libcrc32c: Move implementation to crypto crc32c

This patch swaps the role of libcrc32c and crc32c.  Previously
the implementation was in libcrc32c and crc32c was a wrapper.
Now the code is in crc32c and libcrc32c just calls the crypto
layer.

The reason for the change is to tap into the algorithm selection
capability of the crypto API so that optimised implementations
such as the one utilising Intel's CRC32C instruction can be
used where available.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 112 insertions, 5 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index dc20a34b..aede802 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -256,12 +256,10 @@ comment "Digest"
 config CRYPTO_CRC32C
 	tristate "CRC32c CRC algorithm"
 	select CRYPTO_HASH
-	select LIBCRC32C
 	help
 	  Castagnoli, et al Cyclic Redundancy-Check Algorithm.  Used
 	  by iSCSI for header and data digests and by others.
-	  See Castagnoli93.  This implementation uses lib/libcrc32c.
-	  Module will be crc32c.
+	  See Castagnoli93.  Module will be crc32c.
 
 config CRYPTO_CRC32C_INTEL
 	tristate "CRC32c INTEL hardware acceleration"
diff --git a/crypto/crc32c.c b/crypto/crc32c.c
index b21b93f..973bc2c 100644
--- a/crypto/crc32c.c
+++ b/crypto/crc32c.c
@@ -3,8 +3,29 @@
  *
  * CRC32C chksum
  *
- * This module file is a wrapper to invoke the lib/crc32c routines.
+ *@Article{castagnoli-crc,
+ * author =       { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
+ * title =        {{Optimization of Cyclic Redundancy-Check Codes with 24
+ *                 and 32 Parity Bits}},
+ * journal =      IEEE Transactions on Communication,
+ * year =         {1993},
+ * volume =       {41},
+ * number =       {6},
+ * pages =        {},
+ * month =        {June},
+ *}
+ * Used by the iSCSI driver, possibly others, and derived from the
+ * the iscsi-crc.c module of the linux-iscsi driver at
+ * http://linux-iscsi.sourceforge.net.
  *
+ * Following the example of lib/crc32, this function is intended to be
+ * flexible and useful for all users.  Modules that currently have their
+ * own crc32c, but hopefully may be able to use this one are:
+ *  net/sctp (please add all your doco to here if you change to
+ *            use this one!)
+ *  <endoflist>
+ *
+ * Copyright (c) 2004 Cisco Systems, Inc.
  * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -18,7 +39,6 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/string.h>
-#include <linux/crc32c.h>
 #include <linux/kernel.h>
 
 #define CHKSUM_BLOCK_SIZE	1
@@ -33,6 +53,95 @@ struct chksum_desc_ctx {
 };
 
 /*
+ * This is the CRC-32C table
+ * Generated with:
+ * width = 32 bits
+ * poly = 0x1EDC6F41
+ * reflect input bytes = true
+ * reflect output bytes = true
+ */
+
+static const u32 crc32c_table[256] = {
+	0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
+	0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
+	0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
+	0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
+	0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
+	0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
+	0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
+	0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
+	0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
+	0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
+	0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
+	0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
+	0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
+	0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
+	0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
+	0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
+	0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
+	0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
+	0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
+	0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
+	0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
+	0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
+	0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
+	0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
+	0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
+	0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
+	0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
+	0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
+	0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
+	0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
+	0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
+	0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
+	0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
+	0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
+	0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
+	0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
+	0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
+	0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
+	0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
+	0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
+	0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
+	0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
+	0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
+	0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
+	0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
+	0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
+	0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
+	0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
+	0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
+	0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
+	0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
+	0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
+	0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
+	0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
+	0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
+	0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
+	0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
+	0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
+	0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
+	0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
+	0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
+	0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
+	0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
+	0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
+};
+
+/*
+ * Steps through buffer one byte at at time, calculates reflected
+ * crc using table.
+ */
+
+static u32 crc32c(u32 crc, const u8 *data, unsigned int length)
+{
+	while (length--)
+		crc = crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
+
+	return crc;
+}
+
+/*
  * Steps through buffer one byte at at time, calculates reflected 
  * crc using table.
  */