crypto/842.c

   1 /*
   2  * Cryptographic API for the 842 software compression algorithm.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * Copyright (C) IBM Corporation, 2011-2015
  15  *
  16  * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
  17  *                   Seth Jennings <sjenning@linux.vnet.ibm.com>
  18  *
  19  * Rewrite: Dan Streetman <ddstreet@ieee.org>
  20  *
  21  * This is the software implementation of compression and decompression using
  22  * the 842 format.  This uses the software 842 library at lib/842/ which is
  23  * only a reference implementation, and is very, very slow as compared to other
  24  * software compressors.  You probably do not want to use this software
  25  * compression.  If you have access to the PowerPC 842 compression hardware, you
  26  * want to use the 842 hardware compression interface, which is at:
  27  * drivers/crypto/nx/nx-842-crypto.c
  28  */
  29
  30 #include <linux/init.h>
  31 #include <linux/module.h>
  32 #include <linux/crypto.h>
  33 #include <linux/sw842.h>
  34
  35 struct crypto842_ctx {
  36         char wmem[SW842_MEM_COMPRESS];  /* working memory for compress */
  37 };
  38
  39 static int crypto842_compress(struct crypto_tfm *tfm,
  40                               const u8 *src, unsigned int slen,
  41                               u8 *dst, unsigned int *dlen)
  42 {
  43         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  44
  45         return sw842_compress(src, slen, dst, dlen, ctx->wmem);
  46 }
  47
  48 static int crypto842_decompress(struct crypto_tfm *tfm,
  49                                 const u8 *src, unsigned int slen,
  50                                 u8 *dst, unsigned int *dlen)
  51 {
  52         return sw842_decompress(src, slen, dst, dlen);
  53 }
  54
  55 static struct crypto_alg alg = {
  56         .cra_name               = "842",
  57         .cra_driver_name        = "842-generic",
  58         .cra_priority           = 100,
  59         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
  60         .cra_ctxsize            = sizeof(struct crypto842_ctx),
  61         .cra_module             = THIS_MODULE,
  62         .cra_u                  = { .compress = {
  63         .coa_compress           = crypto842_compress,
  64         .coa_decompress         = crypto842_decompress } }
  65 };
  66
  67 static int __init crypto842_mod_init(void)
  68 {
  69         return crypto_register_alg(&alg);
  70 }
  71 module_init(crypto842_mod_init);
  72
  73 static void __exit crypto842_mod_exit(void)
  74 {
  75         crypto_unregister_alg(&alg);
  76 }
  77 module_exit(crypto842_mod_exit);
  78
  79 MODULE_LICENSE("GPL");
  80 MODULE_DESCRIPTION("842 Software Compression Algorithm");
  81 MODULE_ALIAS_CRYPTO("842");
  82 MODULE_ALIAS_CRYPTO("842-generic");
  83 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");