Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 1 | /* Based on "File Verification Using CRC" by Mark R. Nelson in Dr. Dobbs' |
| 2 | * Journal, May 1992, pp. 64-67. This algorithm generates the same CRC |
| 3 | * values as ZMODEM and PKZIP |
| 4 | * |
| 5 | * Copyright (C) 2002-2005 SBE, Inc. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | */ |
| 17 | |
| 18 | #include <linux/types.h> |
| 19 | #include "pmcc4_sysdep.h" |
| 20 | #include "sbecom_inline_linux.h" |
| 21 | #include "sbe_promformat.h" |
| 22 | |
| 23 | /* defines */ |
| 24 | #define CRC32_POLYNOMIAL 0xEDB88320L |
| 25 | #define CRC_TABLE_ENTRIES 256 |
| 26 | |
| 27 | |
| 28 | |
| 29 | static u_int32_t crcTableInit; |
| 30 | |
| 31 | #ifdef STATIC_CRC_TABLE |
| 32 | static u_int32_t CRCTable[CRC_TABLE_ENTRIES]; |
| 33 | |
| 34 | #endif |
| 35 | |
| 36 | |
| 37 | /*************************************************************************** |
| 38 | * |
| 39 | * genCrcTable - fills in CRCTable, as used by sbeCrc() |
| 40 | * |
| 41 | * RETURNS: N/A |
| 42 | * |
| 43 | * ERRNO: N/A |
| 44 | ***************************************************************************/ |
| 45 | |
| 46 | static void |
Johan Meiring | 477953e | 2012-11-20 19:28:51 +0200 | [diff] [blame] | 47 | genCrcTable(u_int32_t *CRCTable) |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 48 | { |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 49 | int ii, jj; |
| 50 | u_int32_t crc; |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 51 | |
Johan Meiring | 3effcd0 | 2012-11-20 19:28:50 +0200 | [diff] [blame] | 52 | for (ii = 0; ii < CRC_TABLE_ENTRIES; ii++) { |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 53 | crc = ii; |
Johan Meiring | 3effcd0 | 2012-11-20 19:28:50 +0200 | [diff] [blame] | 54 | for (jj = 8; jj > 0; jj--) { |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 55 | if (crc & 1) |
| 56 | crc = (crc >> 1) ^ CRC32_POLYNOMIAL; |
| 57 | else |
| 58 | crc >>= 1; |
| 59 | } |
| 60 | CRCTable[ii] = crc; |
| 61 | } |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 62 | |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 63 | crcTableInit++; |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 64 | } |
| 65 | |
| 66 | |
| 67 | /*************************************************************************** |
| 68 | * |
| 69 | * sbeCrc - generates a CRC on a given buffer, and initial CRC |
| 70 | * |
| 71 | * This routine calculates the CRC for a buffer of data using the |
| 72 | * table lookup method. It accepts an original value for the crc, |
| 73 | * and returns the updated value. This permits "catenation" of |
| 74 | * discontiguous buffers. An original value of 0 for the "first" |
| 75 | * buffer is the norm. |
| 76 | * |
| 77 | * Based on "File Verification Using CRC" by Mark R. Nelson in Dr. Dobb's |
| 78 | * Journal, May 1992, pp. 64-67. This algorithm generates the same CRC |
| 79 | * values as ZMODEM and PKZIP. |
| 80 | * |
| 81 | * RETURNS: calculated crc of block |
| 82 | * |
| 83 | */ |
| 84 | |
| 85 | void |
Johan Meiring | 477953e | 2012-11-20 19:28:51 +0200 | [diff] [blame] | 86 | sbeCrc(u_int8_t *buffer, /* data buffer to crc */ |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 87 | u_int32_t count, /* length of block in bytes */ |
| 88 | u_int32_t initialCrc, /* starting CRC */ |
| 89 | u_int32_t *result) |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 90 | { |
Sachin Kamat | c11afaa | 2013-09-27 09:36:34 +0530 | [diff] [blame] | 91 | u_int32_t *tbl = NULL; |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 92 | u_int32_t temp1, temp2, crc; |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 93 | |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 94 | /* |
| 95 | * if table not yet created, do so. Don't care about "extra" time |
| 96 | * checking this every time sbeCrc() is called, since CRC calculations |
| 97 | * are already time consuming |
| 98 | */ |
Johan Meiring | 3effcd0 | 2012-11-20 19:28:50 +0200 | [diff] [blame] | 99 | if (!crcTableInit) { |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 100 | #ifdef STATIC_CRC_TABLE |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 101 | tbl = &CRCTable; |
Johan Meiring | 477953e | 2012-11-20 19:28:51 +0200 | [diff] [blame] | 102 | genCrcTable(tbl); |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 103 | #else |
Daeseok Youn | 693d963 | 2014-04-18 09:31:35 +0900 | [diff] [blame] | 104 | tbl = kzalloc(CRC_TABLE_ENTRIES * sizeof(u_int32_t), |
| 105 | GFP_KERNEL); |
Sachin Kamat | c11afaa | 2013-09-27 09:36:34 +0530 | [diff] [blame] | 106 | if (!tbl) { |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 107 | *result = 0; /* dummy up return value due to malloc |
| 108 | * failure */ |
| 109 | return; |
| 110 | } |
Johan Meiring | 477953e | 2012-11-20 19:28:51 +0200 | [diff] [blame] | 111 | genCrcTable(tbl); |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 112 | #endif |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 113 | } |
| 114 | /* inverting bits makes ZMODEM & PKZIP compatible */ |
| 115 | crc = initialCrc ^ 0xFFFFFFFFL; |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 116 | |
Johan Meiring | 3effcd0 | 2012-11-20 19:28:50 +0200 | [diff] [blame] | 117 | while (count-- != 0) { |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 118 | temp1 = (crc >> 8) & 0x00FFFFFFL; |
| 119 | temp2 = tbl[((int) crc ^ *buffer++) & 0xff]; |
| 120 | crc = temp1 ^ temp2; |
| 121 | } |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 122 | |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 123 | crc ^= 0xFFFFFFFFL; |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 124 | |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 125 | *result = crc; |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 126 | |
| 127 | #ifndef STATIC_CRC_TABLE |
Johan Meiring | 0b7ccbe | 2012-11-20 19:28:49 +0200 | [diff] [blame] | 128 | crcTableInit = 0; |
Daeseok Youn | 693d963 | 2014-04-18 09:31:35 +0900 | [diff] [blame] | 129 | kfree(tbl); |
Bob Beers | 50ee11f | 2010-03-04 08:40:46 -0500 | [diff] [blame] | 130 | #endif |
| 131 | } |
| 132 | |
| 133 | /*** End-of-File ***/ |