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 /* HW length is only available on SPI */
65 QCAFRM_HW_LEN0 = 0x8000,
66 QCAFRM_HW_LEN1 = QCAFRM_HW_LEN0 - 1,
67 QCAFRM_HW_LEN2 = QCAFRM_HW_LEN1 - 1,
68 QCAFRM_HW_LEN3 = QCAFRM_HW_LEN2 - 1,
69
70 /* Waiting first 0xAA of header */
71 QCAFRM_WAIT_AA1 = QCAFRM_HW_LEN3 - 1,
72
73 /* Waiting second 0xAA of header */
74 QCAFRM_WAIT_AA2 = QCAFRM_WAIT_AA1 - 1,
75
76 /* Waiting third 0xAA of header */
77 QCAFRM_WAIT_AA3 = QCAFRM_WAIT_AA2 - 1,
78
79 /* Waiting fourth 0xAA of header */
80 QCAFRM_WAIT_AA4 = QCAFRM_WAIT_AA3 - 1,
81
82 /* Waiting Byte 0-1 of length (litte endian) */
83 QCAFRM_WAIT_LEN_BYTE0 = QCAFRM_WAIT_AA4 - 1,
84 QCAFRM_WAIT_LEN_BYTE1 = QCAFRM_WAIT_AA4 - 2,
85
86 /* Reserved bytes */
87 QCAFRM_WAIT_RSVD_BYTE1 = QCAFRM_WAIT_AA4 - 3,
88 QCAFRM_WAIT_RSVD_BYTE2 = QCAFRM_WAIT_AA4 - 4,
89
90 /* The frame length is used as the state until
91 * the end of the Ethernet frame
92 * Waiting for first 0x55 of footer
93 */
94 QCAFRM_WAIT_551 = 1,
95
96 /* Waiting for second 0x55 of footer */
97 QCAFRM_WAIT_552 = QCAFRM_WAIT_551 - 1
98 };
99
100 /* Structure to maintain the frame decoding during reception. */
101
102 struct qcafrm_handle {
103 /* Current decoding state */
104 enum qcafrm_state state;
105 /* Initial state depends on connection type */
106 enum qcafrm_state init;
107
108 /* Offset in buffer (borrowed for length too) */
109 u16 offset;
110
111 /* Frame length as kept by this module */
112 u16 len;
113 };
114
115 u16 qcafrm_create_header(u8 *buf, u16 len);
116
117 u16 qcafrm_create_footer(u8 *buf);
118
119 static inline void qcafrm_fsm_init_spi(struct qcafrm_handle *handle)
120 {
121 handle->init = QCAFRM_HW_LEN0;
122 handle->state = handle->init;
123 }
124
125 static inline void qcafrm_fsm_init_uart(struct qcafrm_handle *handle)
126 {
127 handle->init = QCAFRM_WAIT_AA1;
128 handle->state = handle->init;
129 }
130
131 /* Gather received bytes and try to extract a full Ethernet frame
132 * by following a simple state machine.
133 *
134 * Return: QCAFRM_GATHER No Ethernet frame fully received yet.
135 * QCAFRM_NOHEAD Header expected but not found.
136 * QCAFRM_INVLEN QCA7K frame length is invalid
137 * QCAFRM_NOTAIL Footer expected but not found.
138 * > 0 Number of byte in the fully received
139 * Ethernet frame
140 */
141
142 s32 qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte);
143
144 #endif /* _QCA_FRAMING_H */