arch/powerpc/platforms/pseries/hotplug-memory.c - kernel/common.git - Git at Google

 /*
  * pseries Memory Hotplug infrastructure.
  *
  * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
  *
  *      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.
  */

 #define pr_fmt(fmt)	"pseries-hotplug-mem: " fmt

 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/memblock.h>
 #include <linux/memory.h>
 #include <linux/memory_hotplug.h>
 #include <linux/slab.h>

 #include <asm/firmware.h>
 #include <asm/machdep.h>
 #include <asm/prom.h>
 #include <asm/sparsemem.h>
 #include "pseries.h"

 static bool rtas_hp_event;

 unsigned long pseries_memory_block_size(void)
 {
 	struct device_node *np;
 	unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
 	struct resource r;

 	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
 	if (np) {
 		const __be64 *size;

 		size = of_get_property(np, "ibm,lmb-size", NULL);
 		if (size)
 			memblock_size = be64_to_cpup(size);
 		of_node_put(np);
 	} else  if (machine_is(pseries)) {
 		/* This fallback really only applies to pseries */
 		unsigned int memzero_size = 0;

 		np = of_find_node_by_path("/memory@0");
 		if (np) {
 			if (!of_address_to_resource(np, 0, &r))
 				memzero_size = resource_size(&r);
 			of_node_put(np);
 		}

 		if (memzero_size) {
 			/* We now know the size of memory@0, use this to find
 			 * the first memoryblock and get its size.
 			 */
 			char buf[64];

 			sprintf(buf, "/memory@%x", memzero_size);
 			np = of_find_node_by_path(buf);
 			if (np) {
 				if (!of_address_to_resource(np, 0, &r))
 					memblock_size = resource_size(&r);
 				of_node_put(np);
 			}
 		}
 	}
 	return memblock_size;
 }

 static void dlpar_free_property(struct property *prop)
 {
 	kfree(prop->name);
 	kfree(prop->value);
 	kfree(prop);
 }

 static struct property *dlpar_clone_property(struct property *prop,
 					     u32 prop_size)
 {
 	struct property *new_prop;

 	new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
 	if (!new_prop)
 		return NULL;

 	new_prop->name = kstrdup(prop->name, GFP_KERNEL);
 	new_prop->value = kzalloc(prop_size, GFP_KERNEL);
 	if (!new_prop->name || !new_prop->value) {
 		dlpar_free_property(new_prop);
 		return NULL;
 	}

 	memcpy(new_prop->value, prop->value, prop->length);
 	new_prop->length = prop_size;

 	of_property_set_flag(new_prop, OF_DYNAMIC);
 	return new_prop;
 }

 static struct property *dlpar_clone_drconf_property(struct device_node *dn)
 {
 	struct property *prop, *new_prop;
 	struct of_drconf_cell *lmbs;
 	u32 num_lmbs, *p;
 	int i;

 	prop = of_find_property(dn, "ibm,dynamic-memory", NULL);
 	if (!prop)
 		return NULL;

 	new_prop = dlpar_clone_property(prop, prop->length);
 	if (!new_prop)
 		return NULL;

 	/* Convert the property to cpu endian-ness */
 	p = new_prop->value;
 	*p = be32_to_cpu(*p);

 	num_lmbs = *p++;
 	lmbs = (struct of_drconf_cell *)p;

 	for (i = 0; i < num_lmbs; i++) {
 		lmbs[i].base_addr = be64_to_cpu(lmbs[i].base_addr);
 		lmbs[i].drc_index = be32_to_cpu(lmbs[i].drc_index);
 		lmbs[i].aa_index = be32_to_cpu(lmbs[i].aa_index);
 		lmbs[i].flags = be32_to_cpu(lmbs[i].flags);
 	}

 	return new_prop;
 }

 static void dlpar_update_drconf_property(struct device_node *dn,
 					 struct property *prop)
 {
 	struct of_drconf_cell *lmbs;
 	u32 num_lmbs, *p;
 	int i;

 	/* Convert the property back to BE */
 	p = prop->value;
 	num_lmbs = *p;
 	*p = cpu_to_be32(*p);
 	p++;

 	lmbs = (struct of_drconf_cell *)p;
 	for (i = 0; i < num_lmbs; i++) {
 		lmbs[i].base_addr = cpu_to_be64(lmbs[i].base_addr);
 		lmbs[i].drc_index = cpu_to_be32(lmbs[i].drc_index);
 		lmbs[i].aa_index = cpu_to_be32(lmbs[i].aa_index);
 		lmbs[i].flags = cpu_to_be32(lmbs[i].flags);
 	}

 	rtas_hp_event = true;
 	of_update_property(dn, prop);
 	rtas_hp_event = false;
 }

 static int dlpar_update_device_tree_lmb(struct of_drconf_cell *lmb)
 {
 	struct device_node *dn;
 	struct property *prop;
 	struct of_drconf_cell *lmbs;
 	u32 *p, num_lmbs;
 	int i;

 	dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
 	if (!dn)
 		return -ENODEV;

 	prop = dlpar_clone_drconf_property(dn);
 	if (!prop) {
 		of_node_put(dn);
 		return -ENODEV;
 	}

 	p = prop->value;
 	num_lmbs = *p++;
 	lmbs = (struct of_drconf_cell *)p;

 	for (i = 0; i < num_lmbs; i++) {
 		if (lmbs[i].drc_index == lmb->drc_index) {
 			lmbs[i].flags = lmb->flags;
 			lmbs[i].aa_index = lmb->aa_index;

 			dlpar_update_drconf_property(dn, prop);
 			break;
 		}
 	}

 	of_node_put(dn);
 	return 0;
 }

 static u32 find_aa_index(struct device_node *dr_node,
 			 struct property *ala_prop, const u32 *lmb_assoc)
 {
 	u32 *assoc_arrays;
 	u32 aa_index;
 	int aa_arrays, aa_array_entries, aa_array_sz;
 	int i, index;

 	/*
 	 * The ibm,associativity-lookup-arrays property is defined to be
 	 * a 32-bit value specifying the number of associativity arrays
 	 * followed by a 32-bitvalue specifying the number of entries per
 	 * array, followed by the associativity arrays.
 	 */
 	assoc_arrays = ala_prop->value;

 	aa_arrays = be32_to_cpu(assoc_arrays[0]);
 	aa_array_entries = be32_to_cpu(assoc_arrays[1]);
 	aa_array_sz = aa_array_entries * sizeof(u32);

 	aa_index = -1;
 	for (i = 0; i < aa_arrays; i++) {
 		index = (i * aa_array_entries) + 2;

 		if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz))
 			continue;

 		aa_index = i;
 		break;
 	}

 	if (aa_index == -1) {
 		struct property *new_prop;
 		u32 new_prop_size;

 		new_prop_size = ala_prop->length + aa_array_sz;
 		new_prop = dlpar_clone_property(ala_prop, new_prop_size);
 		if (!new_prop)
 			return -1;

 		assoc_arrays = new_prop->value;

