mbedtls: add digest shim layer for MbedTLS

Implement digest shim layer on top of MbedTLS crypto library.
Introduce <alg>_MBEDTLS kconfig for MbedTLS crypto implementations.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/lib/mbedtls/md5.c b/lib/mbedtls/md5.c
new file mode 100644
index 00000000000..04388fce249
--- /dev/null
+++ b/lib/mbedtls/md5.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hash shim layer on MbedTLS Crypto library
+ *
+ * Copyright (c) 2024 Linaro Limited
+ * Author: Raymond Mao <raymond.mao@linaro.org>
+ */
+#include "compiler.h"
+
+#ifndef USE_HOSTCC
+#include <watchdog.h>
+#endif /* USE_HOSTCC */
+#include <u-boot/md5.h>
+
+void MD5Init(MD5Context *ctx)
+{
+	mbedtls_md5_init(ctx);
+	mbedtls_md5_starts(ctx);
+}
+
+void MD5Update(MD5Context *ctx, unsigned char const *buf, unsigned int len)
+{
+	mbedtls_md5_update(ctx, buf, len);
+}
+
+void MD5Final(unsigned char digest[16], MD5Context *ctx)
+{
+	mbedtls_md5_finish(ctx, digest);
+	mbedtls_md5_free(ctx);
+}
+
+void md5_wd(const unsigned char *input, unsigned int len,
+	    unsigned char output[16], unsigned int chunk_sz)
+{
+	MD5Context context;
+
+	MD5Init(&context);
+
+	if (IS_ENABLED(CONFIG_HW_WATCHDOG) || IS_ENABLED(CONFIG_WATCHDOG)) {
+		const unsigned char *curr = input;
+		const unsigned char *end = input + len;
+		int chunk;
+
+		while (curr < end) {
+			chunk = end - curr;
+			if (chunk > chunk_sz)
+				chunk = chunk_sz;
+			MD5Update(&context, curr, chunk);
+			curr += chunk;
+			schedule();
+		}
+	} else {
+		MD5Update(&context, input, len);
+	}
+
+	MD5Final(output, &context);
+}