+/*
+ * 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(x) (x)
+# define __mem_ioswabb(x) (x)
+# ifdef CONFIG_SGI_IP22
+/*
+ * IP22 seems braindead enough to swap 16bits values in hardware, but
+ * not 32bits. Go figure... Can't tell without documentation.
+ */
+# define ioswabw(x) (x)
+# define __mem_ioswabw(x) le16_to_cpu(x)
+# else
+# define ioswabw(x) le16_to_cpu(x)
+# define __mem_ioswabw(x) (x)
+# endif
+# define ioswabl(x) le32_to_cpu(x)
+# define __mem_ioswabl(x) (x)
+# define ioswabq(x) le64_to_cpu(x)
+# define __mem_ioswabq(x) (x)
+
+#else
+
+# define ioswabb(x) (x)
+# define __mem_ioswabb(x) (x)
+# define ioswabw(x) (x)
+# define __mem_ioswabw(x) cpu_to_le16(x)
+# define ioswabl(x) (x)
+# define __mem_ioswabl(x) cpu_to_le32(x)
+# define ioswabq(x) (x)
+# define __mem_ioswabq(x) cpu_to_le32(x)
+
+#endif