arch/microblaze/kernel/prom.c - kernel/msm-4.9 - Gitiles

 /*
  * Procedures for creating, accessing and interpreting the device tree.
  *
  * Paul Mackerras	August 1996.
  * Copyright (C) 1996-2005 Paul Mackerras.
  *
  *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
  *    {engebret|bergner}@us.ibm.com
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
  */

 #include <stdarg.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/threads.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/pci.h>
 #include <linux/stringify.h>
 #include <linux/delay.h>
 #include <linux/initrd.h>
 #include <linux/bitops.h>
 #include <linux/module.h>
 #include <linux/kexec.h>
 #include <linux/debugfs.h>
 #include <linux/irq.h>
 #include <linux/lmb.h>

 #include <asm/prom.h>
 #include <asm/page.h>
 #include <asm/processor.h>
 #include <asm/irq.h>
 #include <linux/io.h>
 #include <asm/system.h>
 #include <asm/mmu.h>
 #include <asm/pgtable.h>
 #include <asm/sections.h>
 #include <asm/pci-bridge.h>

 /* export that to outside world */
 struct device_node *of_chosen;

 #define early_init_dt_scan_drconf_memory(node) 0

 static int __init early_init_dt_scan_cpus(unsigned long node,
 					  const char *uname, int depth,
 					  void *data)
 {
 	static int logical_cpuid;
 	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 	const u32 *intserv;
 	int i, nthreads;
 	int found = 0;

 	/* We are scanning "cpu" nodes only */
 	if (type == NULL || strcmp(type, "cpu") != 0)
 		return 0;

 	/* Get physical cpuid */
 	intserv = of_get_flat_dt_prop(node, "reg", NULL);
 	nthreads = 1;

 	/*
 	 * Now see if any of these threads match our boot cpu.
 	 * NOTE: This must match the parsing done in smp_setup_cpu_maps.
 	 */
 	for (i = 0; i < nthreads; i++) {
 		/*
 		 * version 2 of the kexec param format adds the phys cpuid of
 		 * booted proc.
 		 */
 		if (initial_boot_params && initial_boot_params->version >= 2) {
 			if (intserv[i] ==
 					initial_boot_params->boot_cpuid_phys) {
 				found = 1;
 				break;
 			}
 		} else {
 			/*
 			 * Check if it's the boot-cpu, set it's hw index now,
 			 * unfortunately this format did not support booting
 			 * off secondary threads.
 			 */
 			if (of_get_flat_dt_prop(node,
 					"linux,boot-cpu", NULL) != NULL) {
 				found = 1;
 				break;
 			}
 		}

 #ifdef CONFIG_SMP
 		/* logical cpu id is always 0 on UP kernels */
 		logical_cpuid++;
 #endif
 	}

 	if (found) {
 		pr_debug("boot cpu: logical %d physical %d\n", logical_cpuid,
 			intserv[i]);
 		boot_cpuid = logical_cpuid;
 	}

 	return 0;
 }

 void __init early_init_dt_scan_chosen_arch(unsigned long node)
 {
 	/* No Microblaze specific code here */
 }

 static int __init early_init_dt_scan_memory(unsigned long node,
 				const char *uname, int depth, void *data)
 {
 	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 	__be32 *reg, *endp;
 	unsigned long l;

 	/* Look for the ibm,dynamic-reconfiguration-memory node */
 /*	if (depth == 1 &&
 		strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0)
 		return early_init_dt_scan_drconf_memory(node);
 */
 	/* We are scanning "memory" nodes only */
 	if (type == NULL) {
 		/*
 		 * The longtrail doesn't have a device_type on the
 		 * /memory node, so look for the node called /memory@0.
 		 */
 		if (depth != 1 || strcmp(uname, "memory@0") != 0)
 			return 0;
 	} else if (strcmp(type, "memory") != 0)
 		return 0;

 	reg = (__be32 *)of_get_flat_dt_prop(node, "linux,usable-memory", &l);
 	if (reg == NULL)
 		reg = (__be32 *)of_get_flat_dt_prop(node, "reg", &l);
 	if (reg == NULL)
 		return 0;

 	endp = reg + (l / sizeof(__be32));

 	pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
 		uname, l, reg[0], reg[1], reg[2], reg[3]);

