mips: octeon: Add mangle-port.h

Import platform specific mangle-port.h header, allowing a area specific
swapping, which is needed on Octeon for USB & PCI areas.

Imported from Linux v5.7.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/mips/mach-octeon/include/mangle-port.h b/arch/mips/mach-octeon/include/mangle-port.h
new file mode 100644
index 0000000..7e95dce
--- /dev/null
+++ b/arch/mips/mach-octeon/include/mangle-port.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2003, 2004 Ralf Baechle
+ */
+
+#ifndef __ASM_MACH_GENERIC_MANGLE_PORT_H
+#define __ASM_MACH_GENERIC_MANGLE_PORT_H
+
+#include <asm/byteorder.h>
+
+#ifdef __BIG_ENDIAN
+
+static inline bool __should_swizzle_bits(volatile void *a)
+{
+	extern const bool octeon_should_swizzle_table[];
+	u64 did = ((u64)(uintptr_t)a >> 40) & 0xff;
+
+	return octeon_should_swizzle_table[did];
+}
+
+# define __swizzle_addr_b(port)	(port)
+# define __swizzle_addr_w(port)	(port)
+# define __swizzle_addr_l(port)	(port)
+# define __swizzle_addr_q(port)	(port)
+
+#else /* __LITTLE_ENDIAN */
+
+#define __should_swizzle_bits(a)	false
+
+static inline bool __should_swizzle_addr(u64 p)
+{
+	/* boot bus? */
+	return ((p >> 40) & 0xff) == 0;
+}
+
+# define __swizzle_addr_b(port)	\
+	(__should_swizzle_addr(port) ? (port) ^ 7 : (port))
+# define __swizzle_addr_w(port)	\
+	(__should_swizzle_addr(port) ? (port) ^ 6 : (port))
+# define __swizzle_addr_l(port)	\
+	(__should_swizzle_addr(port) ? (port) ^ 4 : (port))
+# define __swizzle_addr_q(port)	(port)
+
+#endif /* __BIG_ENDIAN */
+
+
+# define ioswabb(a, x)		(x)
+# define __mem_ioswabb(a, x)	(x)
+# define ioswabw(a, x)		(__should_swizzle_bits(a) ? le16_to_cpu(x) : x)
+# define __mem_ioswabw(a, x)	(x)
+# define ioswabl(a, x)		(__should_swizzle_bits(a) ? le32_to_cpu(x) : x)
+# define __mem_ioswabl(a, x)	(x)
+# define ioswabq(a, x)		(__should_swizzle_bits(a) ? le64_to_cpu(x) : x)
+# define __mem_ioswabq(a, x)	(x)
+
+#endif /* __ASM_MACH_GENERIC_MANGLE_PORT_H */