/*
 * Copyright 2019 The Hafnium Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include "hf/types.h"

/* clang-format off */

#define SPCI_LOW_32_ID  0x84000060
#define SPCI_HIGH_32_ID 0x8400007F
#define SPCI_LOW_64_ID  0xC4000060
#define SPCI_HIGH_32_ID 0x8400007F

/* SPCI function identifiers. */
#define SPCI_ERROR_32                 0x84000060
#define SPCI_SUCCESS_32               0x84000061
#define SPCI_INTERRUPT_32             0x84000062
#define SPCI_VERSION_32               0x84000063
#define SPCI_FEATURES_32              0x84000064
#define SPCI_RX_RELEASE_32            0x84000065
#define SPCI_RXTX_MAP_32              0x84000066
#define SPCI_RXTX_UNMAP_32            0x84000067
#define SPCI_PARTITION_INFO_GET_32    0x84000068
#define SPCI_ID_GET_32                0x84000069
#define SPCI_MSG_POLL_32              0x8400006A
#define SPCI_MSG_WAIT_32              0x8400006B
#define SPCI_YIELD_32                 0x8400006C
#define SPCI_RUN_32                   0x8400006D
#define SPCI_MSG_SEND_32              0x8400006E
#define SPCI_MSG_SEND_DIRECT_REQ_32   0x8400006F
#define SPCI_MSG_SEND_DIRECT_RESP_32  0x84000070

/* SPCI error codes. */
#define SPCI_NOT_SUPPORTED      INT32_C(-1)
#define SPCI_INVALID_PARAMETERS INT32_C(-2)
#define SPCI_NO_MEMORY          INT32_C(-3)
#define SPCI_BUSY               INT32_C(-4)
#define SPCI_INTERRUPTED        INT32_C(-5)
#define SPCI_DENIED             INT32_C(-6)
#define SPCI_RETRY              INT32_C(-7)

/* Architected memory sharing message IDs. */
enum spci_memory_share {
	SPCI_MEMORY_LEND = 0x0,
	SPCI_MEMORY_RELINQUISH = 0x1,
	SPCI_MEMORY_DONATE = 0x2,
};

/* SPCI function specific constants. */
#define SPCI_MSG_RECV_BLOCK  0x1
#define SPCI_MSG_RECV_BLOCK_MASK  0x1

#define SPCI_MSG_SEND_NOTIFY 0x1
#define SPCI_MSG_SEND_NOTIFY_MASK 0x1
#define SPCI_MSG_SEND_LEGACY_MEMORY      0x2
#define SPCI_MSG_SEND_LEGACY_MEMORY_MASK 0x2

/* The maximum length possible for a single message. */
#define SPCI_MSG_PAYLOAD_MAX HF_MAILBOX_SIZE

enum spci_memory_access {
	SPCI_MEMORY_RO_NX,
	SPCI_MEMORY_RO_X,
	SPCI_MEMORY_RW_NX,
	SPCI_MEMORY_RW_X,
};

enum spci_memory_type {
	SPCI_MEMORY_DEVICE_MEM,
	SPCI_MEMORY_NORMAL_MEM,
};

enum spci_memory_cacheability {
	SPCI_MEMORY_CACHE_RESERVED = 0x0,
	SPCI_MEMORY_CACHE_NON_CACHEABLE = 0x1,
	SPCI_MEMORY_CACHE_WRITE_THROUGH = 0x2,
	SPCI_MEMORY_CACHE_WRITE_BACK = 0x4,
	SPCI_MEMORY_DEV_NGNRNE = 0x0,
	SPCI_MEMORY_DEV_NGNRE = 0x1,
	SPCI_MEMORY_DEV_NGRE = 0x2,
	SPCI_MEMORY_DEV_GRE = 0x3,
};

enum spci_memory_shareability {
	SPCI_MEMORY_SHARE_NON_SHAREABLE,
	SPCI_MEMORY_RESERVED,
	SPCI_MEMORY_OUTER_SHAREABLE,
	SPCI_MEMORY_INNER_SHAREABLE,
};

