1/*
2 * Cryptographic API for the 842 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 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
17 *
18 * Copyright (C) IBM Corporation, 2011
19 *
20 * Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
21 *          Seth Jennings <sjenning@linux.vnet.ibm.com>
22 */
23
24#include <linux/init.h>
25#include <linux/module.h>
26#include <linux/crypto.h>
27#include <linux/vmalloc.h>
28#include <linux/nx842.h>
29#include <linux/lzo.h>
30#include <linux/timer.h>
31
32static int nx842_uselzo;
33
34struct nx842_ctx {
35	void *nx842_wmem; /* working memory for 842/lzo */
36};
37
38enum nx842_crypto_type {
39	NX842_CRYPTO_TYPE_842,
40	NX842_CRYPTO_TYPE_LZO
41};
42
43#define NX842_SENTINEL 0xdeadbeef
44
45struct nx842_crypto_header {
46	unsigned int sentinel; /* debug */
47	enum nx842_crypto_type type;
48};
49
50static int nx842_init(struct crypto_tfm *tfm)
51{
52	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
53	int wmemsize;
54
55	wmemsize = max_t(int, nx842_get_workmem_size(), LZO1X_MEM_COMPRESS);
56	ctx->nx842_wmem = kmalloc(wmemsize, GFP_NOFS);
57	if (!ctx->nx842_wmem)
58		return -ENOMEM;
59
60	return 0;
61}
62
63static void nx842_exit(struct crypto_tfm *tfm)
64{
65	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
66
67	kfree(ctx->nx842_wmem);
68}
69
70static void nx842_reset_uselzo(unsigned long data)
71{
72	nx842_uselzo = 0;
73}
74
75static DEFINE_TIMER(failover_timer, nx842_reset_uselzo, 0, 0);
76
77static int nx842_crypto_compress(struct crypto_tfm *tfm, const u8 *src,
78			    unsigned int slen, u8 *dst, unsigned int *dlen)
79{
80	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
81	struct nx842_crypto_header *hdr;
82	unsigned int tmp_len = *dlen;
83	size_t lzodlen; /* needed for lzo */
84	int err;
85
86	*dlen = 0;
87	hdr = (struct nx842_crypto_header *)dst;
88	hdr->sentinel = NX842_SENTINEL; /* debug */
89	dst += sizeof(struct nx842_crypto_header);
90	tmp_len -= sizeof(struct nx842_crypto_header);
91	lzodlen = tmp_len;
92
93	if (likely(!nx842_uselzo)) {
94		err = nx842_compress(src, slen, dst, &tmp_len, ctx->nx842_wmem);
95
96		if (likely(!err)) {
97			hdr->type = NX842_CRYPTO_TYPE_842;
98			*dlen = tmp_len + sizeof(struct nx842_crypto_header);
99			return 0;
100		}
101
102		/* hardware failed */
103		nx842_uselzo = 1;
104
105		/* set timer to check for hardware again in 1 second */
106		mod_timer(&failover_timer, jiffies + msecs_to_jiffies(1000));
107	}
108
109	/* no hardware, use lzo */
110	err = lzo1x_1_compress(src, slen, dst, &lzodlen, ctx->nx842_wmem);
111	if (err != LZO_E_OK)
112		return -EINVAL;
113
114	hdr->type = NX842_CRYPTO_TYPE_LZO;
115	*dlen = lzodlen + sizeof(struct nx842_crypto_header);
116	return 0;
117}
118
119static int nx842_crypto_decompress(struct crypto_tfm *tfm, const u8 *src,
120			      unsigned int slen, u8 *dst, unsigned int *dlen)
121{
122	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
123	struct nx842_crypto_header *hdr;
124	unsigned int tmp_len = *dlen;
125	size_t lzodlen; /* needed for lzo */
126	int err;
127
128	*dlen = 0;
129	hdr = (struct nx842_crypto_header *)src;
130
131	if (unlikely(hdr->sentinel != NX842_SENTINEL))
132		return -EINVAL;
133
134	src += sizeof(struct nx842_crypto_header);
135	slen -= sizeof(struct nx842_crypto_header);
136
137	if (likely(hdr->type == NX842_CRYPTO_TYPE_842)) {
138		err = nx842_decompress(src, slen, dst, &tmp_len,
139			ctx->nx842_wmem);
140		if (err)
141			return -EINVAL;
142		*dlen = tmp_len;
143	} else if (hdr->type == NX842_CRYPTO_TYPE_LZO) {
144		lzodlen = tmp_len;
145		err = lzo1x_decompress_safe(src, slen, dst, &lzodlen);
146		if (err != LZO_E_OK)
147			return -EINVAL;
148		*dlen = lzodlen;
149	} else
150		return -EINVAL;
151
152	return 0;
153}
154
155static struct crypto_alg alg = {
156	.cra_name		= "842",
157	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
158	.cra_ctxsize		= sizeof(struct nx842_ctx),
159	.cra_module		= THIS_MODULE,
160	.cra_init		= nx842_init,
161	.cra_exit		= nx842_exit,
162	.cra_u			= { .compress = {
163	.coa_compress		= nx842_crypto_compress,
164	.coa_decompress		= nx842_crypto_decompress } }
165};
166
167static int __init nx842_mod_init(void)
168{
169	del_timer(&failover_timer);
170	return crypto_register_alg(&alg);
171}
172
173static void __exit nx842_mod_exit(void)
174{
175	crypto_unregister_alg(&alg);
176}
177
178module_init(nx842_mod_init);
179module_exit(nx842_mod_exit);
180
181MODULE_LICENSE("GPL");
182MODULE_DESCRIPTION("842 Compression Algorithm");
183MODULE_ALIAS_CRYPTO("842");
184