arch/powerpc/mm/numa.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * pSeries NUMA support
  *
  * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
  *
  * 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 <linux/threads.h>
 #include <linux/bootmem.h>
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/mmzone.h>
 #include <linux/module.h>
 #include <linux/nodemask.h>
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/lmb.h>
 #include <asm/sparsemem.h>
 #include <asm/prom.h>
 #include <asm/system.h>
 #include <asm/smp.h>

 static int numa_enabled = 1;

 static char *cmdline __initdata;

 static int numa_debug;
 #define dbg(args...) if (numa_debug) { printk(KERN_INFO args); }

 int numa_cpu_lookup_table[NR_CPUS];
 cpumask_t numa_cpumask_lookup_table[MAX_NUMNODES];
 struct pglist_data *node_data[MAX_NUMNODES];

 EXPORT_SYMBOL(numa_cpu_lookup_table);
 EXPORT_SYMBOL(numa_cpumask_lookup_table);
 EXPORT_SYMBOL(node_data);

 static bootmem_data_t __initdata plat_node_bdata[MAX_NUMNODES];
 static int min_common_depth;
 static int n_mem_addr_cells, n_mem_size_cells;

 static int __cpuinit fake_numa_create_new_node(unsigned long end_pfn,
 						unsigned int *nid)
 {
 	unsigned long long mem;
 	char *p = cmdline;
 	static unsigned int fake_nid;
 	static unsigned long long curr_boundary;

 	/*
 	 * Modify node id, iff we started creating NUMA nodes
 	 * We want to continue from where we left of the last time
 	 */
 	if (fake_nid)
 		*nid = fake_nid;
 	/*
 	 * In case there are no more arguments to parse, the
 	 * node_id should be the same as the last fake node id
 	 * (we've handled this above).
 	 */
 	if (!p)
 		return 0;

 	mem = memparse(p, &p);
 	if (!mem)
 		return 0;

 	if (mem < curr_boundary)
 		return 0;

 	curr_boundary = mem;

 	if ((end_pfn << PAGE_SHIFT) > mem) {
 		/*
 		 * Skip commas and spaces
 		 */
 		while (*p == ',' || *p == ' ' || *p == '\t')
 			p++;

 		cmdline = p;
 		fake_nid++;
 		*nid = fake_nid;
 		dbg("created new fake_node with id %d\n", fake_nid);
 		return 1;
 	}
 	return 0;
 }

 static void __cpuinit map_cpu_to_node(int cpu, int node)
 {
 	numa_cpu_lookup_table[cpu] = node;

 	dbg("adding cpu %d to node %d\n", cpu, node);

 	if (!(cpu_isset(cpu, numa_cpumask_lookup_table[node])))
 		cpu_set(cpu, numa_cpumask_lookup_table[node]);
 }

 #ifdef CONFIG_HOTPLUG_CPU
 static void unmap_cpu_from_node(unsigned long cpu)
 {
 	int node = numa_cpu_lookup_table[cpu];

 	dbg("removing cpu %lu from node %d\n", cpu, node);

 	if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
 		cpu_clear(cpu, numa_cpumask_lookup_table[node]);
 	} else {
 		printk(KERN_ERR "WARNING: cpu %lu not found in node %d\n",
 		       cpu, node);
 	}
 }
 #endif /* CONFIG_HOTPLUG_CPU */

 static struct device_node * __cpuinit find_cpu_node(unsigned int cpu)
 {
 	unsigned int hw_cpuid = get_hard_smp_processor_id(cpu);
 	struct device_node *cpu_node = NULL;
 	const unsigned int *interrupt_server, *reg;
 	int len;

 	while ((cpu_node = of_find_node_by_type(cpu_node, "cpu")) != NULL) {
 		/* Try interrupt server first */
 		interrupt_server = of_get_property(cpu_node,
 					"ibm,ppc-interrupt-server#s", &len);

 		len = len / sizeof(u32);

 		if (interrupt_server && (len > 0)) {
 			while (len--) {
 				if (interrupt_server[len] == hw_cpuid)
 					return cpu_node;
 			}
 		} else {
 			reg = of_get_property(cpu_node, "reg", &len);
 			if (reg && (len > 0) && (reg[0] == hw_cpuid))
 				return cpu_node;
 		}
 	}

 	return NULL;
 }

 /* must hold reference to node during call */
 static const int *of_get_associativity(struct device_node *dev)
 {
 	return of_get_property(dev, "ibm,associativity", NULL);
 }

 /* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
  * info is found.
  */
 static int of_node_to_nid_single(struct device_node *device)
 {
 	int nid = -1;
 	const unsigned int *tmp;

 	if (min_common_depth == -1)
 		goto out;

 	tmp = of_get_associativity(device);
 	if (!tmp)
 		goto out;

 	if (tmp[0] >= min_common_depth)
 		nid = tmp[min_common_depth];

 	/* POWER4 LPAR uses 0xffff as invalid node */
 	if (nid == 0xffff || nid >= MAX_NUMNODES)
 		nid = -1;
 out:
 	return nid;
 }

 /* Walk the device tree upwards, looking for an associativity id */
 int of_node_to_nid(struct device_node *device)
 {
 	struct device_node *tmp;
 	int nid = -1;

 	of_node_get(device);
 	while (device) {
 		nid = of_node_to_nid_single(device);
 		if (nid != -1)
 			break;

 	        tmp = device;
 		device = of_get_parent(tmp);
 		of_node_put(tmp);
 	}
 	of_node_put(device);

 	return nid;
 }
 EXPORT_SYMBOL_GPL(of_node_to_nid);

 /*
  * In theory, the "ibm,associativity" property may contain multiple
  * associativity lists because a resource may be multiply connected
  * into the machine.  This resource then has different associativity
  * characteristics relative to its multiple connections.  We ignore
  * this for now.  We also assume that all cpu and memory sets have
  * their distances represented at a common level.  This won't be
  * true for hierarchical NUMA.
  *
  * In any case the ibm,associativity-reference-points should give
  * the correct depth for a normal NUMA system.
  *
  * - Dave Hansen <haveblue@us.ibm.com>
  */
 static int __init find_min_common_depth(void)
 {
 	int depth;
 	const unsigned int *ref_points;
 	struct device_node *rtas_root;
 	unsigned int len;

 	rtas_root = of_find_node_by_path("/rtas");

 	if (!rtas_root)
 		return -1;

