Move endianness definitions and provide it inside Makefile
Add an `endiantest.c` similar to `archtest.c` to provide the endianness
inside the Makefile. The __FLASHROM_(LITTLE|BIG)_ENDIAN__ definitions
had to move from `hwaccess.h` into `platform.h`, therefor. This will
be used to decide whether to build the internal programmer in a follow-
up.
Change-Id: I55dcf5a88da48f885cda9ad89ab87395d895a891
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/22670
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
diff --git a/platform.h b/platform.h
index b2fdcd0..e3b7674 100644
--- a/platform.h
+++ b/platform.h
@@ -81,4 +81,86 @@
#error Unknown architecture
#endif
+/* The next big hunk tries to guess endianess from various preprocessor macros */
+/* First some error checking in case some weird header has defined both.
+ * NB: OpenBSD always defines _BIG_ENDIAN and _LITTLE_ENDIAN. */
+#if defined (__LITTLE_ENDIAN__) && defined (__BIG_ENDIAN__)
+#error Conflicting endianness #define
+#endif
+
+#if IS_X86
+
+/* All x86 is little-endian. */
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+
+#elif IS_MIPS
+
+/* MIPS can be either endian. */
+#if defined (__MIPSEL) || defined (__MIPSEL__) || defined (_MIPSEL) || defined (MIPSEL)
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#elif defined (__MIPSEB) || defined (__MIPSEB__) || defined (_MIPSEB) || defined (MIPSEB)
+#define __FLASHROM_BIG_ENDIAN__ 1
+#endif
+
+#elif IS_PPC
+
+/* PowerPC can be either endian. */
+#if defined (_BIG_ENDIAN) || defined (__BIG_ENDIAN__)
+#define __FLASHROM_BIG_ENDIAN__ 1
+#elif defined (_LITTLE_ENDIAN) || defined (__LITTLE_ENDIAN__)
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#endif
+
+#elif IS_ARM
+
+/* ARM can be either endian. */
+#if defined (__ARMEB__)
+#define __FLASHROM_BIG_ENDIAN__ 1
+#elif defined (__ARMEL__)
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#endif
+
+#elif IS_SPARC
+/* SPARC is big endian in general (but allows to access data in little endian too). */
+#define __FLASHROM_BIG_ENDIAN__ 1
+
+#endif /* IS_? */
+
+#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
+
+/* If architecture-specific approaches fail try generic variants. First: BSD (works about everywhere). */
+#if !IS_WINDOWS
+#include <sys/param.h>
+
+#if defined (__BYTE_ORDER)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define __FLASHROM_LITTLE_ENDIAN__
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define __FLASHROM_BIG_ENDIAN__
+#else
+#error Unknown byte order!
+#endif
+#endif /* defined __BYTE_ORDER */
+#endif /* !IS_WINDOWS */
+
+#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
+
+/* Nonstandard libc-specific macros for determining endianness. */
+/* musl provides an endian.h as well... but it can not be detected from within C. */
+#if defined(__GLIBC__)
+#include <endian.h>
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define __FLASHROM_LITTLE_ENDIAN__ 1
+#elif BYTE_ORDER == BIG_ENDIAN
+#define __FLASHROM_BIG_ENDIAN__ 1
+#endif
+#endif
+#endif
+
+#endif
+
+#if !defined (__FLASHROM_BIG_ENDIAN__) && !defined (__FLASHROM_LITTLE_ENDIAN__)
+#error Unable to determine endianness.
+#endif
+
#endif /* !__PLATFORM_H__ */