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 } 143