1 | // SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause |
---|---|
2 | /* |
3 | * Copyright (c) 2011, 2012, Atheros Communications Inc. |
4 | * Copyright (c) 2014, I2SE GmbH |
5 | */ |
6 | |
7 | /* Atheros ethernet framing. Every Ethernet frame is surrounded |
8 | * by an atheros frame while transmitted over a serial channel; |
9 | */ |
10 | |
11 | #include <linux/init.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> |
14 | |
15 | #include "qca_7k_common.h" |
16 | |
17 | u16 |
18 | qcafrm_create_header(u8 *buf, u16 length) |
19 | { |
20 | __le16 len; |
21 | |
22 | if (!buf) |
23 | return 0; |
24 | |
25 | len = cpu_to_le16(length); |
26 | |
27 | buf[0] = 0xAA; |
28 | buf[1] = 0xAA; |
29 | buf[2] = 0xAA; |
30 | buf[3] = 0xAA; |
31 | buf[4] = len & 0xff; |
32 | buf[5] = (len >> 8) & 0xff; |
33 | buf[6] = 0; |
34 | buf[7] = 0; |
35 | |
36 | return QCAFRM_HEADER_LEN; |
37 | } |
38 | EXPORT_SYMBOL_GPL(qcafrm_create_header); |
39 | |
40 | u16 |
41 | qcafrm_create_footer(u8 *buf) |
42 | { |
43 | if (!buf) |
44 | return 0; |
45 | |
46 | buf[0] = 0x55; |
47 | buf[1] = 0x55; |
48 | return QCAFRM_FOOTER_LEN; |
49 | } |
50 | EXPORT_SYMBOL_GPL(qcafrm_create_footer); |
51 | |
52 | /* Gather received bytes and try to extract a full ethernet frame by |
53 | * following a simple state machine. |
54 | * |
55 | * Return: QCAFRM_GATHER No ethernet frame fully received yet. |
56 | * QCAFRM_NOHEAD Header expected but not found. |
57 | * QCAFRM_INVLEN Atheros frame length is invalid |
58 | * QCAFRM_NOTAIL Footer expected but not found. |
59 | * > 0 Number of byte in the fully received |
60 | * Ethernet frame |
61 | */ |
62 | |
63 | s32 |
64 | qcafrm_fsm_decode(struct qcafrm_handle *handle, u8 *buf, u16 buf_len, u8 recv_byte) |
65 | { |
66 | s32 ret = QCAFRM_GATHER; |
67 | u16 len; |
68 | |
69 | switch (handle->state) { |
70 | case QCAFRM_HW_LEN0: |
71 | case QCAFRM_HW_LEN1: |
72 | /* by default, just go to next state */ |
73 | handle->state--; |
74 | |
75 | if (recv_byte != 0x00) { |
76 | /* first two bytes of length must be 0 */ |
77 | handle->state = handle->init; |
78 | } |
79 | break; |
80 | case QCAFRM_HW_LEN2: |
81 | case QCAFRM_HW_LEN3: |
82 | handle->state--; |
83 | break; |
84 | /* 4 bytes header pattern */ |
85 | case QCAFRM_WAIT_AA1: |
86 | case QCAFRM_WAIT_AA2: |
87 | case QCAFRM_WAIT_AA3: |
88 | case QCAFRM_WAIT_AA4: |
89 | if (recv_byte != 0xAA) { |
90 | ret = QCAFRM_NOHEAD; |
91 | handle->state = handle->init; |
92 | } else { |
93 | handle->state--; |
94 | } |
95 | break; |
96 | /* 2 bytes length. */ |
97 | /* Borrow offset field to hold length for now. */ |
98 | case QCAFRM_WAIT_LEN_BYTE0: |
99 | handle->offset = recv_byte; |
100 | handle->state = QCAFRM_WAIT_LEN_BYTE1; |
101 | break; |
102 | case QCAFRM_WAIT_LEN_BYTE1: |
103 | handle->offset = handle->offset | (recv_byte << 8); |
104 | handle->state = QCAFRM_WAIT_RSVD_BYTE1; |
105 | break; |
106 | case QCAFRM_WAIT_RSVD_BYTE1: |
107 | handle->state = QCAFRM_WAIT_RSVD_BYTE2; |
108 | break; |
109 | case QCAFRM_WAIT_RSVD_BYTE2: |
110 | len = handle->offset; |
111 | if (len > buf_len || len < QCAFRM_MIN_LEN) { |
112 | ret = QCAFRM_INVLEN; |
113 | handle->state = handle->init; |
114 | } else { |
115 | handle->state = (enum qcafrm_state)(len + 1); |
116 | /* Remaining number of bytes. */ |
117 | handle->offset = 0; |
118 | } |
119 | break; |
120 | default: |
121 | /* Receiving Ethernet frame itself. */ |
122 | buf[handle->offset] = recv_byte; |
123 | handle->offset++; |
124 | handle->state--; |
125 | break; |
126 | case QCAFRM_WAIT_551: |
127 | if (recv_byte != 0x55) { |
128 | ret = QCAFRM_NOTAIL; |
129 | handle->state = handle->init; |
130 | } else { |
131 | handle->state = QCAFRM_WAIT_552; |
132 | } |
133 | break; |
134 | case QCAFRM_WAIT_552: |
135 | if (recv_byte != 0x55) { |
136 | ret = QCAFRM_NOTAIL; |
137 | handle->state = handle->init; |
138 | } else { |
139 | ret = handle->offset; |
140 | /* Frame is fully received. */ |
141 | handle->state = handle->init; |
142 | } |
143 | break; |
144 | } |
145 | |
146 | return ret; |
147 | } |
148 | EXPORT_SYMBOL_GPL(qcafrm_fsm_decode); |
149 | |
150 | MODULE_DESCRIPTION("Qualcomm Atheros QCA7000 common"); |
151 | MODULE_AUTHOR("Qualcomm Atheros Communications"); |
152 | MODULE_AUTHOR("Stefan Wahren <wahrenst@gmx.net>"); |
153 | MODULE_LICENSE("Dual BSD/GPL"); |
154 |