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: 46/1500 */ 47 #define QCAFRM_MIN_MTU (ETH_ZLEN - ETH_HLEN) 48 #define QCAFRM_MAX_MTU ETH_DATA_LEN 49 50 /* Min/Max frame lengths */ 51 #define QCAFRM_MIN_LEN (QCAFRM_MIN_MTU + ETH_HLEN) 52 #define QCAFRM_MAX_LEN (QCAFRM_MAX_MTU + 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 63 enum 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. */ 100 101 struct qcafrm_handle { 102 /* Current decoding state */ 103 enum qcafrm_state state; 104 105 /* Offset in buffer (borrowed for length too) */ 106 u16 offset; 107 108 /* Frame length as kept by this module */ 109 u16 len; 110 }; 111 112 u16 qcafrm_create_header(u8 *buf, u16 len); 113 114 u16 qcafrm_create_footer(u8 *buf); 115 116 static 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 */ 131 132 s32 qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte); 133 134 #endif /* _QCA_FRAMING_H */ 135