MIPS: sync I/O related header files with linux-4.4

Mainly sync asm/io.h to get a working ioremap() implementation
as well as the full set of I/O accessors. Pull in additional
header files to make this work.

Furthermore port over the directory 'arch/mips/include/asm/mach-generic/'
with contains default definitions for I/O and memory spaces and default
implementations for mapping those spaces. All files in that directory
can be overwritten by a SoC/machine.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/include/asm/mach-generic/mangle-port.h b/arch/mips/include/asm/mach-generic/mangle-port.h
new file mode 100644
index 0000000..f18e53f
--- /dev/null
+++ b/arch/mips/include/asm/mach-generic/mangle-port.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2003, 2004 Ralf Baechle
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+#ifndef __ASM_MACH_GENERIC_MANGLE_PORT_H
+#define __ASM_MACH_GENERIC_MANGLE_PORT_H
+
+#define __swizzle_addr_b(port)	(port)
+#define __swizzle_addr_w(port)	(port)
+#define __swizzle_addr_l(port)	(port)
+#define __swizzle_addr_q(port)	(port)
+
+/*
+ * Sane hardware offers swapping of PCI/ISA I/O space accesses in hardware;
+ * less sane hardware forces software to fiddle with this...
+ *
+ * Regardless, if the host bus endianness mismatches that of PCI/ISA, then
+ * you can't have the numerical value of data and byte addresses within
+ * multibyte quantities both preserved at the same time.  Hence two
+ * variations of functions: non-prefixed ones that preserve the value
+ * and prefixed ones that preserve byte addresses.  The latters are
+ * typically used for moving raw data between a peripheral and memory (cf.
+ * string I/O functions), hence the "__mem_" prefix.
+ */
+#if defined(CONFIG_SWAP_IO_SPACE)
+
+# define ioswabb(a, x)		(x)
+# define __mem_ioswabb(a, x)	(x)
+# define ioswabw(a, x)		le16_to_cpu(x)
+# define __mem_ioswabw(a, x)	(x)
+# define ioswabl(a, x)		le32_to_cpu(x)
+# define __mem_ioswabl(a, x)	(x)
+# define ioswabq(a, x)		le64_to_cpu(x)
+# define __mem_ioswabq(a, x)	(x)
+
+#else
+
+# define ioswabb(a, x)		(x)
+# define __mem_ioswabb(a, x)	(x)
+# define ioswabw(a, x)		(x)
+# define __mem_ioswabw(a, x)	cpu_to_le16(x)
+# define ioswabl(a, x)		(x)
+# define __mem_ioswabl(a, x)	cpu_to_le32(x)
+# define ioswabq(a, x)		(x)
+# define __mem_ioswabq(a, x)	cpu_to_le32(x)
+
+#endif
+
+#endif /* __ASM_MACH_GENERIC_MANGLE_PORT_H */