 	/*
 	 * this property is 2 32-bit integers, each representing a level of
 	 * depth in the associativity nodes.  The first is for an SMP
 	 * configuration (should be all 0's) and the second is for a normal
 	 * NUMA configuration.
 	 */
 	ref_points = of_get_property(rtas_root,
 			"ibm,associativity-reference-points", &len);

 	if ((len >= 1) && ref_points) {
 		depth = ref_points[1];
 	} else {
 		dbg("NUMA: ibm,associativity-reference-points not found.\n");
 		depth = -1;
 	}
 	of_node_put(rtas_root);

 	return depth;
 }

 static void __init get_n_mem_cells(int *n_addr_cells, int *n_size_cells)
 {
 	struct device_node *memory = NULL;

 	memory = of_find_node_by_type(memory, "memory");
 	if (!memory)
 		panic("numa.c: No memory nodes found!");

 	*n_addr_cells = of_n_addr_cells(memory);
 	*n_size_cells = of_n_size_cells(memory);
 	of_node_put(memory);
 }

 static unsigned long __devinit read_n_cells(int n, const unsigned int **buf)
 {
 	unsigned long result = 0;

 	while (n--) {
 		result = (result << 32) | **buf;
 		(*buf)++;
 	}
 	return result;
 }

 /*
  * Figure out to which domain a cpu belongs and stick it there.
  * Return the id of the domain used.
  */
 static int __cpuinit numa_setup_cpu(unsigned long lcpu)
 {
 	int nid = 0;
 	struct device_node *cpu = find_cpu_node(lcpu);

 	if (!cpu) {
 		WARN_ON(1);
 		goto out;
 	}

 	nid = of_node_to_nid_single(cpu);

 	if (nid < 0 || !node_online(nid))
 		nid = any_online_node(NODE_MASK_ALL);
 out:
 	map_cpu_to_node(lcpu, nid);

 	of_node_put(cpu);

 	return nid;
 }

 static int __cpuinit cpu_numa_callback(struct notifier_block *nfb,
 			     unsigned long action,
 			     void *hcpu)
 {
 	unsigned long lcpu = (unsigned long)hcpu;
 	int ret = NOTIFY_DONE;

 	switch (action) {
 	case CPU_UP_PREPARE:
 	case CPU_UP_PREPARE_FROZEN:
 		numa_setup_cpu(lcpu);
 		ret = NOTIFY_OK;
 		break;
 #ifdef CONFIG_HOTPLUG_CPU
 	case CPU_DEAD:
 	case CPU_DEAD_FROZEN:
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
 		unmap_cpu_from_node(lcpu);
 		break;
 		ret = NOTIFY_OK;
 #endif
 	}
 	return ret;
 }

 /*
  * Check and possibly modify a memory region to enforce the memory limit.
  *
  * Returns the size the region should have to enforce the memory limit.
  * This will either be the original value of size, a truncated value,
  * or zero. If the returned value of size is 0 the region should be
  * discarded as it lies wholy above the memory limit.
  */
 static unsigned long __init numa_enforce_memory_limit(unsigned long start,
 						      unsigned long size)
 {
 	/*
 	 * We use lmb_end_of_DRAM() in here instead of memory_limit because
 	 * we've already adjusted it for the limit and it takes care of
 	 * having memory holes below the limit.
 	 */

 	if (! memory_limit)
 		return size;

 	if (start + size <= lmb_end_of_DRAM())
 		return size;

 	if (start >= lmb_end_of_DRAM())
 		return 0;

 	return lmb_end_of_DRAM() - start;
 }

 /*
  * Extract NUMA information from the ibm,dynamic-reconfiguration-memory
  * node.  This assumes n_mem_{addr,size}_cells have been set.
  */
 static void __init parse_drconf_memory(struct device_node *memory)
 {
 	const unsigned int *lm, *dm, *aa;
 	unsigned int ls, ld, la;
 	unsigned int n, aam, aalen;
 	unsigned long lmb_size, size, start;
 	int nid, default_nid = 0;
 	unsigned int ai, flags;

 	lm = of_get_property(memory, "ibm,lmb-size", &ls);
 	dm = of_get_property(memory, "ibm,dynamic-memory", &ld);
 	aa = of_get_property(memory, "ibm,associativity-lookup-arrays", &la);
 	if (!lm || !dm || !aa ||
 	    ls < sizeof(unsigned int) || ld < sizeof(unsigned int) ||
 	    la < 2 * sizeof(unsigned int))
 		return;

 	lmb_size = read_n_cells(n_mem_size_cells, &lm);
 	n = *dm++;		/* number of LMBs */
 	aam = *aa++;		/* number of associativity lists */
 	aalen = *aa++;		/* length of each associativity list */
 	if (ld < (n * (n_mem_addr_cells + 4) + 1) * sizeof(unsigned int) ||
 	    la < (aam * aalen + 2) * sizeof(unsigned int))
 		return;

 	for (; n != 0; --n) {
 		start = read_n_cells(n_mem_addr_cells, &dm);
 		ai = dm[2];
 		flags = dm[3];
 		dm += 4;
 		/* 0x80 == reserved, 0x8 = assigned to us */
 		if ((flags & 0x80) || !(flags & 0x8))
 			continue;
 		nid = default_nid;
 		/* flags & 0x40 means associativity index is invalid */
 		if (min_common_depth > 0 && min_common_depth <= aalen &&
 		    (flags & 0x40) == 0 && ai < aam) {
 			/* this is like of_node_to_nid_single */
 			nid = aa[ai * aalen + min_common_depth - 1];
 			if (nid == 0xffff || nid >= MAX_NUMNODES)
 				nid = default_nid;
 		}

 		fake_numa_create_new_node(((start + lmb_size) >> PAGE_SHIFT),
 						&nid);
 		node_set_online(nid);

 		size = numa_enforce_memory_limit(start, lmb_size);
 		if (!size)
 			continue;

 		add_active_range(nid, start >> PAGE_SHIFT,
 				 (start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));
 	}
 }

 static int __init parse_numa_properties(void)
 {
 	struct device_node *cpu = NULL;
 	struct device_node *memory = NULL;
 	int default_nid = 0;
 	unsigned long i;

 	if (numa_enabled == 0) {
 		printk(KERN_WARNING "NUMA disabled by user\n");
 		return -1;
 	}

 	min_common_depth = find_min_common_depth();

 	if (min_common_depth < 0)
 		return min_common_depth;

 	dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);

