1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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> |
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(buffer: in, |
84 | CHAR_BITS, |
85 | bits_avail: &bits_avail, |
86 | in_index: &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(buffer: in, bits: 1, bits_avail: &bits_avail, |
98 | in_index: &in_index) == 0) { |
99 | for (j = 0; j < DATA_BLOB_LENGTH; ++j) { |
100 | if (i < data_length) { |
101 | out[i] = (u8)altera_read_packed(buffer: in, |
102 | CHAR_BITS, |
103 | bits_avail: &bits_avail, |
104 | in_index: &in_index); |
105 | i++; |
106 | } |
107 | } |
108 | } else { |
109 | /* A 1 bit indicates offset/length to follow. */ |
110 | offset = altera_read_packed(buffer: in, bits: altera_bits_req(n: (s16) |
111 | (i > match_data_length ? |
112 | match_data_length : i)), |
113 | bits_avail: &bits_avail, |
114 | in_index: &in_index); |
115 | length = altera_read_packed(buffer: in, CHAR_BITS, |
116 | bits_avail: &bits_avail, |
117 | in_index: &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 | } |
129 | |