tpm: add flag in hash_algo_list and API to check if algorithm is supported

Add a bool var into hash_algo_list to indicate whether the algorithm
is supported or not and move the IS_ENABLED to only cover this var.
So that we can have the name, hash, mask and size no matter the
digest kconfigs are enabled or not.

In before, tpm2_algorithm_to_len() and tcg2_algorithm_to_mask() are used to
identify an unsupported algorithm when they return 0.
It is not the case now when hash_algo_list always provides algorithm size
and mask, thus a new API is introduced to check if an algorithm is
supported by U-Boot.

Suggested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 0edb0aa90c9..96c164f2a54 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -884,6 +884,18 @@ const char *tpm2_algorithm_name(enum tpm2_algorithms algo)
 	return "";
 }
 
+bool tpm2_algorithm_supported(enum tpm2_algorithms algo)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(hash_algo_list); ++i) {
+		if (hash_algo_list[i].hash_alg == algo)
+			return hash_algo_list[i].supported;
+	}
+
+	return false;
+}
+
 u16 tpm2_algorithm_to_len(enum tpm2_algorithms algo)
 {
 	size_t i;
@@ -908,7 +920,7 @@ bool tpm2_check_active_banks(struct udevice *dev)
 
 	for (i = 0; i < pcrs.count; i++) {
 		if (tpm2_is_active_bank(&pcrs.selection[i]) &&
-		    !tpm2_algorithm_to_len(pcrs.selection[i].hash))
+		    !tpm2_algorithm_supported(pcrs.selection[i].hash))
 			return false;
 	}