 	/*
 	 * Even though we connect cpus to numa domains later in SMP
 	 * init, we need to know the node ids now. This is because
 	 * each node to be onlined must have NODE_DATA etc backing it.
 	 */
 	for_each_present_cpu(i) {
 		int nid;

 		cpu = find_cpu_node(i);
 		BUG_ON(!cpu);
 		nid = of_node_to_nid_single(cpu);
 		of_node_put(cpu);

 		/*
 		 * Don't fall back to default_nid yet -- we will plug
 		 * cpus into nodes once the memory scan has discovered
 		 * the topology.
 		 */
 		if (nid < 0)
 			continue;
 		node_set_online(nid);
 	}

 	get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
 	memory = NULL;
 	while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
 		unsigned long start;
 		unsigned long size;
 		int nid;
 		int ranges;
 		const unsigned int *memcell_buf;
 		unsigned int len;

 		memcell_buf = of_get_property(memory,
 			"linux,usable-memory", &len);
 		if (!memcell_buf || len <= 0)
 			memcell_buf = of_get_property(memory, "reg", &len);
 		if (!memcell_buf || len <= 0)
 			continue;

 		/* ranges in cell */
 		ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
 new_range:
 		/* these are order-sensitive, and modify the buffer pointer */
 		start = read_n_cells(n_mem_addr_cells, &memcell_buf);
 		size = read_n_cells(n_mem_size_cells, &memcell_buf);

 		/*
 		 * Assumption: either all memory nodes or none will
 		 * have associativity properties.  If none, then
 		 * everything goes to default_nid.
 		 */
 		nid = of_node_to_nid_single(memory);
 		if (nid < 0)
 			nid = default_nid;

 		fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
 		node_set_online(nid);

 		if (!(size = numa_enforce_memory_limit(start, size))) {
 			if (--ranges)
 				goto new_range;
 			else
 				continue;
 		}

 		add_active_range(nid, start >> PAGE_SHIFT,
 				(start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));

 		if (--ranges)
 			goto new_range;
 	}

 	/*
 	 * Now do the same thing for each LMB listed in the ibm,dynamic-memory
 	 * property in the ibm,dynamic-reconfiguration-memory node.
 	 */
 	memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
 	if (memory)
 		parse_drconf_memory(memory);

 	return 0;
 }

 static void __init setup_nonnuma(void)
 {
 	unsigned long top_of_ram = lmb_end_of_DRAM();
 	unsigned long total_ram = lmb_phys_mem_size();
 	unsigned long start_pfn, end_pfn;
 	unsigned int i, nid = 0;

 	printk(KERN_DEBUG "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
 	       top_of_ram, total_ram);
 	printk(KERN_DEBUG "Memory hole size: %ldMB\n",
 	       (top_of_ram - total_ram) >> 20);

 	for (i = 0; i < lmb.memory.cnt; ++i) {
 		start_pfn = lmb.memory.region[i].base >> PAGE_SHIFT;
 		end_pfn = start_pfn + lmb_size_pages(&lmb.memory, i);

 		fake_numa_create_new_node(end_pfn, &nid);
 		add_active_range(nid, start_pfn, end_pfn);
 		node_set_online(nid);
 	}
 }

 void __init dump_numa_cpu_topology(void)
 {
 	unsigned int node;
 	unsigned int cpu, count;

 	if (min_common_depth == -1 || !numa_enabled)
 		return;

 	for_each_online_node(node) {
 		printk(KERN_DEBUG "Node %d CPUs:", node);

 		count = 0;
 		/*
 		 * If we used a CPU iterator here we would miss printing
 		 * the holes in the cpumap.
 		 */
 		for (cpu = 0; cpu < NR_CPUS; cpu++) {
 			if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
 				if (count == 0)
 					printk(" %u", cpu);
 				++count;
 			} else {
 				if (count > 1)
 					printk("-%u", cpu - 1);
 				count = 0;
 			}
 		}

 		if (count > 1)
 			printk("-%u", NR_CPUS - 1);
 		printk("\n");
 	}
 }

 static void __init dump_numa_memory_topology(void)
 {
 	unsigned int node;
 	unsigned int count;

 	if (min_common_depth == -1 || !numa_enabled)
 		return;

 	for_each_online_node(node) {
 		unsigned long i;

 		printk(KERN_DEBUG "Node %d Memory:", node);

 		count = 0;

 		for (i = 0; i < lmb_end_of_DRAM();
 		     i += (1 << SECTION_SIZE_BITS)) {
 			if (early_pfn_to_nid(i >> PAGE_SHIFT) == node) {
 				if (count == 0)
 					printk(" 0x%lx", i);
 				++count;
 			} else {
 				if (count > 0)
 					printk("-0x%lx", i);
 				count = 0;
 			}
 		}

 		if (count > 0)
 			printk("-0x%lx", i);
 		printk("\n");
 	}
 }

 /*
  * Allocate some memory, satisfying the lmb or bootmem allocator where
  * required. nid is the preferred node and end is the physical address of
  * the highest address in the node.
  *
  * Returns the physical address of the memory.
  */
 static void __init *careful_allocation(int nid, unsigned long size,
 				       unsigned long align,
 				       unsigned long end_pfn)
 {
 	int new_nid;
 	unsigned long ret = __lmb_alloc_base(size, align, end_pfn << PAGE_SHIFT);

 	/* retry over all memory */
 	if (!ret)
 		ret = __lmb_alloc_base(size, align, lmb_end_of_DRAM());

 	if (!ret)
 		panic("numa.c: cannot allocate %lu bytes on node %d",
 		      size, nid);

