crypto: inside-secure - improve error reporting

This patch improves the error reporting from the Inside Secure driver to
the upper layers and crypto consumers. All errors reported by the engine
aren't fatal, and some may be genuine.
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/inside-secure/safexcel.c

@@ -537,6 +537,27 @@ void safexcel_dequeue(struct safexcel_crypto_priv *priv, int ring)
 	       EIP197_HIA_CDR(priv, ring) + EIP197_HIA_xDR_PREP_COUNT);
 }
 
+inline int safexcel_rdesc_check_errors(struct safexcel_crypto_priv *priv,
+				       struct safexcel_result_desc *rdesc)
+{
+	if (likely(!rdesc->result_data.error_code))
+		return 0;
+
+	if (rdesc->result_data.error_code & 0x407f) {
+		/* Fatal error (bits 0-7, 14) */
+		dev_err(priv->dev,
+			"cipher: result: result descriptor error (%d)\n",
+			rdesc->result_data.error_code);
+		return -EIO;
+	} else if (rdesc->result_data.error_code == BIT(9)) {
+		/* Authentication failed */
+		return -EBADMSG;
+	}
+
+	/* All other non-fatal errors */
+	return -EINVAL;
+}
+
 void safexcel_complete(struct safexcel_crypto_priv *priv, int ring)
 {
 	struct safexcel_command_desc *cdesc;

drivers/crypto/inside-secure/safexcel.h

@@ -610,6 +610,8 @@ struct safexcel_inv_result {
 };
 
 void safexcel_dequeue(struct safexcel_crypto_priv *priv, int ring);
+int safexcel_rdesc_check_errors(struct safexcel_crypto_priv *priv,
+				struct safexcel_result_desc *rdesc);
 void safexcel_complete(struct safexcel_crypto_priv *priv, int ring);
 int safexcel_invalidate_cache(struct crypto_async_request *async,
 			      struct safexcel_crypto_priv *priv,

drivers/crypto/inside-secure/safexcel_cipher.c

@@ -160,12 +160,8 @@ static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv, int rin
 			break;
 		}
 
-		if (rdesc->result_data.error_code) {
-			dev_err(priv->dev,
-				"cipher: result: result descriptor error (%d)\n",
-				rdesc->result_data.error_code);
-			*ret = -EIO;
-		}
+		if (likely(!*ret))
+			*ret = safexcel_rdesc_check_errors(priv, rdesc);
 
 		ndesc++;
 	} while (!rdesc->last_seg);

drivers/crypto/inside-secure/safexcel_hash.c

@@ -146,11 +146,8 @@ static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv, int rin
 		dev_err(priv->dev,
 			"hash: result: could not retrieve the result descriptor\n");
 		*ret = PTR_ERR(rdesc);
-	} else if (rdesc->result_data.error_code) {
-		dev_err(priv->dev,
-			"hash: result: result descriptor error (%d)\n",
-			rdesc->result_data.error_code);
-		*ret = -EINVAL;
+	} else {
+		*ret = safexcel_rdesc_check_errors(priv, rdesc);
 	}
 
 	safexcel_complete(priv, ring);