[GitHub] [mynewt-core] mkiiskila commented on a change in pull request #1876: [RFC] Add cryptographic HASH driver

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mkiiskila commented on a change in pull request #1876: [RFC] Add cryptographic HASH driver
URL: https://github.com/apache/mynewt-core/pull/1876#discussion_r295208846
 
 

 ##########
 File path: hw/drivers/hash/include/hash/hash.h
 ##########
 @@ -0,0 +1,235 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef __HASH_H__
+#define __HASH_H__
+
+#include <inttypes.h>
+#include <stddef.h>
+#include "os/mynewt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * HASH definitions
+ */
+#define MD5_DIGEST_LEN                 16
+#define SHA1_DIGEST_LEN                20
+#define SHA224_DIGEST_LEN              28
+#define SHA256_DIGEST_LEN              32
+#define HASH_MAX_DIGEST_LEN            SHA256_DIGEST_LEN
+
+#define SHA256_BLOCK_LEN               64  /* 512 bits */
+#define HASH_MAX_BLOCK_LEN             SHA256_BLOCK_LEN
+
+/*
+ * MCU specific context structs
+ */
+#include "hash_context.h"
+
+struct hash_generic_context {
+    union {
+        struct hash_md5_context md5ctx;
+        struct hash_sha1_context sha1ctx;
+        struct hash_sha224_context sha224ctx;
+        struct hash_sha256_context sha256ctx;
+    };
+};
+
+/*
+ * Driver capabilities
+ */
+#define HASH_ALGO_MD5                  0x0001
+#define HASH_ALGO_SHA1                 0x0002
+#define HASH_ALGO_SHA224               0x0004
+#define HASH_ALGO_SHA256               0x0008
+
+struct hash_dev;
+
+typedef int (* hash_start_op_func_t)(struct hash_dev *hash, void *ctx,
+        uint16_t algo);
+typedef int (* hash_update_op_func_t)(struct hash_dev *hash, void *ctx,
+        uint16_t algo, const void *inbuf, uint32_t inlen);
+typedef int (* hash_finish_op_func_t)(struct hash_dev *hash, void *ctx,
+        uint16_t algo, void *outbuf);
+typedef bool (* hash_support_func_t)(struct hash_dev *hash, uint16_t algo);
+
+/**
+ * @struct hash_interface
+ * @brief Provides the interface into a HW hash driver
+ *
+ * @var hash_interface::start
+ * start is a hash_start_op_func_t pointer to the hashing routine used
+ * to start a new stream operation
+ *
+ * @var hash_interface::update
+ * update is a hash_update_op_func_t pointer to the hashing routine used
+ * to update the current stream operation with new data
+ *
+ * @var hash_interface::finish
+ * finish is a hash_finish_op_func_t pointer to the hashing routine used
+ * to finish the current stream operation and return a digest
+ *
+ * @var hash_interface::has_support
+ * has_support is used to inquire about which algos are natively
+ * supported
+ */
+struct hash_interface {
+    hash_start_op_func_t start;
+    hash_update_op_func_t update;
+    hash_finish_op_func_t finish;
+    hash_support_func_t has_support;
 
 Review comment:
   I would make the capabilities field a uint within struct hash_dev instead. Have an inline function to inspect it. So we ever run out of bits for capabilities, it can turned into a function.
   I think we'd end up with less text space use that way.

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