 		/* increment the number of entries in the lookup array */
 		assoc_arrays[0] = cpu_to_be32(aa_arrays + 1);

 		/* copy the new associativity into the lookup array */
 		index = aa_arrays * aa_array_entries + 2;
 		memcpy(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz);

 		of_update_property(dr_node, new_prop);

 		/*
 		 * The associativity lookup array index for this lmb is
 		 * number of entries - 1 since we added its associativity
 		 * to the end of the lookup array.
 		 */
 		aa_index = be32_to_cpu(assoc_arrays[0]) - 1;
 	}

 	return aa_index;
 }

 static u32 lookup_lmb_associativity_index(struct of_drconf_cell *lmb)
 {
 	struct device_node *parent, *lmb_node, *dr_node;
 	struct property *ala_prop;
 	const u32 *lmb_assoc;
 	u32 aa_index;

 	parent = of_find_node_by_path("/");
 	if (!parent)
 		return -ENODEV;

 	lmb_node = dlpar_configure_connector(cpu_to_be32(lmb->drc_index),
 					     parent);
 	of_node_put(parent);
 	if (!lmb_node)
 		return -EINVAL;

 	lmb_assoc = of_get_property(lmb_node, "ibm,associativity", NULL);
 	if (!lmb_assoc) {
 		dlpar_free_cc_nodes(lmb_node);
 		return -ENODEV;
 	}

 	dr_node = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
 	if (!dr_node) {
 		dlpar_free_cc_nodes(lmb_node);
 		return -ENODEV;
 	}

 	ala_prop = of_find_property(dr_node, "ibm,associativity-lookup-arrays",
 				    NULL);
 	if (!ala_prop) {
 		of_node_put(dr_node);
 		dlpar_free_cc_nodes(lmb_node);
 		return -ENODEV;
 	}

 	aa_index = find_aa_index(dr_node, ala_prop, lmb_assoc);

 	dlpar_free_cc_nodes(lmb_node);
 	return aa_index;
 }

 static int dlpar_add_device_tree_lmb(struct of_drconf_cell *lmb)
 {
 	int aa_index;

 	lmb->flags |= DRCONF_MEM_ASSIGNED;

 	aa_index = lookup_lmb_associativity_index(lmb);
 	if (aa_index < 0) {
 		pr_err("Couldn't find associativity index for drc index %x\n",
 		       lmb->drc_index);
 		return aa_index;
 	}

 	lmb->aa_index = aa_index;
 	return dlpar_update_device_tree_lmb(lmb);
 }

 static int dlpar_remove_device_tree_lmb(struct of_drconf_cell *lmb)
 {
 	lmb->flags &= ~DRCONF_MEM_ASSIGNED;
 	lmb->aa_index = 0xffffffff;
 	return dlpar_update_device_tree_lmb(lmb);
 }

 #ifdef CONFIG_MEMORY_HOTREMOVE
 static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
 {
 	unsigned long block_sz, start_pfn;
 	int sections_per_block;
 	int i, nid;

 	start_pfn = base >> PAGE_SHIFT;

 	lock_device_hotplug();

 	if (!pfn_valid(start_pfn))
 		goto out;

 	block_sz = pseries_memory_block_size();
 	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
 	nid = memory_add_physaddr_to_nid(base);

 	for (i = 0; i < sections_per_block; i++) {
 		remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
 		base += MIN_MEMORY_BLOCK_SIZE;
 	}

 out:
 	/* Update memory regions for memory remove */
 	memblock_remove(base, memblock_size);
 	unlock_device_hotplug();
 	return 0;
 }

 static int pseries_remove_mem_node(struct device_node *np)
 {
 	const char *type;
 	const __be32 *regs;
 	unsigned long base;
 	unsigned int lmb_size;
 	int ret = -EINVAL;

 	/*
 	 * Check to see if we are actually removing memory
 	 */
 	type = of_get_property(np, "device_type", NULL);
 	if (type == NULL || strcmp(type, "memory") != 0)
 		return 0;

 	/*
 	 * Find the base address and size of the memblock
 	 */
 	regs = of_get_property(np, "reg", NULL);
 	if (!regs)
 		return ret;

 	base = be64_to_cpu(*(unsigned long *)regs);
 	lmb_size = be32_to_cpu(regs[3]);

 	pseries_remove_memblock(base, lmb_size);
 	return 0;
 }

 static bool lmb_is_removable(struct of_drconf_cell *lmb)
 {
 	int i, scns_per_block;
 	int rc = 1;
 	unsigned long pfn, block_sz;
 	u64 phys_addr;

 	if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
 		return false;

 	block_sz = memory_block_size_bytes();
 	scns_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
 	phys_addr = lmb->base_addr;

 	for (i = 0; i < scns_per_block; i++) {
 		pfn = PFN_DOWN(phys_addr);
 		if (!pfn_present(pfn))
 			continue;

 		rc &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
 		phys_addr += MIN_MEMORY_BLOCK_SIZE;
 	}

 	return rc ? true : false;
 }

 static int dlpar_add_lmb(struct of_drconf_cell *);

 static struct memory_block *lmb_to_memblock(struct of_drconf_cell *lmb)
 {
 	unsigned long section_nr;
 	struct mem_section *mem_sect;
 	struct memory_block *mem_block;

 	section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr));
 	mem_sect = __nr_to_section(section_nr);

 	mem_block = find_memory_block(mem_sect);
 	return mem_block;
 }

 static int dlpar_remove_lmb(struct of_drconf_cell *lmb)
 {
 	struct memory_block *mem_block;
 	unsigned long block_sz;
 	int nid, rc;

 	if (!lmb_is_removable(lmb))
 		return -EINVAL;

 	mem_block = lmb_to_memblock(lmb);
 	if (!mem_block)
 		return -EINVAL;

 	rc = device_offline(&mem_block->dev);
 	put_device(&mem_block->dev);
 	if (rc)
 		return rc;

 	block_sz = pseries_memory_block_size();
 	nid = memory_add_physaddr_to_nid(lmb->base_addr);

 	remove_memory(nid, lmb->base_addr, block_sz);

