firmware: scmi: implement SCMI base protocol

SCMI base protocol is mandatory according to the SCMI specification.

With this patch, SCMI base protocol can be accessed via SCMI transport
layers. All the commands, except SCMI_BASE_NOTIFY_ERRORS, are supported.
This is because U-Boot doesn't support interrupts and the current transport
layers are not able to handle asynchronous messages properly.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Etienne Carriere <etienne.carriere@foss.st.com>
diff --git a/drivers/firmware/scmi/Makefile b/drivers/firmware/scmi/Makefile
index b2ff483..1a23d49 100644
--- a/drivers/firmware/scmi/Makefile
+++ b/drivers/firmware/scmi/Makefile
@@ -1,4 +1,5 @@
 obj-y	+= scmi_agent-uclass.o
+obj-y	+= base.o
 obj-y	+= smt.o
 obj-$(CONFIG_SCMI_AGENT_SMCCC)		+= smccc_agent.o
 obj-$(CONFIG_SCMI_AGENT_MAILBOX)	+= mailbox_agent.o
diff --git a/drivers/firmware/scmi/base.c b/drivers/firmware/scmi/base.c
new file mode 100644
index 0000000..ee84e26
--- /dev/null
+++ b/drivers/firmware/scmi/base.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * SCMI Base protocol as U-Boot device
+ *
+ * Copyright (C) 2023 Linaro Limited
+ *		author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <scmi_agent.h>
+#include <scmi_protocols.h>
+#include <stdlib.h>
+#include <string.h>
+#include <asm/types.h>
+#include <dm/device_compat.h>
+#include <linux/kernel.h>
+
+/**
+ * scmi_generic_protocol_version - get protocol version
+ * @dev:	SCMI device
+ * @id:		SCMI protocol ID
+ * @version:	Pointer to SCMI protocol version
+ *
+ * Obtain the protocol version number in @version.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_generic_protocol_version(struct udevice *dev,
+				  enum scmi_std_protocol id, u32 *version)
+{
+	struct scmi_protocol_version_out out;
+	struct scmi_msg msg = {
+		.protocol_id = id,
+		.message_id = SCMI_PROTOCOL_VERSION,
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	*version = out.version;
+
+	return 0;
+}
+
+/**
+ * scmi_base_protocol_version_int - get Base protocol version
+ * @dev:	SCMI device
+ * @version:	Pointer to SCMI protocol version
+ *
+ * Obtain the protocol version number in @version for Base protocol.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_protocol_version_int(struct udevice *dev, u32 *version)
+{
+	return scmi_generic_protocol_version(dev, SCMI_PROTOCOL_ID_BASE,
+					     version);
+}
+
+/**
+ * scmi_protocol_attrs_int - get protocol attributes
+ * @dev:		SCMI device
+ * @num_agents:		Number of SCMI agents
+ * @num_protocols:	Number of SCMI protocols
+ *
+ * Obtain the protocol attributes, the number of agents and the number
+ * of protocols, in @num_agents and @num_protocols respectively, that
+ * the device provides.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_protocol_attrs_int(struct udevice *dev, u32 *num_agents,
+				   u32 *num_protocols)
+{
+	struct scmi_protocol_attrs_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_PROTOCOL_ATTRIBUTES,
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	*num_agents = SCMI_PROTOCOL_ATTRS_NUM_AGENTS(out.attributes);
+	*num_protocols = SCMI_PROTOCOL_ATTRS_NUM_PROTOCOLS(out.attributes);
+
+	return 0;
+}
+
+/**
+ * scmi_protocol_message_attrs_int - get message-specific attributes
+ * @dev:		SCMI device
+ * @message_id:		SCMI message ID
+ * @attributes:		Message-specific attributes
+ *
+ * Obtain the message-specific attributes in @attributes.
+ * This command succeeds if the message is implemented and available.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_protocol_message_attrs_int(struct udevice *dev, u32 message_id,
+					   u32 *attributes)
+{
+	struct scmi_protocol_msg_attrs_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_PROTOCOL_MESSAGE_ATTRIBUTES,
+		.in_msg = (u8 *)&message_id,
+		.in_msg_sz = sizeof(message_id),
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	*attributes = out.attributes;
+
+	return 0;
+}
+
+/**
+ * scmi_base_discover_vendor_int - get vendor name
+ * @dev:	SCMI device
+ * @vendor:	Pointer to vendor name
+ *
+ * Obtain the vendor's name in @vendor.
