128 lines
4.2 KiB
C
128 lines
4.2 KiB
C
/* buf.h - Bluetooth buffer management */
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/*
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* Copyright (c) 2015 Intel Corporation
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Intel Corporation nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __BT_BUF_H
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#define __BT_BUF_H
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/* The biggest foreseeable buffer size requirement right now comes from
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* the Bluetooth 4.2 SMP MTU which is 65. This then become 65 + 4 (L2CAP
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* header) + 4 (ACL header) + 1 (H4 header) = 74. This also covers the
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* biggest HCI commands and events which are a bit under the 70 byte
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* mark.
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*/
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#define BT_BUF_MAX_DATA 74
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/* Type of data contained in this buffer */
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enum bt_buf_type {
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BT_CMD, /* HCI command */
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BT_EVT, /* HCI event */
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BT_ACL_OUT, /* Outgoing ACL data */
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BT_ACL_IN, /* Incoming ACL data */
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BT_DUMMY = BT_CMD, /* Only used for waking up fibers */
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};
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/* HCI command specific info */
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struct bt_buf_hci_data {
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/* Used by bt_hci_cmd_send_sync. Initially contains the waiting
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* semaphore, as the semaphore is given back contains the bt_buf
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* for the return parameters.
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*/
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void *sync;
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/* The command OpCode that the buffer contains */
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uint16_t opcode;
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};
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struct bt_buf_acl_data {
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uint16_t handle;
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};
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struct bt_buf {
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/* FIFO uses first 4 bytes itself, reserve space */
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int __unused;
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union {
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struct bt_buf_hci_data hci;
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struct bt_buf_acl_data acl;
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};
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/* Reference count */
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uint8_t ref;
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/* Type of data contained in the buffer */
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uint8_t type;
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/* Buffer data variables */
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uint8_t len;
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uint8_t *data;
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uint8_t buf[BT_BUF_MAX_DATA];
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};
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/* Get buffer from the available buffers pool with specified type and
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* reserved headroom.
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*/
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struct bt_buf *bt_buf_get(enum bt_buf_type type, size_t reserve_head);
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/* Place buffer back into the available buffers pool */
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void bt_buf_put(struct bt_buf *buf);
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/* Increment the reference count of a buffer */
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struct bt_buf *bt_buf_hold(struct bt_buf *buf);
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/* Prepare data to be added at the end of the buffer */
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void *bt_buf_add(struct bt_buf *buf, size_t len);
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/* Push data to the beginning of the buffer */
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void *bt_buf_push(struct bt_buf *buf, size_t len);
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/* Remove data from the beginning of the buffer */
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void *bt_buf_pull(struct bt_buf *buf, size_t len);
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/* Remove and convert 16 bits from the beginning of the buffer */
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uint16_t bt_buf_pull_le16(struct bt_buf *buf);
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/* Returns how much free space there is at the end of the buffer */
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size_t bt_buf_tailroom(struct bt_buf *buf);
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/* Returns how much free space there is at the beginning of the buffer */
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size_t bt_buf_headroom(struct bt_buf *buf);
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/* Return pointer to the end of the data in the buffer */
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#define bt_buf_tail(buf) ((buf)->data + (buf)->len)
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/* Initialize the buffers with specified amount of incoming and outgoing
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* ACL buffers. The HCI command and event buffers will be allocated from
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* whatever is left over.
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*/
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int bt_buf_init(int acl_in, int acl_out);
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#endif /* __BT_BUF_H */
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