 	/*
 	 * If the memory came from a previously allocated node, we must
 	 * retry with the bootmem allocator.
 	 */
 	new_nid = early_pfn_to_nid(ret >> PAGE_SHIFT);
 	if (new_nid < nid) {
 		ret = (unsigned long)__alloc_bootmem_node(NODE_DATA(new_nid),
 				size, align, 0);

 		if (!ret)
 			panic("numa.c: cannot allocate %lu bytes on node %d",
 			      size, new_nid);

 		ret = __pa(ret);

 		dbg("alloc_bootmem %lx %lx\n", ret, size);
 	}

 	return (void *)ret;
 }

 static struct notifier_block __cpuinitdata ppc64_numa_nb = {
 	.notifier_call = cpu_numa_callback,
 	.priority = 1 /* Must run before sched domains notifier. */
 };

 void __init do_init_bootmem(void)
 {
 	int nid;
 	unsigned int i;

 	min_low_pfn = 0;
 	max_low_pfn = lmb_end_of_DRAM() >> PAGE_SHIFT;
 	max_pfn = max_low_pfn;

 	if (parse_numa_properties())
 		setup_nonnuma();
 	else
 		dump_numa_memory_topology();

 	register_cpu_notifier(&ppc64_numa_nb);
 	cpu_numa_callback(&ppc64_numa_nb, CPU_UP_PREPARE,
 			  (void *)(unsigned long)boot_cpuid);

 	for_each_online_node(nid) {
 		unsigned long start_pfn, end_pfn;
 		unsigned long bootmem_paddr;
 		unsigned long bootmap_pages;

 		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

 		/* Allocate the node structure node local if possible */
 		NODE_DATA(nid) = careful_allocation(nid,
 					sizeof(struct pglist_data),
 					SMP_CACHE_BYTES, end_pfn);
 		NODE_DATA(nid) = __va(NODE_DATA(nid));
 		memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));

   		dbg("node %d\n", nid);
 		dbg("NODE_DATA() = %p\n", NODE_DATA(nid));

 		NODE_DATA(nid)->bdata = &plat_node_bdata[nid];
 		NODE_DATA(nid)->node_start_pfn = start_pfn;
 		NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;

 		if (NODE_DATA(nid)->node_spanned_pages == 0)
   			continue;

   		dbg("start_paddr = %lx\n", start_pfn << PAGE_SHIFT);
   		dbg("end_paddr = %lx\n", end_pfn << PAGE_SHIFT);

 		bootmap_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
 		bootmem_paddr = (unsigned long)careful_allocation(nid,
 					bootmap_pages << PAGE_SHIFT,
 					PAGE_SIZE, end_pfn);
 		memset(__va(bootmem_paddr), 0, bootmap_pages << PAGE_SHIFT);

 		dbg("bootmap_paddr = %lx\n", bootmem_paddr);

 		init_bootmem_node(NODE_DATA(nid), bootmem_paddr >> PAGE_SHIFT,
 				  start_pfn, end_pfn);

 		free_bootmem_with_active_regions(nid, end_pfn);

 		/* Mark reserved regions on this node */
 		for (i = 0; i < lmb.reserved.cnt; i++) {
 			unsigned long physbase = lmb.reserved.region[i].base;
 			unsigned long size = lmb.reserved.region[i].size;
 			unsigned long start_paddr = start_pfn << PAGE_SHIFT;
 			unsigned long end_paddr = end_pfn << PAGE_SHIFT;

 			if (early_pfn_to_nid(physbase >> PAGE_SHIFT) != nid &&
 			    early_pfn_to_nid((physbase+size-1) >> PAGE_SHIFT) != nid)
 				continue;

 			if (physbase < end_paddr &&
 			    (physbase+size) > start_paddr) {
 				/* overlaps */
 				if (physbase < start_paddr) {
 					size -= start_paddr - physbase;
 					physbase = start_paddr;
 				}

 				if (size > end_paddr - physbase)
 					size = end_paddr - physbase;

 				dbg("reserve_bootmem %lx %lx\n", physbase,
 				    size);
 				reserve_bootmem_node(NODE_DATA(nid), physbase,
 						     size, BOOTMEM_DEFAULT);
 			}
 		}

 		sparse_memory_present_with_active_regions(nid);
 	}
 }

 void __init paging_init(void)
 {
 	unsigned long max_zone_pfns[MAX_NR_ZONES];
 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 	max_zone_pfns[ZONE_DMA] = lmb_end_of_DRAM() >> PAGE_SHIFT;
 	free_area_init_nodes(max_zone_pfns);
 }

 static int __init early_numa(char *p)
 {
 	if (!p)
 		return 0;

 	if (strstr(p, "off"))
 		numa_enabled = 0;

 	if (strstr(p, "debug"))
 		numa_debug = 1;

 	p = strstr(p, "fake=");
 	if (p)
 		cmdline = p + strlen("fake=");

 	return 0;
 }
 early_param("numa", early_numa);

 #ifdef CONFIG_MEMORY_HOTPLUG
 /*
  * Find the node associated with a hot added memory section.  Section
  * corresponds to a SPARSEMEM section, not an LMB.  It is assumed that
  * sections are fully contained within a single LMB.
  */
 int hot_add_scn_to_nid(unsigned long scn_addr)
 {
 	struct device_node *memory = NULL;
 	nodemask_t nodes;
 	int default_nid = any_online_node(NODE_MASK_ALL);
 	int nid;

 	if (!numa_enabled || (min_common_depth < 0))
 		return default_nid;

 	while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
 		unsigned long start, size;
 		int ranges;
 		const unsigned int *memcell_buf;
 		unsigned int len;

 		memcell_buf = of_get_property(memory, "reg", &len);
 		if (!memcell_buf || len <= 0)
 			continue;

 		/* ranges in cell */
 		ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
 ha_new_range:
 		start = read_n_cells(n_mem_addr_cells, &memcell_buf);
 		size = read_n_cells(n_mem_size_cells, &memcell_buf);
 		nid = of_node_to_nid_single(memory);

 		/* Domains not present at boot default to 0 */
 		if (nid < 0 || !node_online(nid))
 			nid = default_nid;

 		if ((scn_addr >= start) && (scn_addr < (start + size))) {
 			of_node_put(memory);
 			goto got_nid;
 		}

 		if (--ranges)		/* process all ranges in cell */
 			goto ha_new_range;
 	}
 	BUG();	/* section address should be found above */
 	return 0;

