/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _USB_MBUF_H_
#define _USB_MBUF_H_

/*
 * The following structure defines a minimum re-implementation of the
 * mbuf system in the kernel.
 */
struct usb_mbuf {
        uint8_t *cur_data_ptr;
        uint8_t *min_data_ptr;
        struct usb_mbuf *usb_nextpkt;
        struct usb_mbuf *usb_next;

        usb_size_t cur_data_len;
        usb_size_t max_data_len;
        uint8_t last_packet:1;
        uint8_t unused:7;
};

#define USB_IF_ENQUEUE(ifq, m) do {             \
    (m)->usb_nextpkt = NULL;                    \
    if ((ifq)->ifq_tail == NULL)                \
        (ifq)->ifq_head = (m);                  \
    else                                        \
        (ifq)->ifq_tail->usb_nextpkt = (m);     \
    (ifq)->ifq_tail = (m);                      \
    (ifq)->ifq_len++;                           \
  } while (0)

#define USB_IF_DEQUEUE(ifq, m) do {                             \
    (m) = (ifq)->ifq_head;                                      \
    if (m) {                                                    \
        if (((ifq)->ifq_head = (m)->usb_nextpkt) == NULL) {     \
             (ifq)->ifq_tail = NULL;                            \
        }                                                       \
        (m)->usb_nextpkt = NULL;                                \
        (ifq)->ifq_len--;                                       \
    }                                                           \
  } while (0)

#define USB_IF_PREPEND(ifq, m) do {             \
      (m)->usb_nextpkt = (ifq)->ifq_head;       \
      if ((ifq)->ifq_tail == NULL) {            \
          (ifq)->ifq_tail = (m);                \
      }                                         \
      (ifq)->ifq_head = (m);                    \
      (ifq)->ifq_len++;                         \
  } while (0)

#define USB_IF_QFULL(ifq)   ((ifq)->ifq_len >= (ifq)->ifq_maxlen)
#define USB_IF_QLEN(ifq)    ((ifq)->ifq_len)
#define USB_IF_POLL(ifq, m) ((m) = (ifq)->ifq_head)

#define USB_MBUF_RESET(m) do {                  \
    (m)->cur_data_ptr = (m)->min_data_ptr;      \
    (m)->cur_data_len = (m)->max_data_len;      \
    (m)->last_packet = 0;                       \
  } while (0)

/* prototypes */
void   *usb_alloc_mbufs(struct malloc_type *type, struct usb_ifqueue *ifq,
            usb_size_t block_size, uint16_t nblocks);

#endif                                  /* _USB_MBUF_H_ */