
+	char vendor_id[SCMI_MAX_STR_SIZE];
+	char sub_vendor_id[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_clock_info {
+	char name[SCMI_MAX_STR_SIZE];
+	bool rate_discrete;
+	union {
+		struct {
+			int num_rates;
+			u64 rates[SCMI_MAX_NUM_RATES];
+		} list;
+		struct {
+			u64 min_rate;
+			u64 max_rate;
+			u64 step_size;
+		} range;
+	};
+};
+
+struct scmi_handle;
+
+/**
+ * struct scmi_clk_ops - represents the various operations provided
+ *	by SCMI Clock Protocol
+ *
+ * @count_get: get the count of clocks provided by SCMI
+ * @info_get: get the information of the specified clock
+ * @rate_get: request the current clock rate of a clock
+ * @rate_set: set the clock rate of a clock
+ * @enable: enables the specified clock
+ * @disable: disables the specified clock
+ */
+struct scmi_clk_ops {
+	int (*count_get)(const struct scmi_handle *handle);
+
+	const struct scmi_clock_info *(*info_get)
+		(const struct scmi_handle *handle, u32 clk_id);
+	int (*rate_get)(const struct scmi_handle *handle, u32 clk_id,
+			u64 *rate);
+	int (*rate_set)(const struct scmi_handle *handle, u32 clk_id,
+			u32 config, u64 rate);
+	int (*enable)(const struct scmi_handle *handle, u32 clk_id);
+	int (*disable)(const struct scmi_handle *handle, u32 clk_id);
+};
+
+/**
+ * struct scmi_perf_ops - represents the various operations provided
+ *	by SCMI Performance Protocol
+ *
+ * @limits_set: sets limits on the performance level of a domain
+ * @limits_get: gets limits on the performance level of a domain
+ * @level_set: sets the performance level of a domain
+ * @level_get: gets the performance level of a domain
+ * @device_domain_id: gets the scmi domain id for a given device
+ * @get_transition_latency: gets the DVFS transition latency for a given device
+ * @add_opps_to_device: adds all the OPPs for a given device
+ * @freq_set: sets the frequency for a given device using sustained frequency
+ *	to sustained performance level mapping
+ * @freq_get: gets the frequency for a given device using sustained frequency
+ *	to sustained performance level mapping
+ */
+struct scmi_perf_ops {
+	int (*limits_set)(const struct scmi_handle *handle, u32 domain,
+			  u32 max_perf, u32 min_perf);
+	int (*limits_get)(const struct scmi_handle *handle, u32 domain,
+			  u32 *max_perf, u32 *min_perf);
+	int (*level_set)(const struct scmi_handle *handle, u32 domain,
+			 u32 level, bool poll);
+	int (*level_get)(const struct scmi_handle *handle, u32 domain,
+			 u32 *level, bool poll);
+	int (*device_domain_id)(struct device *dev);
+	int (*get_transition_latency)(const struct scmi_handle *handle,
+				      struct device *dev);
+	int (*add_opps_to_device)(const struct scmi_handle *handle,
+				  struct device *dev);
+	int (*freq_set)(const struct scmi_handle *handle, u32 domain,
+			unsigned long rate, bool poll);
+	int (*freq_get)(const struct scmi_handle *handle, u32 domain,
+			unsigned long *rate, bool poll);
+};
+
+/**
+ * struct scmi_power_ops - represents the various operations provided
+ *	by SCMI Power Protocol
+ *
+ * @num_domains_get: get the count of power domains provided by SCMI
+ * @name_get: gets the name of a power domain
+ * @state_set: sets the power state of a power domain
+ * @state_get: gets the power state of a power domain
+ */
+struct scmi_power_ops {
+	int (*num_domains_get)(const struct scmi_handle *handle);
+	char *(*name_get)(const struct scmi_handle *handle, u32 domain);
+#define SCMI_POWER_STATE_TYPE_SHIFT	30
+#define SCMI_POWER_STATE_ID_MASK	(BIT(28) - 1)
+#define SCMI_POWER_STATE_PARAM(type, id) \
+	((((type) & BIT(0)) << SCMI_POWER_STATE_TYPE_SHIFT) | \
+		((id) & SCMI_POWER_STATE_ID_MASK))
+#define SCMI_POWER_STATE_GENERIC_ON	SCMI_POWER_STATE_PARAM(0, 0)
+#define SCMI_POWER_STATE_GENERIC_OFF	SCMI_POWER_STATE_PARAM(1, 0)
+	int (*state_set)(const struct scmi_handle *handle, u32 domain,
+			 u32 state);
+	int (*state_get)(const struct scmi_handle *handle, u32 domain,
+			 u32 *state);
+};
+
+struct scmi_sensor_info {
+	u32 id;
+	u8 type;
+	char name[SCMI_MAX_STR_SIZE];
+};
+
+/*
+ * Partial list from Distributed Management Task Force (DMTF) specification:
+ * DSP0249 (Platform Level Data Model specification)
+ */
+enum scmi_sensor_class {
+	NONE = 0x0,
+	TEMPERATURE_C = 0x2,
+	VOLTAGE = 0x5,
+	CURRENT = 0x6,
+	POWER = 0x7,
+	ENERGY = 0x8,
+};
+
+/**
+ * struct scmi_sensor_ops - represents the various operations provided
+ *	by SCMI Sensor Protocol
+ *
+ * @count_get: get the count of sensors provided by SCMI
+ * @info_get: get the information of the specified sensor
+ * @configuration_set: control notifications on cross-over events for
+ *	the trip-points
+ * @trip_point_set: selects and configures a trip-point of interest
+ * @reading_get: gets the current value of the sensor
+ */
+struct scmi_sensor_ops {
+	int (*count_get)(const struct scmi_handle *handle);
+
+	const struct scmi_sensor_info *(*info_get)
+		(const struct scmi_handle *handle, u32 sensor_id);
+	int (*configuration_set)(const struct scmi_handle *handle,
+				 u32 sensor_id);
+	int (*trip_point_set)(const struct scmi_handle *handle, u32 sensor_id,
+			      u8 trip_id, u64 trip_value);
+	int (*reading_get)(const struct scmi_handle *handle, u32 sensor_id,
+			   bool async, u64 *value);
+};
+
+/**
+ * struct scmi_handle - Handle returned to ARM SCMI clients for usage.