 	/* Temporary code to ensure that returned node is not empty */
 got_nid:
 	nodes_setall(nodes);
 	while (NODE_DATA(nid)->node_spanned_pages == 0) {
 		node_clear(nid, nodes);
 		nid = any_online_node(nodes);
 	}
 	return nid;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */
	/*
	* pSeries NUMA support
	*
	* Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
	*
	* 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 <linux/threads.h>
	#include <linux/bootmem.h>
	#include <linux/init.h>
	#include <linux/mm.h>
	#include <linux/mmzone.h>
	#include <linux/module.h>
	#include <linux/nodemask.h>
	#include <linux/cpu.h>
	#include <linux/notifier.h>
	#include <linux/lmb.h>
	#include <asm/sparsemem.h>
	#include <asm/prom.h>
	#include <asm/system.h>
	#include <asm/smp.h>

	static int numa_enabled = 1;

	static char *cmdline __initdata;

	static int numa_debug;
	#define dbg(args...) if (numa_debug) { printk(KERN_INFO args); }

	int numa_cpu_lookup_table[NR_CPUS];
	cpumask_t numa_cpumask_lookup_table[MAX_NUMNODES];
	struct pglist_data *node_data[MAX_NUMNODES];

	EXPORT_SYMBOL(numa_cpu_lookup_table);
	EXPORT_SYMBOL(numa_cpumask_lookup_table);
	EXPORT_SYMBOL(node_data);

	static bootmem_data_t __initdata plat_node_bdata[MAX_NUMNODES];
	static int min_common_depth;
	static int n_mem_addr_cells, n_mem_size_cells;

	static int __cpuinit fake_numa_create_new_node(unsigned long end_pfn,
	unsigned int *nid)
	{
	unsigned long long mem;
	char *p = cmdline;
	static unsigned int fake_nid;
	static unsigned long long curr_boundary;

	/*
	* Modify node id, iff we started creating NUMA nodes
	* We want to continue from where we left of the last time
	*/
	if (fake_nid)
	*nid = fake_nid;
	/*
	* In case there are no more arguments to parse, the
	* node_id should be the same as the last fake node id
	* (we've handled this above).
	*/
	if (!p)
	return 0;

	mem = memparse(p, &p);
	if (!mem)
	return 0;

	if (mem < curr_boundary)
	return 0;

	curr_boundary = mem;

	if ((end_pfn << PAGE_SHIFT) > mem) {
	/*
	* Skip commas and spaces
	*/
	while (p == ',' \|\| p == ' ' \|\| *p == '\t')
	p++;

	cmdline = p;
	fake_nid++;
	*nid = fake_nid;
	dbg("created new fake_node with id %d\n", fake_nid);
	return 1;
	}
	return 0;
	}

	static void __cpuinit map_cpu_to_node(int cpu, int node)
	{
	numa_cpu_lookup_table[cpu] = node;

	dbg("adding cpu %d to node %d\n", cpu, node);

	if (!(cpu_isset(cpu, numa_cpumask_lookup_table[node])))
	cpu_set(cpu, numa_cpumask_lookup_table[node]);
	}

	#ifdef CONFIG_HOTPLUG_CPU
	static void unmap_cpu_from_node(unsigned long cpu)
	{
	int node = numa_cpu_lookup_table[cpu];

	dbg("removing cpu %lu from node %d\n", cpu, node);

	if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
	cpu_clear(cpu, numa_cpumask_lookup_table[node]);
	} else {
	printk(KERN_ERR "WARNING: cpu %lu not found in node %d\n",
	cpu, node);
	}
	}
	#endif /* CONFIG_HOTPLUG_CPU */

	static struct device_node * __cpuinit find_cpu_node(unsigned int cpu)
	{
	unsigned int hw_cpuid = get_hard_smp_processor_id(cpu);
	struct device_node *cpu_node = NULL;
	const unsigned int interrupt_server, reg;
	int len;

	while ((cpu_node = of_find_node_by_type(cpu_node, "cpu")) != NULL) {
	/* Try interrupt server first */
	interrupt_server = of_get_property(cpu_node,
	"ibm,ppc-interrupt-server#s", &len);

	len = len / sizeof(u32);

	if (interrupt_server && (len > 0)) {
	while (len--) {
	if (interrupt_server[len] == hw_cpuid)
	return cpu_node;
	}
	} else {
	reg = of_get_property(cpu_node, "reg", &len);
	if (reg && (len > 0) && (reg[0] == hw_cpuid))
	return cpu_node;
	}
	}

	return NULL;
	}

	/* must hold reference to node during call */
	static const int of_get_associativity(struct device_node dev)
	{
	return of_get_property(dev, "ibm,associativity", NULL);
	}

	/* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
	* info is found.
	*/
	static int of_node_to_nid_single(struct device_node *device)
	{
	int nid = -1;
	const unsigned int *tmp;

	if (min_common_depth == -1)
	goto out;

	tmp = of_get_associativity(device);
	if (!tmp)
	goto out;

	if (tmp[0] >= min_common_depth)
	nid = tmp[min_common_depth];

	/* POWER4 LPAR uses 0xffff as invalid node */
	if (nid == 0xffff \|\| nid >= MAX_NUMNODES)
	nid = -1;
	out:
	return nid;
	}

	/* Walk the device tree upwards, looking for an associativity id */
	int of_node_to_nid(struct device_node *device)
	{
	struct device_node *tmp;
	int nid = -1;

	of_node_get(device);
	while (device) {
	nid = of_node_to_nid_single(device);
	if (nid != -1)
	break;

	tmp = device;
	device = of_get_parent(tmp);
	of_node_put(tmp);
	}
	of_node_put(device);

	return nid;
	}
	EXPORT_SYMBOL_GPL(of_node_to_nid);

