commonlib: add endian related accessor functions

This commit adds read/write functions for both big and
little endian interpretations. Additionally there are
variants that allow an offset to be provided into the
source buffer.

BUG=None
TEST=Wrote test harness for functions.  Also booted ARM QEMU
     through end of payload.

Change-Id: If44c4d489f0dab86a73b73580c039e364c7e517d
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11677
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
diff --git a/src/commonlib/include/commonlib/endian.h b/src/commonlib/include/commonlib/endian.h
new file mode 100644
index 0000000..bcd3b39c
--- /dev/null
+++ b/src/commonlib/include/commonlib/endian.h
@@ -0,0 +1,261 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#ifndef _COMMONLIB_ENDIAN_H_
+#define _COMMONLIB_ENDIAN_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* Endian agnostic functions working on single byte. */
+
+static inline uint8_t read_ble8(const void *src)
+{
+	const uint8_t *s = src;
+	return *s;
+}
+
+static inline uint8_t read_at_ble8(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_ble8(s);
+}
+
+static inline void write_ble8(void *dest, uint8_t val)
+{
+	*(uint8_t *)dest = val;
+}
+
+static inline void write_at_ble8(void *dest, uint8_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_ble8(d, val);
+}
+
+/* Big Endian functions. */
+
+static inline uint8_t read_be8(const void *src)
+{
+	return read_ble8(src);
+}
+
+static inline uint8_t read_at_be8(const void *src, size_t offset)
+{
+	return read_at_ble8(src, offset);
+}
+
+static inline void write_be8(void *dest, uint8_t val)
+{
+	write_ble8(dest, val);
+}
+
+static inline void write_at_be8(void *dest, uint8_t val, size_t offset)
+{
+	write_at_ble8(dest, val, offset);
+}
+
+static inline uint16_t read_be16(const void *src)
+{
+	const uint8_t *s = src;
+	return (((uint16_t)s[0]) << 8) | (((uint16_t)s[1]) << 0);
+}
+
+static inline uint16_t read_at_be16(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_be16(s);
+}
+
+static inline void write_be16(void *dest, uint16_t val)
+{
+	write_be8(dest, val >> 8);
+	write_at_be8(dest, val >> 0, sizeof(uint8_t));
+}
+
+static inline void write_at_be16(void *dest, uint16_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_be16(d, val);
+}
+
+static inline uint32_t read_be32(const void *src)
+{
+	const uint8_t *s = src;
+	return (((uint32_t)s[0]) << 24) | (((uint32_t)s[1]) << 16) |
+		(((uint32_t)s[2]) << 8) | (((uint32_t)s[3]) << 0);
+}
+
+static inline uint32_t read_at_be32(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_be32(s);
+}
+
+static inline void write_be32(void *dest, uint32_t val)
+{
+	write_be16(dest, val >> 16);
+	write_at_be16(dest, val >> 0, sizeof(uint16_t));
+}
+
+static inline void write_at_be32(void *dest, uint32_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_be32(d, val);
+}
+
+static inline uint64_t read_be64(const void *src)
+{
+	uint64_t val;
+	val = read_be32(src);
+	val <<= 32;
+	val |= read_at_be32(src, sizeof(uint32_t));
+	return val;
+}
+
+static inline uint64_t read_at_be64(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_be64(s);
+}
+
+static inline void write_be64(void *dest, uint64_t val)
+{
+	write_be32(dest, val >> 32);
+	write_at_be32(dest, val >> 0, sizeof(uint32_t));
+}
+
+static inline void write_at_be64(void *dest, uint64_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_be64(d, val);
+}
+
+/* Little Endian functions. */
+
+static inline uint8_t read_le8(const void *src)
+{
+	return read_ble8(src);
+}
+
+static inline uint8_t read_at_le8(const void *src, size_t offset)
+{
+	return read_at_ble8(src, offset);
+}
+
+static inline void write_le8(void *dest, uint8_t val)
+{
+	write_ble8(dest, val);
+}
+
+static inline void write_at_le8(void *dest, uint8_t val, size_t offset)
+{
+	write_at_ble8(dest, val, offset);
+}
+
+static inline uint16_t read_le16(const void *src)
+{
+	const uint8_t *s = src;
+	return (((uint16_t)s[1]) << 8) | (((uint16_t)s[0]) << 0);
+}
+
+static inline uint16_t read_at_le16(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_le16(s);
+}
+
+static inline void write_le16(void *dest, uint16_t val)
+{
+	write_le8(dest, val >> 0);
+	write_at_le8(dest, val >> 8, sizeof(uint8_t));
+}
+
+static inline void write_at_le16(void *dest, uint16_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_le16(d, val);
+}
+
+static inline uint32_t read_le32(const void *src)
+{
+	const uint8_t *s = src;
+	return (((uint32_t)s[3]) << 24) | (((uint32_t)s[2]) << 16) |
+		(((uint32_t)s[1]) << 8) | (((uint32_t)s[0]) << 0);
+}
+
+static inline uint32_t read_at_le32(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_le32(s);
+}
+
+static inline void write_le32(void *dest, uint32_t val)
+{
+	write_le16(dest, val >> 0);
+	write_at_le16(dest, val >> 16, sizeof(uint16_t));
+}
+
+static inline void write_at_le32(void *dest, uint32_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_le32(d, val);
+}
+
+static inline uint64_t read_le64(const void *src)
+{
+	uint64_t val;
+	val = read_at_le32(src, sizeof(uint32_t));
+	val <<= 32;
+	val |= read_le32(src);
+	return val;
+}
+
+static inline uint64_t read_at_le64(const void *src, size_t offset)
+{
+	const uint8_t *s = src;
+	s += offset;
+	return read_le64(s);
+}
+
+static inline void write_le64(void *dest, uint64_t val)
+{
+	write_le32(dest, val >> 0);
+	write_at_le32(dest, val >> 32, sizeof(uint32_t));
+}
+
+static inline void write_at_le64(void *dest, uint64_t val, size_t offset)
+{
+	uint8_t *d = dest;
+	d += offset;
+	write_le64(d, val);
+}
+
+#endif