[PATCH 4/4] powerpc/crypto: add 842 crypto driver

[Seth Jennings]

This patch add the 842 cryptographic API driver that
submits compression requests to the 842 hardware compression
accelerator driver (nx-compress).

If the hardware accelerator goes offline for any reason
(dynamic disable, migration, etc...), this driver will use LZO
as a software failover for all future compression requests.
For decompression requests, the 842 hardware driver contains
a software implementation of the 842 decompressor to support
the decompression of data that was compressed before the accelerator
went offline.

Signed-off-by: Robert Jennings <rcj@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>
---
 crypto/842.c    |  183 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 crypto/Kconfig  |    9 +++
 crypto/Makefile |    1 +
 3 files changed, 193 insertions(+)
 create mode 100644 crypto/842.c

diff --git a/crypto/842.c b/crypto/842.c
new file mode 100644
index 0000000..144767d
--- /dev/null
+++ b/crypto/842.c
@@ -0,0 +1,183 @@
+/*
+ * Cryptographic API for the 842 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (C) IBM Corporation, 2011
+ *
+ * Authors: Robert Jennings <rcj@xxxxxxxxxxxxxxxxxx>
+ *          Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/crypto.h>
+#include <linux/vmalloc.h>
+#include <linux/nx842.h>
+#include <linux/lzo.h>
+#include <linux/timer.h>
+
+static int nx842_uselzo;
+
+struct nx842_ctx {
+	void *nx842_wmem; /* working memory for 842/lzo */
+};
+
+enum nx842_crypto_type {
+	NX842_CRYPTO_TYPE_842,
+	NX842_CRYPTO_TYPE_LZO
+};
+
+#define NX842_SENTINEL 0xdeadbeef
+
+struct nx842_crypto_header {
+	unsigned int sentinel; /* debug */
+	enum nx842_crypto_type type;
+};
+
+static int nx842_init(struct crypto_tfm *tfm)
+{
+	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
+	int wmemsize;
+
+	wmemsize = max_t(int, nx842_get_workmem_size(), LZO1X_MEM_COMPRESS);
+	ctx->nx842_wmem = kmalloc(wmemsize, GFP_NOFS);
+	if (!ctx->nx842_wmem)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void nx842_exit(struct crypto_tfm *tfm)
+{
+	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	kfree(ctx->nx842_wmem);
+}
+
+static void nx842_reset_uselzo(unsigned long data)
+{
+	nx842_uselzo = 0;
+}
+
+static DEFINE_TIMER(failover_timer, nx842_reset_uselzo, 0, 0);
+
+static int nx842_crypto_compress(struct crypto_tfm *tfm, const u8 *src,
+			    unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct nx842_crypto_header *hdr;
+	unsigned int tmp_len = *dlen;
+	size_t lzodlen; /* needed for lzo */
+	int err;
+
+	*dlen = 0;
+	hdr = (struct nx842_crypto_header *)dst;
+	hdr->sentinel = NX842_SENTINEL; /* debug */
+	dst += sizeof(struct nx842_crypto_header);
+	tmp_len -= sizeof(struct nx842_crypto_header);
+	lzodlen = tmp_len;
+
+	if (likely(!nx842_uselzo)) {
+		err = nx842_compress(src, slen, dst, &tmp_len, ctx->nx842_wmem);
+
+		if (likely(!err)) {
+			hdr->type = NX842_CRYPTO_TYPE_842;
+			*dlen = tmp_len + sizeof(struct nx842_crypto_header);
+			return 0;
+		}
+
+		/* hardware failed */
+		nx842_uselzo = 1;
+
+		/* set timer to check for hardware again in 1 second */
+		mod_timer(&failover_timer, jiffies + msecs_to_jiffies(1000));
+	}
+
+	/* no hardware, use lzo */
+	err = lzo1x_1_compress(src, slen, dst, &lzodlen, ctx->nx842_wmem);
+	if (err != LZO_E_OK)
+		return -EINVAL;
+
+	hdr->type = NX842_CRYPTO_TYPE_LZO;
+	*dlen = lzodlen + sizeof(struct nx842_crypto_header);
+	return 0;
+}
+
+static int nx842_crypto_decompress(struct crypto_tfm *tfm, const u8 *src,
+			      unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+	struct nx842_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct nx842_crypto_header *hdr;
+	unsigned int tmp_len = *dlen;
+	size_t lzodlen; /* needed for lzo */
+	int err;
+
+	*dlen = 0;
+	hdr = (struct nx842_crypto_header *)src;
+
+	if (unlikely(hdr->sentinel != NX842_SENTINEL))
+		return -EINVAL;
+
+	src += sizeof(struct nx842_crypto_header);
+	slen -= sizeof(struct nx842_crypto_header);
+
+	if (likely(hdr->type == NX842_CRYPTO_TYPE_842)) {
+		err = nx842_decompress(src, slen, dst, &tmp_len,
+			ctx->nx842_wmem);
+		if (err)
+			return -EINVAL;
+		*dlen = tmp_len;
+	} else if (hdr->type == NX842_CRYPTO_TYPE_LZO) {
+		lzodlen = tmp_len;
+		err = lzo1x_decompress_safe(src, slen, dst, &lzodlen);
+		if (err != LZO_E_OK)
+			return -EINVAL;
+		*dlen = lzodlen;
+	} else
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct crypto_alg alg = {
+	.cra_name		= "842",
+	.cra_flags		= CRYPTO_ALG_TYPE_COMPRESS,
+	.cra_ctxsize		= sizeof(struct nx842_ctx),
+	.cra_module		= THIS_MODULE,
+	.cra_list		= LIST_HEAD_INIT(alg.cra_list),
+	.cra_init		= nx842_init,
+	.cra_exit		= nx842_exit,
+	.cra_u			= { .compress = {
+	.coa_compress		= nx842_crypto_compress,
+	.coa_decompress		= nx842_crypto_decompress } }
+};
+
+static int __init nx842_mod_init(void)
+{
+	del_timer(&failover_timer);
+	return crypto_register_alg(&alg);
+}
+
+static void __exit nx842_mod_exit(void)
+{
+	crypto_unregister_alg(&alg);
+}
+
+module_init(nx842_mod_init);
+module_exit(nx842_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("842 Compression Algorithm");
diff --git a/crypto/Kconfig b/crypto/Kconfig
index a323805..7876358 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1008,6 +1008,15 @@ config CRYPTO_LZO
 	help
 	  This is the LZO algorithm.
 
+config CRYPTO_842
+	tristate "842 compression algorithm"
+	depends on CRYPTO_DEV_NX_COMPRESS
+	# 842 uses lzo if the hardware becomes unavailable
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+	help
+	  This is the 842 algorithm.
+
 comment "Random Number Generation"
 
 config CRYPTO_ANSI_CPRNG
diff --git a/crypto/Makefile b/crypto/Makefile
index 30f33d6..5d5675c 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_CRYPTO_MICHAEL_MIC) += michael_mic.o
 obj-$(CONFIG_CRYPTO_CRC32C) += crc32c.o
 obj-$(CONFIG_CRYPTO_AUTHENC) += authenc.o authencesn.o
 obj-$(CONFIG_CRYPTO_LZO) += lzo.o
+obj-$(CONFIG_CRYPTO_842) += 842.o
 obj-$(CONFIG_CRYPTO_RNG2) += rng.o
 obj-$(CONFIG_CRYPTO_RNG2) += krng.o
 obj-$(CONFIG_CRYPTO_ANSI_CPRNG) += ansi_cprng.o
-- 
1.7.9.5

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