hash: Add a way to calculate a hash for any algortihm

Rather than needing to call one of many hashing algorithms in U-Boot,
provide a function hash_block() which handles this, and can support all
available hash algorithms.

Once we have md5 supported within hashing, we can use this function in
the FIT image code.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/include/hash.h b/include/hash.h
index 2dbbd9b7d..c402067af 100644
--- a/include/hash.h
+++ b/include/hash.h
@@ -71,4 +71,26 @@ enum {
 int hash_command(const char *algo_name, int flags, cmd_tbl_t *cmdtp, int flag,
 		 int argc, char * const argv[]);
 
+/**
+ * hash_block() - Hash a block according to the requested algorithm
+ *
+ * The caller probably knows the hash length for the chosen algorithm, but
+ * in order to provide a general interface, and output_size parameter is
+ * provided.
+ *
+ * @algo_name:		Hash algorithm to use
+ * @data:		Data to hash
+ * @len:		Lengh of data to hash in bytes
+ * @output:		Place to put hash value
+ * @output_size:	On entry, pointer to the number of bytes available in
+ *			output. On exit, pointer to the number of bytes used.
+ *			If NULL, then it is assumed that the caller has
+ *			allocated enough space for the hash. This is possible
+ *			since the caller is selecting the algorithm.
+ * @return 0 if ok, -ve on error: -EPROTONOSUPPORT for an unknown algorithm,
+ * -ENOSPC if the output buffer is not large enough.
+ */
+int hash_block(const char *algo_name, const void *data, unsigned int len,
+	       uint8_t *output, int *output_size);
+
 #endif