	/*
	* In theory, the "ibm,associativity" property may contain multiple
	* associativity lists because a resource may be multiply connected
	* into the machine. This resource then has different associativity
	* characteristics relative to its multiple connections. We ignore
	* this for now. We also assume that all cpu and memory sets have
	* their distances represented at a common level. This won't be
	* true for hierarchical NUMA.
	*
	* In any case the ibm,associativity-reference-points should give
	* the correct depth for a normal NUMA system.
	*
	* - Dave Hansen <haveblue@us.ibm.com>
	*/
	static int __init find_min_common_depth(void)
	{
	int depth;
	const unsigned int *ref_points;
	struct device_node *rtas_root;
	unsigned int len;

	rtas_root = of_find_node_by_path("/rtas");

	if (!rtas_root)
	return -1;

	/*
	* this property is 2 32-bit integers, each representing a level of
	* depth in the associativity nodes. The first is for an SMP
	* configuration (should be all 0's) and the second is for a normal
	* NUMA configuration.
	*/
	ref_points = of_get_property(rtas_root,
	"ibm,associativity-reference-points", &len);

	if ((len >= 1) && ref_points) {
	depth = ref_points[1];
	} else {
	dbg("NUMA: ibm,associativity-reference-points not found.\n");
	depth = -1;
	}
	of_node_put(rtas_root);

	return depth;
	}

	static void __init get_n_mem_cells(int n_addr_cells, int n_size_cells)
	{
	struct device_node *memory = NULL;

	memory = of_find_node_by_type(memory, "memory");
	if (!memory)
	panic("numa.c: No memory nodes found!");

	*n_addr_cells = of_n_addr_cells(memory);
	*n_size_cells = of_n_size_cells(memory);
	of_node_put(memory);
	}

	static unsigned long __devinit read_n_cells(int n, const unsigned int **buf)
	{
	unsigned long result = 0;

	while (n--) {
	result = (result << 32) \| **buf;
	(*buf)++;
	}
	return result;
	}

	/*
	* Figure out to which domain a cpu belongs and stick it there.
	* Return the id of the domain used.
	*/
	static int __cpuinit numa_setup_cpu(unsigned long lcpu)
	{
	int nid = 0;
	struct device_node *cpu = find_cpu_node(lcpu);

	if (!cpu) {
	WARN_ON(1);
	goto out;
	}

	nid = of_node_to_nid_single(cpu);

	if (nid < 0 \|\| !node_online(nid))
	nid = any_online_node(NODE_MASK_ALL);
	out:
	map_cpu_to_node(lcpu, nid);

	of_node_put(cpu);

	return nid;
	}

	static int __cpuinit cpu_numa_callback(struct notifier_block *nfb,
	unsigned long action,
	void *hcpu)
	{
	unsigned long lcpu = (unsigned long)hcpu;
	int ret = NOTIFY_DONE;

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
	numa_setup_cpu(lcpu);
	ret = NOTIFY_OK;
	break;
	#ifdef CONFIG_HOTPLUG_CPU
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
	unmap_cpu_from_node(lcpu);
	break;
	ret = NOTIFY_OK;
	#endif
	}
	return ret;
	}

	/*
	* Check and possibly modify a memory region to enforce the memory limit.
	*
	* Returns the size the region should have to enforce the memory limit.
	* This will either be the original value of size, a truncated value,
	* or zero. If the returned value of size is 0 the region should be
	* discarded as it lies wholy above the memory limit.
	*/
	static unsigned long __init numa_enforce_memory_limit(unsigned long start,
	unsigned long size)
	{
	/*
	* We use lmb_end_of_DRAM() in here instead of memory_limit because
	* we've already adjusted it for the limit and it takes care of
	* having memory holes below the limit.
	*/

	if (! memory_limit)
	return size;

	if (start + size <= lmb_end_of_DRAM())
	return size;

	if (start >= lmb_end_of_DRAM())
	return 0;

	return lmb_end_of_DRAM() - start;
	}

	/*
	* Extract NUMA information from the ibm,dynamic-reconfiguration-memory
	* node. This assumes n_mem_{addr,size}_cells have been set.
	*/
	static void __init parse_drconf_memory(struct device_node *memory)
	{
	const unsigned int lm, dm, *aa;
	unsigned int ls, ld, la;
	unsigned int n, aam, aalen;
	unsigned long lmb_size, size, start;
	int nid, default_nid = 0;
	unsigned int ai, flags;

	lm = of_get_property(memory, "ibm,lmb-size", &ls);
	dm = of_get_property(memory, "ibm,dynamic-memory", &ld);
	aa = of_get_property(memory, "ibm,associativity-lookup-arrays", &la);
	if (!lm \|\| !dm \|\| !aa \|\|
	ls < sizeof(unsigned int) \|\| ld < sizeof(unsigned int) \|\|
	la < 2 * sizeof(unsigned int))
	return;

	lmb_size = read_n_cells(n_mem_size_cells, &lm);
	n = dm++; / number of LMBs */
	aam = aa++; / number of associativity lists */
	aalen = aa++; / length of each associativity list */
	if (ld < (n * (n_mem_addr_cells + 4) + 1) * sizeof(unsigned int) \|\|
	la < (aam * aalen + 2) * sizeof(unsigned int))
	return;

	for (; n != 0; --n) {
	start = read_n_cells(n_mem_addr_cells, &dm);
	ai = dm[2];
	flags = dm[3];
	dm += 4;
	/* 0x80 == reserved, 0x8 = assigned to us */
	if ((flags & 0x80) \|\| !(flags & 0x8))
	continue;
	nid = default_nid;
	/* flags & 0x40 means associativity index is invalid */
	if (min_common_depth > 0 && min_common_depth <= aalen &&
	(flags & 0x40) == 0 && ai < aam) {
	/* this is like of_node_to_nid_single */
	nid = aa[ai * aalen + min_common_depth - 1];
	if (nid == 0xffff \|\| nid >= MAX_NUMNODES)
	nid = default_nid;
	}

	fake_numa_create_new_node(((start + lmb_size) >> PAGE_SHIFT),
	&nid);
	node_set_online(nid);

	size = numa_enforce_memory_limit(start, lmb_size);
	if (!size)
	continue;

	add_active_range(nid, start >> PAGE_SHIFT,
	(start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));
	}
	}

	static int __init parse_numa_properties(void)
	{
	struct device_node *cpu = NULL;
	struct device_node *memory = NULL;
	int default_nid = 0;
	unsigned long i;

	if (numa_enabled == 0) {
	printk(KERN_WARNING "NUMA disabled by user\n");
	return -1;
	}

	min_common_depth = find_min_common_depth();

	if (min_common_depth < 0)
	return min_common_depth;

	dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);