 	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
 		u64 base, size;

 		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
 		size = dt_mem_next_cell(dt_root_size_cells, &reg);

 		if (size == 0)
 			continue;
 		pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
 			(unsigned long long)size);

 		lmb_add(base, size);
 	}
 	return 0;
 }

 #ifdef CONFIG_PHYP_DUMP
 /**
  * phyp_dump_calculate_reserve_size() - reserve variable boot area 5% or arg
  *
  * Function to find the largest size we need to reserve
  * during early boot process.
  *
  * It either looks for boot param and returns that OR
  * returns larger of 256 or 5% rounded down to multiples of 256MB.
  *
  */
 static inline unsigned long phyp_dump_calculate_reserve_size(void)
 {
 	unsigned long tmp;

 	if (phyp_dump_info->reserve_bootvar)
 		return phyp_dump_info->reserve_bootvar;

 	/* divide by 20 to get 5% of value */
 	tmp = lmb_end_of_DRAM();
 	do_div(tmp, 20);

 	/* round it down in multiples of 256 */
 	tmp = tmp & ~0x0FFFFFFFUL;

 	return (tmp > PHYP_DUMP_RMR_END ? tmp : PHYP_DUMP_RMR_END);
 }

 /**
  * phyp_dump_reserve_mem() - reserve all not-yet-dumped mmemory
  *
  * This routine may reserve memory regions in the kernel only
  * if the system is supported and a dump was taken in last
  * boot instance or if the hardware is supported and the
  * scratch area needs to be setup. In other instances it returns
  * without reserving anything. The memory in case of dump being
  * active is freed when the dump is collected (by userland tools).
  */
 static void __init phyp_dump_reserve_mem(void)
 {
 	unsigned long base, size;
 	unsigned long variable_reserve_size;

 	if (!phyp_dump_info->phyp_dump_configured) {
 		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
 		return;
 	}

 	if (!phyp_dump_info->phyp_dump_at_boot) {
 		printk(KERN_INFO "Phyp-dump disabled at boot time\n");
 		return;
 	}

 	variable_reserve_size = phyp_dump_calculate_reserve_size();

 	if (phyp_dump_info->phyp_dump_is_active) {
 		/* Reserve *everything* above RMR.Area freed by userland tools*/
 		base = variable_reserve_size;
 		size = lmb_end_of_DRAM() - base;

 		/* XXX crashed_ram_end is wrong, since it may be beyond
 		 * the memory_limit, it will need to be adjusted. */
 		lmb_reserve(base, size);

 		phyp_dump_info->init_reserve_start = base;
 		phyp_dump_info->init_reserve_size = size;
 	} else {
 		size = phyp_dump_info->cpu_state_size +
 			phyp_dump_info->hpte_region_size +
 			variable_reserve_size;
 		base = lmb_end_of_DRAM() - size;
 		lmb_reserve(base, size);
 		phyp_dump_info->init_reserve_start = base;
 		phyp_dump_info->init_reserve_size = size;
 	}
 }
 #else
 static inline void __init phyp_dump_reserve_mem(void) {}
 #endif /* CONFIG_PHYP_DUMP  && CONFIG_PPC_RTAS */

 #ifdef CONFIG_EARLY_PRINTK
 /* MS this is Microblaze specifig function */
 static int __init early_init_dt_scan_serial(unsigned long node,
 				const char *uname, int depth, void *data)
 {
 	unsigned long l;
 	char *p;
 	int *addr;

 	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);

 /* find all serial nodes */
 	if (strncmp(uname, "serial", 6) != 0)
 		return 0;

 	early_init_dt_check_for_initrd(node);

 /* find compatible node with uartlite */
 	p = of_get_flat_dt_prop(node, "compatible", &l);
 	if ((strncmp(p, "xlnx,xps-uartlite", 17) != 0) &&
 			(strncmp(p, "xlnx,opb-uartlite", 17) != 0))
 		return 0;

 	addr = of_get_flat_dt_prop(node, "reg", &l);
 	return *addr; /* return address */
 }

