/*

   * Cryptographic API for the 842 software compression algorithm.

   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *

   * Copyright (C) IBM Corporation, 2011-2015

   *

   * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
   *                   Seth Jennings <sjenning@linux.vnet.ibm.com>

   *

   * Rewrite: Dan Streetman <ddstreet@ieee.org>
   *
   * This is the software implementation of compression and decompression using
   * the 842 format.  This uses the software 842 library at lib/842/ which is
   * only a reference implementation, and is very, very slow as compared to other
   * software compressors.  You probably do not want to use this software
   * compression.  If you have access to the PowerPC 842 compression hardware, you
   * want to use the 842 hardware compression interface, which is at:
   * drivers/crypto/nx/nx-842-crypto.c

   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/crypto.h>

  #include <linux/sw842.h>

  #include <crypto/internal/scompress.h>

  struct crypto842_ctx {

  	void *wmem;	/* working memory for compress */

  };

  static void *crypto842_alloc_ctx(struct crypto_scomp *tfm)
  {
  	void *ctx;
  
  	ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
  	if (!ctx)
  		return ERR_PTR(-ENOMEM);
  
  	return ctx;
  }
  
  static int crypto842_init(struct crypto_tfm *tfm)
  {
  	struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	ctx->wmem = crypto842_alloc_ctx(NULL);
  	if (IS_ERR(ctx->wmem))
  		return -ENOMEM;
  
  	return 0;
  }
  
  static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
  {
  	kfree(ctx);
  }
  
  static void crypto842_exit(struct crypto_tfm *tfm)
  {
  	struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	crypto842_free_ctx(NULL, ctx->wmem);
  }

  static int crypto842_compress(struct crypto_tfm *tfm,
  			      const u8 *src, unsigned int slen,
  			      u8 *dst, unsigned int *dlen)

  {

  	struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);

  	return sw842_compress(src, slen, dst, dlen, ctx->wmem);

  }

  static int crypto842_scompress(struct crypto_scomp *tfm,
  			       const u8 *src, unsigned int slen,
  			       u8 *dst, unsigned int *dlen, void *ctx)
  {
  	return sw842_compress(src, slen, dst, dlen, ctx);
  }

  static int crypto842_decompress(struct crypto_tfm *tfm,
  				const u8 *src, unsigned int slen,
  				u8 *dst, unsigned int *dlen)

  {

  	return sw842_decompress(src, slen, dst, dlen);

  }

  static int crypto842_sdecompress(struct crypto_scomp *tfm,
  				 const u8 *src, unsigned int slen,
  				 u8 *dst, unsigned int *dlen, void *ctx)
  {
  	return sw842_decompress(src, slen, dst, dlen);
  }

  static struct crypto_alg alg = {
  	.cra_name		= "842",

  	.cra_driver_name	= "842-generic",
  	.cra_priority		= 100,

  	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,

  	.cra_ctxsize		= sizeof(struct crypto842_ctx),

  	.cra_module		= THIS_MODULE,

  	.cra_init		= crypto842_init,
  	.cra_exit		= crypto842_exit,

  	.cra_u			= { .compress = {

  	.coa_compress		= crypto842_compress,
  	.coa_decompress		= crypto842_decompress } }

  };

  static struct scomp_alg scomp = {
  	.alloc_ctx		= crypto842_alloc_ctx,
  	.free_ctx		= crypto842_free_ctx,
  	.compress		= crypto842_scompress,
  	.decompress		= crypto842_sdecompress,
  	.base			= {
  		.cra_name	= "842",
  		.cra_driver_name = "842-scomp",
  		.cra_priority	 = 100,
  		.cra_module	 = THIS_MODULE,
  	}
  };

  static int __init crypto842_mod_init(void)

  {

  	int ret;
  
  	ret = crypto_register_alg(&alg);
  	if (ret)
  		return ret;
  
  	ret = crypto_register_scomp(&scomp);
  	if (ret) {
  		crypto_unregister_alg(&alg);
  		return ret;
  	}
  
  	return ret;

  }

  module_init(crypto842_mod_init);

  static void __exit crypto842_mod_exit(void)

  {
  	crypto_unregister_alg(&alg);

  	crypto_unregister_scomp(&scomp);

  }

  module_exit(crypto842_mod_exit);

  
  MODULE_LICENSE("GPL");

  MODULE_DESCRIPTION("842 Software Compression Algorithm");

  MODULE_ALIAS_CRYPTO("842");

  MODULE_ALIAS_CRYPTO("842-generic");
  MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");