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/init.h> |
25 | #include <linux/kernel.h> |
26 | #include <linux/module.h> |
27 | |
28 | #include "qca_7k_common.h" |
29 | |
30 | u16 |
31 | (u8 *buf, u16 length) |
32 | { |
33 | __le16 len; |
34 | |
35 | if (!buf) |
36 | return 0; |
37 | |
38 | len = cpu_to_le16(length); |
39 | |
40 | buf[0] = 0xAA; |
41 | buf[1] = 0xAA; |
42 | buf[2] = 0xAA; |
43 | buf[3] = 0xAA; |
44 | buf[4] = len & 0xff; |
45 | buf[5] = (len >> 8) & 0xff; |
46 | buf[6] = 0; |
47 | buf[7] = 0; |
48 | |
49 | return QCAFRM_HEADER_LEN; |
50 | } |
51 | EXPORT_SYMBOL_GPL(qcafrm_create_header); |
52 | |
53 | u16 |
54 | (u8 *buf) |
55 | { |
56 | if (!buf) |
57 | return 0; |
58 | |
59 | buf[0] = 0x55; |
60 | buf[1] = 0x55; |
61 | return QCAFRM_FOOTER_LEN; |
62 | } |
63 | EXPORT_SYMBOL_GPL(qcafrm_create_footer); |
64 | |
65 | /* Gather received bytes and try to extract a full ethernet frame by |
66 | * following a simple state machine. |
67 | * |
68 | * Return: QCAFRM_GATHER No ethernet frame fully received yet. |
69 | * QCAFRM_NOHEAD Header expected but not found. |
70 | * QCAFRM_INVLEN Atheros frame length is invalid |
71 | * QCAFRM_NOTAIL Footer expected but not found. |
72 | * > 0 Number of byte in the fully received |
73 | * Ethernet frame |
74 | */ |
75 | |
76 | s32 |
77 | qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte) |
78 | { |
79 | s32 ret = QCAFRM_GATHER; |
80 | u16 len; |
81 | |
82 | switch (handle->state) { |
83 | case QCAFRM_HW_LEN0: |
84 | case QCAFRM_HW_LEN1: |
85 | /* by default, just go to next state */ |
86 | handle->state--; |
87 | |
88 | if (recv_byte != 0x00) { |
89 | /* first two bytes of length must be 0 */ |
90 | handle->state = handle->init; |
91 | } |
92 | break; |
93 | case QCAFRM_HW_LEN2: |
94 | case QCAFRM_HW_LEN3: |
95 | handle->state--; |
96 | break; |
97 | /* 4 bytes header pattern */ |
98 | case QCAFRM_WAIT_AA1: |
99 | case QCAFRM_WAIT_AA2: |
100 | case QCAFRM_WAIT_AA3: |
101 | case QCAFRM_WAIT_AA4: |
102 | if (recv_byte != 0xAA) { |
103 | ret = QCAFRM_NOHEAD; |
104 | handle->state = handle->init; |
105 | } else { |
106 | handle->state--; |
107 | } |
108 | break; |
109 | /* 2 bytes length. */ |
110 | /* Borrow offset field to hold length for now. */ |
111 | case QCAFRM_WAIT_LEN_BYTE0: |
112 | handle->offset = recv_byte; |
113 | handle->state = QCAFRM_WAIT_LEN_BYTE1; |
114 | break; |
115 | case QCAFRM_WAIT_LEN_BYTE1: |
116 | handle->offset = handle->offset | (recv_byte << 8); |
117 | handle->state = QCAFRM_WAIT_RSVD_BYTE1; |
118 | break; |
119 | case QCAFRM_WAIT_RSVD_BYTE1: |
120 | handle->state = QCAFRM_WAIT_RSVD_BYTE2; |
121 | break; |
122 | case QCAFRM_WAIT_RSVD_BYTE2: |
123 | len = handle->offset; |
124 | if (len > buf_len || len < QCAFRM_MIN_LEN) { |
125 | ret = QCAFRM_INVLEN; |
126 | handle->state = handle->init; |
127 | } else { |
128 | handle->state = (enum qcafrm_state)(len + 1); |
129 | /* Remaining number of bytes. */ |
130 | handle->offset = 0; |
131 | } |
132 | break; |
133 | default: |
134 | /* Receiving Ethernet frame itself. */ |
135 | buf[handle->offset] = recv_byte; |
136 | handle->offset++; |
137 | handle->state--; |
138 | break; |
139 | case QCAFRM_WAIT_551: |
140 | if (recv_byte != 0x55) { |
141 | ret = QCAFRM_NOTAIL; |
142 | handle->state = handle->init; |
143 | } else { |
144 | handle->state = QCAFRM_WAIT_552; |
145 | } |
146 | break; |
147 | case QCAFRM_WAIT_552: |
148 | if (recv_byte != 0x55) { |
149 | ret = QCAFRM_NOTAIL; |
150 | handle->state = handle->init; |
151 | } else { |
152 | ret = handle->offset; |
153 | /* Frame is fully received. */ |
154 | handle->state = handle->init; |
155 | } |
156 | break; |
157 | } |
158 | |
159 | return ret; |
160 | } |
161 | EXPORT_SYMBOL_GPL(qcafrm_fsm_decode); |
162 | |
163 | MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 common" ); |
164 | MODULE_AUTHOR("Qualcomm Atheros Communications" ); |
165 | MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>" ); |
166 | MODULE_LICENSE("Dual BSD/GPL" ); |
167 | |