 /* this function is looking for early uartlite console - Microblaze specific */
 int __init early_uartlite_console(void)
 {
 	return of_scan_flat_dt(early_init_dt_scan_serial, NULL);
 }
 #endif

 void __init early_init_devtree(void *params)
 {
 	pr_debug(" -> early_init_devtree(%p)\n", params);

 	/* Setup flat device-tree pointer */
 	initial_boot_params = params;

 #ifdef CONFIG_PHYP_DUMP
 	/* scan tree to see if dump occured during last boot */
 	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 #endif

 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
 	 * size, TCE reserve, and more ...
 	 */
 	of_scan_flat_dt(early_init_dt_scan_chosen, NULL);

 	/* Scan memory nodes and rebuild LMBs */
 	lmb_init();
 	of_scan_flat_dt(early_init_dt_scan_root, NULL);
 	of_scan_flat_dt(early_init_dt_scan_memory, NULL);

 	/* Save command line for /proc/cmdline and then parse parameters */
 	strlcpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
 	parse_early_param();

 	lmb_analyze();

 	pr_debug("Phys. mem: %lx\n", (unsigned long) lmb_phys_mem_size());

 	pr_debug("Scanning CPUs ...\n");

 	/* Retreive CPU related informations from the flat tree
 	 * (altivec support, boot CPU ID, ...)
 	 */
 	of_scan_flat_dt(early_init_dt_scan_cpus, NULL);

 	pr_debug(" <- early_init_devtree()\n");
 }

 /*******
  *
  * New implementation of the OF "find" APIs, return a refcounted
  * object, call of_node_put() when done.  The device tree and list
  * are protected by a rw_lock.
  *
  * Note that property management will need some locking as well,
  * this isn't dealt with yet.
  *
  *******/

 /**
  *	of_find_node_by_phandle - Find a node given a phandle
  *	@handle:	phandle of the node to find
  *
  *	Returns a node pointer with refcount incremented, use
  *	of_node_put() on it when done.
  */
 struct device_node *of_find_node_by_phandle(phandle handle)
 {
 	struct device_node *np;

 	read_lock(&devtree_lock);
 	for (np = allnodes; np != NULL; np = np->allnext)
 		if (np->phandle == handle)
 			break;
 	of_node_get(np);
 	read_unlock(&devtree_lock);
 	return np;
 }
 EXPORT_SYMBOL(of_find_node_by_phandle);

 /*
  * Plug a device node into the tree and global list.
  */
 void of_attach_node(struct device_node *np)
 {
 	unsigned long flags;

 	write_lock_irqsave(&devtree_lock, flags);
 	np->sibling = np->parent->child;
 	np->allnext = allnodes;
 	np->parent->child = np;
 	allnodes = np;
 	write_unlock_irqrestore(&devtree_lock, flags);
 }

 /*
  * "Unplug" a node from the device tree.  The caller must hold
  * a reference to the node.  The memory associated with the node
  * is not freed until its refcount goes to zero.
  */
 void of_detach_node(struct device_node *np)
 {
 	struct device_node *parent;
 	unsigned long flags;

 	write_lock_irqsave(&devtree_lock, flags);

 	parent = np->parent;
 	if (!parent)
 		goto out_unlock;

 	if (allnodes == np)
 		allnodes = np->allnext;
 	else {
 		struct device_node *prev;
 		for (prev = allnodes;
 		     prev->allnext != np;
 		     prev = prev->allnext)
 			;
 		prev->allnext = np->allnext;
 	}

 	if (parent->child == np)
 		parent->child = np->sibling;
 	else {
 		struct device_node *prevsib;
 		for (prevsib = np->parent->child;
 		     prevsib->sibling != np;
 		     prevsib = prevsib->sibling)
 			;
 		prevsib->sibling = np->sibling;
 	}

 	of_node_set_flag(np, OF_DETACHED);

 out_unlock:
 	write_unlock_irqrestore(&devtree_lock, flags);
 }

 #if defined(CONFIG_DEBUG_FS) && defined(DEBUG)
 static struct debugfs_blob_wrapper flat_dt_blob;

 static int __init export_flat_device_tree(void)
 {
 	struct dentry *d;

 	flat_dt_blob.data = initial_boot_params;
 	flat_dt_blob.size = initial_boot_params->totalsize;

 	d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
 				of_debugfs_root, &flat_dt_blob);
 	if (!d)
 		return 1;