#define SPCI_MEMORY_ACCESS_OFFSET (0x5U)
#define SPCI_MEMORY_ACCESS_MASK ((0x3U) << SPCI_MEMORY_ACCESS_OFFSET)

#define SPCI_MEMORY_TYPE_OFFSET (0x4U)
#define SPCI_MEMORY_TYPE_MASK ((0x1U) << SPCI_MEMORY_TYPE_OFFSET)

#define SPCI_MEMORY_CACHEABILITY_OFFSET (0x2U)
#define SPCI_MEMORY_CACHEABILITY_MASK ((0x3U) <<\
	SPCI_MEMORY_CACHEABILITY_OFFSET)

#define SPCI_MEMORY_SHAREABILITY_OFFSET (0x0U)
#define SPCI_MEMORY_SHAREABILITY_MASK ((0x3U) <<\
	SPCI_MEMORY_SHAREABILITY_OFFSET)

#define LEND_ATTR_FUNCTION_SET(name, offset, mask) \
static inline void spci_set_memory_##name##_attr(uint16_t *attr,\
	const enum spci_memory_##name perm)\
{\
	*attr = (*attr & ~(mask)) | ((perm  << offset) & mask);\
}

#define LEND_ATTR_FUNCTION_GET(name, offset, mask) \
static inline enum spci_memory_##name spci_get_memory_##name##_attr(\
	uint16_t attr)\
{\
	return (enum spci_memory_##name)((attr & mask) >> offset);\
}

LEND_ATTR_FUNCTION_SET(access, SPCI_MEMORY_ACCESS_OFFSET,
	SPCI_MEMORY_ACCESS_MASK)
LEND_ATTR_FUNCTION_GET(access, SPCI_MEMORY_ACCESS_OFFSET,
	SPCI_MEMORY_ACCESS_MASK)

LEND_ATTR_FUNCTION_SET(type, SPCI_MEMORY_TYPE_OFFSET, SPCI_MEMORY_TYPE_MASK)
LEND_ATTR_FUNCTION_GET(type, SPCI_MEMORY_TYPE_OFFSET, SPCI_MEMORY_TYPE_MASK)

LEND_ATTR_FUNCTION_SET(cacheability, SPCI_MEMORY_CACHEABILITY_OFFSET,
	SPCI_MEMORY_CACHEABILITY_MASK)

LEND_ATTR_FUNCTION_GET(cacheability, SPCI_MEMORY_CACHEABILITY_OFFSET,
	SPCI_MEMORY_CACHEABILITY_MASK)

LEND_ATTR_FUNCTION_SET(shareability, SPCI_MEMORY_SHAREABILITY_OFFSET,
	SPCI_MEMORY_SHAREABILITY_MASK)

LEND_ATTR_FUNCTION_GET(shareability, SPCI_MEMORY_SHAREABILITY_OFFSET,
	SPCI_MEMORY_SHAREABILITY_MASK)

/* clang-format on */

/** The ID of a VM. These are assigned sequentially starting with an offset. */
typedef uint16_t spci_vm_id_t;
typedef uint32_t spci_memory_handle_t;

/**
 * A count of VMs. This has the same range as the VM IDs but we give it a
 * different name to make the different semantics clear.
 */
typedef spci_vm_id_t spci_vm_count_t;

/** The index of a vCPU within a particular VM. */
typedef uint16_t spci_vcpu_index_t;

/**
 * A count of vCPUs. This has the same range as the vCPU indices but we give it
 * a different name to make the different semantics clear.
 */
typedef spci_vcpu_index_t spci_vcpu_count_t;

/** Parameter and return type of SPCI functions. */
struct spci_value {
	uint64_t func;
	uint64_t arg1;
	uint64_t arg2;
	uint64_t arg3;
	uint64_t arg4;
	uint64_t arg5;
	uint64_t arg6;
	uint64_t arg7;
};

static inline spci_vm_id_t spci_msg_send_sender(struct spci_value args)
{
	return (args.arg1 >> 16) & 0xffff;
}

static inline spci_vm_id_t spci_msg_send_receiver(struct spci_value args)
{
	return args.arg1 & 0xffff;
}

static inline uint32_t spci_msg_send_size(struct spci_value args)
{
	return args.arg3;
}

static inline uint32_t spci_msg_send_attributes(struct spci_value args)
{
	return args.arg4;
}

struct spci_architected_message_header {
	uint16_t type;

