/*
 * Copyright 2020 Max Planck Institute for Software Systems
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "dummy_nic.h"

static volatile union cosim_pcie_proto_d2h *d2h_alloc(void)
{
    volatile union cosim_pcie_proto_d2h *msg =
        (volatile union cosim_pcie_proto_d2h *)
        (d2h_queue + d2h_pos * D2H_ELEN);

    if ((msg->dummy.own_type & COSIM_PCIE_PROTO_D2H_OWN_MASK) !=
            COSIM_PCIE_PROTO_D2H_OWN_DEV)
    {
        fprintf(stderr, "d2h_alloc: no entry available\n");
        abort();
    }

    d2h_pos = (d2h_pos + 1) % D2H_ENUM;
    return msg;
}

static void h2d_read(volatile struct cosim_pcie_proto_h2d_read *read)
{
    volatile union cosim_pcie_proto_d2h *msg;
    volatile struct cosim_pcie_proto_d2h_readcomp *rc;
    uint64_t val;

    msg = d2h_alloc();
    rc = &msg->readcomp;

    val = read->offset + 42;
    printf("read(bar=%u, off=%lu, len=%u) = %lu\n", read->bar, read->offset,
            read->len, val);

    memcpy((void *) rc->data, &val, read->len);
    rc->req_id = read->req_id;

    //WMB();
    rc->own_type = COSIM_PCIE_PROTO_D2H_MSG_READCOMP |
        COSIM_PCIE_PROTO_D2H_OWN_HOST;
}

static void h2d_write(volatile struct cosim_pcie_proto_h2d_write *write)
{
    volatile union cosim_pcie_proto_d2h *msg;
    volatile struct cosim_pcie_proto_d2h_writecomp *wc;
    uint64_t val;

    msg = d2h_alloc();
    wc = &msg->writecomp;

    val = 0;
    memcpy(&val, (void *) write->data, write->len);

    printf("write(bar=%u, off=%lu, len=%u, val=%lu)\n", write->bar,
            write->offset, write->len, val);

    wc->req_id = write->req_id;

    //WMB();
    wc->own_type = COSIM_PCIE_PROTO_D2H_MSG_WRITECOMP |
        COSIM_PCIE_PROTO_D2H_OWN_HOST;
}

void poll_h2d(void)
{
    volatile union cosim_pcie_proto_h2d *msg =
        (volatile union cosim_pcie_proto_h2d *)
        (h2d_queue + h2d_pos * H2D_ELEN);
    uint8_t type;

    /* message not ready */
    if ((msg->dummy.own_type & COSIM_PCIE_PROTO_H2D_OWN_MASK) !=
            COSIM_PCIE_PROTO_H2D_OWN_DEV)
        return;

    type = msg->dummy.own_type & COSIM_PCIE_PROTO_H2D_MSG_MASK;
    switch (type) {
        case COSIM_PCIE_PROTO_H2D_MSG_READ:
            h2d_read(&msg->read);
            break;

        case COSIM_PCIE_PROTO_H2D_MSG_WRITE:
            h2d_write(&msg->write);
            break;

        default:
            fprintf(stderr, "poll_h2d: unsupported type=%u\n", type);
    }

    //WMB();
    msg->dummy.own_type = type | COSIM_PCIE_PROTO_H2D_OWN_HOST;

    h2d_pos = (h2d_pos + 1) % H2D_ENUM;
}