 	return 0;
 }
 device_initcall(export_flat_device_tree);
 #endif
	/*
	* Procedures for creating, accessing and interpreting the device tree.
	*
	* Paul Mackerras August 1996.
	* Copyright (C) 1996-2005 Paul Mackerras.
	*
	* Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
	* {engebret\|bergner}@us.ibm.com
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <stdarg.h>
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/init.h>
	#include <linux/threads.h>
	#include <linux/spinlock.h>
	#include <linux/types.h>
	#include <linux/pci.h>
	#include <linux/stringify.h>
	#include <linux/delay.h>
	#include <linux/initrd.h>
	#include <linux/bitops.h>
	#include <linux/module.h>
	#include <linux/kexec.h>
	#include <linux/debugfs.h>
	#include <linux/irq.h>
	#include <linux/lmb.h>

	#include <asm/prom.h>
	#include <asm/page.h>
	#include <asm/processor.h>
	#include <asm/irq.h>
	#include <linux/io.h>
	#include <asm/system.h>
	#include <asm/mmu.h>
	#include <asm/pgtable.h>
	#include <asm/sections.h>
	#include <asm/pci-bridge.h>

	/* export that to outside world */
	struct device_node *of_chosen;

	#define early_init_dt_scan_drconf_memory(node) 0

	static int __init early_init_dt_scan_cpus(unsigned long node,
	const char *uname, int depth,
	void *data)
	{
	static int logical_cpuid;
	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
	const u32 *intserv;
	int i, nthreads;
	int found = 0;

	/* We are scanning "cpu" nodes only */
	if (type == NULL \|\| strcmp(type, "cpu") != 0)
	return 0;

	/* Get physical cpuid */
	intserv = of_get_flat_dt_prop(node, "reg", NULL);
	nthreads = 1;

	/*
	* Now see if any of these threads match our boot cpu.
	* NOTE: This must match the parsing done in smp_setup_cpu_maps.
	*/
	for (i = 0; i < nthreads; i++) {
	/*
	* version 2 of the kexec param format adds the phys cpuid of
	* booted proc.
	*/
	if (initial_boot_params && initial_boot_params->version >= 2) {
	if (intserv[i] ==
	initial_boot_params->boot_cpuid_phys) {
	found = 1;
	break;
	}
	} else {
	/*
	* Check if it's the boot-cpu, set it's hw index now,
	* unfortunately this format did not support booting
	* off secondary threads.
	*/
	if (of_get_flat_dt_prop(node,
	"linux,boot-cpu", NULL) != NULL) {
	found = 1;
	break;
	}
	}

	#ifdef CONFIG_SMP
	/* logical cpu id is always 0 on UP kernels */
	logical_cpuid++;
	#endif
	}

	if (found) {
	pr_debug("boot cpu: logical %d physical %d\n", logical_cpuid,
	intserv[i]);
	boot_cpuid = logical_cpuid;
	}

	return 0;
	}

	void __init early_init_dt_scan_chosen_arch(unsigned long node)
	{
	/* No Microblaze specific code here */
	}

	static int __init early_init_dt_scan_memory(unsigned long node,
	const char uname, int depth, void data)
	{
	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
	__be32 reg, endp;
	unsigned long l;

	/* Look for the ibm,dynamic-reconfiguration-memory node */
	/* if (depth == 1 &&
	strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0)
	return early_init_dt_scan_drconf_memory(node);
	*/
	/* We are scanning "memory" nodes only */
	if (type == NULL) {
	/*
	* The longtrail doesn't have a device_type on the
	* /memory node, so look for the node called /memory@0.
	*/
	if (depth != 1 \|\| strcmp(uname, "memory@0") != 0)
	return 0;
	} else if (strcmp(type, "memory") != 0)
	return 0;

	reg = (__be32 *)of_get_flat_dt_prop(node, "linux,usable-memory", &l);
	if (reg == NULL)
	reg = (__be32 *)of_get_flat_dt_prop(node, "reg", &l);
	if (reg == NULL)
	return 0;

	endp = reg + (l / sizeof(__be32));

	pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
	uname, l, reg[0], reg[1], reg[2], reg[3]);

