hwaccess: replace macros by C code

Split the code for endian conversion into separate files for big and
little endian. The buildsystem selects the correct file for the used
endianness. Replace the swab macros with `static inline` c functions.
Define macros for returning the same or swapped value. Call those macros
in the endian specific files.

Change-Id: I86d38d816b37c283279c485fac8027f8fb94364a
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/62898
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72315
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/Makefile b/Makefile
index 07c9b04..7692b98 100644
--- a/Makefile
+++ b/Makefile
@@ -382,7 +382,9 @@
 ###############################################################################
 # Library code.
 
-LIB_OBJS = libflashrom.o layout.o flashrom.o udelay.o programmer.o programmer_table.o helpers.o ich_descriptors.o fmap.o
+LIB_OBJS = libflashrom.o layout.o flashrom.o udelay.o programmer.o programmer_table.o \
+	helpers.o ich_descriptors.o fmap.o hwaccess_endian_$(ENDIAN).o
+
 
 ###############################################################################
 # Frontend related stuff.
diff --git a/hwaccess.h b/hwaccess.h
index 98ca08e..4f7458a 100644
--- a/hwaccess.h
+++ b/hwaccess.h
@@ -2,6 +2,8 @@
  * This file is part of the flashrom project.
  *
  * Copyright (C) 2009 Carl-Daniel Hailfinger
+ * Copyright (C) 2022 secunet Security Networks AG
+ * (written by Thomas Heijligen <thomas.heijligen@secunet.com)
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,74 +22,83 @@
 #ifndef __HWACCESS_H__
 #define __HWACCESS_H__ 1
 
-#define ___constant_swab8(x) ((uint8_t) (				\
-	(((uint8_t)(x) & (uint8_t)0xffU))))
+#include <stdint.h>
 
-#define ___constant_swab16(x) ((uint16_t) (				\
-	(((uint16_t)(x) & (uint16_t)0x00ffU) << 8) |			\
-	(((uint16_t)(x) & (uint16_t)0xff00U) >> 8)))
-
-#define ___constant_swab32(x) ((uint32_t) (				\
-	(((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) |		\
-	(((uint32_t)(x) & (uint32_t)0x0000ff00UL) <<  8) |		\
-	(((uint32_t)(x) & (uint32_t)0x00ff0000UL) >>  8) |		\
-	(((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24)))
-
-#define ___constant_swab64(x) ((uint64_t) (				\
-	(((uint64_t)(x) & (uint64_t)0x00000000000000ffULL) << 56) |	\
-	(((uint64_t)(x) & (uint64_t)0x000000000000ff00ULL) << 40) |	\
-	(((uint64_t)(x) & (uint64_t)0x0000000000ff0000ULL) << 24) |	\
-	(((uint64_t)(x) & (uint64_t)0x00000000ff000000ULL) <<  8) |	\
-	(((uint64_t)(x) & (uint64_t)0x000000ff00000000ULL) >>  8) |	\
-	(((uint64_t)(x) & (uint64_t)0x0000ff0000000000ULL) >> 24) |	\
-	(((uint64_t)(x) & (uint64_t)0x00ff000000000000ULL) >> 40) |	\
-	(((uint64_t)(x) & (uint64_t)0xff00000000000000ULL) >> 56)))
-
-#if defined (__FLASHROM_BIG_ENDIAN__)
-
-#define cpu_to_le(bits)							\
-static inline uint##bits##_t cpu_to_le##bits(uint##bits##_t val)	\
-{									\
-	return ___constant_swab##bits(val);				\
+/* swap bytes */
+/* OpenBSD has conflicting definitions for swapX and __swapX */
+static inline uint8_t ___swap8(const uint8_t value)
+{
+	return  (value & (uint8_t)0xffU);
 }
 
-cpu_to_le(8)
-cpu_to_le(16)
-cpu_to_le(32)
-cpu_to_le(64)
-
-#define cpu_to_be8
-#define cpu_to_be16
-#define cpu_to_be32
-#define cpu_to_be64
-
-#elif defined (__FLASHROM_LITTLE_ENDIAN__)
-
-#define cpu_to_be(bits)							\
-static inline uint##bits##_t cpu_to_be##bits(uint##bits##_t val)	\
-{									\
-	return ___constant_swab##bits(val);				\
+static inline uint16_t ___swap16(const uint16_t value)
+{
+	return  ((value & (uint16_t)0x00ffU) << 8) |
+		((value & (uint16_t)0xff00U) >> 8);
 }
 
