1/*
  2 *   Copyright (c) 2011, 2012, Atheros Communications Inc.
  3 *   Copyright (c) 2014, I2SE GmbH
  4 *
  5 *   Permission to use, copy, modify, and/or distribute this software
  6 *   for any purpose with or without fee is hereby granted, provided
  7 *   that the above copyright notice and this permission notice appear
  8 *   in all copies.
  9 *
 10 *   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 11 *   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 12 *   WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 13 *   THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 14 *   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 15 *   LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 16 *   NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 17 *   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 18 */
 19
 20/*   Atheros Ethernet framing. Every Ethernet frame is surrounded by an atheros
 21 *   frame while transmitted over a serial channel.
 22 */
 23
 24#ifndef _QCA_FRAMING_H
 25#define _QCA_FRAMING_H
 26
 27#include <linux/if_ether.h>
 28#include <linux/if_vlan.h>
 29#include <linux/types.h>
 30
 31/* Frame is currently being received */
 32#define QCAFRM_GATHER 0
 33
 34/*  No header byte while expecting it */
 35#define QCAFRM_NOHEAD (QCAFRM_ERR_BASE - 1)
 36
 37/* No tailer byte while expecting it */
 38#define QCAFRM_NOTAIL (QCAFRM_ERR_BASE - 2)
 39
 40/* Frame length is invalid */
 41#define QCAFRM_INVLEN (QCAFRM_ERR_BASE - 3)
 42
 43/* Frame length is invalid */
 44#define QCAFRM_INVFRAME (QCAFRM_ERR_BASE - 4)
 45
 46/* Min/Max Ethernet MTU */
 47#define QCAFRM_ETHMINMTU 46
 48#define QCAFRM_ETHMAXMTU 1500
 49
 50/* Min/Max frame lengths */
 51#define QCAFRM_ETHMINLEN (QCAFRM_ETHMINMTU + ETH_HLEN)
 52#define QCAFRM_ETHMAXLEN (QCAFRM_ETHMAXMTU + VLAN_ETH_HLEN)
 53
 54/* QCA7K header len */
 55#define QCAFRM_HEADER_LEN 8
 56
 57/* QCA7K footer len */
 58#define QCAFRM_FOOTER_LEN 2
 59
 60/* QCA7K Framing. */
 61#define QCAFRM_ERR_BASE -1000
 62
 63enum qcafrm_state {
 64	QCAFRM_HW_LEN0 = 0x8000,
 65	QCAFRM_HW_LEN1 = QCAFRM_HW_LEN0 - 1,
 66	QCAFRM_HW_LEN2 = QCAFRM_HW_LEN1 - 1,
 67	QCAFRM_HW_LEN3 = QCAFRM_HW_LEN2 - 1,
 68
 69	/*  Waiting first 0xAA of header */
 70	QCAFRM_WAIT_AA1 = QCAFRM_HW_LEN3 - 1,
 71
 72	/*  Waiting second 0xAA of header */
 73	QCAFRM_WAIT_AA2 = QCAFRM_WAIT_AA1 - 1,
 74
 75	/*  Waiting third 0xAA of header */
 76	QCAFRM_WAIT_AA3 = QCAFRM_WAIT_AA2 - 1,
 77
 78	/*  Waiting fourth 0xAA of header */
 79	QCAFRM_WAIT_AA4 = QCAFRM_WAIT_AA3 - 1,
 80
 81	/*  Waiting Byte 0-1 of length (litte endian) */
 82	QCAFRM_WAIT_LEN_BYTE0 = QCAFRM_WAIT_AA4 - 1,
 83	QCAFRM_WAIT_LEN_BYTE1 = QCAFRM_WAIT_AA4 - 2,
 84
 85	/* Reserved bytes */
 86	QCAFRM_WAIT_RSVD_BYTE1 = QCAFRM_WAIT_AA4 - 3,
 87	QCAFRM_WAIT_RSVD_BYTE2 = QCAFRM_WAIT_AA4 - 4,
 88
 89	/*  The frame length is used as the state until
 90	 *  the end of the Ethernet frame
 91	 *  Waiting for first 0x55 of footer
 92	 */
 93	QCAFRM_WAIT_551 = 1,
 94
 95	/*  Waiting for second 0x55 of footer */
 96	QCAFRM_WAIT_552 = QCAFRM_WAIT_551 - 1
 97};
 98
 99/*   Structure to maintain the frame decoding during reception. */
100
101struct qcafrm_handle {
102	/*  Current decoding state */
103	enum qcafrm_state state;
104
105	/* Offset in buffer (borrowed for length too) */
106	s16 offset;
107
108	/* Frame length as kept by this module */
109	u16 len;
110};
111
112u16 qcafrm_create_header(u8 *buf, u16 len);
113
114u16 qcafrm_create_footer(u8 *buf);
115
116static inline void qcafrm_fsm_init(struct qcafrm_handle *handle)
117{
118	handle->state = QCAFRM_HW_LEN0;
119}
120
121/*   Gather received bytes and try to extract a full Ethernet frame
122 *   by following a simple state machine.
123 *
124 * Return:   QCAFRM_GATHER       No Ethernet frame fully received yet.
125 *           QCAFRM_NOHEAD       Header expected but not found.
126 *           QCAFRM_INVLEN       QCA7K frame length is invalid
127 *           QCAFRM_NOTAIL       Footer expected but not found.
128 *           > 0                 Number of byte in the fully received
129 *                               Ethernet frame
130 */
131
132s32 qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte);
133
134#endif /* _QCA_FRAMING_H */