Add ChaCha20+Poly1305 to the Cipher module
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index c5a50c0..f954cce 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -37,7 +37,7 @@
 
 #include <stddef.h>
 
-#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CCM_C)
+#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CCM_C) || defined(MBEDTLS_AEAD_CHACHA20_POLY1305_C)
 #define MBEDTLS_CIPHER_MODE_AEAD
 #endif
 
@@ -147,6 +147,7 @@
     MBEDTLS_CIPHER_CAMELLIA_192_CCM,     /**< Camellia cipher with 192-bit CCM mode. */
     MBEDTLS_CIPHER_CAMELLIA_256_CCM,     /**< Camellia cipher with 256-bit CCM mode. */
     MBEDTLS_CIPHER_CHACHA20,             /**< Chacha20 stream cipher. */
+    MBEDTLS_CIPHER_CHACHA20_POLY1305,    /**< Chacha20-Poly1305 AEAD cipher. */
 } mbedtls_cipher_type_t;
 
 /** Supported cipher modes. */
@@ -562,11 +563,11 @@
  */
 int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx );
 
-#if defined(MBEDTLS_GCM_C)
+#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_AEAD_CHACHA20_POLY1305_C)
 /**
  * \brief               This function adds additional data for AEAD ciphers.
- *                      Only supported with GCM. Must be called
- *                      exactly once, after mbedtls_cipher_reset().
+ *                      Currently supported with GCM and ChaCha20+Poly1305.
+ *                      Must be called exactly once, after mbedtls_cipher_reset().
  *
  * \param ctx           The generic cipher context.
  * \param ad            The additional data to use.
@@ -577,7 +578,7 @@
  */
 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
                       const unsigned char *ad, size_t ad_len );
-#endif /* MBEDTLS_GCM_C */
+#endif /* MBEDTLS_GCM_C || MBEDTLS_AEAD_CHACHA20_POLY1305_C */
 
 /**
  * \brief               The generic cipher update function. It encrypts or
@@ -635,10 +636,10 @@
 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
                    unsigned char *output, size_t *olen );
 
-#if defined(MBEDTLS_GCM_C)
+#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_AEAD_CHACHA20_POLY1305_C)
 /**
  * \brief               This function writes a tag for AEAD ciphers.
- *                      Only supported with GCM.
+ *                      Currently supported with GCM and ChaCha20+Poly1305.
  *                      Must be called after mbedtls_cipher_finish().
  *
  * \param ctx           The generic cipher context.
@@ -653,7 +654,7 @@
 
 /**
  * \brief               This function checks the tag for AEAD ciphers.
- *                      Only supported with GCM.
+ *                      Currently supported with GCM and ChaCha20+Poly1305.
  *                      Must be called after mbedtls_cipher_finish().
  *
  * \param ctx           The generic cipher context.
@@ -665,7 +666,7 @@
  */
 int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
                       const unsigned char *tag, size_t tag_len );
-#endif /* MBEDTLS_GCM_C */
+#endif /* MBEDTLS_GCM_C || MBEDTLS_AEAD_CHACHA20_POLY1305_C */
 
 /**
  * \brief               The generic all-in-one encryption/decryption function,