hwaccess: add endianness converting deserialization functions

Add functions like
  `uint32_t read_le32(const void *base, size_t offset);`
Read a 32 bit unsigned from a base with an offset.
Having prototypes and a macro generated implementation makes it easier
to read, understand and spot errors in one of them.

Change-Id: Idde177acf8bc5f94cd046b6539dc31532c98e452
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/31016
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

1 files changed, 42 insertions, 0 deletions

diff --git a/platform/memaccess.c b/platform/memaccess.c
new file mode 100644
index 00000000..44ef4108
--- /dev/null
+++ b/platform/memaccess.c
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2016 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 "../platform.h"
+
+/*
+ * macro to return endian aware read function
+ *
+ * `___read(le, 8)`
+ * 	expands to
+ * `uint8_t read_le8 (const void *const base, const size_t offset)
+ *  { return le_to_cpu8 (*(uint8_t *)((uintptr_t)base + offset)); }`
+ */
+#define ___read(endian, bits) \
+	uint##bits##_t read_##endian##bits (const void *const base, const size_t offset) \
+	{ return endian##_to_cpu##bits (*(uint##bits##_t *)((uintptr_t)base + offset)); }
+
+/* read value from base at offset in little endian */
+___read(le,  8)
+___read(le, 16)
+___read(le, 32)
+___read(le, 64)
+
+/* read value from base at offset in big endian */
+___read(be,  8)
+___read(be, 16)
+___read(be, 32)
+___read(be, 64)