+ * It is a caller's responsibility to free @vendor.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_discover_vendor_int(struct udevice *dev, u8 **vendor)
+{
+	struct scmi_base_discover_vendor_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_DISCOVER_VENDOR,
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	if (!vendor)
+		return -EINVAL;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	*vendor = strdup(out.vendor_identifier);
+	if (!*vendor)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * scmi_base_discover_sub_vendor_int - get sub-vendor name
+ * @dev:	SCMI device
+ * @sub_vendor:	Pointer to sub-vendor name
+ *
+ * Obtain the sub-vendor's name in @sub_vendor.
+ * It is a caller's responsibility to free @sub_vendor.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_discover_sub_vendor_int(struct udevice *dev,
+					     u8 **sub_vendor)
+{
+	struct scmi_base_discover_vendor_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_DISCOVER_SUB_VENDOR,
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	if (!sub_vendor)
+		return -EINVAL;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	*sub_vendor = strdup(out.vendor_identifier);
+	if (!*sub_vendor)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * scmi_base_discover_impl_version_int - get implementation version
+ * @dev:		SCMI device
+ * @impl_version:	Pointer to implementation version
+ *
+ * Obtain the implementation version number in @impl_version.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_discover_impl_version_int(struct udevice *dev,
+					       u32 *impl_version)
+{
+	struct scmi_base_discover_impl_version_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_DISCOVER_IMPL_VERSION,
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	*impl_version = out.impl_version;
+
+	return 0;
+}
+
+/**
+ * scmi_base_discover_list_protocols_int - get list of protocols
+ * @dev:	SCMI device
+ * @protocols:	Pointer to array of SCMI protocols
+ *
+ * Obtain the list of protocols provided in @protocols.
+ * The number of elements in @protocols always match to the number of
+ * protocols returned by smci_protocol_attrs() when this function succeeds.
+ * It is a caller's responsibility to free @protocols.
+ *
+ * Return: the number of protocols in @protocols on success, error code on
+ * failure
+ */
+static int scmi_base_discover_list_protocols_int(struct udevice *dev,
+						 u8 **protocols)
+{
+	struct scmi_base_discover_list_protocols_out out;
+	int cur;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_DISCOVER_LIST_PROTOCOLS,
+		.in_msg = (u8 *)&cur,
+		.in_msg_sz = sizeof(cur),
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	u32 num_agents, num_protocols;
+	u8 *buf;
+	int i, ret;
+
+	ret = scmi_base_protocol_attrs(dev, &num_agents, &num_protocols);
+	if (ret)
+		return ret;
+
+	buf = calloc(sizeof(u8), num_protocols);
+	if (!buf)
+		return -ENOMEM;
+
+	cur = 0;
+	do {
+		ret = devm_scmi_process_msg(dev, &msg);
+		if (ret)
+			goto err;
+		if (out.status) {
+			ret = scmi_to_linux_errno(out.status);
+			goto err;
+		}
+
+		for (i = 0; i < out.num_protocols; i++, cur++)
+			buf[cur] = out.protocols[i / 4] >> ((i % 4) * 8);
+	} while (cur < num_protocols);
+
+	*protocols = buf;
+
+	return num_protocols;
+err:
+	free(buf);
+
+	return ret;
+}
+
+/**
+ * scmi_base_discover_agent_int - identify agent
+ * @dev:		SCMI device
+ * @agent_id:		SCMI agent ID
+ * @ret_agent_id:	Pointer to SCMI agent ID
+ * @name:		Pointer to SCMI agent name
+ *
+ * Obtain the agent's name in @name. If @agent_id is equal to 0xffffffff,
+ * this function returns the caller's agent id in @ret_agent_id.
+ * It is a caller's responsibility to free @name.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_discover_agent_int(struct udevice *dev, u32 agent_id,
+					u32 *ret_agent_id, u8 **name)
+{
+	struct scmi_base_discover_agent_out out;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_DISCOVER_AGENT,
+		.in_msg = (u8 *)&agent_id,
+		.in_msg_sz = sizeof(agent_id),
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (out.status)
+		return scmi_to_linux_errno(out.status);
+
+	if (ret_agent_id)
+		*ret_agent_id = out.agent_id;
+	if (name) {
+		*name = strdup(out.name);
+		if (!*name)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * scmi_base_set_device_permissions_int - configure access permission to device
+ * @dev:	SCMI device
+ * @agent_id:	SCMI agent ID
+ * @device_id:	ID of device to access
+ * @flags:	A set of flags
+ *
+ * Ask for allowing or denying access permission to the device, @device_id.
