diff --git a/drivers/crypto/atmel-aes.c b/drivers/crypto/atmel-aes.c
index 12628a75fbccebdc7a28cc7dd682ea60f1921f67..a083474991abbb343aa330160ff988f34635b268 100644
--- a/drivers/crypto/atmel-aes.c
+++ b/drivers/crypto/atmel-aes.c
@@ -716,6 +716,12 @@ static int atmel_aes_crypt(struct ablkcipher_request *req, unsigned long mode)
 			return -EINVAL;
 		}
 		ctx->block_size = CFB32_BLOCK_SIZE;
+	} else if (mode & AES_FLAGS_CFB64) {
+		if (!IS_ALIGNED(req->nbytes, CFB64_BLOCK_SIZE)) {
+			pr_err("request size is not exact amount of CFB64 blocks\n");
+			return -EINVAL;
+		}
+		ctx->block_size = CFB64_BLOCK_SIZE;
 	} else {
 		if (!IS_ALIGNED(req->nbytes, AES_BLOCK_SIZE)) {
 			pr_err("request size is not exact amount of AES blocks\n");