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
altera_bits_req(u32 n)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
altera_read_packed(u8 * buffer,u32 bits,u32 * bits_avail,u32 * in_index)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
altera_shrink(u8 * in,u32 in_length,u8 * out,u32 out_length,s32 version)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 }
143