+ * The meaning of @flags is defined in SCMI specification.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_set_device_permissions_int(struct udevice *dev, u32 agent_id,
+						u32 device_id, u32 flags)
+{
+	struct scmi_base_set_device_permissions_in in = {
+		.agent_id = agent_id,
+		.device_id = device_id,
+		.flags = flags,
+	};
+	s32 status;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_SET_DEVICE_PERMISSIONS,
+		.in_msg = (u8 *)&in,
+		.in_msg_sz = sizeof(in),
+		.out_msg = (u8 *)&status,
+		.out_msg_sz = sizeof(status),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (status)
+		return scmi_to_linux_errno(status);
+
+	return 0;
+}
+
+/**
+ * scmi_base_set_protocol_permissions_int - configure access permission to
+ *					    protocol on device
+ * @dev:	SCMI device
+ * @agent_id:	SCMI agent ID
+ * @device_id:	ID of device to access
+ * @command_id:	SCMI command ID
+ * @flags:	A set of flags
+ *
+ * Ask for allowing or denying access permission to the protocol, @command_id,
+ * on the device, @device_id.
+ * The meaning of @flags is defined in SCMI specification.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_set_protocol_permissions_int(struct udevice *dev,
+						  u32 agent_id, u32 device_id,
+						  u32 command_id, u32 flags)
+{
+	struct scmi_base_set_protocol_permissions_in in = {
+		.agent_id = agent_id,
+		.device_id = device_id,
+		.command_id = command_id,
+		.flags = flags,
+	};
+	s32 status;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_SET_PROTOCOL_PERMISSIONS,
+		.in_msg = (u8 *)&in,
+		.in_msg_sz = sizeof(in),
+		.out_msg = (u8 *)&status,
+		.out_msg_sz = sizeof(status),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (status)
+		return scmi_to_linux_errno(status);
+
+	return 0;
+}
+
+/**
+ * scmi_base_reset_agent_configuration_int - reset resource settings
+ * @dev:	SCMI device
+ * @agent_id:	SCMI agent ID
+ * @flags:	A set of flags
+ *
+ * Reset all the resource settings against @agent_id.
+ * The meaning of @flags is defined in SCMI specification.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_reset_agent_configuration_int(struct udevice *dev,
+						   u32 agent_id, u32 flags)
+{
+	struct scmi_base_reset_agent_configuration_in in = {
+		.agent_id = agent_id,
+		.flags = flags,
+	};
+	s32 status;
+	struct scmi_msg msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_BASE,
+		.message_id = SCMI_BASE_RESET_AGENT_CONFIGURATION,
+		.in_msg = (u8 *)&in,
+		.in_msg_sz = sizeof(in),
+		.out_msg = (u8 *)&status,
+		.out_msg_sz = sizeof(status),
+	};
+	int ret;
+
+	ret = devm_scmi_process_msg(dev, &msg);
+	if (ret)
+		return ret;
+	if (status)
+		return scmi_to_linux_errno(status);
+
+	return 0;
+}
+
+/**
+ * scmi_base_probe - probe base protocol device
+ * @dev:	SCMI device
+ *
+ * Probe the device for SCMI base protocol and initialize the private data.