	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
	u64 base, size;

	base = dt_mem_next_cell(dt_root_addr_cells, &reg);
	size = dt_mem_next_cell(dt_root_size_cells, &reg);

	if (size == 0)
	continue;
	pr_debug(" - %llx , %llx\n", (unsigned long long)base,
	(unsigned long long)size);

	lmb_add(base, size);
	}
	return 0;
	}

	#ifdef CONFIG_PHYP_DUMP
	/**
	* phyp_dump_calculate_reserve_size() - reserve variable boot area 5% or arg
	*
	* Function to find the largest size we need to reserve
	* during early boot process.
	*
	* It either looks for boot param and returns that OR
	* returns larger of 256 or 5% rounded down to multiples of 256MB.
	*
	*/
	static inline unsigned long phyp_dump_calculate_reserve_size(void)
	{
	unsigned long tmp;

	if (phyp_dump_info->reserve_bootvar)
	return phyp_dump_info->reserve_bootvar;

	/* divide by 20 to get 5% of value */
	tmp = lmb_end_of_DRAM();
	do_div(tmp, 20);

	/* round it down in multiples of 256 */
	tmp = tmp & ~0x0FFFFFFFUL;

	return (tmp > PHYP_DUMP_RMR_END ? tmp : PHYP_DUMP_RMR_END);
	}

	/**
	* phyp_dump_reserve_mem() - reserve all not-yet-dumped mmemory
	*
	* This routine may reserve memory regions in the kernel only
	* if the system is supported and a dump was taken in last
	* boot instance or if the hardware is supported and the
	* scratch area needs to be setup. In other instances it returns
	* without reserving anything. The memory in case of dump being
	* active is freed when the dump is collected (by userland tools).
	*/
	static void __init phyp_dump_reserve_mem(void)
	{
	unsigned long base, size;
	unsigned long variable_reserve_size;

	if (!phyp_dump_info->phyp_dump_configured) {
	printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
	return;
	}

	if (!phyp_dump_info->phyp_dump_at_boot) {
	printk(KERN_INFO "Phyp-dump disabled at boot time\n");
	return;
	}

	variable_reserve_size = phyp_dump_calculate_reserve_size();

	if (phyp_dump_info->phyp_dump_is_active) {
	/* Reserve everything above RMR.Area freed by userland tools*/
	base = variable_reserve_size;
	size = lmb_end_of_DRAM() - base;

	/* XXX crashed_ram_end is wrong, since it may be beyond
	* the memory_limit, it will need to be adjusted. */
	lmb_reserve(base, size);

	phyp_dump_info->init_reserve_start = base;
	phyp_dump_info->init_reserve_size = size;
	} else {
	size = phyp_dump_info->cpu_state_size +
	phyp_dump_info->hpte_region_size +
	variable_reserve_size;
	base = lmb_end_of_DRAM() - size;
	lmb_reserve(base, size);
	phyp_dump_info->init_reserve_start = base;
	phyp_dump_info->init_reserve_size = size;
	}
	}
	#else
	static inline void __init phyp_dump_reserve_mem(void) {}
	#endif /* CONFIG_PHYP_DUMP && CONFIG_PPC_RTAS */

	#ifdef CONFIG_EARLY_PRINTK
	/* MS this is Microblaze specifig function */
	static int __init early_init_dt_scan_serial(unsigned long node,
	const char uname, int depth, void data)
	{
	unsigned long l;
	char *p;
	int *addr;

	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);

	/* find all serial nodes */
	if (strncmp(uname, "serial", 6) != 0)
	return 0;

	early_init_dt_check_for_initrd(node);

	/* find compatible node with uartlite */
	p = of_get_flat_dt_prop(node, "compatible", &l);
	if ((strncmp(p, "xlnx,xps-uartlite", 17) != 0) &&
	(strncmp(p, "xlnx,opb-uartlite", 17) != 0))
	return 0;

	addr = of_get_flat_dt_prop(node, "reg", &l);
	return addr; / return address */
	}

	/* this function is looking for early uartlite console - Microblaze specific */
	int __init early_uartlite_console(void)
	{
	return of_scan_flat_dt(early_init_dt_scan_serial, NULL);
	}
	#endif

	void __init early_init_devtree(void *params)
	{
	pr_debug(" -> early_init_devtree(%p)\n", params);

