/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2021 ARM Ltd.
 */

#ifndef _LINUX_ARM_FFA_H
#define _LINUX_ARM_FFA_H

#include <linux/device.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/uuid.h>

/* FFA Bus/Device/Driver related */
struct ffa_device {
        int vm_id;
        bool mode_32bit;
        uuid_t uuid;
        struct device dev;
};

#define to_ffa_dev(d) container_of(d, struct ffa_device, dev)

struct ffa_device_id {
        uuid_t uuid;
};

struct ffa_driver {
        const char *name;
        int (*probe)(struct ffa_device *sdev);
        void (*remove)(struct ffa_device *sdev);
        const struct ffa_device_id *id_table;

        struct device_driver driver;
};

#define to_ffa_driver(d) container_of(d, struct ffa_driver, driver)

static inline void ffa_dev_set_drvdata(struct ffa_device *fdev, void *data)
{
        fdev->dev.driver_data = data;
}

#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id);
void ffa_device_unregister(struct ffa_device *ffa_dev);
int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
                        const char *mod_name);
void ffa_driver_unregister(struct ffa_driver *driver);
bool ffa_device_is_valid(struct ffa_device *ffa_dev);
const struct ffa_dev_ops *ffa_dev_ops_get(struct ffa_device *dev);

#else
static inline
struct ffa_device *ffa_device_register(const uuid_t *uuid, int vm_id)
{
        return NULL;
}

static inline void ffa_device_unregister(struct ffa_device *dev) {}

static inline int
ffa_driver_register(struct ffa_driver *driver, struct module *owner,
                    const char *mod_name)
{
        return -EINVAL;
}

static inline void ffa_driver_unregister(struct ffa_driver *driver) {}

static inline
bool ffa_device_is_valid(struct ffa_device *ffa_dev) { return false; }

static inline
const struct ffa_dev_ops *ffa_dev_ops_get(struct ffa_device *dev)
{
        return NULL;
}
#endif /* CONFIG_ARM_FFA_TRANSPORT */

#define ffa_register(driver) \
        ffa_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
#define ffa_unregister(driver) \
        ffa_driver_unregister(driver)

/**
 * module_ffa_driver() - Helper macro for registering a psa_ffa driver
 * @__ffa_driver: ffa_driver structure
 *
 * Helper macro for psa_ffa 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_ffa_driver(__ffa_driver) \
        module_driver(__ffa_driver, ffa_register, ffa_unregister)

/* FFA transport related */
struct ffa_partition_info {
        u16 id;
        u16 exec_ctxt;
/* partition supports receipt of direct requests */
#define FFA_PARTITION_DIRECT_RECV       BIT(0)
/* partition can send direct requests. */
#define FFA_PARTITION_DIRECT_SEND       BIT(1)
/* partition can send and receive indirect messages. */
#define FFA_PARTITION_INDIRECT_MSG      BIT(2)
        u32 properties;
};

/* For use with FFA_MSG_SEND_DIRECT_{REQ,RESP} which pass data via registers */
struct ffa_send_direct_data {
        unsigned long data0; /* w3/x3 */
        unsigned long data1; /* w4/x4 */
        unsigned long data2; /* w5/x5 */
        unsigned long data3; /* w6/x6 */
        unsigned long data4; /* w7/x7 */
};

struct ffa_mem_region_addr_range {
        /* The base IPA of the constituent memory region, aligned to 4 kiB */
        u64 address;
        /* The number of 4 kiB pages in the constituent memory region. */
        u32 pg_cnt;
        u32 reserved;
};

struct ffa_composite_mem_region {
        /*
         * 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
         * `struct ffa_mem_region_addr_range`.
         */
        u32 total_pg_cnt;
        /* The number of constituents included in this memory region range */
        u32 addr_range_cnt;
        u64 reserved;
        /** An array of `addr_range_cnt` memory region constituents. */
        struct ffa_mem_region_addr_range constituents[];
};

struct ffa_mem_region_attributes {
        /* The ID of the VM to which the memory is being given or shared. */
        u16 receiver;
        /*
         * The permissions with which the memory region should be mapped in the
         * receiver's page table.
         */
#define FFA_MEM_EXEC            BIT(3)
#define FFA_MEM_NO_EXEC         BIT(2)
#define FFA_MEM_RW              BIT(1)
#define FFA_MEM_RO              BIT(0)
        u8 attrs;
        /*
         * Flags used during FFA_MEM_RETRIEVE_REQ and FFA_MEM_RETRIEVE_RESP
         * for memory regions with multiple borrowers.
         */
#define FFA_MEM_RETRIEVE_SELF_BORROWER  BIT(0)
        u8 flag;
        u32 composite_off;
        /*
         * Offset in bytes from the start of the outer `ffa_memory_region` to
         * an `struct ffa_mem_region_addr_range`.
         */
        u64 reserved;
};

struct ffa_mem_region {
        /* The ID of the VM/owner which originally sent the memory region */
        u16 sender_id;
#define FFA_MEM_NORMAL          BIT(5)
#define FFA_MEM_DEVICE          BIT(4)