+ *
+ * Return: 0 on success, error code on failure
+ */
+static int scmi_base_probe(struct udevice *dev)
+{
+	int ret;
+
+	ret = devm_scmi_of_get_channel(dev);
+	if (ret) {
+		dev_err(dev, "get_channel failed\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+static struct scmi_base_ops scmi_base_ops = {
+	/* Commands */
+	.protocol_version = scmi_base_protocol_version_int,
+	.protocol_attrs = scmi_protocol_attrs_int,
+	.protocol_message_attrs = scmi_protocol_message_attrs_int,
+	.base_discover_vendor = scmi_base_discover_vendor_int,
+	.base_discover_sub_vendor = scmi_base_discover_sub_vendor_int,
+	.base_discover_impl_version = scmi_base_discover_impl_version_int,
+	.base_discover_list_protocols = scmi_base_discover_list_protocols_int,
+	.base_discover_agent = scmi_base_discover_agent_int,
+	.base_notify_errors = NULL,
+	.base_set_device_permissions = scmi_base_set_device_permissions_int,
+	.base_set_protocol_permissions = scmi_base_set_protocol_permissions_int,
+	.base_reset_agent_configuration =
+			scmi_base_reset_agent_configuration_int,
+};
+
+int scmi_base_protocol_version(struct udevice *dev, u32 *version)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->protocol_version)
+		return (*ops->protocol_version)(dev, version);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_protocol_attrs(struct udevice *dev, u32 *num_agents,
+			     u32 *num_protocols)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->protocol_attrs)
+		return (*ops->protocol_attrs)(dev, num_agents, num_protocols);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_protocol_message_attrs(struct udevice *dev, u32 message_id,
+				     u32 *attributes)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->protocol_message_attrs)
+		return (*ops->protocol_message_attrs)(dev, message_id,
+						      attributes);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_discover_vendor(struct udevice *dev, u8 **vendor)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_discover_vendor)
+		return (*ops->base_discover_vendor)(dev, vendor);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_discover_sub_vendor(struct udevice *dev, u8 **sub_vendor)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_discover_sub_vendor)
+		return (*ops->base_discover_sub_vendor)(dev, sub_vendor);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_discover_impl_version(struct udevice *dev, u32 *impl_version)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_discover_impl_version)
+		return (*ops->base_discover_impl_version)(dev, impl_version);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_discover_list_protocols(struct udevice *dev, u8 **protocols)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_discover_list_protocols)
+		return (*ops->base_discover_list_protocols)(dev, protocols);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_discover_agent(struct udevice *dev, u32 agent_id,
+			     u32 *ret_agent_id, u8 **name)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_discover_agent)
+		return (*ops->base_discover_agent)(dev, agent_id, ret_agent_id,
+						   name);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_notify_errors(struct udevice *dev, u32 enable)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_notify_errors)
+		return (*ops->base_notify_errors)(dev, enable);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_set_device_permissions(struct udevice *dev, u32 agent_id,
+				     u32 device_id, u32 flags)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_set_device_permissions)
+		return (*ops->base_set_device_permissions)(dev, agent_id,
+							   device_id, flags);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_set_protocol_permissions(struct udevice *dev,
+				       u32 agent_id, u32 device_id,
+				       u32 command_id, u32 flags)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_set_protocol_permissions)
+		return (*ops->base_set_protocol_permissions)(dev, agent_id,
+							     device_id,
+							     command_id,