	/*
	 * TODO: Padding is present to ensure that the field
	 * payload is aligned on a 64B boundary. SPCI
	 * spec must be updated to reflect this.
	 */
	uint16_t reserved[3];
	uint8_t payload[];
};

struct spci_memory_region_constituent {
	/**
	 * The base IPA of the constituent memory region, aligned to 4 kiB page
	 * size granularity.
	 */
	uint64_t address;
	/** The number of 4 kiB pages in the constituent memory region. */
	uint32_t page_count;

	uint32_t reserved;
};

struct spci_memory_region_attributes {
	/** The ID of the VM to which the memory is being given or shared. */
	spci_vm_id_t receiver;
	/**
	 * The attributes with which the memory region should be mapped in the
	 * receiver's page table.
	 */
	uint16_t memory_attributes;
};

struct spci_memory_region {
	/**
	 * An implementation defined value associated with the receiver and the
	 * memory region.
	 */
	uint32_t tag;
	/** Flags to control behaviour of the transaction. */
	uint32_t flags;
	/**
	 * The total number of 4 kiB pages included in this memory region. This
	 * must be equal to the sum of page counts specified in each
	 * `spci_memory_region_constituent`.
	 */
	uint32_t page_count;
	/**
	 * The number of constituents (`spci_memory_region_constituent`)
	 * included in this memory region.
	 */
	uint32_t constituent_count;
	/**
	 * The offset in bytes from the base address of this
	 * `spci_memory_region` to the start of the first
	 * `spci_memory_region_constituent`.
	 */
	uint32_t constituent_offset;
	/**
	 * The number of `spci_memory_region_attributes` entries included in
	 * this memory region.
	 */
	uint32_t attribute_count;
	/**
	 * An array of `attribute_count` memory region attribute descriptors.
	 * Each one specifies an endpoint and the attributes with which this
	 * memory region should be mapped in that endpoint's page table.
	 */
	struct spci_memory_region_attributes attributes[];
};

/* TODO: Move all the functions below this line to a support library. */

/**
 * Gets the constituent array for an `spci_memory_region`.
 */
static inline struct spci_memory_region_constituent *
spci_memory_region_get_constituents(struct spci_memory_region *memory_region)
{
	return (struct spci_memory_region_constituent
			*)((uint8_t *)memory_region +
			   memory_region->constituent_offset);
}

/**
 * Helper method to fill in the information about the architected message.
 */
static inline void spci_architected_message_init(void *message,
						 enum spci_memory_share type)
{
	/* Fill the architected header. */
	struct spci_architected_message_header *architected_header =
		(struct spci_architected_message_header *)message;
	architected_header->type = type;
	architected_header->reserved[0] = 0;
	architected_header->reserved[1] = 0;
	architected_header->reserved[2] = 0;
}

/** Gets the spci_memory_region within an architected message. */
static inline struct spci_memory_region *spci_get_memory_region(void *message)
{
	struct spci_architected_message_header *architected_header =
		(struct spci_architected_message_header *)message;
	return (struct spci_memory_region *)architected_header->payload;
}

/**
 * Initialises the given `spci_memory_region` and copies the constituent
 * information to it. Returns the length in bytes occupied by the data copied to
 * `memory_region` (attributes, constituents and memory region header size).
 */
static inline uint32_t spci_memory_region_init(
	struct spci_memory_region *memory_region, spci_vm_id_t receiver,
	const struct spci_memory_region_constituent constituents[],
	uint32_t constituent_count, uint32_t tag,
	enum spci_memory_access access, enum spci_memory_type type,
	enum spci_memory_cacheability cacheability,
	enum spci_memory_shareability shareability)
{
	uint32_t constituents_length =
		constituent_count *
		sizeof(struct spci_memory_region_constituent);
	uint32_t index;
	struct spci_memory_region_constituent *region_constituents;
	uint16_t attributes = 0;

