[MIPS] Iomap implementation.

This implementation has support for the concept of one separate ioport
address space by PCI domain.  A pointer to the virtual address where
the port space of a domain has been mapped has been added to struct
pci_controller and systems should be fixed to fill in this value. For
single domain systems this will be the same value as passed to
set_io_port_base().

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/lib/iomap-pci.c b/arch/mips/lib/iomap-pci.c
new file mode 100644
index 0000000..c11b249
--- /dev/null
+++ b/arch/mips/lib/iomap-pci.c
@@ -0,0 +1,74 @@
+/*
+ * Implement the default iomap interfaces
+ *
+ * (C) Copyright 2004 Linus Torvalds
+ * (C) Copyright 2006 Ralf Baechle <ralf@linux-mips.org>
+ * (C) Copyright 2007 MIPS Technologies, Inc.
+ *     written by Ralf Baechle <ralf@linux-mips.org>
+ */
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <asm/io.h>
+
+static void __iomem *ioport_map_pci(struct pci_dev *dev,
+                                     unsigned long port, unsigned int nr)
+{
+	struct pci_controller *ctrl = dev->bus->sysdata;
+	unsigned long base = ctrl->io_map_base;
+
+	/* This will eventually become a BUG_ON but for now be gentle */
+	if (unlikely(!ctrl->io_map_base)) {
+		struct pci_bus *bus = dev->bus;
+		char name[8];
+
+		while (bus->parent)
+			bus = bus->parent;
+
+		ctrl->io_map_base = base = mips_io_port_base;
+
+		sprintf(name, "%04x:%02x", pci_domain_nr(bus), bus->number);
+		printk(KERN_WARNING "io_map_base of root PCI bus %s unset.  "
+		       "Trying to continue but you better\nfix this issue or "
+		       "report it to linux-mips@linux-mips.org or your "
+		       "vendor.\n", name);
+#ifdef CONFIG_PCI_DOMAINS
+		panic("To avoid data corruption io_map_base MUST be set with "
+		      "multiple PCI domains.");
+#endif
+	}
+
+	return (void __iomem *) (ctrl->io_map_base + port);
+}
+
+/*
+ * Create a virtual mapping cookie for a PCI BAR (memory or IO)
+ */
+void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
+{
+	unsigned long start = pci_resource_start(dev, bar);
+	unsigned long len = pci_resource_len(dev, bar);
+	unsigned long flags = pci_resource_flags(dev, bar);
+
+	if (!len || !start)
+		return NULL;
+	if (maxlen && len > maxlen)
+		len = maxlen;
+	if (flags & IORESOURCE_IO)
+		return ioport_map_pci(dev, start, len);
+	if (flags & IORESOURCE_MEM) {
+		if (flags & IORESOURCE_CACHEABLE)
+			return ioremap(start, len);
+		return ioremap_nocache(start, len);
+	}
+	/* What? */
+	return NULL;
+}
+
+EXPORT_SYMBOL(pci_iomap);
+
+void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
+{
+	iounmap(addr);
+}
+
+EXPORT_SYMBOL(pci_iounmap);