#define FFA_MEM_WRITE_BACK      (3 << 2)
#define FFA_MEM_NON_CACHEABLE   (1 << 2)

#define FFA_DEV_nGnRnE          (0 << 2)
#define FFA_DEV_nGnRE           (1 << 2)
#define FFA_DEV_nGRE            (2 << 2)
#define FFA_DEV_GRE             (3 << 2)

#define FFA_MEM_NON_SHAREABLE   (0)
#define FFA_MEM_OUTER_SHAREABLE (2)
#define FFA_MEM_INNER_SHAREABLE (3)
        u8 attributes;
        u8 reserved_0;
/*
 * Clear memory region contents after unmapping it from the sender and
 * before mapping it for any receiver.
 */
#define FFA_MEM_CLEAR                   BIT(0)
/*
 * Whether the hypervisor may time slice the memory sharing or retrieval
 * operation.
 */
#define FFA_TIME_SLICE_ENABLE           BIT(1)

#define FFA_MEM_RETRIEVE_TYPE_IN_RESP   (0 << 3)
#define FFA_MEM_RETRIEVE_TYPE_SHARE     (1 << 3)
#define FFA_MEM_RETRIEVE_TYPE_LEND      (2 << 3)
#define FFA_MEM_RETRIEVE_TYPE_DONATE    (3 << 3)

#define FFA_MEM_RETRIEVE_ADDR_ALIGN_HINT        BIT(9)
#define FFA_MEM_RETRIEVE_ADDR_ALIGN(x)          ((x) << 5)
        /* Flags to control behaviour of the transaction. */
        u32 flags;
#define HANDLE_LOW_MASK         GENMASK_ULL(31, 0)
#define HANDLE_HIGH_MASK        GENMASK_ULL(63, 32)
#define HANDLE_LOW(x)           ((u32)(FIELD_GET(HANDLE_LOW_MASK, (x))))
#define HANDLE_HIGH(x)          ((u32)(FIELD_GET(HANDLE_HIGH_MASK, (x))))

#define PACK_HANDLE(l, h)               \
        (FIELD_PREP(HANDLE_LOW_MASK, (l)) | FIELD_PREP(HANDLE_HIGH_MASK, (h)))
        /*
         * A globally-unique ID assigned by the hypervisor for a region
         * of memory being sent between VMs.
         */
        u64 handle;
        /*
         * An implementation defined value associated with the receiver and the
         * memory region.
         */
        u64 tag;
        u32 reserved_1;
        /*
         * The number of `ffa_mem_region_attributes` entries included in this
         * transaction.
         */
        u32 ep_count;
        /*
         * An array of endpoint memory access descriptors.
         * Each one specifies a memory region offset, an endpoint and the
         * attributes with which this memory region should be mapped in that
         * endpoint's page table.
         */
        struct ffa_mem_region_attributes ep_mem_access[];
};

#define COMPOSITE_OFFSET(x)     \
        (offsetof(struct ffa_mem_region, ep_mem_access[x]))
#define CONSTITUENTS_OFFSET(x)  \
        (offsetof(struct ffa_composite_mem_region, constituents[x]))
#define COMPOSITE_CONSTITUENTS_OFFSET(x, y)     \
        (COMPOSITE_OFFSET(x) + CONSTITUENTS_OFFSET(y))

struct ffa_mem_ops_args {
        bool use_txbuf;
        u32 nattrs;
        u32 flags;
        u64 tag;
        u64 g_handle;
        struct scatterlist *sg;
        struct ffa_mem_region_attributes *attrs;
};

struct ffa_dev_ops {
        u32 (*api_version_get)(void);
        int (*partition_info_get)(const char *uuid_str,
                                  struct ffa_partition_info *buffer);
        void (*mode_32bit_set)(struct ffa_device *dev);
        int (*sync_send_receive)(struct ffa_device *dev,
                                 struct ffa_send_direct_data *data);
        int (*memory_reclaim)(u64 g_handle, u32 flags);
        int (*memory_share)(struct ffa_device *dev,
                            struct ffa_mem_ops_args *args);
};

#endif /* _LINUX_ARM_FFA_H */