Deprecate hardware acceleration errors
Deprecate the module-specific XXX_HW_ACCEL_FAILED and
XXX_FEATURE_UNAVAILABLE errors, as alternative implementations should now
return `MBEDTLS_ERR_PLATFORM_HW_FAILED` and
`MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED`.
diff --git a/include/mbedtls/chacha20.h b/include/mbedtls/chacha20.h
index cfea40a..529f22d 100644
--- a/include/mbedtls/chacha20.h
+++ b/include/mbedtls/chacha20.h
@@ -43,7 +43,13 @@
#include <stddef.h>
#define MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA -0x0051 /**< Invalid input parameter(s). */
+
+/* MBEDTLS_ERR_CHACHA20_FEATURE_UNAVAILABLE is deprecated and should not be
+ * used. */
#define MBEDTLS_ERR_CHACHA20_FEATURE_UNAVAILABLE -0x0053 /**< Feature not available. For example, s part of the API is not implemented. */
+
+/* MBEDTLS_ERR_CHACHA20_HW_ACCEL_FAILED is deprecated and should not be used.
+ */
#define MBEDTLS_ERR_CHACHA20_HW_ACCEL_FAILED -0x0055 /**< Chacha20 hardware accelerator failed. */
#ifdef __cplusplus