+							     flags);
+
+	return -EOPNOTSUPP;
+}
+
+int scmi_base_reset_agent_configuration(struct udevice *dev, u32 agent_id,
+					u32 flags)
+{
+	const struct scmi_base_ops *ops = device_get_ops(dev);
+
+	if (ops->base_reset_agent_configuration)
+		return (*ops->base_reset_agent_configuration)(dev, agent_id,
+							      flags);
+
+	return -EOPNOTSUPP;
+}
+
+U_BOOT_DRIVER(scmi_base_drv) = {
+	.id = UCLASS_SCMI_BASE,
+	.name = "scmi_base_drv",
+	.ops = &scmi_base_ops,
+	.probe = scmi_base_probe,
+};
+
+UCLASS_DRIVER(scmi_base) = {
+	.id		= UCLASS_SCMI_BASE,
+	.name		= "scmi_base",
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 0432c95..ab31580 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -123,6 +123,7 @@
 	UCLASS_RNG,		/* Random Number Generator */
 	UCLASS_RTC,		/* Real time clock device */
 	UCLASS_SCMI_AGENT,	/* Interface with an SCMI server */
+	UCLASS_SCMI_BASE,	/* Interface for SCMI Base protocol */
 	UCLASS_SCSI,		/* SCSI device */
 	UCLASS_SERIAL,		/* Serial UART */
 	UCLASS_SIMPLE_BUS,	/* Bus with child devices */
diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
index a220cb2..163647a 100644
--- a/include/scmi_protocols.h
+++ b/include/scmi_protocols.h
@@ -50,6 +50,501 @@
 };
 
 /*
+ * SCMI Base Protocol
+ */
+#define SCMI_BASE_PROTOCOL_VERSION 0x20000
+
+enum scmi_base_message_id {
+	SCMI_BASE_DISCOVER_VENDOR = 0x3,
+	SCMI_BASE_DISCOVER_SUB_VENDOR = 0x4,
+	SCMI_BASE_DISCOVER_IMPL_VERSION = 0x5,
+	SCMI_BASE_DISCOVER_LIST_PROTOCOLS = 0x6,
+	SCMI_BASE_DISCOVER_AGENT = 0x7,
+	SCMI_BASE_NOTIFY_ERRORS = 0x8,
+	SCMI_BASE_SET_DEVICE_PERMISSIONS = 0x9,
+	SCMI_BASE_SET_PROTOCOL_PERMISSIONS = 0xa,
+	SCMI_BASE_RESET_AGENT_CONFIGURATION = 0xb,
+};
+
+#define SCMI_BASE_NAME_LENGTH_MAX 16
+
+/**
+ * struct scmi_protocol_version_out - Response for SCMI_PROTOCOL_VERSION
+ *					command
+ * @status:	SCMI command status
+ * @version:	Protocol version
+ */
+struct scmi_protocol_version_out {
+	s32 status;
+	u32 version;
+};
+
+/**
+ * struct scmi_protocol_attrs_out - Response for SCMI_PROTOCOL_ATTRIBUTES
+ *					command
+ * @status:	SCMI command status
+ * @attributes:	Protocol attributes or implementation details
+ */
+struct scmi_protocol_attrs_out {
+	s32 status;
+	u32 attributes;
+};
+
+#define SCMI_PROTOCOL_ATTRS_NUM_AGENTS(attributes) \
+				(((attributes) & GENMASK(15, 8)) >> 8)
+#define SCMI_PROTOCOL_ATTRS_NUM_PROTOCOLS(attributes) \
+				((attributes) & GENMASK(7, 0))
+
+/**
+ * struct scmi_protocol_msg_attrs_out - Response for
+ *					SCMI_PROTOCOL_MESSAGE_ATTRIBUTES command
+ * @status:	SCMI command status
+ * @attributes:	Message-specific attributes
+ */
+struct scmi_protocol_msg_attrs_out {
+	s32 status;
+	u32 attributes;
+};
+
+/**
+ * struct scmi_base_discover_vendor_out - Response for
+ *					  SCMI_BASE_DISCOVER_VENDOR or
+ *					  SCMI_BASE_DISCOVER_SUB_VENDOR command
+ * @status:		SCMI command status
+ * @vendor_identifier:	Name of vendor or sub-vendor in string
+ */
+struct scmi_base_discover_vendor_out {
+	s32 status;
+	u8 vendor_identifier[SCMI_BASE_NAME_LENGTH_MAX];
+};
+
+/**
+ * struct scmi_base_discover_impl_version_out - Response for
+ *					SCMI_BASE_DISCOVER_IMPL_VERSION command
+ * @status:		SCMI command status
+ * @impl_version:	Vendor-specific implementation version
+ */
+struct scmi_base_discover_impl_version_out {
+	s32 status;
+	u32 impl_version;
+};
+
+/**
+ * struct scmi_base_discover_list_protocols_out - Response for
+ *				SCMI_BASE_DISCOVER_LIST_PROTOCOLS command
+ * @status:		SCMI command status
+ * @num_protocols:	Number of SCMI protocols in @protocol
+ * @protocols:		Array of packed SCMI protocol ID's
+ */
+struct scmi_base_discover_list_protocols_out {
+	s32 status;
+	u32 num_protocols;
+	u32 protocols[3];
+};
+
+/**
+ * struct scmi_base_discover_agent_out - Response for
+ *					 SCMI_BASE_DISCOVER_AGENT command
+ * @status:	SCMI command status
+ * @agent_id:	SCMI agent ID
+ * @name:	Name of agent in string
+ */
+struct scmi_base_discover_agent_out {
+	s32 status;
+	u32 agent_id;
