Factor out cross-BL API into export headers suitable for 3rd party code

This patch adds a new include/export/ directory meant for inclusion in
third-party code. This is useful for cases where third-party code needs
to interact with TF-A interfaces and data structures (such as a custom
BL2-implementation like coreboot handing off to BL31). Directly
including headers from the TF-A repository avoids having to duplicate
all these definitions (and risk them going stale), but with the current
header structure this is not possible because handoff API definitions
are too deeply intertwined with other TF code/headers and chain-include
other headers that will not be available in the other environment.

The new approach aims to solve this by separating only the parts that
are really needed into these special headers that are self-contained and
will not chain-include other (non-export) headers. TF-A code should
never include them directly but should instead always include the
respective wrapper header, which will include the required prerequisites
(like <stdint.h>) before including the export header. Third-party code
can include the export headers via its own wrappers that make sure the
necessary definitions are available in whatever way that environment can
provide them.

Change-Id: Ifd769320ba51371439a8e5dd5b79c2516c3b43ab
Signed-off-by: Julius Werner <jwerner@chromium.org>

1 files changed, 7 insertions, 30 deletions

diff --git a/include/common/param_header.h b/include/common/param_header.h
index 0c1503f1b..b8852869a 100644
--- a/include/common/param_header.h
+++ b/include/common/param_header.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,20 +9,14 @@
 
 #include <stdbool.h>
 
-#include <lib/utils_def.h>
+#ifndef __ASSEMBLY__
+#include <stdint.h>
+#endif /*__ASSEMBLY__*/
 
-/* Param header types */
-#define PARAM_EP			U(0x01)
-#define PARAM_IMAGE_BINARY		U(0x02)
-#define PARAM_BL31			U(0x03)
-#define PARAM_BL_LOAD_INFO		U(0x04)
-#define PARAM_BL_PARAMS			U(0x05)
-#define PARAM_PSCI_LIB_ARGS		U(0x06)
-#define PARAM_SP_IMAGE_BOOT_INFO	U(0x07)
+#include <export/common/param_header_exp.h>
 
-/* Param header version */
-#define VERSION_1	U(0x01)
-#define VERSION_2	U(0x02)
+#define VERSION_1	PARAM_VERSION_1
+#define VERSION_2	PARAM_VERSION_2
 
 #define SET_PARAM_HEAD(_p, _type, _ver, _attr) do { \
 	(_p)->h.type = (uint8_t)(_type); \
@@ -38,21 +32,4 @@
 	._p.h.size = (uint16_t)sizeof(_p_type), \
 	._p.h.attr = (uint32_t)(_attr)
 
-#ifndef __ASSEMBLY__
-
-#include <stdint.h>
-
-/***************************************************************************
- * This structure provides version information and the size of the
- * structure, attributes for the structure it represents
- ***************************************************************************/
-typedef struct param_header {
-	uint8_t type;		/* type of the structure */
-	uint8_t version;    /* version of this structure */
-	uint16_t size;      /* size of this structure in bytes */
-	uint32_t attr;      /* attributes: unused bits SBZ */
-} param_header_t;
-
-#endif /*__ASSEMBLY__*/
-
 #endif /* PARAM_HEADER_H */