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fa766c9b IL |
1 | /* |
2 | * altera-comp.c | |
3 | * | |
4 | * altera FPGA driver | |
5 | * | |
6 | * Copyright (C) Altera Corporation 1998-2001 | |
7 | * Copyright (C) 2010 NetUP Inc. | |
8 | * Copyright (C) 2010 Igor M. Liplianin <liplianin@netup.ru> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * | |
19 | * GNU General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License | |
22 | * along with this program; if not, write to the Free Software | |
23 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include "altera-exprt.h" | |
28 | ||
29 | #define SHORT_BITS 16 | |
30 | #define CHAR_BITS 8 | |
31 | #define DATA_BLOB_LENGTH 3 | |
32 | #define MATCH_DATA_LENGTH 8192 | |
33 | #define ALTERA_REQUEST_SIZE 1024 | |
34 | #define ALTERA_BUFFER_SIZE (MATCH_DATA_LENGTH + ALTERA_REQUEST_SIZE) | |
35 | ||
36 | static u32 altera_bits_req(u32 n) | |
37 | { | |
38 | u32 result = SHORT_BITS; | |
39 | ||
40 | if (n == 0) | |
41 | result = 1; | |
42 | else { | |
43 | /* Look for the highest non-zero bit position */ | |
44 | while ((n & (1 << (SHORT_BITS - 1))) == 0) { | |
45 | n <<= 1; | |
46 | --result; | |
47 | } | |
48 | } | |
49 | ||
50 | return result; | |
51 | } | |
52 | ||
53 | static u32 altera_read_packed(u8 *buffer, u32 bits, u32 *bits_avail, | |
54 | u32 *in_index) | |
55 | { | |
56 | u32 result = 0; | |
57 | u32 shift = 0; | |
58 | u32 databyte = 0; | |
59 | ||
60 | while (bits > 0) { | |
61 | databyte = buffer[*in_index]; | |
62 | result |= (((databyte >> (CHAR_BITS - *bits_avail)) | |
63 | & (0xff >> (CHAR_BITS - *bits_avail))) << shift); | |
64 | ||
65 | if (bits <= *bits_avail) { | |
66 | result &= (0xffff >> (SHORT_BITS - (bits + shift))); | |
67 | *bits_avail -= bits; | |
68 | bits = 0; | |
69 | } else { | |
70 | ++(*in_index); | |
71 | shift += *bits_avail; | |
72 | bits -= *bits_avail; | |
73 | *bits_avail = CHAR_BITS; | |
74 | } | |
75 | } | |
76 | ||
77 | return result; | |
78 | } | |
79 | ||
80 | u32 altera_shrink(u8 *in, u32 in_length, u8 *out, u32 out_length, s32 version) | |
81 | { | |
82 | u32 i, j, data_length = 0L; | |
83 | u32 offset, length; | |
84 | u32 match_data_length = MATCH_DATA_LENGTH; | |
85 | u32 bits_avail = CHAR_BITS; | |
86 | u32 in_index = 0L; | |
87 | ||
88 | if (version > 0) | |
89 | --match_data_length; | |
90 | ||
91 | for (i = 0; i < out_length; ++i) | |
92 | out[i] = 0; | |
93 | ||
94 | /* Read number of bytes in data. */ | |
95 | for (i = 0; i < sizeof(in_length); ++i) { | |
96 | data_length = data_length | ( | |
97 | altera_read_packed(in, | |
98 | CHAR_BITS, | |
99 | &bits_avail, | |
100 | &in_index) << (i * CHAR_BITS)); | |
101 | } | |
102 | ||
103 | if (data_length > out_length) { | |
104 | data_length = 0L; | |
105 | return data_length; | |
106 | } | |
107 | ||
108 | i = 0; | |
109 | while (i < data_length) { | |
110 | /* A 0 bit indicates literal data. */ | |
111 | if (altera_read_packed(in, 1, &bits_avail, | |
112 | &in_index) == 0) { | |
113 | for (j = 0; j < DATA_BLOB_LENGTH; ++j) { | |
114 | if (i < data_length) { | |
115 | out[i] = (u8)altera_read_packed(in, | |
116 | CHAR_BITS, | |
117 | &bits_avail, | |
118 | &in_index); | |
119 | i++; | |
120 | } | |
121 | } | |
122 | } else { | |
123 | /* A 1 bit indicates offset/length to follow. */ | |
124 | offset = altera_read_packed(in, altera_bits_req((s16) | |
125 | (i > match_data_length ? | |
126 | match_data_length : i)), | |
127 | &bits_avail, | |
128 | &in_index); | |
129 | length = altera_read_packed(in, CHAR_BITS, | |
130 | &bits_avail, | |
131 | &in_index); | |
132 | for (j = 0; j < length; ++j) { | |
133 | if (i < data_length) { | |
134 | out[i] = out[i - offset]; | |
135 | i++; | |
136 | } | |
137 | } | |
138 | } | |
139 | } | |
140 | ||
141 | return data_length; | |
142 | } |