lib: add BLAKE2 hash support

The code is cross-ported from BLAKE2 reference implementation
(https://github.com/BLAKE2/BLAKE2).

With minimal change to remove unused macros/features.

Currently there is only one user inside U-boot (btrfs), and since it
only utilize BLAKE2B, all other favors are all removed.

Signed-off-by: Qu Wenruo <wqu@suse.com>
[trini: Rename ROUND to R to avoid clash with <linux/bitops.h>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/u-boot/blake2.h b/include/u-boot/blake2.h
new file mode 100644
index 0000000..4984023
--- /dev/null
+++ b/include/u-boot/blake2.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: CC0-1.0 */
+/*
+   BLAKE2 reference source code package - reference C implementations
+
+   Copyright 2012, Samuel Neves <sneves@dei.uc.pt>.  You may use this under the
+   terms of the CC0, the OpenSSL Licence, or the Apache Public License 2.0, at
+   your option.  The terms of these licenses can be found at:
+
+   - CC0 1.0 Universal : http://creativecommons.org/publicdomain/zero/1.0
+   - OpenSSL license   : https://www.openssl.org/source/license.html
+   - Apache 2.0        : http://www.apache.org/licenses/LICENSE-2.0
+
+   More information about the BLAKE2 hash function can be found at
+   https://blake2.net.
+*/
+
+/*
+ * Cross-ported from BLAKE2 (https://github.com/BLAKE2/BLAKE2).
+ * Modifications includes:
+ *
+ * - Remove unsupported compilers like MSC/CPP
+ * - Remove blake2s/blake2sp/blake2bp
+ *   This blake2 implementation is mostly for btrfs, which only utilizes
+ *   blake2b.
+ */
+#ifndef BLAKE2_H
+#define BLAKE2_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#if defined(_MSC_VER)
+#define BLAKE2_PACKED(x) __pragma(pack(push, 1)) x __pragma(pack(pop))
+#else
+#define BLAKE2_PACKED(x) x __attribute__((packed))
+#endif
+
+  enum blake2b_constant
+  {
+    BLAKE2B_BLOCKBYTES = 128,
+    BLAKE2B_OUTBYTES   = 64,
+    BLAKE2B_KEYBYTES   = 64,
+    BLAKE2B_SALTBYTES  = 16,
+    BLAKE2B_PERSONALBYTES = 16
+  };
+
+  typedef struct blake2b_state__
+  {
+    uint64_t h[8];
+    uint64_t t[2];
+    uint64_t f[2];
+    uint8_t  buf[BLAKE2B_BLOCKBYTES];
+    size_t   buflen;
+    size_t   outlen;
+    uint8_t  last_node;
+  } blake2b_state;
+
+  BLAKE2_PACKED(struct blake2b_param__
+  {
+    uint8_t  digest_length; /* 1 */
+    uint8_t  key_length;    /* 2 */
+    uint8_t  fanout;        /* 3 */
+    uint8_t  depth;         /* 4 */
+    uint32_t leaf_length;   /* 8 */
+    uint32_t node_offset;   /* 12 */
+    uint32_t xof_length;    /* 16 */
+    uint8_t  node_depth;    /* 17 */
+    uint8_t  inner_length;  /* 18 */
+    uint8_t  reserved[14];  /* 32 */
+    uint8_t  salt[BLAKE2B_SALTBYTES]; /* 48 */
+    uint8_t  personal[BLAKE2B_PERSONALBYTES];  /* 64 */
+  });
+
+  typedef struct blake2b_param__ blake2b_param;
+
+  /* Padded structs result in a compile-time error */
+  enum {
+    BLAKE2_DUMMY_2 = 1/(int)(sizeof(blake2b_param) == BLAKE2B_OUTBYTES)
+  };
+
+  /* Streaming API */
+  int blake2b_init( blake2b_state *S, size_t outlen );
+  int blake2b_init_key( blake2b_state *S, size_t outlen, const void *key, size_t keylen );
+  int blake2b_init_param( blake2b_state *S, const blake2b_param *P );
+  int blake2b_update( blake2b_state *S, const void *in, size_t inlen );
+  int blake2b_final( blake2b_state *S, void *out, size_t outlen );
+
+  /* Simple API */
+  int blake2b( void *out, size_t outlen, const void *in, size_t inlen, const void *key, size_t keylen );
+
+  /* This is simply an alias for blake2b */
+  int blake2( void *out, size_t outlen, const void *in, size_t inlen, const void *key, size_t keylen );
+
+#endif