crypto: nx - add NX-842 platform frontend driver

Add NX-842 frontend that allows using either the pSeries platform or
PowerNV platform driver (to be added by later patch) for the NX-842
hardware.  Update the MAINTAINERS file to include the new filenames.
Update Kconfig files to clarify titles and descriptions, and correct
dependencies.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 144 insertions, 0 deletions

diff --git a/drivers/crypto/nx/nx-842.c b/drivers/crypto/nx/nx-842.c
new file mode 100644
index 000000000000..f1f378eef373
--- /dev/null
+++ b/drivers/crypto/nx/nx-842.c
@@ -0,0 +1,144 @@
+/*
+ * Driver frontend for IBM Power 842 compression accelerator
+ *
+ * Copyright (C) 2015 Dan Streetman, IBM Corp
+ *
+ * Designer of the Power data compression engine:
+ *   Bulent Abali <abali@us.ibm.com>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "nx-842.h"
+
+#define MODULE_NAME "nx-compress"
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
+MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");
+
+/* Only one driver is expected, based on the HW platform */
+static struct nx842_driver *nx842_driver;
+static DEFINE_SPINLOCK(nx842_driver_lock); /* protects driver pointers */
+
+void nx842_register_driver(struct nx842_driver *driver)
+{
+	spin_lock(&nx842_driver_lock);
+
+	if (nx842_driver) {
+		pr_err("can't register driver %s, already using driver %s\n",
+		       driver->owner->name, nx842_driver->owner->name);
+	} else {
+		pr_info("registering driver %s\n", driver->owner->name);
+		nx842_driver = driver;
+	}
+
+	spin_unlock(&nx842_driver_lock);
+}
+EXPORT_SYMBOL_GPL(nx842_register_driver);
+
+void nx842_unregister_driver(struct nx842_driver *driver)
+{
+	spin_lock(&nx842_driver_lock);
+
+	if (nx842_driver == driver) {
+		pr_info("unregistering driver %s\n", driver->owner->name);
+		nx842_driver = NULL;
+	} else if (nx842_driver) {
+		pr_err("can't unregister driver %s, using driver %s\n",
+		       driver->owner->name, nx842_driver->owner->name);
+	} else {
+		pr_err("can't unregister driver %s, no driver in use\n",
+		       driver->owner->name);
+	}
+
+	spin_unlock(&nx842_driver_lock);
+}
+EXPORT_SYMBOL_GPL(nx842_unregister_driver);
+
+static struct nx842_driver *get_driver(void)
+{
+	struct nx842_driver *driver = NULL;
+
+	spin_lock(&nx842_driver_lock);
+
+	driver = nx842_driver;
+
+	if (driver && !try_module_get(driver->owner))
+		driver = NULL;
+
+	spin_unlock(&nx842_driver_lock);
+
+	return driver;
+}
+
+static void put_driver(struct nx842_driver *driver)
+{
+	module_put(driver->owner);
+}
+
+int nx842_compress(const unsigned char *in, unsigned int in_len,
+		   unsigned char *out, unsigned int *out_len,
+		   void *wrkmem)
+{
+	struct nx842_driver *driver = get_driver();
+	int ret;
+
+	if (!driver)
+		return -ENODEV;
+
+	ret = driver->compress(in, in_len, out, out_len, wrkmem);
+
+	put_driver(driver);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nx842_compress);
+
+int nx842_decompress(const unsigned char *in, unsigned int in_len,
+		     unsigned char *out, unsigned int *out_len,
+		     void *wrkmem)
+{
+	struct nx842_driver *driver = get_driver();
+	int ret;
+
+	if (!driver)
+		return -ENODEV;
+
+	ret = driver->decompress(in, in_len, out, out_len, wrkmem);
+
+	put_driver(driver);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nx842_decompress);
+
+static __init int nx842_init(void)
+{
+	pr_info("loading\n");
+
+	if (of_find_compatible_node(NULL, NULL, NX842_PSERIES_COMPAT_NAME))
+		request_module_nowait(NX842_PSERIES_MODULE_NAME);
+	else
+		pr_err("no nx842 driver found.\n");
+
+	pr_info("loaded\n");
+
+	return 0;
+}
+module_init(nx842_init);
+
+static void __exit nx842_exit(void)
+{
+	pr_info("NX842 unloaded\n");
+}
+module_exit(nx842_exit);