+	u8 name[SCMI_BASE_NAME_LENGTH_MAX];
+};
+
+#define SCMI_BASE_NOTIFY_ERRORS_ENABLE BIT(0)
+
+/**
+ * struct scmi_base_set_device_permissions_in - Parameters for
+ *					SCMI_BASE_SET_DEVICE_PERMISSIONS command
+ * @agent_id:	SCMI agent ID
+ * @device_id:	device ID
+ * @flags:	A set of flags
+ */
+struct scmi_base_set_device_permissions_in {
+	u32 agent_id;
+	u32 device_id;
+	u32 flags;
+};
+
+#define SCMI_BASE_SET_DEVICE_PERMISSIONS_ACCESS BIT(0)
+
+/**
+ * struct scmi_base_set_protocol_permissions_in - Parameters for
+ *				SCMI_BASE_SET_PROTOCOL_PERMISSIONS command
+ * @agent_id:		SCMI agent ID
+ * @device_id:		device ID
+ * @command_id:		command ID
+ * @flags:		A set of flags
+ */
+struct scmi_base_set_protocol_permissions_in {
+	u32 agent_id;
+	u32 device_id;
+	u32 command_id;
+	u32 flags;
+};
+
+#define SCMI_BASE_SET_PROTOCOL_PERMISSIONS_COMMAND GENMASK(7, 0)
+#define SCMI_BASE_SET_PROTOCOL_PERMISSIONS_ACCESS BIT(0)
+
+/**
+ * struct scmi_base_reset_agent_configuration_in - Parameters for
+ *				SCMI_BASE_RESET_AGENT_CONFIGURATION command
+ * @agent_id:	SCMI agent ID
+ * @flags:	A set of flags
+ */
+struct scmi_base_reset_agent_configuration_in {
+	u32 agent_id;
+	u32 flags;
+};
+
+#define SCMI_BASE_RESET_ALL_ACCESS_PERMISSIONS BIT(0)
+
+/**
+ * struct scmi_base_ops - SCMI base protocol interfaces
+ */
+struct scmi_base_ops {
+	/**
+	 * protocol_version - get Base protocol version
+	 * @dev:	SCMI protocol device
+	 * @version:	Pointer to SCMI protocol version
+	 *
+	 * Obtain the protocol version number in @version for Base protocol.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*protocol_version)(struct udevice *dev, u32 *version);
+	/**
+	 * protocol_attrs - get protocol attributes
+	 * @dev:		SCMI protocol device
+	 * @num_agents:		Number of SCMI agents
+	 * @num_protocols:	Number of SCMI protocols
+	 *
+	 * Obtain the protocol attributes, the number of agents and the number
+	 * of protocols, in @num_agents and @num_protocols respectively, that
+	 * the device provides.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*protocol_attrs)(struct udevice *dev, u32 *num_agents,
+			      u32 *num_protocols);
+	/**
+	 * protocol_message_attrs - get message-specific attributes
+	 * @dev:		SCMI protocol device
+	 * @message_id:		SCMI message ID
+	 * @attributes:		Message-specific attributes
+	 *
+	 * Obtain the message-specific attributes in @attributes.
+	 * This command succeeds if the message is implemented and available.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*protocol_message_attrs)(struct udevice *dev, u32 message_id,
+				      u32 *attributes);
+	/**
+	 * base_discover_vendor - get vendor name
+	 * @dev:	SCMI protocol device
+	 * @vendor:	Pointer to vendor name
+	 *
+	 * Obtain the vendor's name in @vendor.
+	 * It is a caller's responsibility to free @vendor.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_discover_vendor)(struct udevice *dev, u8 **vendor);
+	/**
+	 * base_discover_sub_vendor - get sub-vendor name
+	 * @dev:	SCMI protocol device
+	 * @sub_vendor:	Pointer to sub-vendor name
+	 *
+	 * Obtain the sub-vendor's name in @sub_vendor.
+	 * It is a caller's responsibility to free @sub_vendor.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_discover_sub_vendor)(struct udevice *dev, u8 **sub_vendor);
+	/**
+	 * base_discover_impl_version - get implementation version
+	 * @dev:		SCMI protocol device
+	 * @impl_version:	Pointer to implementation version
+	 *
+	 * Obtain the implementation version number in @impl_version.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_discover_impl_version)(struct udevice *dev,
+					  u32 *impl_version);
+	/**
+	 * base_discover_list_protocols - get list of protocols
+	 * @dev:	SCMI protocol device
+	 * @protocols:	Pointer to array of SCMI protocols
+	 *
+	 * Obtain the list of protocols provided in @protocols.
+	 * The number of elements in @protocols always match to the number of
+	 * protocols returned by smci_protocol_attrs() when this function
+	 * succeeds.