 	/* Update memory regions for memory remove */
 	memblock_remove(lmb->base_addr, block_sz);

 	dlpar_release_drc(lmb->drc_index);
 	dlpar_remove_device_tree_lmb(lmb);

 	return 0;
 }

 static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
 					struct property *prop)
 {
 	struct of_drconf_cell *lmbs;
 	int lmbs_removed = 0;
 	int lmbs_available = 0;
 	u32 num_lmbs, *p;
 	int i, rc;

 	pr_info("Attempting to hot-remove %d LMB(s)\n", lmbs_to_remove);

 	if (lmbs_to_remove == 0)
 		return -EINVAL;

 	p = prop->value;
 	num_lmbs = *p++;
 	lmbs = (struct of_drconf_cell *)p;

 	/* Validate that there are enough LMBs to satisfy the request */
 	for (i = 0; i < num_lmbs; i++) {
 		if (lmbs[i].flags & DRCONF_MEM_ASSIGNED)
 			lmbs_available++;
 	}

 	if (lmbs_available < lmbs_to_remove)
 		return -EINVAL;

 	for (i = 0; i < num_lmbs && lmbs_removed < lmbs_to_remove; i++) {
 		rc = dlpar_remove_lmb(&lmbs[i]);
 		if (rc)
 			continue;

 		lmbs_removed++;

 		/* Mark this lmb so we can add it later if all of the
 		 * requested LMBs cannot be removed.
 		 */
 		lmbs[i].reserved = 1;
 	}

 	if (lmbs_removed != lmbs_to_remove) {
 		pr_err("Memory hot-remove failed, adding LMB's back\n");

 		for (i = 0; i < num_lmbs; i++) {
 			if (!lmbs[i].reserved)
 				continue;

 			rc = dlpar_add_lmb(&lmbs[i]);
 			if (rc)
 				pr_err("Failed to add LMB back, drc index %x\n",
 				       lmbs[i].drc_index);

 			lmbs[i].reserved = 0;
 		}

 		rc = -EINVAL;
 	} else {
 		for (i = 0; i < num_lmbs; i++) {
 			if (!lmbs[i].reserved)
 				continue;

 			pr_info("Memory at %llx was hot-removed\n",
 				lmbs[i].base_addr);

 			lmbs[i].reserved = 0;
 		}
 		rc = 0;
 	}

 	return rc;
 }

 static int dlpar_memory_remove_by_index(u32 drc_index, struct property *prop)
 {
 	struct of_drconf_cell *lmbs;
 	u32 num_lmbs, *p;
 	int lmb_found;
 	int i, rc;

 	pr_info("Attempting to hot-remove LMB, drc index %x\n", drc_index);

 	p = prop->value;
 	num_lmbs = *p++;
 	lmbs = (struct of_drconf_cell *)p;

 	lmb_found = 0;
 	for (i = 0; i < num_lmbs; i++) {
 		if (lmbs[i].drc_index == drc_index) {
 			lmb_found = 1;
 			rc = dlpar_remove_lmb(&lmbs[i]);
 			break;
 		}
 	}

 	if (!lmb_found)
 		rc = -EINVAL;

 	if (rc)
 		pr_info("Failed to hot-remove memory at %llx\n",
 			lmbs[i].base_addr);
 	else
 		pr_info("Memory at %llx was hot-removed\n", lmbs[i].base_addr);

 	return rc;
 }

 #else
 static inline int pseries_remove_memblock(unsigned long base,
 					  unsigned int memblock_size)
 {
 	return -EOPNOTSUPP;
 }
 static inline int pseries_remove_mem_node(struct device_node *np)
 {
 	return 0;
 }
 static inline int dlpar_memory_remove(struct pseries_hp_errorlog *hp_elog)
 {
 	return -EOPNOTSUPP;
 }
 static int dlpar_remove_lmb(struct of_drconf_cell *lmb)
 {
 	return -EOPNOTSUPP;
 }
 static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
 					struct property *prop)
 {
 	return -EOPNOTSUPP;
 }
 static int dlpar_memory_remove_by_index(u32 drc_index, struct property *prop)
 {
 	return -EOPNOTSUPP;
 }

 #endif /* CONFIG_MEMORY_HOTREMOVE */

 static int dlpar_add_lmb(struct of_drconf_cell *lmb)
 {
 	unsigned long block_sz;
 	int nid, rc;

 	if (lmb->flags & DRCONF_MEM_ASSIGNED)
 		return -EINVAL;

 	rc = dlpar_acquire_drc(lmb->drc_index);
 	if (rc)
 		return rc;

 	rc = dlpar_add_device_tree_lmb(lmb);
 	if (rc) {
 		pr_err("Couldn't update device tree for drc index %x\n",
 		       lmb->drc_index);
 		dlpar_release_drc(lmb->drc_index);
 		return rc;
 	}

 	block_sz = memory_block_size_bytes();

 	/* Find the node id for this address */
 	nid = memory_add_physaddr_to_nid(lmb->base_addr);

 	/* Add the memory */
 	rc = add_memory(nid, lmb->base_addr, block_sz);
 	if (rc) {
 		dlpar_remove_device_tree_lmb(lmb);
 		dlpar_release_drc(lmb->drc_index);
 	} else {
 		lmb->flags |= DRCONF_MEM_ASSIGNED;
 	}

 	return rc;
 }

 static int dlpar_memory_add_by_count(u32 lmbs_to_add, struct property *prop)
 {
 	struct of_drconf_cell *lmbs;
 	u32 num_lmbs, *p;
 	int lmbs_available = 0;
 	int lmbs_added = 0;
 	int i, rc;

 	pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);

 	if (lmbs_to_add == 0)
 		return -EINVAL;

 	p = prop->value;
 	num_lmbs = *p++;
 	lmbs = (struct of_drconf_cell *)p;

 	/* Validate that there are enough LMBs to satisfy the request */
 	for (i = 0; i < num_lmbs; i++) {
 		if (!(lmbs[i].flags & DRCONF_MEM_ASSIGNED))
 			lmbs_available++;
 	}

 	if (lmbs_available < lmbs_to_add)
 		return -EINVAL;

 	for (i = 0; i < num_lmbs && lmbs_to_add != lmbs_added; i++) {
 		rc = dlpar_add_lmb(&lmbs[i]);
 		if (rc)
 			continue;

 		lmbs_added++;

