interface/src/tfm_ns_interface_cmsis_rtos.c

/*
 * Copyright (c) 2017-2019, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */
#include <stdint.h>
#include <stdbool.h>

#include "cmsis_os2.h"

#include "tfm_api.h"
#include "tfm_ns_interface.h"

/**
 * This file contains an example implementation of the NS interface APIs
 * described in tfm_ns_interface.h
 *
 */

/**
 * \brief struct ns_lock_state type
 */
struct ns_lock_state {
    bool        init;
    osMutexId_t id;
};

/**
 * \brief ns_lock status
 */
static struct ns_lock_state ns_lock = {.init=false, .id=NULL};

/**
 * \brief Mutex properties, NS lock
 */
static const osMutexAttr_t ns_lock_attrib = {
    .name = "ns_lock",
    .attr_bits = osMutexPrioInherit,
    .cb_mem = NULL,
    .cb_size = 0U
};

__attribute__((weak))
uint32_t tfm_ns_interface_dispatch(veneer_fn fn,
                                   uint32_t arg0, uint32_t arg1,
                                   uint32_t arg2, uint32_t arg3)
{
    int32_t result;

    /* Check the NS lock has been initialized */
    if (ns_lock.init == false) {
        return (int32_t)TFM_ERROR_GENERIC;
    }

    /* TFM request protected by NS lock */
    if (osMutexAcquire(ns_lock.id, osWaitForever) != osOK) {
        return (int32_t)TFM_ERROR_GENERIC;
    }

    result = fn(arg0, arg1, arg2, arg3);

    if (osMutexRelease(ns_lock.id) != osOK) {
        return (int32_t)TFM_ERROR_GENERIC;
    }

    return result;
}

__attribute__((weak))
enum tfm_status_e tfm_ns_interface_init()
{
    if (ns_lock.init == false) {
        ns_lock.id = osMutexNew(&ns_lock_attrib);
        ns_lock.init = true;
        return TFM_SUCCESS;
    } else {
        return TFM_ERROR_GENERIC;
    }
}