	/*
	* Even though we connect cpus to numa domains later in SMP
	* init, we need to know the node ids now. This is because
	* each node to be onlined must have NODE_DATA etc backing it.
	*/
	for_each_present_cpu(i) {
	int nid;

	cpu = find_cpu_node(i);
	BUG_ON(!cpu);
	nid = of_node_to_nid_single(cpu);
	of_node_put(cpu);

	/*
	* Don't fall back to default_nid yet -- we will plug
	* cpus into nodes once the memory scan has discovered
	* the topology.
	*/
	if (nid < 0)
	continue;
	node_set_online(nid);
	}

	get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
	memory = NULL;
	while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
	unsigned long start;
	unsigned long size;
	int nid;
	int ranges;
	const unsigned int *memcell_buf;
	unsigned int len;

	memcell_buf = of_get_property(memory,
	"linux,usable-memory", &len);
	if (!memcell_buf \|\| len <= 0)
	memcell_buf = of_get_property(memory, "reg", &len);
	if (!memcell_buf \|\| len <= 0)
	continue;

	/* ranges in cell */
	ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
	new_range:
	/* these are order-sensitive, and modify the buffer pointer */
	start = read_n_cells(n_mem_addr_cells, &memcell_buf);
	size = read_n_cells(n_mem_size_cells, &memcell_buf);

	/*
	* Assumption: either all memory nodes or none will
	* have associativity properties. If none, then
	* everything goes to default_nid.
	*/
	nid = of_node_to_nid_single(memory);
	if (nid < 0)
	nid = default_nid;

	fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
	node_set_online(nid);

	if (!(size = numa_enforce_memory_limit(start, size))) {
	if (--ranges)
	goto new_range;
	else
	continue;
	}

	add_active_range(nid, start >> PAGE_SHIFT,
	(start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));

	if (--ranges)
	goto new_range;
	}

	/*
	* Now do the same thing for each LMB listed in the ibm,dynamic-memory
	* property in the ibm,dynamic-reconfiguration-memory node.
	*/
	memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (memory)
	parse_drconf_memory(memory);

	return 0;
	}

	static void __init setup_nonnuma(void)
	{
	unsigned long top_of_ram = lmb_end_of_DRAM();
	unsigned long total_ram = lmb_phys_mem_size();
	unsigned long start_pfn, end_pfn;
	unsigned int i, nid = 0;

	printk(KERN_DEBUG "Top of RAM: 0x%lx, Total RAM: 0x%lx\n",
	top_of_ram, total_ram);
	printk(KERN_DEBUG "Memory hole size: %ldMB\n",
	(top_of_ram - total_ram) >> 20);

	for (i = 0; i < lmb.memory.cnt; ++i) {
	start_pfn = lmb.memory.region[i].base >> PAGE_SHIFT;
	end_pfn = start_pfn + lmb_size_pages(&lmb.memory, i);

	fake_numa_create_new_node(end_pfn, &nid);
	add_active_range(nid, start_pfn, end_pfn);
	node_set_online(nid);
	}
	}

	void __init dump_numa_cpu_topology(void)
	{
	unsigned int node;
	unsigned int cpu, count;

	if (min_common_depth == -1 \|\| !numa_enabled)
	return;

	for_each_online_node(node) {
	printk(KERN_DEBUG "Node %d CPUs:", node);

	count = 0;
	/*
	* If we used a CPU iterator here we would miss printing
	* the holes in the cpumap.
	*/
	for (cpu = 0; cpu < NR_CPUS; cpu++) {
	if (cpu_isset(cpu, numa_cpumask_lookup_table[node])) {
	if (count == 0)
	printk(" %u", cpu);
	++count;
	} else {
	if (count > 1)
	printk("-%u", cpu - 1);
	count = 0;
	}
	}

	if (count > 1)
	printk("-%u", NR_CPUS - 1);
	printk("\n");
	}
	}

	static void __init dump_numa_memory_topology(void)
	{
	unsigned int node;
	unsigned int count;

	if (min_common_depth == -1 \|\| !numa_enabled)
	return;

	for_each_online_node(node) {
	unsigned long i;

	printk(KERN_DEBUG "Node %d Memory:", node);

	count = 0;

	for (i = 0; i < lmb_end_of_DRAM();
	i += (1 << SECTION_SIZE_BITS)) {
	if (early_pfn_to_nid(i >> PAGE_SHIFT) == node) {
	if (count == 0)
	printk(" 0x%lx", i);
	++count;
	} else {
	if (count > 0)
	printk("-0x%lx", i);
	count = 0;
	}
	}

	if (count > 0)
	printk("-0x%lx", i);
	printk("\n");
	}
	}

	/*
	* Allocate some memory, satisfying the lmb or bootmem allocator where
	* required. nid is the preferred node and end is the physical address of
	* the highest address in the node.
	*
	* Returns the physical address of the memory.
	*/
	static void __init *careful_allocation(int nid, unsigned long size,
	unsigned long align,
	unsigned long end_pfn)
	{
	int new_nid;
	unsigned long ret = __lmb_alloc_base(size, align, end_pfn << PAGE_SHIFT);

	/* retry over all memory */
	if (!ret)
	ret = __lmb_alloc_base(size, align, lmb_end_of_DRAM());

	if (!ret)
	panic("numa.c: cannot allocate %lu bytes on node %d",
	size, nid);