 		/* Mark this lmb so we can remove it later if all of the
 		 * requested LMBs cannot be added.
 		 */
 		lmbs[i].reserved = 1;
 	}

 	if (lmbs_added != lmbs_to_add) {
 		pr_err("Memory hot-add failed, removing any added LMBs\n");

 		for (i = 0; i < num_lmbs; i++) {
 			if (!lmbs[i].reserved)
 				continue;

 			rc = dlpar_remove_lmb(&lmbs[i]);
 			if (rc)
 				pr_err("Failed to remove LMB, drc index %x\n",
 				       be32_to_cpu(lmbs[i].drc_index));
 		}
 		rc = -EINVAL;
 	} else {
 		for (i = 0; i < num_lmbs; i++) {
 			if (!lmbs[i].reserved)
 				continue;

 			pr_info("Memory at %llx (drc index %x) was hot-added\n",
 				lmbs[i].base_addr, lmbs[i].drc_index);
 			lmbs[i].reserved = 0;
 		}
 	}

 	return rc;
 }

 static int dlpar_memory_add_by_index(u32 drc_index, struct property *prop)
 {
 	struct of_drconf_cell *lmbs;
 	u32 num_lmbs, *p;
 	int i, lmb_found;
 	int rc;

 	pr_info("Attempting to hot-add LMB, drc index %x\n", drc_index);

 	p = prop->value;
 	num_lmbs = *p++;
 	lmbs = (struct of_drconf_cell *)p;

 	lmb_found = 0;
 	for (i = 0; i < num_lmbs; i++) {
 		if (lmbs[i].drc_index == drc_index) {
 			lmb_found = 1;
 			rc = dlpar_add_lmb(&lmbs[i]);
 			break;
 		}
 	}

 	if (!lmb_found)
 		rc = -EINVAL;

 	if (rc)
 		pr_info("Failed to hot-add memory, drc index %x\n", drc_index);
 	else
 		pr_info("Memory at %llx (drc index %x) was hot-added\n",
 			lmbs[i].base_addr, drc_index);

 	return rc;
 }

 int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
 {
 	struct device_node *dn;
 	struct property *prop;
 	u32 count, drc_index;
 	int rc;

 	count = hp_elog->_drc_u.drc_count;
 	drc_index = hp_elog->_drc_u.drc_index;

 	lock_device_hotplug();

 	dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
 	if (!dn) {
 		rc = -EINVAL;
 		goto dlpar_memory_out;
 	}

 	prop = dlpar_clone_drconf_property(dn);
 	if (!prop) {
 		rc = -EINVAL;
 		goto dlpar_memory_out;
 	}

 	switch (hp_elog->action) {
 	case PSERIES_HP_ELOG_ACTION_ADD:
 		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
 			rc = dlpar_memory_add_by_count(count, prop);
 		else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
 			rc = dlpar_memory_add_by_index(drc_index, prop);
 		else
 			rc = -EINVAL;
 		break;
 	case PSERIES_HP_ELOG_ACTION_REMOVE:
 		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
 			rc = dlpar_memory_remove_by_count(count, prop);
 		else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
 			rc = dlpar_memory_remove_by_index(drc_index, prop);
 		else
 			rc = -EINVAL;
 		break;
 	default:
 		pr_err("Invalid action (%d) specified\n", hp_elog->action);
 		rc = -EINVAL;
 		break;
 	}

 	dlpar_free_property(prop);

 dlpar_memory_out:
 	of_node_put(dn);
 	unlock_device_hotplug();
 	return rc;
 }

 static int pseries_add_mem_node(struct device_node *np)
 {
 	const char *type;
 	const __be32 *regs;
 	unsigned long base;
 	unsigned int lmb_size;
 	int ret = -EINVAL;

 	/*
 	 * Check to see if we are actually adding memory
 	 */
 	type = of_get_property(np, "device_type", NULL);
 	if (type == NULL || strcmp(type, "memory") != 0)
 		return 0;

 	/*
 	 * Find the base and size of the memblock
 	 */
 	regs = of_get_property(np, "reg", NULL);
 	if (!regs)
 		return ret;

 	base = be64_to_cpu(*(unsigned long *)regs);
 	lmb_size = be32_to_cpu(regs[3]);

 	/*
 	 * Update memory region to represent the memory add
 	 */
 	ret = memblock_add(base, lmb_size);
 	return (ret < 0) ? -EINVAL : 0;
 }

 static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
 {
 	struct of_drconf_cell *new_drmem, *old_drmem;
 	unsigned long memblock_size;
 	u32 entries;
 	__be32 *p;
 	int i, rc = -EINVAL;

 	if (rtas_hp_event)
 		return 0;

 	memblock_size = pseries_memory_block_size();
 	if (!memblock_size)
 		return -EINVAL;

 	p = (__be32 *) pr->old_prop->value;
 	if (!p)
 		return -EINVAL;

 	/* The first int of the property is the number of lmb's described
 	 * by the property. This is followed by an array of of_drconf_cell
 	 * entries. Get the number of entries and skip to the array of
 	 * of_drconf_cell's.
 	 */
 	entries = be32_to_cpu(*p++);
 	old_drmem = (struct of_drconf_cell *)p;

 	p = (__be32 *)pr->prop->value;
 	p++;
 	new_drmem = (struct of_drconf_cell *)p;

 	for (i = 0; i < entries; i++) {
 		if ((be32_to_cpu(old_drmem[i].flags) & DRCONF_MEM_ASSIGNED) &&
 		    (!(be32_to_cpu(new_drmem[i].flags) & DRCONF_MEM_ASSIGNED))) {
 			rc = pseries_remove_memblock(
 				be64_to_cpu(old_drmem[i].base_addr),
 						     memblock_size);
 			break;
 		} else if ((!(be32_to_cpu(old_drmem[i].flags) &
 			    DRCONF_MEM_ASSIGNED)) &&
 			    (be32_to_cpu(new_drmem[i].flags) &
 			    DRCONF_MEM_ASSIGNED)) {
 			rc = memblock_add(be64_to_cpu(old_drmem[i].base_addr),
 					  memblock_size);
 			rc = (rc < 0) ? -EINVAL : 0;
 			break;
 		}
 	}
 	return rc;
 }

 static int pseries_memory_notifier(struct notifier_block *nb,
 				   unsigned long action, void *data)
 {
 	struct of_reconfig_data *rd = data;
 	int err = 0;

 	switch (action) {
 	case OF_RECONFIG_ATTACH_NODE:
 		err = pseries_add_mem_node(rd->dn);
 		break;
 	case OF_RECONFIG_DETACH_NODE:
 		err = pseries_remove_mem_node(rd->dn);
 		break;
 	case OF_RECONFIG_UPDATE_PROPERTY:
 		if (!strcmp(rd->prop->name, "ibm,dynamic-memory"))
 			err = pseries_update_drconf_memory(rd);
 		break;
 	}
 	return notifier_from_errno(err);
 }

 static struct notifier_block pseries_mem_nb = {
 	.notifier_call = pseries_memory_notifier,
 };

 static int __init pseries_memory_hotplug_init(void)
 {
 	if (firmware_has_feature(FW_FEATURE_LPAR))
 		of_reconfig_notifier_register(&pseries_mem_nb);

 	return 0;
 }
 machine_device_initcall(pseries, pseries_memory_hotplug_init);
	/*
	* pseries Memory Hotplug infrastructure.
	*
	* Copyright (C) 2008 Badari Pulavarty, IBM Corporation
	*
	* 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.
	*/