	/* Set memory region's page attributes. */
	spci_set_memory_access_attr(&attributes, access);
	spci_set_memory_type_attr(&attributes, type);
	spci_set_memory_cacheability_attr(&attributes, cacheability);
	spci_set_memory_shareability_attr(&attributes, shareability);

	memory_region->tag = tag;
	memory_region->flags = 0;
	memory_region->page_count = 0;
	memory_region->constituent_count = constituent_count;
	memory_region->attribute_count = 1;
	memory_region->attributes[0].receiver = receiver;
	memory_region->attributes[0].memory_attributes = attributes;

	memory_region->constituent_offset =
		sizeof(struct spci_memory_region) +
		memory_region->attribute_count *
			sizeof(struct spci_memory_region_attributes);
	region_constituents =
		spci_memory_region_get_constituents(memory_region);

	for (index = 0; index < constituent_count; index++) {
		region_constituents[index] = constituents[index];
		region_constituents[index].reserved = 0;
		memory_region->page_count += constituents[index].page_count;
	}

	/*
	 * TODO: Add assert ensuring that the specified message
	 * length is not greater than SPCI_MSG_PAYLOAD_MAX.
	 */

	return memory_region->constituent_offset + constituents_length;
}

/** Constructs an SPCI donate memory region message. */
static inline uint32_t spci_memory_donate_init(
	void *message, spci_vm_id_t receiver,
	struct spci_memory_region_constituent *region_constituents,
	uint32_t constituent_count, uint32_t tag,
	enum spci_memory_access access, enum spci_memory_type type,
	enum spci_memory_cacheability cacheability,
	enum spci_memory_shareability shareability)
{
	uint32_t message_length =
		sizeof(struct spci_architected_message_header);
	struct spci_memory_region *memory_region =
		spci_get_memory_region(message);

	/* Fill in the details on the common message header. */
	spci_architected_message_init(message, SPCI_MEMORY_DONATE);

	/* Fill in memory region. */
	message_length += spci_memory_region_init(
		memory_region, receiver, region_constituents, constituent_count,
		tag, access, type, cacheability, shareability);
	return message_length;
}

/**
 * Constructs an SPCI memory region relinquish message.
 * A set of memory regions can be given back to the owner.
 */
static inline uint32_t spci_memory_relinquish_init(
	void *message, spci_vm_id_t receiver,
	struct spci_memory_region_constituent *region_constituents,
	uint32_t constituent_count, uint32_t tag)
{
	uint32_t message_length =
		sizeof(struct spci_architected_message_header);
	struct spci_memory_region *memory_region =
		spci_get_memory_region(message);

	/* Fill in the details on the common message header. */
	spci_architected_message_init(message, SPCI_MEMORY_RELINQUISH);

	/* Fill in memory region. */
	message_length += spci_memory_region_init(
		memory_region, receiver, region_constituents, constituent_count,
		tag, SPCI_MEMORY_RW_X, SPCI_MEMORY_DEVICE_MEM,
		SPCI_MEMORY_DEV_NGNRNE, SPCI_MEMORY_SHARE_NON_SHAREABLE);
	return message_length;
}

/**
 * Constructs an SPCI memory region lend message.
 */
static inline uint32_t spci_memory_lend_init(
	void *message, spci_vm_id_t receiver,
	struct spci_memory_region_constituent *region_constituents,
	uint32_t constituent_count, uint32_t tag,
	enum spci_memory_access access, enum spci_memory_type type,
	enum spci_memory_cacheability cacheability,
	enum spci_memory_shareability shareability)
{
	uint32_t message_length =
		sizeof(struct spci_architected_message_header);
	struct spci_memory_region *memory_region =
		spci_get_memory_region(message);

	/* Fill in the details on the common message header. */
	spci_architected_message_init(message, SPCI_MEMORY_LEND);

	/* Fill in memory region. */
	message_length += spci_memory_region_init(
		memory_region, receiver, region_constituents, constituent_count,
		tag, access, type, cacheability, shareability);
	return message_length;
}