-cpu_to_be(8)
-cpu_to_be(16)
-cpu_to_be(32)
-cpu_to_be(64)
+static inline uint32_t ___swap32(const uint32_t value)
+{
+	return  ((value & (uint32_t)0x000000ffUL) << 24) |
+		((value & (uint32_t)0x0000ff00UL) <<  8) |
+		((value & (uint32_t)0x00ff0000UL) >>  8) |
+		((value & (uint32_t)0xff000000UL) >> 24);
+}
 
-#define cpu_to_le8
-#define cpu_to_le16
-#define cpu_to_le32
-#define cpu_to_le64
+static inline uint64_t ___swap64(const uint64_t value)
+{
+	return  ((value & (uint64_t)0x00000000000000ffULL) << 56) |
+		((value & (uint64_t)0x000000000000ff00ULL) << 40) |
+		((value & (uint64_t)0x0000000000ff0000ULL) << 24) |
+		((value & (uint64_t)0x00000000ff000000ULL) <<  8) |
+		((value & (uint64_t)0x000000ff00000000ULL) >>  8) |
+		((value & (uint64_t)0x0000ff0000000000ULL) >> 24) |
+		((value & (uint64_t)0x00ff000000000000ULL) >> 40) |
+		((value & (uint64_t)0xff00000000000000ULL) >> 56);
+}
 
-#endif /* __FLASHROM_BIG_ENDIAN__ / __FLASHROM_LITTLE_ENDIAN__ */
+/*
+ * macro to return the same value as passed.
+ *
+ * `___return_same(cpu_to_le, 8)`
+ *	expands to
+ * `uint8_t cpu_to_le8 (const uint8_t value) { return value; }`
+ */
+#define ___return_same(name, bits) \
+	uint##bits##_t name##bits (const uint##bits##_t value) { return value; }
 
-#define be_to_cpu8 cpu_to_be8
-#define be_to_cpu16 cpu_to_be16
-#define be_to_cpu32 cpu_to_be32
-#define be_to_cpu64 cpu_to_be64
-#define le_to_cpu8 cpu_to_le8
-#define le_to_cpu16 cpu_to_le16
-#define le_to_cpu32 cpu_to_le32
-#define le_to_cpu64 cpu_to_le64
+/*
+ * macro to return the swapped value as passed.
+ *
+ * `___return_swapped(cpu_to_be, 8)`
+ *	expands to
+ * `uint8_t cpu_to_be8 (const uint8_t value) { return ___swap8 (value); }`
+ */
+#define ___return_swapped(name, bits) \
+	uint##bits##_t name##bits (const uint##bits##_t value) { return ___swap##bits (value); }
+
+/* convert cpu native endian to little endian */
+uint8_t  cpu_to_le8 (uint8_t  value);
+uint16_t cpu_to_le16(uint16_t value);
+uint32_t cpu_to_le32(uint32_t value);
+uint64_t cpu_to_le64(uint64_t value);
+
+/* convert cpu native endian to big endian */
+uint8_t  cpu_to_be8 (uint8_t  value);
+uint16_t cpu_to_be16(uint16_t value);
+uint32_t cpu_to_be32(uint32_t value);
+uint64_t cpu_to_be64(uint64_t value);
+
+/* convert little endian to cpu native endian */
+uint8_t  le_to_cpu8 (uint8_t  value);
+uint16_t le_to_cpu16(uint16_t value);
+uint32_t le_to_cpu32(uint32_t value);
+uint64_t le_to_cpu64(uint64_t value);
+
+/* convert big endian to cpu native endian */
+uint8_t  be_to_cpu8 (uint8_t  value);
+uint16_t be_to_cpu16(uint16_t value);
+uint32_t be_to_cpu32(uint32_t value);
+uint64_t be_to_cpu64(uint64_t value);
 
