linux/crypto/842.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Cryptographic API for the 842 software compression algorithm.
   4 *
   5 * Copyright (C) IBM Corporation, 2011-2015
   6 *
   7 * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
   8 *                   Seth Jennings <sjenning@linux.vnet.ibm.com>
   9 *
  10 * Rewrite: Dan Streetman <ddstreet@ieee.org>
  11 *
  12 * This is the software implementation of compression and decompression using
  13 * the 842 format.  This uses the software 842 library at lib/842/ which is
  14 * only a reference implementation, and is very, very slow as compared to other
  15 * software compressors.  You probably do not want to use this software
  16 * compression.  If you have access to the PowerPC 842 compression hardware, you
  17 * want to use the 842 hardware compression interface, which is at:
  18 * drivers/crypto/nx/nx-842-crypto.c
  19 */
  20
  21#include <linux/init.h>
  22#include <linux/module.h>
  23#include <linux/crypto.h>
  24#include <linux/sw842.h>
  25#include <crypto/internal/scompress.h>
  26
  27struct crypto842_ctx {
  28        void *wmem;     /* working memory for compress */
  29};
  30
  31static void *crypto842_alloc_ctx(struct crypto_scomp *tfm)
  32{
  33        void *ctx;
  34
  35        ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
  36        if (!ctx)
  37                return ERR_PTR(-ENOMEM);
  38
  39        return ctx;
  40}
  41
  42static int crypto842_init(struct crypto_tfm *tfm)
  43{
  44        struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  45
  46        ctx->wmem = crypto842_alloc_ctx(NULL);
  47        if (IS_ERR(ctx->wmem))
  48                return -ENOMEM;
  49
  50        return 0;
  51}
  52
  53static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
  54{
  55        kfree(ctx);
  56}
  57
  58static void crypto842_exit(struct crypto_tfm *tfm)
  59{
  60        struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  61
  62        crypto842_free_ctx(NULL, ctx->wmem);
  63}
  64
  65static int crypto842_compress(struct crypto_tfm *tfm,
  66                              const u8 *src, unsigned int slen,
  67                              u8 *dst, unsigned int *dlen)
  68{
  69        struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  70
  71        return sw842_compress(src, slen, dst, dlen, ctx->wmem);
  72}
  73
  74static int crypto842_scompress(struct crypto_scomp *tfm,
  75                               const u8 *src, unsigned int slen,
  76                               u8 *dst, unsigned int *dlen, void *ctx)
  77{
  78        return sw842_compress(src, slen, dst, dlen, ctx);
  79}
  80
  81static int crypto842_decompress(struct crypto_tfm *tfm,
  82                                const u8 *src, unsigned int slen,
  83                                u8 *dst, unsigned int *dlen)
  84{
  85        return sw842_decompress(src, slen, dst, dlen);
  86}
  87
  88static int crypto842_sdecompress(struct crypto_scomp *tfm,
  89                                 const u8 *src, unsigned int slen,
  90                                 u8 *dst, unsigned int *dlen, void *ctx)
  91{
  92        return sw842_decompress(src, slen, dst, dlen);
  93}
  94
  95static struct crypto_alg alg = {
  96        .cra_name               = "842",
  97        .cra_driver_name        = "842-generic",
  98        .cra_priority           = 100,
  99        .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 100        .cra_ctxsize            = sizeof(struct crypto842_ctx),
 101        .cra_module             = THIS_MODULE,
 102        .cra_init               = crypto842_init,
 103        .cra_exit               = crypto842_exit,
 104        .cra_u                  = { .compress = {
 105        .coa_compress           = crypto842_compress,
 106        .coa_decompress         = crypto842_decompress } }
 107};
 108
 109static struct scomp_alg scomp = {
 110        .alloc_ctx              = crypto842_alloc_ctx,
 111        .free_ctx               = crypto842_free_ctx,
 112        .compress               = crypto842_scompress,
 113        .decompress             = crypto842_sdecompress,
 114        .base                   = {
 115                .cra_name       = "842",
 116                .cra_driver_name = "842-scomp",
 117                .cra_priority    = 100,
 118                .cra_module      = THIS_MODULE,
 119        }
 120};
 121
 122static int __init crypto842_mod_init(void)
 123{
 124        int ret;
 125
 126        ret = crypto_register_alg(&alg);
 127        if (ret)
 128                return ret;
 129
 130        ret = crypto_register_scomp(&scomp);
 131        if (ret) {
 132                crypto_unregister_alg(&alg);
 133                return ret;
 134        }
 135
 136        return ret;
 137}
 138subsys_initcall(crypto842_mod_init);
 139
 140static void __exit crypto842_mod_exit(void)
 141{
 142        crypto_unregister_alg(&alg);
 143        crypto_unregister_scomp(&scomp);
 144}
 145module_exit(crypto842_mod_exit);
 146
 147MODULE_LICENSE("GPL");
 148MODULE_DESCRIPTION("842 Software Compression Algorithm");
 149MODULE_ALIAS_CRYPTO("842");
 150MODULE_ALIAS_CRYPTO("842-generic");
 151MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
 152
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