Commit | Line | Data |
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291ab06e SW |
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 | |
21 | * by an atheros frame while transmitted over a serial channel; | |
22 | */ | |
23 | ||
24 | #include <linux/kernel.h> | |
25 | ||
26 | #include "qca_framing.h" | |
27 | ||
28 | u16 | |
29 | qcafrm_create_header(u8 *buf, u16 length) | |
30 | { | |
31 | __le16 len; | |
32 | ||
33 | if (!buf) | |
34 | return 0; | |
35 | ||
36 | len = cpu_to_le16(length); | |
37 | ||
38 | buf[0] = 0xAA; | |
39 | buf[1] = 0xAA; | |
40 | buf[2] = 0xAA; | |
41 | buf[3] = 0xAA; | |
42 | buf[4] = len & 0xff; | |
43 | buf[5] = (len >> 8) & 0xff; | |
44 | buf[6] = 0; | |
45 | buf[7] = 0; | |
46 | ||
47 | return QCAFRM_HEADER_LEN; | |
48 | } | |
49 | ||
50 | u16 | |
51 | qcafrm_create_footer(u8 *buf) | |
52 | { | |
53 | if (!buf) | |
54 | return 0; | |
55 | ||
56 | buf[0] = 0x55; | |
57 | buf[1] = 0x55; | |
58 | return QCAFRM_FOOTER_LEN; | |
59 | } | |
60 | ||
61 | /* Gather received bytes and try to extract a full ethernet frame by | |
62 | * following a simple state machine. | |
63 | * | |
64 | * Return: QCAFRM_GATHER No ethernet frame fully received yet. | |
65 | * QCAFRM_NOHEAD Header expected but not found. | |
66 | * QCAFRM_INVLEN Atheros frame length is invalid | |
67 | * QCAFRM_NOTAIL Footer expected but not found. | |
68 | * > 0 Number of byte in the fully received | |
69 | * Ethernet frame | |
70 | */ | |
71 | ||
72 | s32 | |
73 | qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte) | |
74 | { | |
75 | s32 ret = QCAFRM_GATHER; | |
76 | u16 len; | |
77 | ||
78 | switch (handle->state) { | |
79 | case QCAFRM_HW_LEN0: | |
80 | case QCAFRM_HW_LEN1: | |
81 | /* by default, just go to next state */ | |
82 | handle->state--; | |
83 | ||
84 | if (recv_byte != 0x00) { | |
85 | /* first two bytes of length must be 0 */ | |
86 | handle->state = QCAFRM_HW_LEN0; | |
87 | } | |
88 | break; | |
89 | case QCAFRM_HW_LEN2: | |
90 | case QCAFRM_HW_LEN3: | |
91 | handle->state--; | |
92 | break; | |
93 | /* 4 bytes header pattern */ | |
94 | case QCAFRM_WAIT_AA1: | |
95 | case QCAFRM_WAIT_AA2: | |
96 | case QCAFRM_WAIT_AA3: | |
97 | case QCAFRM_WAIT_AA4: | |
98 | if (recv_byte != 0xAA) { | |
99 | ret = QCAFRM_NOHEAD; | |
100 | handle->state = QCAFRM_HW_LEN0; | |
101 | } else { | |
102 | handle->state--; | |
103 | } | |
104 | break; | |
105 | /* 2 bytes length. */ | |
106 | /* Borrow offset field to hold length for now. */ | |
107 | case QCAFRM_WAIT_LEN_BYTE0: | |
108 | handle->offset = recv_byte; | |
109 | handle->state = QCAFRM_WAIT_LEN_BYTE1; | |
110 | break; | |
111 | case QCAFRM_WAIT_LEN_BYTE1: | |
112 | handle->offset = handle->offset | (recv_byte << 8); | |
113 | handle->state = QCAFRM_WAIT_RSVD_BYTE1; | |
114 | break; | |
115 | case QCAFRM_WAIT_RSVD_BYTE1: | |
116 | handle->state = QCAFRM_WAIT_RSVD_BYTE2; | |
117 | break; | |
118 | case QCAFRM_WAIT_RSVD_BYTE2: | |
119 | len = handle->offset; | |
120 | if (len > buf_len || len < QCAFRM_ETHMINLEN) { | |
121 | ret = QCAFRM_INVLEN; | |
122 | handle->state = QCAFRM_HW_LEN0; | |
123 | } else { | |
124 | handle->state = (enum qcafrm_state)(len + 1); | |
125 | /* Remaining number of bytes. */ | |
126 | handle->offset = 0; | |
127 | } | |
128 | break; | |
129 | default: | |
130 | /* Receiving Ethernet frame itself. */ | |
131 | buf[handle->offset] = recv_byte; | |
132 | handle->offset++; | |
133 | handle->state--; | |
134 | break; | |
135 | case QCAFRM_WAIT_551: | |
136 | if (recv_byte != 0x55) { | |
137 | ret = QCAFRM_NOTAIL; | |
138 | handle->state = QCAFRM_HW_LEN0; | |
139 | } else { | |
140 | handle->state = QCAFRM_WAIT_552; | |
141 | } | |
142 | break; | |
143 | case QCAFRM_WAIT_552: | |
144 | if (recv_byte != 0x55) { | |
145 | ret = QCAFRM_NOTAIL; | |
146 | handle->state = QCAFRM_HW_LEN0; | |
147 | } else { | |
148 | ret = handle->offset; | |
149 | /* Frame is fully received. */ | |
150 | handle->state = QCAFRM_HW_LEN0; | |
151 | } | |
152 | break; | |
153 | } | |
154 | ||
155 | return ret; | |
156 | } |