	#define pr_fmt(fmt) "pseries-hotplug-mem: " fmt

	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/memblock.h>
	#include <linux/memory.h>
	#include <linux/memory_hotplug.h>
	#include <linux/slab.h>

	#include <asm/firmware.h>
	#include <asm/machdep.h>
	#include <asm/prom.h>
	#include <asm/sparsemem.h>
	#include "pseries.h"

	static bool rtas_hp_event;

	unsigned long pseries_memory_block_size(void)
	{
	struct device_node *np;
	unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
	struct resource r;

	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (np) {
	const __be64 *size;

	size = of_get_property(np, "ibm,lmb-size", NULL);
	if (size)
	memblock_size = be64_to_cpup(size);
	of_node_put(np);
	} else if (machine_is(pseries)) {
	/* This fallback really only applies to pseries */
	unsigned int memzero_size = 0;

	np = of_find_node_by_path("/memory@0");
	if (np) {
	if (!of_address_to_resource(np, 0, &r))
	memzero_size = resource_size(&r);
	of_node_put(np);
	}

	if (memzero_size) {
	/* We now know the size of memory@0, use this to find
	* the first memoryblock and get its size.
	*/
	char buf[64];

	sprintf(buf, "/memory@%x", memzero_size);
	np = of_find_node_by_path(buf);
	if (np) {
	if (!of_address_to_resource(np, 0, &r))
	memblock_size = resource_size(&r);
	of_node_put(np);
	}
	}
	}
	return memblock_size;
	}

	static void dlpar_free_property(struct property *prop)
	{
	kfree(prop->name);
	kfree(prop->value);
	kfree(prop);
	}

	static struct property dlpar_clone_property(struct property prop,
	u32 prop_size)
	{
	struct property *new_prop;

	new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
	if (!new_prop)
	return NULL;

	new_prop->name = kstrdup(prop->name, GFP_KERNEL);
	new_prop->value = kzalloc(prop_size, GFP_KERNEL);
	if (!new_prop->name \|\| !new_prop->value) {
	dlpar_free_property(new_prop);
	return NULL;
	}

	memcpy(new_prop->value, prop->value, prop->length);
	new_prop->length = prop_size;

	of_property_set_flag(new_prop, OF_DYNAMIC);
	return new_prop;
	}

	static struct property dlpar_clone_drconf_property(struct device_node dn)
	{
	struct property prop, new_prop;
	struct of_drconf_cell *lmbs;
	u32 num_lmbs, *p;
	int i;

	prop = of_find_property(dn, "ibm,dynamic-memory", NULL);
	if (!prop)
	return NULL;

	new_prop = dlpar_clone_property(prop, prop->length);
	if (!new_prop)
	return NULL;

	/* Convert the property to cpu endian-ness */
	p = new_prop->value;
	p = be32_to_cpu(p);

	num_lmbs = *p++;
	lmbs = (struct of_drconf_cell *)p;

	for (i = 0; i < num_lmbs; i++) {
	lmbs[i].base_addr = be64_to_cpu(lmbs[i].base_addr);
	lmbs[i].drc_index = be32_to_cpu(lmbs[i].drc_index);
	lmbs[i].aa_index = be32_to_cpu(lmbs[i].aa_index);
	lmbs[i].flags = be32_to_cpu(lmbs[i].flags);
	}

	return new_prop;
	}

	static void dlpar_update_drconf_property(struct device_node *dn,
	struct property *prop)
	{
	struct of_drconf_cell *lmbs;
	u32 num_lmbs, *p;
	int i;

	/* Convert the property back to BE */
	p = prop->value;
	num_lmbs = *p;
	p = cpu_to_be32(p);
	p++;

	lmbs = (struct of_drconf_cell *)p;
	for (i = 0; i < num_lmbs; i++) {
	lmbs[i].base_addr = cpu_to_be64(lmbs[i].base_addr);
	lmbs[i].drc_index = cpu_to_be32(lmbs[i].drc_index);
	lmbs[i].aa_index = cpu_to_be32(lmbs[i].aa_index);
	lmbs[i].flags = cpu_to_be32(lmbs[i].flags);
	}

	rtas_hp_event = true;
	of_update_property(dn, prop);
	rtas_hp_event = false;
	}

	static int dlpar_update_device_tree_lmb(struct of_drconf_cell *lmb)
	{
	struct device_node *dn;
	struct property *prop;
	struct of_drconf_cell *lmbs;
	u32 *p, num_lmbs;
	int i;

	dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (!dn)
	return -ENODEV;

	prop = dlpar_clone_drconf_property(dn);
	if (!prop) {
	of_node_put(dn);
	return -ENODEV;
	}

	p = prop->value;
	num_lmbs = *p++;
	lmbs = (struct of_drconf_cell *)p;

	for (i = 0; i < num_lmbs; i++) {
	if (lmbs[i].drc_index == lmb->drc_index) {
	lmbs[i].flags = lmb->flags;
	lmbs[i].aa_index = lmb->aa_index;

	dlpar_update_drconf_property(dn, prop);
	break;
	}
	}

	of_node_put(dn);
	return 0;
	}

	static u32 find_aa_index(struct device_node *dr_node,
	struct property ala_prop, const u32 lmb_assoc)
	{
	u32 *assoc_arrays;
	u32 aa_index;
	int aa_arrays, aa_array_entries, aa_array_sz;
	int i, index;