+	 * It is a caller's responsibility to free @protocols.
+	 *
+	 * Return: the number of protocols in @protocols on success,
+	 * error code on failure
+	 */
+	int (*base_discover_list_protocols)(struct udevice *dev,
+					    u8 **protocols);
+	/**
+	 * base_discover_agent - identify agent
+	 * @dev:		SCMI protocol device
+	 * @agent_id:		SCMI agent ID
+	 * @ret_agent_id:	Pointer to SCMI agent ID
+	 * @name:		Pointer to SCMI agent name
+	 *
+	 * Obtain the agent's name in @name. If @agent_id is equal to
+	 * 0xffffffff, * this function returns the caller's agent id in
+	 * @ret_agent_id.
+	 * It is a caller's responsibility to free @name.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_discover_agent)(struct udevice *dev, u32 agent_id,
+				   u32 *ret_agent_id, u8 **name);
+	/**
+	 * base_notify_errors - configure error notification
+	 * @dev:	SCMI protocol device
+	 * @enable:	Operation
+	 *
+	 * Enable or disable error notification from SCMI firmware.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_notify_errors)(struct udevice *dev, u32 enable);
+	/**
+	 * base_set_device_permissions - configure access permission to device
+	 * @dev:	SCMI protocol device
+	 * @agent_id:	SCMI agent ID
+	 * @device_id:	ID of device to access
+	 * @flags:	A set of flags
+	 *
+	 * Ask for allowing or denying access permission to the device,
+	 * @device_id. The meaning of @flags is defined in SCMI specification.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_set_device_permissions)(struct udevice *dev, u32 agent_id,
+					   u32 device_id, u32 flags);
+	/**
+	 * base_set_protocol_permissions - configure access permission to
+	 *				   protocol on device
+	 * @dev:	SCMI protocol device
+	 * @agent_id:	SCMI agent ID
+	 * @device_id:	ID of device to access
+	 * @command_id:	command ID
+	 * @flags:	A set of flags
+	 *
+	 * Ask for allowing or denying access permission to the protocol,
+	 * @command_id, on the device, @device_id.
+	 * The meaning of @flags is defined in SCMI specification.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_set_protocol_permissions)(struct udevice *dev, u32 agent_id,
+					     u32 device_id, u32 command_id,
+					     u32 flags);
+	/**
+	 * base_reset_agent_configuration - reset resource settings
+	 * @dev:	SCMI protocol device
+	 * @agent_id:	SCMI agent ID
+	 * @flags:	A set of flags
+	 *
+	 * Reset all the resource settings against @agent_id.
+	 * The meaning of @flags is defined in SCMI specification.
+	 *
+	 * Return: 0 on success, error code on failure
+	 */
+	int (*base_reset_agent_configuration)(struct udevice *dev, u32 agent_id,
+					      u32 flags);
+};
+
+/**
+ * scmi_generic_protocol_version - get protocol version
+ * @dev:	SCMI protocol device
+ * @id:		SCMI protocol ID
+ * @version:	Pointer to SCMI protocol version
+ *
+ * Obtain the protocol version number in @version.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_generic_protocol_version(struct udevice *dev,
+				  enum scmi_std_protocol id, u32 *version);
+
+/**
+ * scmi_base_protocol_version - get Base protocol version
+ * @dev:	SCMI protocol device
+ * @version:	Pointer to SCMI protocol version
+ *
+ * Obtain the protocol version number in @version for Base protocol.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_protocol_version(struct udevice *dev, u32 *version);
+
+/**
+ * scmi_protocol_attrs - get protocol attributes
+ * @dev:		SCMI protocol device
+ * @num_agents:		Number of SCMI agents
+ * @num_protocols:	Number of SCMI protocols
+ *
+ * Obtain the protocol attributes, the number of agents and the number
+ * of protocols, in @num_agents and @num_protocols respectively, that
+ * the device provides.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_protocol_attrs(struct udevice *dev, u32 *num_agents,
+			     u32 *num_protocols);
+
+/**
+ * scmi_protocol_message_attrs - get message-specific attributes
+ * @dev:		SCMI protocol device
+ * @message_id:		SCMI message ID
+ * @attributes:		Message-specific attributes
+ *
+ * Obtain the message-specific attributes in @attributes.