	/*
	* If the memory came from a previously allocated node, we must
	* retry with the bootmem allocator.
	*/
	new_nid = early_pfn_to_nid(ret >> PAGE_SHIFT);
	if (new_nid < nid) {
	ret = (unsigned long)__alloc_bootmem_node(NODE_DATA(new_nid),
	size, align, 0);

	if (!ret)
	panic("numa.c: cannot allocate %lu bytes on node %d",
	size, new_nid);

	ret = __pa(ret);

	dbg("alloc_bootmem %lx %lx\n", ret, size);
	}

	return (void *)ret;
	}

	static struct notifier_block __cpuinitdata ppc64_numa_nb = {
	.notifier_call = cpu_numa_callback,
	.priority = 1 /* Must run before sched domains notifier. */
	};

	void __init do_init_bootmem(void)
	{
	int nid;
	unsigned int i;

	min_low_pfn = 0;
	max_low_pfn = lmb_end_of_DRAM() >> PAGE_SHIFT;
	max_pfn = max_low_pfn;

	if (parse_numa_properties())
	setup_nonnuma();
	else
	dump_numa_memory_topology();

	register_cpu_notifier(&ppc64_numa_nb);
	cpu_numa_callback(&ppc64_numa_nb, CPU_UP_PREPARE,
	(void *)(unsigned long)boot_cpuid);

	for_each_online_node(nid) {
	unsigned long start_pfn, end_pfn;
	unsigned long bootmem_paddr;
	unsigned long bootmap_pages;

	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);

	/* Allocate the node structure node local if possible */
	NODE_DATA(nid) = careful_allocation(nid,
	sizeof(struct pglist_data),
	SMP_CACHE_BYTES, end_pfn);
	NODE_DATA(nid) = __va(NODE_DATA(nid));
	memset(NODE_DATA(nid), 0, sizeof(struct pglist_data));

	dbg("node %d\n", nid);
	dbg("NODE_DATA() = %p\n", NODE_DATA(nid));

	NODE_DATA(nid)->bdata = &plat_node_bdata[nid];
	NODE_DATA(nid)->node_start_pfn = start_pfn;
	NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;

	if (NODE_DATA(nid)->node_spanned_pages == 0)
	continue;

	dbg("start_paddr = %lx\n", start_pfn << PAGE_SHIFT);
	dbg("end_paddr = %lx\n", end_pfn << PAGE_SHIFT);

	bootmap_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
	bootmem_paddr = (unsigned long)careful_allocation(nid,
	bootmap_pages << PAGE_SHIFT,
	PAGE_SIZE, end_pfn);
	memset(__va(bootmem_paddr), 0, bootmap_pages << PAGE_SHIFT);

	dbg("bootmap_paddr = %lx\n", bootmem_paddr);

	init_bootmem_node(NODE_DATA(nid), bootmem_paddr >> PAGE_SHIFT,
	start_pfn, end_pfn);

	free_bootmem_with_active_regions(nid, end_pfn);

	/* Mark reserved regions on this node */
	for (i = 0; i < lmb.reserved.cnt; i++) {
	unsigned long physbase = lmb.reserved.region[i].base;
	unsigned long size = lmb.reserved.region[i].size;
	unsigned long start_paddr = start_pfn << PAGE_SHIFT;
	unsigned long end_paddr = end_pfn << PAGE_SHIFT;

	if (early_pfn_to_nid(physbase >> PAGE_SHIFT) != nid &&
	early_pfn_to_nid((physbase+size-1) >> PAGE_SHIFT) != nid)
	continue;

	if (physbase < end_paddr &&
	(physbase+size) > start_paddr) {
	/* overlaps */
	if (physbase < start_paddr) {
	size -= start_paddr - physbase;
	physbase = start_paddr;
	}

	if (size > end_paddr - physbase)
	size = end_paddr - physbase;

	dbg("reserve_bootmem %lx %lx\n", physbase,
	size);
	reserve_bootmem_node(NODE_DATA(nid), physbase,
	size, BOOTMEM_DEFAULT);
	}
	}

	sparse_memory_present_with_active_regions(nid);
	}
	}

	void __init paging_init(void)
	{
	unsigned long max_zone_pfns[MAX_NR_ZONES];
	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
	max_zone_pfns[ZONE_DMA] = lmb_end_of_DRAM() >> PAGE_SHIFT;
	free_area_init_nodes(max_zone_pfns);
	}

	static int __init early_numa(char *p)
	{
	if (!p)
	return 0;

	if (strstr(p, "off"))
	numa_enabled = 0;

	if (strstr(p, "debug"))
	numa_debug = 1;

	p = strstr(p, "fake=");
	if (p)
	cmdline = p + strlen("fake=");

	return 0;
	}
	early_param("numa", early_numa);

	#ifdef CONFIG_MEMORY_HOTPLUG
	/*
	* Find the node associated with a hot added memory section. Section
	* corresponds to a SPARSEMEM section, not an LMB. It is assumed that
	* sections are fully contained within a single LMB.
	*/
	int hot_add_scn_to_nid(unsigned long scn_addr)
	{
	struct device_node *memory = NULL;
	nodemask_t nodes;
	int default_nid = any_online_node(NODE_MASK_ALL);
	int nid;

	if (!numa_enabled \|\| (min_common_depth < 0))
	return default_nid;

	while ((memory = of_find_node_by_type(memory, "memory")) != NULL) {
	unsigned long start, size;
	int ranges;
	const unsigned int *memcell_buf;
	unsigned int len;

	memcell_buf = of_get_property(memory, "reg", &len);
	if (!memcell_buf \|\| len <= 0)
	continue;

	/* ranges in cell */
	ranges = (len >> 2) / (n_mem_addr_cells + n_mem_size_cells);
	ha_new_range:
	start = read_n_cells(n_mem_addr_cells, &memcell_buf);
	size = read_n_cells(n_mem_size_cells, &memcell_buf);
	nid = of_node_to_nid_single(memory);

	/* Domains not present at boot default to 0 */
	if (nid < 0 \|\| !node_online(nid))
	nid = default_nid;

	if ((scn_addr >= start) && (scn_addr < (start + size))) {
	of_node_put(memory);
	goto got_nid;
	}

	if (--ranges) /* process all ranges in cell */
	goto ha_new_range;
	}
	BUG(); /* section address should be found above */
	return 0;

	/* Temporary code to ensure that returned node is not empty */
	got_nid:
	nodes_setall(nodes);
	while (NODE_DATA(nid)->node_spanned_pages == 0) {
	node_clear(nid, nodes);
	nid = any_online_node(nodes);
	}
	return nid;
	}
	#endif /* CONFIG_MEMORY_HOTPLUG */