of/mips: Add device tree support to MIPS

Add the ability to enable CONFIG_OF on the MIPS architecture.

Signed-off-by: Dezhong Diao <dediao@cisco.com>
[grant.likely@secretlab.ca: cleared out obsolete hooks,
	removed ARCH_HAS_DEVTREE_MEM,
	remove __init tags from header file,
	removed debugfs support hunk]
[ddaney@linux-mips.org: backed out over aggressive trimming of hooks]
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

arch/mips/kernel/prom.c

@@ -0,0 +1,112 @@
+/*
+ * MIPS support for CONFIG_OF device tree support
+ *
+ * Copyright (C) 2010 Cisco Systems Inc. <dediao@cisco.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/bootmem.h>
+#include <linux/initrd.h>
+#include <linux/debugfs.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+#include <asm/page.h>
+#include <asm/prom.h>
+
+int __init early_init_dt_scan_memory_arch(unsigned long node,
+					  const char *uname, int depth,
+					  void *data)
+{
+	return early_init_dt_scan_memory(node, uname, depth, data);
+}
+
+void __init early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	return add_memory_region(base, size, BOOT_MEM_RAM);
+}
+
+int __init reserve_mem_mach(unsigned long addr, unsigned long size)
+{
+	return reserve_bootmem(addr, size, BOOTMEM_DEFAULT);
+}
+
+void __init free_mem_mach(unsigned long addr, unsigned long size)
+{
+	return free_bootmem(addr, size);
+}
+
+u64 __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
+{
+	return virt_to_phys(
+		__alloc_bootmem(size, align, __pa(MAX_DMA_ADDRESS))
+		);
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init early_init_dt_setup_initrd_arch(unsigned long start,
+					    unsigned long end)
+{
+	initrd_start = (unsigned long)__va(start);
+	initrd_end = (unsigned long)__va(end);
+	initrd_below_start_ok = 1;
+}
+#endif
+
+/*
+ * irq_create_of_mapping - Hook to resolve OF irq specifier into a Linux irq#
+ *
+ * Currently the mapping mechanism is trivial; simple flat hwirq numbers are
+ * mapped 1:1 onto Linux irq numbers.  Cascaded irq controllers are not
+ * supported.
+ */
+unsigned int irq_create_of_mapping(struct device_node *controller,
+				   const u32 *intspec, unsigned int intsize)
+{
+	return intspec[0];
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+void __init early_init_devtree(void *params)
+{
+	/* Setup flat device-tree pointer */
+	initial_boot_params = params;
+
+	/* Retrieve various informations from the /chosen node of the
+	 * device-tree, including the platform type, initrd location and
+	 * size, and more ...
+	 */
+	of_scan_flat_dt(early_init_dt_scan_chosen, NULL);
+
+	/* Scan memory nodes */
+	of_scan_flat_dt(early_init_dt_scan_root, NULL);
+	of_scan_flat_dt(early_init_dt_scan_memory_arch, NULL);
+}
+
+void __init device_tree_init(void)
+{
+	unsigned long base, size;
+
+	if (!initial_boot_params)
+		return;
+
+	base = virt_to_phys((void *)initial_boot_params);
+	size = initial_boot_params->totalsize;
+
+	/* Before we do anything, lets reserve the dt blob */
+	reserve_mem_mach(base, size);
+
+	unflatten_device_tree();
+
+	/* free the space reserved for the dt blob */
+	free_mem_mach(base, size);
+}