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* pseries Memory Hotplug infrastructure.
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* Copyright (C) 2008 Badari Pulavarty, IBM Corporation
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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#include <linux/memblock.h>
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#include <linux/vmalloc.h>
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#include <linux/memory.h>
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#include <asm/firmware.h>
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#include <asm/machdep.h>
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#include <asm/pSeries_reconfig.h>
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#include <asm/sparsemem.h>
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static unsigned long get_memblock_size(void)
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struct device_node *np;
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unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
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np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
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size = of_get_property(np, "ibm,lmb-size", NULL);
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memblock_size = be64_to_cpup(size);
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} else if (machine_is(pseries)) {
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/* This fallback really only applies to pseries */
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unsigned int memzero_size = 0;
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np = of_find_node_by_path("/memory@0");
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if (!of_address_to_resource(np, 0, &r))
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memzero_size = resource_size(&r);
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/* We now know the size of memory@0, use this to find
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* the first memoryblock and get its size.
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sprintf(buf, "/memory@%x", memzero_size);
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np = of_find_node_by_path(buf);
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if (!of_address_to_resource(np, 0, &r))
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memblock_size = resource_size(&r);
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/* WARNING: This is going to override the generic definition whenever
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* pseries is built-in regardless of what platform is active at boot
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* time. This is fine for now as this is the only "option" and it
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* should work everywhere. If not, we'll have to turn this into a
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unsigned long memory_block_size_bytes(void)
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return get_memblock_size();
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static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
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unsigned long start, start_pfn;
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start_pfn = base >> PAGE_SHIFT;
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if (!pfn_valid(start_pfn)) {
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memblock_remove(base, memblock_size);
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zone = page_zone(pfn_to_page(start_pfn));
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* Remove section mappings and sysfs entries for the
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* section of the memory we are removing.
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* NOTE: Ideally, this should be done in generic code like
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* remove_memory(). But remove_memory() gets called by writing
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* to sysfs "state" file and we can't remove sysfs entries
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* while writing to it. So we have to defer it to here.
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ret = __remove_pages(zone, start_pfn, memblock_size >> PAGE_SHIFT);
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* Update memory regions for memory remove
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memblock_remove(base, memblock_size);
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* Remove htab bolted mappings for this section of memory
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start = (unsigned long)__va(base);
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ret = remove_section_mapping(start, start + memblock_size);
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/* Ensure all vmalloc mappings are flushed in case they also
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* hit that section of memory
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static int pseries_remove_memory(struct device_node *np)
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const unsigned int *regs;
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unsigned int lmb_size;
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* Check to see if we are actually removing memory
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type = of_get_property(np, "device_type", NULL);
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if (type == NULL || strcmp(type, "memory") != 0)
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* Find the bae address and size of the memblock
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regs = of_get_property(np, "reg", NULL);
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base = *(unsigned long *)regs;
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ret = pseries_remove_memblock(base, lmb_size);
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static int pseries_add_memory(struct device_node *np)
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const unsigned int *regs;
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unsigned int lmb_size;
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* Check to see if we are actually adding memory
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type = of_get_property(np, "device_type", NULL);
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if (type == NULL || strcmp(type, "memory") != 0)
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* Find the base and size of the memblock
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regs = of_get_property(np, "reg", NULL);
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base = *(unsigned long *)regs;
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* Update memory region to represent the memory add
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ret = memblock_add(base, lmb_size);
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return (ret < 0) ? -EINVAL : 0;
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static int pseries_drconf_memory(unsigned long *base, unsigned int action)
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unsigned long memblock_size;
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memblock_size = get_memblock_size();
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if (action == PSERIES_DRCONF_MEM_ADD) {
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rc = memblock_add(*base, memblock_size);
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rc = (rc < 0) ? -EINVAL : 0;
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} else if (action == PSERIES_DRCONF_MEM_REMOVE) {
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rc = pseries_remove_memblock(*base, memblock_size);
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static int pseries_memory_notifier(struct notifier_block *nb,
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unsigned long action, void *node)
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case PSERIES_RECONFIG_ADD:
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err = pseries_add_memory(node);
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case PSERIES_RECONFIG_REMOVE:
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err = pseries_remove_memory(node);
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case PSERIES_DRCONF_MEM_ADD:
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case PSERIES_DRCONF_MEM_REMOVE:
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err = pseries_drconf_memory(node, action);
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return notifier_from_errno(err);
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static struct notifier_block pseries_mem_nb = {
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.notifier_call = pseries_memory_notifier,
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static int __init pseries_memory_hotplug_init(void)
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if (firmware_has_feature(FW_FEATURE_LPAR))
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pSeries_reconfig_notifier_register(&pseries_mem_nb);
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machine_device_initcall(pseries, pseries_memory_hotplug_init);