	/*
	* The ibm,associativity-lookup-arrays property is defined to be
	* a 32-bit value specifying the number of associativity arrays
	* followed by a 32-bitvalue specifying the number of entries per
	* array, followed by the associativity arrays.
	*/
	assoc_arrays = ala_prop->value;

	aa_arrays = be32_to_cpu(assoc_arrays[0]);
	aa_array_entries = be32_to_cpu(assoc_arrays[1]);
	aa_array_sz = aa_array_entries * sizeof(u32);

	aa_index = -1;
	for (i = 0; i < aa_arrays; i++) {
	index = (i * aa_array_entries) + 2;

	if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz))
	continue;

	aa_index = i;
	break;
	}

	if (aa_index == -1) {
	struct property *new_prop;
	u32 new_prop_size;

	new_prop_size = ala_prop->length + aa_array_sz;
	new_prop = dlpar_clone_property(ala_prop, new_prop_size);
	if (!new_prop)
	return -1;

	assoc_arrays = new_prop->value;

	/* increment the number of entries in the lookup array */
	assoc_arrays[0] = cpu_to_be32(aa_arrays + 1);

	/* copy the new associativity into the lookup array */
	index = aa_arrays * aa_array_entries + 2;
	memcpy(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz);

	of_update_property(dr_node, new_prop);

	/*
	* The associativity lookup array index for this lmb is
	* number of entries - 1 since we added its associativity
	* to the end of the lookup array.
	*/
	aa_index = be32_to_cpu(assoc_arrays[0]) - 1;
	}

	return aa_index;
	}

	static u32 lookup_lmb_associativity_index(struct of_drconf_cell *lmb)
	{
	struct device_node parent, lmb_node, *dr_node;
	struct property *ala_prop;
	const u32 *lmb_assoc;
	u32 aa_index;

	parent = of_find_node_by_path("/");
	if (!parent)
	return -ENODEV;

	lmb_node = dlpar_configure_connector(cpu_to_be32(lmb->drc_index),
	parent);
	of_node_put(parent);
	if (!lmb_node)
	return -EINVAL;

	lmb_assoc = of_get_property(lmb_node, "ibm,associativity", NULL);
	if (!lmb_assoc) {
	dlpar_free_cc_nodes(lmb_node);
	return -ENODEV;
	}

	dr_node = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (!dr_node) {
	dlpar_free_cc_nodes(lmb_node);
	return -ENODEV;
	}

	ala_prop = of_find_property(dr_node, "ibm,associativity-lookup-arrays",
	NULL);
	if (!ala_prop) {
	of_node_put(dr_node);
	dlpar_free_cc_nodes(lmb_node);
	return -ENODEV;
	}

	aa_index = find_aa_index(dr_node, ala_prop, lmb_assoc);

	dlpar_free_cc_nodes(lmb_node);
	return aa_index;
	}

	static int dlpar_add_device_tree_lmb(struct of_drconf_cell *lmb)
	{
	int aa_index;

	lmb->flags \|= DRCONF_MEM_ASSIGNED;

	aa_index = lookup_lmb_associativity_index(lmb);
	if (aa_index < 0) {
	pr_err("Couldn't find associativity index for drc index %x\n",
	lmb->drc_index);
	return aa_index;
	}

	lmb->aa_index = aa_index;
	return dlpar_update_device_tree_lmb(lmb);
	}

	static int dlpar_remove_device_tree_lmb(struct of_drconf_cell *lmb)
	{
	lmb->flags &= ~DRCONF_MEM_ASSIGNED;
	lmb->aa_index = 0xffffffff;
	return dlpar_update_device_tree_lmb(lmb);
	}

	#ifdef CONFIG_MEMORY_HOTREMOVE
	static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
	{
	unsigned long block_sz, start_pfn;
	int sections_per_block;
	int i, nid;

	start_pfn = base >> PAGE_SHIFT;

	lock_device_hotplug();

	if (!pfn_valid(start_pfn))
	goto out;

	block_sz = pseries_memory_block_size();
	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
	nid = memory_add_physaddr_to_nid(base);

	for (i = 0; i < sections_per_block; i++) {
	remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
	base += MIN_MEMORY_BLOCK_SIZE;
	}

	out:
	/* Update memory regions for memory remove */
	memblock_remove(base, memblock_size);
	unlock_device_hotplug();
	return 0;
	}

	static int pseries_remove_mem_node(struct device_node *np)
	{
	const char *type;
	const __be32 *regs;
	unsigned long base;
	unsigned int lmb_size;
	int ret = -EINVAL;

	/*
	* Check to see if we are actually removing memory
	*/
	type = of_get_property(np, "device_type", NULL);
	if (type == NULL \|\| strcmp(type, "memory") != 0)
	return 0;

	/*
	* Find the base address and size of the memblock
	*/
	regs = of_get_property(np, "reg", NULL);
	if (!regs)
	return ret;

	base = be64_to_cpu((unsigned long )regs);
	lmb_size = be32_to_cpu(regs[3]);

	pseries_remove_memblock(base, lmb_size);
	return 0;
	}

	static bool lmb_is_removable(struct of_drconf_cell *lmb)
	{
	int i, scns_per_block;
	int rc = 1;
	unsigned long pfn, block_sz;
	u64 phys_addr;

	if (!(lmb->flags & DRCONF_MEM_ASSIGNED))
	return false;

	block_sz = memory_block_size_bytes();
	scns_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
	phys_addr = lmb->base_addr;

	for (i = 0; i < scns_per_block; i++) {
	pfn = PFN_DOWN(phys_addr);
	if (!pfn_present(pfn))
	continue;

	rc &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
	phys_addr += MIN_MEMORY_BLOCK_SIZE;
	}

	return rc ? true : false;
	}

	static int dlpar_add_lmb(struct of_drconf_cell *);

	static struct memory_block lmb_to_memblock(struct of_drconf_cell lmb)
	{
	unsigned long section_nr;
	struct mem_section *mem_sect;
	struct memory_block *mem_block;

	section_nr = pfn_to_section_nr(PFN_DOWN(lmb->base_addr));
	mem_sect = __nr_to_section(section_nr);

	mem_block = find_memory_block(mem_sect);
	return mem_block;
	}

	static int dlpar_remove_lmb(struct of_drconf_cell *lmb)
	{
	struct memory_block *mem_block;
	unsigned long block_sz;
	int nid, rc;

	if (!lmb_is_removable(lmb))
	return -EINVAL;

	mem_block = lmb_to_memblock(lmb);
	if (!mem_block)
	return -EINVAL;

	rc = device_offline(&mem_block->dev);
	put_device(&mem_block->dev);
	if (rc)
	return rc;

	block_sz = pseries_memory_block_size();
	nid = memory_add_physaddr_to_nid(lmb->base_addr);

	remove_memory(nid, lmb->base_addr, block_sz);

