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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
fa766c9b IL |
2 | /* |
3 | * altera-comp.c | |
4 | * | |
5 | * altera FPGA driver | |
6 | * | |
7 | * Copyright (C) Altera Corporation 1998-2001 | |
8 | * Copyright (C) 2010 NetUP Inc. | |
9 | * Copyright (C) 2010 Igor M. Liplianin <liplianin@netup.ru> | |
fa766c9b IL |
10 | */ |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include "altera-exprt.h" | |
14 | ||
15 | #define SHORT_BITS 16 | |
16 | #define CHAR_BITS 8 | |
17 | #define DATA_BLOB_LENGTH 3 | |
18 | #define MATCH_DATA_LENGTH 8192 | |
19 | #define ALTERA_REQUEST_SIZE 1024 | |
20 | #define ALTERA_BUFFER_SIZE (MATCH_DATA_LENGTH + ALTERA_REQUEST_SIZE) | |
21 | ||
22 | static u32 altera_bits_req(u32 n) | |
23 | { | |
24 | u32 result = SHORT_BITS; | |
25 | ||
26 | if (n == 0) | |
27 | result = 1; | |
28 | else { | |
29 | /* Look for the highest non-zero bit position */ | |
30 | while ((n & (1 << (SHORT_BITS - 1))) == 0) { | |
31 | n <<= 1; | |
32 | --result; | |
33 | } | |
34 | } | |
35 | ||
36 | return result; | |
37 | } | |
38 | ||
39 | static u32 altera_read_packed(u8 *buffer, u32 bits, u32 *bits_avail, | |
40 | u32 *in_index) | |
41 | { | |
42 | u32 result = 0; | |
43 | u32 shift = 0; | |
44 | u32 databyte = 0; | |
45 | ||
46 | while (bits > 0) { | |
47 | databyte = buffer[*in_index]; | |
48 | result |= (((databyte >> (CHAR_BITS - *bits_avail)) | |
49 | & (0xff >> (CHAR_BITS - *bits_avail))) << shift); | |
50 | ||
51 | if (bits <= *bits_avail) { | |
52 | result &= (0xffff >> (SHORT_BITS - (bits + shift))); | |
53 | *bits_avail -= bits; | |
54 | bits = 0; | |
55 | } else { | |
56 | ++(*in_index); | |
57 | shift += *bits_avail; | |
58 | bits -= *bits_avail; | |
59 | *bits_avail = CHAR_BITS; | |
60 | } | |
61 | } | |
62 | ||
63 | return result; | |
64 | } | |
65 | ||
66 | u32 altera_shrink(u8 *in, u32 in_length, u8 *out, u32 out_length, s32 version) | |
67 | { | |
68 | u32 i, j, data_length = 0L; | |
69 | u32 offset, length; | |
70 | u32 match_data_length = MATCH_DATA_LENGTH; | |
71 | u32 bits_avail = CHAR_BITS; | |
72 | u32 in_index = 0L; | |
73 | ||
74 | if (version > 0) | |
75 | --match_data_length; | |
76 | ||
77 | for (i = 0; i < out_length; ++i) | |
78 | out[i] = 0; | |
79 | ||
80 | /* Read number of bytes in data. */ | |
81 | for (i = 0; i < sizeof(in_length); ++i) { | |
82 | data_length = data_length | ( | |
83 | altera_read_packed(in, | |
84 | CHAR_BITS, | |
85 | &bits_avail, | |
86 | &in_index) << (i * CHAR_BITS)); | |
87 | } | |
88 | ||
89 | if (data_length > out_length) { | |
90 | data_length = 0L; | |
91 | return data_length; | |
92 | } | |
93 | ||
94 | i = 0; | |
95 | while (i < data_length) { | |
96 | /* A 0 bit indicates literal data. */ | |
97 | if (altera_read_packed(in, 1, &bits_avail, | |
98 | &in_index) == 0) { | |
99 | for (j = 0; j < DATA_BLOB_LENGTH; ++j) { | |
100 | if (i < data_length) { | |
101 | out[i] = (u8)altera_read_packed(in, | |
102 | CHAR_BITS, | |
103 | &bits_avail, | |
104 | &in_index); | |
105 | i++; | |
106 | } | |
107 | } | |
108 | } else { | |
109 | /* A 1 bit indicates offset/length to follow. */ | |
110 | offset = altera_read_packed(in, altera_bits_req((s16) | |
111 | (i > match_data_length ? | |
112 | match_data_length : i)), | |
113 | &bits_avail, | |
114 | &in_index); | |
115 | length = altera_read_packed(in, CHAR_BITS, | |
116 | &bits_avail, | |
117 | &in_index); | |
118 | for (j = 0; j < length; ++j) { | |
119 | if (i < data_length) { | |
120 | out[i] = out[i - offset]; | |
121 | i++; | |
122 | } | |
123 | } | |
124 | } | |
125 | } | |
126 | ||
127 | return data_length; | |
128 | } |