	/* Setup flat device-tree pointer */
	initial_boot_params = params;

	#ifdef CONFIG_PHYP_DUMP
	/* scan tree to see if dump occured during last boot */
	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
	#endif

	/* Retrieve various informations from the /chosen node of the
	* device-tree, including the platform type, initrd location and
	* size, TCE reserve, and more ...
	*/
	of_scan_flat_dt(early_init_dt_scan_chosen, NULL);

	/* Scan memory nodes and rebuild LMBs */
	lmb_init();
	of_scan_flat_dt(early_init_dt_scan_root, NULL);
	of_scan_flat_dt(early_init_dt_scan_memory, NULL);

	/* Save command line for /proc/cmdline and then parse parameters */
	strlcpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
	parse_early_param();

	lmb_analyze();

	pr_debug("Phys. mem: %lx\n", (unsigned long) lmb_phys_mem_size());

	pr_debug("Scanning CPUs ...\n");

	/* Retreive CPU related informations from the flat tree
	* (altivec support, boot CPU ID, ...)
	*/
	of_scan_flat_dt(early_init_dt_scan_cpus, NULL);

	pr_debug(" <- early_init_devtree()\n");
	}

	/*******
	*
	* New implementation of the OF "find" APIs, return a refcounted
	* object, call of_node_put() when done. The device tree and list
	* are protected by a rw_lock.
	*
	* Note that property management will need some locking as well,
	* this isn't dealt with yet.
	*
	*******/

	/**
	* of_find_node_by_phandle - Find a node given a phandle
	* @handle: phandle of the node to find
	*
	* Returns a node pointer with refcount incremented, use
	* of_node_put() on it when done.
	*/
	struct device_node *of_find_node_by_phandle(phandle handle)
	{
	struct device_node *np;

	read_lock(&devtree_lock);
	for (np = allnodes; np != NULL; np = np->allnext)
	if (np->phandle == handle)
	break;
	of_node_get(np);
	read_unlock(&devtree_lock);
	return np;
	}
	EXPORT_SYMBOL(of_find_node_by_phandle);

	/*
	* Plug a device node into the tree and global list.
	*/
	void of_attach_node(struct device_node *np)
	{
	unsigned long flags;

	write_lock_irqsave(&devtree_lock, flags);
	np->sibling = np->parent->child;
	np->allnext = allnodes;
	np->parent->child = np;
	allnodes = np;
	write_unlock_irqrestore(&devtree_lock, flags);
	}

	/*
	* "Unplug" a node from the device tree. The caller must hold
	* a reference to the node. The memory associated with the node
	* is not freed until its refcount goes to zero.
	*/
	void of_detach_node(struct device_node *np)
	{
	struct device_node *parent;
	unsigned long flags;

	write_lock_irqsave(&devtree_lock, flags);

	parent = np->parent;
	if (!parent)
	goto out_unlock;

	if (allnodes == np)
	allnodes = np->allnext;
	else {
	struct device_node *prev;
	for (prev = allnodes;
	prev->allnext != np;
	prev = prev->allnext)
	;
	prev->allnext = np->allnext;
	}

	if (parent->child == np)
	parent->child = np->sibling;
	else {
	struct device_node *prevsib;
	for (prevsib = np->parent->child;
	prevsib->sibling != np;
	prevsib = prevsib->sibling)
	;
	prevsib->sibling = np->sibling;
	}

	of_node_set_flag(np, OF_DETACHED);

	out_unlock:
	write_unlock_irqrestore(&devtree_lock, flags);
	}

	#if defined(CONFIG_DEBUG_FS) && defined(DEBUG)
	static struct debugfs_blob_wrapper flat_dt_blob;

	static int __init export_flat_device_tree(void)
	{
	struct dentry *d;

	flat_dt_blob.data = initial_boot_params;
	flat_dt_blob.size = initial_boot_params->totalsize;

	d = debugfs_create_blob("flat-device-tree", S_IFREG \| S_IRUSR,
	of_debugfs_root, &flat_dt_blob);
	if (!d)
	return 1;

	return 0;
	}
	device_initcall(export_flat_device_tree);
	#endif