	/* Update memory regions for memory remove */
	memblock_remove(lmb->base_addr, block_sz);

	dlpar_release_drc(lmb->drc_index);
	dlpar_remove_device_tree_lmb(lmb);

	return 0;
	}

	static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
	struct property *prop)
	{
	struct of_drconf_cell *lmbs;
	int lmbs_removed = 0;
	int lmbs_available = 0;
	u32 num_lmbs, *p;
	int i, rc;

	pr_info("Attempting to hot-remove %d LMB(s)\n", lmbs_to_remove);

	if (lmbs_to_remove == 0)
	return -EINVAL;

	p = prop->value;
	num_lmbs = *p++;
	lmbs = (struct of_drconf_cell *)p;

	/* Validate that there are enough LMBs to satisfy the request */
	for (i = 0; i < num_lmbs; i++) {
	if (lmbs[i].flags & DRCONF_MEM_ASSIGNED)
	lmbs_available++;
	}

	if (lmbs_available < lmbs_to_remove)
	return -EINVAL;

	for (i = 0; i < num_lmbs && lmbs_removed < lmbs_to_remove; i++) {
	rc = dlpar_remove_lmb(&lmbs[i]);
	if (rc)
	continue;

	lmbs_removed++;

	/* Mark this lmb so we can add it later if all of the
	* requested LMBs cannot be removed.
	*/
	lmbs[i].reserved = 1;
	}

	if (lmbs_removed != lmbs_to_remove) {
	pr_err("Memory hot-remove failed, adding LMB's back\n");

	for (i = 0; i < num_lmbs; i++) {
	if (!lmbs[i].reserved)
	continue;

	rc = dlpar_add_lmb(&lmbs[i]);
	if (rc)
	pr_err("Failed to add LMB back, drc index %x\n",
	lmbs[i].drc_index);

	lmbs[i].reserved = 0;
	}

	rc = -EINVAL;
	} else {
	for (i = 0; i < num_lmbs; i++) {
	if (!lmbs[i].reserved)
	continue;

	pr_info("Memory at %llx was hot-removed\n",
	lmbs[i].base_addr);

	lmbs[i].reserved = 0;
	}
	rc = 0;
	}

	return rc;
	}

	static int dlpar_memory_remove_by_index(u32 drc_index, struct property *prop)
	{
	struct of_drconf_cell *lmbs;
	u32 num_lmbs, *p;
	int lmb_found;
	int i, rc;

	pr_info("Attempting to hot-remove LMB, drc index %x\n", drc_index);

	p = prop->value;
	num_lmbs = *p++;
	lmbs = (struct of_drconf_cell *)p;

	lmb_found = 0;
	for (i = 0; i < num_lmbs; i++) {
	if (lmbs[i].drc_index == drc_index) {
	lmb_found = 1;
	rc = dlpar_remove_lmb(&lmbs[i]);
	break;
	}
	}

	if (!lmb_found)
	rc = -EINVAL;

	if (rc)
	pr_info("Failed to hot-remove memory at %llx\n",
	lmbs[i].base_addr);
	else
	pr_info("Memory at %llx was hot-removed\n", lmbs[i].base_addr);

	return rc;
	}

	#else
	static inline int pseries_remove_memblock(unsigned long base,
	unsigned int memblock_size)
	{
	return -EOPNOTSUPP;
	}
	static inline int pseries_remove_mem_node(struct device_node *np)
	{
	return 0;
	}
	static inline int dlpar_memory_remove(struct pseries_hp_errorlog *hp_elog)
	{
	return -EOPNOTSUPP;
	}
	static int dlpar_remove_lmb(struct of_drconf_cell *lmb)
	{
	return -EOPNOTSUPP;
	}
	static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
	struct property *prop)
	{
	return -EOPNOTSUPP;
	}
	static int dlpar_memory_remove_by_index(u32 drc_index, struct property *prop)
	{
	return -EOPNOTSUPP;
	}

	#endif /* CONFIG_MEMORY_HOTREMOVE */

	static int dlpar_add_lmb(struct of_drconf_cell *lmb)
	{
	unsigned long block_sz;
	int nid, rc;

	if (lmb->flags & DRCONF_MEM_ASSIGNED)
	return -EINVAL;

	rc = dlpar_acquire_drc(lmb->drc_index);
	if (rc)
	return rc;

	rc = dlpar_add_device_tree_lmb(lmb);
	if (rc) {
	pr_err("Couldn't update device tree for drc index %x\n",
	lmb->drc_index);
	dlpar_release_drc(lmb->drc_index);
	return rc;
	}

	block_sz = memory_block_size_bytes();

	/* Find the node id for this address */
	nid = memory_add_physaddr_to_nid(lmb->base_addr);

	/* Add the memory */
	rc = add_memory(nid, lmb->base_addr, block_sz);
	if (rc) {
	dlpar_remove_device_tree_lmb(lmb);
	dlpar_release_drc(lmb->drc_index);
	} else {
	lmb->flags \|= DRCONF_MEM_ASSIGNED;
	}

	return rc;
	}

	static int dlpar_memory_add_by_count(u32 lmbs_to_add, struct property *prop)
	{
	struct of_drconf_cell *lmbs;
	u32 num_lmbs, *p;
	int lmbs_available = 0;
	int lmbs_added = 0;
	int i, rc;

	pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);

	if (lmbs_to_add == 0)
	return -EINVAL;

	p = prop->value;
	num_lmbs = *p++;
	lmbs = (struct of_drconf_cell *)p;

	/* Validate that there are enough LMBs to satisfy the request */
	for (i = 0; i < num_lmbs; i++) {
	if (!(lmbs[i].flags & DRCONF_MEM_ASSIGNED))
	lmbs_available++;
	}

	if (lmbs_available < lmbs_to_add)
	return -EINVAL;

	for (i = 0; i < num_lmbs && lmbs_to_add != lmbs_added; i++) {
	rc = dlpar_add_lmb(&lmbs[i]);
	if (rc)
	continue;

	lmbs_added++;