+ * This command succeeds if the message is implemented and available.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_protocol_message_attrs(struct udevice *dev, u32 message_id,
+				     u32 *attributes);
+
+/**
+ * scmi_base_discover_vendor - get vendor name
+ * @dev:	SCMI protocol device
+ * @vendor:	Pointer to vendor name
+ *
+ * Obtain the vendor's name in @vendor.
+ * It is a caller's responsibility to free @vendor.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_discover_vendor(struct udevice *dev, u8 **vendor);
+
+/**
+ * scmi_base_discover_sub_vendor - get sub-vendor name
+ * @dev:	SCMI protocol device
+ * @sub_vendor:	Pointer to sub-vendor name
+ *
+ * Obtain the sub-vendor's name in @sub_vendor.
+ * It is a caller's responsibility to free @sub_vendor.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_discover_sub_vendor(struct udevice *dev, u8 **sub_vendor);
+
+/**
+ * scmi_base_discover_impl_version - get implementation version
+ * @dev:		SCMI protocol device
+ * @impl_version:	Pointer to implementation version
+ *
+ * Obtain the implementation version number in @impl_version.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_discover_impl_version(struct udevice *dev, u32 *impl_version);
+
+/**
+ * scmi_base_discover_list_protocols - get list of protocols
+ * @dev:	SCMI protocol device
+ * @protocols:	Pointer to array of SCMI protocols
+ *
+ * Obtain the list of protocols provided in @protocols.
+ * The number of elements in @protocols always match to the number of
+ * protocols returned by smci_protocol_attrs() when this function succeeds.
+ * It is a caller's responsibility to free @protocols.
+ *
+ * Return: the number of protocols in @protocols on success, error code on
+ * failure
+ */
+int scmi_base_discover_list_protocols(struct udevice *dev, u8 **protocols);
+
+/**
+ * scmi_base_discover_agent - identify agent
+ * @dev:		SCMI protocol device
+ * @agent_id:		SCMI agent ID
+ * @ret_agent_id:	Pointer to SCMI agent ID
+ * @name:		Pointer to SCMI agent name
+ *
+ * Obtain the agent's name in @name. If @agent_id is equal to 0xffffffff,
+ * this function returns the caller's agent id in @ret_agent_id.
+ * It is a caller's responsibility to free @name.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_discover_agent(struct udevice *dev, u32 agent_id,
+			     u32 *ret_agent_id, u8 **name);
+
+/**
+ * scmi_base_notify_errors - configure error notification
+ * @dev:	SCMI protocol device
+ * @enable:	Operation
+ *
+ * Enable or disable error notification from SCMI firmware.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_notify_errors(struct udevice *dev, u32 enable);
+
+/**
+ * scmi_base_set_device_permissions - configure access permission to device
+ * @dev:	SCMI protocol device
+ * @agent_id:	SCMI agent ID
+ * @device_id:	ID of device to access
+ * @flags:	A set of flags
+ *
+ * Ask for allowing or denying access permission to the device, @device_id.
+ * The meaning of @flags is defined in SCMI specification.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_set_device_permissions(struct udevice *dev, u32 agent_id,
+				     u32 device_id, u32 flags);
+
+/**
+ * scmi_base_set_protocol_permissions - configure access permission to
+ *					protocol on device
+ * @dev:	SCMI protocol device
+ * @agent_id:	SCMI agent ID
+ * @device_id:	ID of device to access
+ * @command_id:	SCMI command ID
+ * @flags:	A set of flags
+ *
+ * Ask for allowing or denying access permission to the protocol, @command_id,
+ * on the device, @device_id.
+ * The meaning of @flags is defined in SCMI specification.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_set_protocol_permissions(struct udevice *dev,
+				       u32 agent_id, u32 device_id,
+				       u32 command_id, u32 flags);
+
+/**
+ * scmi_base_reset_agent_configuration - reset resource settings
+ * @dev:	SCMI protocol device
+ * @agent_id:	SCMI agent ID
+ * @flags:	A set of flags
+ *
+ * Reset all the resource settings against @agent_id.
+ * The meaning of @flags is defined in SCMI specification.
+ *
+ * Return: 0 on success, error code on failure
+ */
+int scmi_base_reset_agent_configuration(struct udevice *dev, u32 agent_id,
+					u32 flags);
+
+/*
  * SCMI Clock Protocol
  */