 #endif /* !__HWACCESS_H__ */
diff --git a/hwaccess_endian_big.c b/hwaccess_endian_big.c
new file mode 100644
index 0000000..1f7b5a3
--- /dev/null
+++ b/hwaccess_endian_big.c
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2022 secunet Security Networks AG
+ * (written by Thomas Heijligen <thomas.heijligen@secunet.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "hwaccess.h"
+
+/* convert cpu native endian to little endian */
+___return_swapped(cpu_to_le, 8)
+___return_swapped(cpu_to_le, 16)
+___return_swapped(cpu_to_le, 32)
+___return_swapped(cpu_to_le, 64)
+
+/* convert cpu native endian to big endian */
+___return_same(cpu_to_be, 8)
+___return_same(cpu_to_be, 16)
+___return_same(cpu_to_be, 32)
+___return_same(cpu_to_be, 64)
+
+/* convert little endian to cpu native endian */
+___return_swapped(le_to_cpu, 8)
+___return_swapped(le_to_cpu, 16)
+___return_swapped(le_to_cpu, 32)
+___return_swapped(le_to_cpu, 64)
+
+/* convert big endian to cpu native endian */
+___return_same(be_to_cpu, 8)
+___return_same(be_to_cpu, 16)
+___return_same(be_to_cpu, 32)
+___return_same(be_to_cpu, 64)
diff --git a/hwaccess_endian_little.c b/hwaccess_endian_little.c
new file mode 100644
index 0000000..c0b493f
--- /dev/null
+++ b/hwaccess_endian_little.c
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2022 secunet Security Networks AG
+ * (written by Thomas Heijligen <thomas.heijligen@secunet.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "hwaccess.h"
+
+/* convert cpu native endian to little endian */
+___return_same(cpu_to_le, 8)
+___return_same(cpu_to_le, 16)
+___return_same(cpu_to_le, 32)
+___return_same(cpu_to_le, 64)
+
+/* convert cpu native endian to big endian */
+___return_swapped(cpu_to_be, 8)
+___return_swapped(cpu_to_be, 16)
+___return_swapped(cpu_to_be, 32)
+___return_swapped(cpu_to_be, 64)
+
+/* convert little endian to cpu native endian */
+___return_same(le_to_cpu, 8)
+___return_same(le_to_cpu, 16)
+___return_same(le_to_cpu, 32)
+___return_same(le_to_cpu, 64)
+
+/* convert big endian to cpu native endian */
+___return_swapped(be_to_cpu, 8)
+___return_swapped(be_to_cpu, 16)
+___return_swapped(be_to_cpu, 32)
+___return_swapped(be_to_cpu, 64)
diff --git a/hwaccess_x86_msr.c b/hwaccess_x86_msr.c
index 79cf2f8..3728061 100644
--- a/hwaccess_x86_msr.c
+++ b/hwaccess_x86_msr.c
@@ -17,7 +17,7 @@
  */
 
 /* MSR abstraction implementations for Linux, OpenBSD, FreeBSD/Dragonfly, OSX, libpayload
- * and a non-working default implementation on the bottom. See also hwaccess.h for some (re)declarations.
+ * and a non-working default implementation on the bottom.
  */
 
 #include "hwaccess_x86_msr.h"
diff --git a/meson.build b/meson.build
index 457823e..e68f8a4 100644
--- a/meson.build
+++ b/meson.build
@@ -29,13 +29,6 @@
 add_project_arguments('-D_BSD_SOURCE', language : 'c') # required for glibc < v2.19
 add_project_arguments('-DFLASHROM_VERSION="' + meson.project_version() + '"', language : 'c')
 
-if host_machine.endian() == 'little'
-  add_project_arguments('-D__FLASHROM_LITTLE_ENDIAN__=1', language : 'c')
-endif
-if host_machine.endian() == 'big'
-  add_project_arguments('-D__FLASHROM_BIG_ENDIAN__=1', language : 'c')
-endif
-
 if host_machine.system() in ['cygwin', 'windows']
   add_project_arguments('-DIS_WINDOWS=1', language : 'c')
 else
@@ -139,6 +132,15 @@
   add_project_arguments('-DHAVE_UTSNAME=1', language : 'c')
 endif
 
+if host_machine.endian() == 'little'
+  srcs += 'hwaccess_endian_little.c'
+  add_project_arguments('-D__FLASHROM_LITTLE_ENDIAN__=1', language : 'c')
+endif
+if host_machine.endian() == 'big'
+  srcs += 'hwaccess_endian_big.c'
+  add_project_arguments('-D__FLASHROM_BIG_ENDIAN__=1', language : 'c')
+endif
+
 # some programmers require libusb
 if get_option('usb')
   srcs += 'usbdev.c'