	/* Mark this lmb so we can remove it later if all of the
	* requested LMBs cannot be added.
	*/
	lmbs[i].reserved = 1;
	}

	if (lmbs_added != lmbs_to_add) {
	pr_err("Memory hot-add failed, removing any added LMBs\n");

	for (i = 0; i < num_lmbs; i++) {
	if (!lmbs[i].reserved)
	continue;

	rc = dlpar_remove_lmb(&lmbs[i]);
	if (rc)
	pr_err("Failed to remove LMB, drc index %x\n",
	be32_to_cpu(lmbs[i].drc_index));
	}
	rc = -EINVAL;
	} else {
	for (i = 0; i < num_lmbs; i++) {
	if (!lmbs[i].reserved)
	continue;

	pr_info("Memory at %llx (drc index %x) was hot-added\n",
	lmbs[i].base_addr, lmbs[i].drc_index);
	lmbs[i].reserved = 0;
	}
	}

	return rc;
	}

	static int dlpar_memory_add_by_index(u32 drc_index, struct property *prop)
	{
	struct of_drconf_cell *lmbs;
	u32 num_lmbs, *p;
	int i, lmb_found;
	int rc;

	pr_info("Attempting to hot-add LMB, drc index %x\n", drc_index);

	p = prop->value;
	num_lmbs = *p++;
	lmbs = (struct of_drconf_cell *)p;

	lmb_found = 0;
	for (i = 0; i < num_lmbs; i++) {
	if (lmbs[i].drc_index == drc_index) {
	lmb_found = 1;
	rc = dlpar_add_lmb(&lmbs[i]);
	break;
	}
	}

	if (!lmb_found)
	rc = -EINVAL;

	if (rc)
	pr_info("Failed to hot-add memory, drc index %x\n", drc_index);
	else
	pr_info("Memory at %llx (drc index %x) was hot-added\n",
	lmbs[i].base_addr, drc_index);

	return rc;
	}

	int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
	{
	struct device_node *dn;
	struct property *prop;
	u32 count, drc_index;
	int rc;

	count = hp_elog->_drc_u.drc_count;
	drc_index = hp_elog->_drc_u.drc_index;

	lock_device_hotplug();

	dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
	if (!dn) {
	rc = -EINVAL;
	goto dlpar_memory_out;
	}

	prop = dlpar_clone_drconf_property(dn);
	if (!prop) {
	rc = -EINVAL;
	goto dlpar_memory_out;
	}

	switch (hp_elog->action) {
	case PSERIES_HP_ELOG_ACTION_ADD:
	if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
	rc = dlpar_memory_add_by_count(count, prop);
	else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
	rc = dlpar_memory_add_by_index(drc_index, prop);
	else
	rc = -EINVAL;
	break;
	case PSERIES_HP_ELOG_ACTION_REMOVE:
	if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
	rc = dlpar_memory_remove_by_count(count, prop);
	else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
	rc = dlpar_memory_remove_by_index(drc_index, prop);
	else
	rc = -EINVAL;
	break;
	default:
	pr_err("Invalid action (%d) specified\n", hp_elog->action);
	rc = -EINVAL;
	break;
	}

	dlpar_free_property(prop);

	dlpar_memory_out:
	of_node_put(dn);
	unlock_device_hotplug();
	return rc;
	}

	static int pseries_add_mem_node(struct device_node *np)
	{
	const char *type;
	const __be32 *regs;
	unsigned long base;
	unsigned int lmb_size;
	int ret = -EINVAL;

	/*
	* Check to see if we are actually adding memory
	*/
	type = of_get_property(np, "device_type", NULL);
	if (type == NULL \|\| strcmp(type, "memory") != 0)
	return 0;

	/*
	* Find the base and size of the memblock
	*/
	regs = of_get_property(np, "reg", NULL);
	if (!regs)
	return ret;

	base = be64_to_cpu((unsigned long )regs);
	lmb_size = be32_to_cpu(regs[3]);

	/*
	* Update memory region to represent the memory add
	*/
	ret = memblock_add(base, lmb_size);
	return (ret < 0) ? -EINVAL : 0;
	}

	static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
	{
	struct of_drconf_cell new_drmem, old_drmem;
	unsigned long memblock_size;
	u32 entries;
	__be32 *p;
	int i, rc = -EINVAL;

	if (rtas_hp_event)
	return 0;

	memblock_size = pseries_memory_block_size();
	if (!memblock_size)
	return -EINVAL;

	p = (__be32 *) pr->old_prop->value;
	if (!p)
	return -EINVAL;

	/* The first int of the property is the number of lmb's described
	* by the property. This is followed by an array of of_drconf_cell
	* entries. Get the number of entries and skip to the array of
	* of_drconf_cell's.
	*/
	entries = be32_to_cpu(*p++);
	old_drmem = (struct of_drconf_cell *)p;

	p = (__be32 *)pr->prop->value;
	p++;
	new_drmem = (struct of_drconf_cell *)p;

	for (i = 0; i < entries; i++) {
	if ((be32_to_cpu(old_drmem[i].flags) & DRCONF_MEM_ASSIGNED) &&
	(!(be32_to_cpu(new_drmem[i].flags) & DRCONF_MEM_ASSIGNED))) {
	rc = pseries_remove_memblock(
	be64_to_cpu(old_drmem[i].base_addr),
	memblock_size);
	break;
	} else if ((!(be32_to_cpu(old_drmem[i].flags) &
	DRCONF_MEM_ASSIGNED)) &&
	(be32_to_cpu(new_drmem[i].flags) &
	DRCONF_MEM_ASSIGNED)) {
	rc = memblock_add(be64_to_cpu(old_drmem[i].base_addr),
	memblock_size);
	rc = (rc < 0) ? -EINVAL : 0;
	break;
	}
	}
	return rc;
	}

	static int pseries_memory_notifier(struct notifier_block *nb,
	unsigned long action, void *data)
	{
	struct of_reconfig_data *rd = data;
	int err = 0;

	switch (action) {
	case OF_RECONFIG_ATTACH_NODE:
	err = pseries_add_mem_node(rd->dn);
	break;
	case OF_RECONFIG_DETACH_NODE:
	err = pseries_remove_mem_node(rd->dn);
	break;
	case OF_RECONFIG_UPDATE_PROPERTY:
	if (!strcmp(rd->prop->name, "ibm,dynamic-memory"))
	err = pseries_update_drconf_memory(rd);
	break;
	}
	return notifier_from_errno(err);
	}

	static struct notifier_block pseries_mem_nb = {
	.notifier_call = pseries_memory_notifier,
	};

	static int __init pseries_memory_hotplug_init(void)
	{
	if (firmware_has_feature(FW_FEATURE_LPAR))
	of_reconfig_notifier_register(&pseries_mem_nb);

	return 0;
	}
	machine_device_initcall(pseries, pseries_memory_hotplug_init);