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/pk.h b/include/mbedtls/pk.h
index 9ec33da..df3a03c 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -64,6 +64,8 @@
#define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00 /**< Elliptic curve is unsupported (only NIST curves are supported). */
#define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980 /**< Unavailable feature, e.g. RSA disabled for RSA key. */
#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH -0x3900 /**< The buffer contains a valid signature followed by more data. */
+
+/* MBEDTLS_ERR_PK_HW_ACCEL_FAILED is deprecated and should not be used. */
#define MBEDTLS_ERR_PK_HW_ACCEL_FAILED -0x3880 /**< PK hardware accelerator failed. */
#ifdef __cplusplus