+ *
+ * @dev: pointer to the SCMI device
+ * @version: pointer to the structure containing SCMI version information
+ * @power_ops: pointer to set of power protocol operations
+ * @perf_ops: pointer to set of performance protocol operations
+ * @clk_ops: pointer to set of clock protocol operations
+ * @sensor_ops: pointer to set of sensor protocol operations
+ */
+struct scmi_handle {
+	struct device *dev;
+	struct scmi_revision_info *version;
+	struct scmi_perf_ops *perf_ops;
+	struct scmi_clk_ops *clk_ops;
+	struct scmi_power_ops *power_ops;
+	struct scmi_sensor_ops *sensor_ops;
+	/* for protocol internal use */
+	void *perf_priv;
+	void *clk_priv;
+	void *power_priv;
+	void *sensor_priv;
+};
+
+enum scmi_std_protocol {
+	SCMI_PROTOCOL_BASE = 0x10,
+	SCMI_PROTOCOL_POWER = 0x11,
+	SCMI_PROTOCOL_SYSTEM = 0x12,
+	SCMI_PROTOCOL_PERF = 0x13,
+	SCMI_PROTOCOL_CLOCK = 0x14,
+	SCMI_PROTOCOL_SENSOR = 0x15,
+};
+
+struct scmi_device {
+	u32 id;
+	u8 protocol_id;
+	struct device dev;
+	struct scmi_handle *handle;
+};
+
+#define to_scmi_dev(d) container_of(d, struct scmi_device, dev)
+
+struct scmi_device *
+scmi_device_create(struct device_node *np, struct device *parent, int protocol);
+void scmi_device_destroy(struct scmi_device *scmi_dev);
+
+struct scmi_device_id {
+	u8 protocol_id;
+};
+
+struct scmi_driver {
+	const char *name;
+	int (*probe)(struct scmi_device *sdev);
+	void (*remove)(struct scmi_device *sdev);
+	const struct scmi_device_id *id_table;
+
+	struct device_driver driver;
+};
+
+#define to_scmi_driver(d) container_of(d, struct scmi_driver, driver)
+
+#ifdef CONFIG_ARM_SCMI_PROTOCOL
+int scmi_driver_register(struct scmi_driver *driver,
+			 struct module *owner, const char *mod_name);
+void scmi_driver_unregister(struct scmi_driver *driver);
+#else
+static inline int
+scmi_driver_register(struct scmi_driver *driver, struct module *owner,
+		     const char *mod_name)
+{
+	return -EINVAL;
+}
+
+static inline void scmi_driver_unregister(struct scmi_driver *driver) {}
+#endif /* CONFIG_ARM_SCMI_PROTOCOL */
+
+#define scmi_register(driver) \
+	scmi_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
+#define scmi_unregister(driver) \
+	scmi_driver_unregister(driver)
+
+/**
+ * module_scmi_driver() - Helper macro for registering a scmi driver
+ * @__scmi_driver: scmi_driver structure
+ *
+ * Helper macro for scmi drivers to set up proper module init / exit
+ * functions.  Replaces module_init() and module_exit() and keeps people from
+ * printing pointless things to the kernel log when their driver is loaded.
+ */
+#define module_scmi_driver(__scmi_driver)	\
+	module_driver(__scmi_driver, scmi_register, scmi_unregister)
+
+typedef int (*scmi_prot_init_fn_t)(struct scmi_handle *);
+int scmi_protocol_register(int protocol_id, scmi_prot_init_fn_t fn);
+void scmi_protocol_unregister(int protocol_id);