arch/powerpc/platforms/pseries/hotplug-memory.c

   1 /*
   2  * pseries Memory Hotplug infrastructure.
   3  *
   4  * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/of.h>
  13 #include <linux/memblock.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/memory.h>
  16
  17 #include <asm/firmware.h>
  18 #include <asm/machdep.h>
  19 #include <asm/pSeries_reconfig.h>
  20 #include <asm/sparsemem.h>
  21
  22 static unsigned long get_memblock_size(void)
  23 {
  24         struct device_node *np;
  25         unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
  26         struct resource r;
  27
  28         np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
  29         if (np) {
  30                 const __be64 *size;
  31
  32                 size = of_get_property(np, "ibm,lmb-size", NULL);
  33                 if (size)
  34                         memblock_size = be64_to_cpup(size);
  35                 of_node_put(np);
  36         } else  if (machine_is(pseries)) {
  37                 /* This fallback really only applies to pseries */
  38                 unsigned int memzero_size = 0;
  39
  40                 np = of_find_node_by_path("/memory@0");
  41                 if (np) {
  42                         if (!of_address_to_resource(np, 0, &r))
  43                                 memzero_size = resource_size(&r);
  44                         of_node_put(np);
  45                 }
  46
  47                 if (memzero_size) {
  48                         /* We now know the size of memory@0, use this to find
  49                          * the first memoryblock and get its size.
  50                          */
  51                         char buf[64];
  52
  53                         sprintf(buf, "/memory@%x", memzero_size);
  54                         np = of_find_node_by_path(buf);
  55                         if (np) {
  56                                 if (!of_address_to_resource(np, 0, &r))
  57                                         memblock_size = resource_size(&r);
  58                                 of_node_put(np);
  59                         }
  60                 }
  61         }
  62         return memblock_size;
  63 }
  64
  65 /* WARNING: This is going to override the generic definition whenever
  66  * pseries is built-in regardless of what platform is active at boot
  67  * time. This is fine for now as this is the only "option" and it
  68  * should work everywhere. If not, we'll have to turn this into a
  69  * ppc_md. callback
  70  */
  71 unsigned long memory_block_size_bytes(void)
  72 {
  73         return get_memblock_size();
  74 }
  75
  76 static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
  77 {
  78         unsigned long start, start_pfn;
  79         struct zone *zone;
  80         int ret;
  81
  82         start_pfn = base >> PAGE_SHIFT;
  83
  84         if (!pfn_valid(start_pfn)) {
  85                 memblock_remove(base, memblock_size);
  86                 return 0;
  87         }
  88
  89         zone = page_zone(pfn_to_page(start_pfn));
  90
  91         /*
  92          * Remove section mappings and sysfs entries for the
  93          * section of the memory we are removing.
  94          *
  95          * NOTE: Ideally, this should be done in generic code like
  96          * remove_memory(). But remove_memory() gets called by writing
  97          * to sysfs "state" file and we can't remove sysfs entries
  98          * while writing to it. So we have to defer it to here.
  99          */
 100         ret = __remove_pages(zone, start_pfn, memblock_size >> PAGE_SHIFT);
 101         if (ret)
 102                 return ret;
 103
 104         /*
 105          * Update memory regions for memory remove
 106          */
 107         memblock_remove(base, memblock_size);
 108
 109         /*
 110          * Remove htab bolted mappings for this section of memory
 111          */
 112         start = (unsigned long)__va(base);
 113         ret = remove_section_mapping(start, start + memblock_size);
 114
 115         /* Ensure all vmalloc mappings are flushed in case they also
 116          * hit that section of memory
 117          */
 118         vm_unmap_aliases();
 119
 120         return ret;
 121 }
 122
 123 static int pseries_remove_memory(struct device_node *np)
 124 {
 125         const char *type;
 126         const unsigned int *regs;
 127         unsigned long base;
 128         unsigned int lmb_size;
 129         int ret = -EINVAL;
 130
 131         /*
 132          * Check to see if we are actually removing memory
 133          */
 134         type = of_get_property(np, "device_type", NULL);
 135         if (type == NULL || strcmp(type, "memory") != 0)
 136                 return 0;
 137
 138         /*
 139          * Find the bae address and size of the memblock
 140          */
 141         regs = of_get_property(np, "reg", NULL);
 142         if (!regs)
 143                 return ret;
 144
 145         base = *(unsigned long *)regs;
 146         lmb_size = regs[3];
 147
 148         ret = pseries_remove_memblock(base, lmb_size);
 149         return ret;
 150 }
 151
 152 static int pseries_add_memory(struct device_node *np)
 153 {
 154         const char *type;
 155         const unsigned int *regs;
 156         unsigned long base;
 157         unsigned int lmb_size;
 158         int ret = -EINVAL;
 159
 160         /*
 161          * Check to see if we are actually adding memory
 162          */
 163         type = of_get_property(np, "device_type", NULL);
 164         if (type == NULL || strcmp(type, "memory") != 0)
 165                 return 0;
 166
 167         /*
 168          * Find the base and size of the memblock
 169          */
 170         regs = of_get_property(np, "reg", NULL);
 171         if (!regs)
 172                 return ret;
 173
 174         base = *(unsigned long *)regs;
 175         lmb_size = regs[3];
 176
 177         /*
 178          * Update memory region to represent the memory add
 179          */
 180         ret = memblock_add(base, lmb_size);
 181         return (ret < 0) ? -EINVAL : 0;
 182 }
 183
 184 static int pseries_drconf_memory(unsigned long *base, unsigned int action)
 185 {
 186         unsigned long memblock_size;
 187         int rc;
 188
 189         memblock_size = get_memblock_size();
 190         if (!memblock_size)
 191                 return -EINVAL;
 192
 193         if (action == PSERIES_DRCONF_MEM_ADD) {
 194                 rc = memblock_add(*base, memblock_size);
 195                 rc = (rc < 0) ? -EINVAL : 0;
 196         } else if (action == PSERIES_DRCONF_MEM_REMOVE) {
 197                 rc = pseries_remove_memblock(*base, memblock_size);
 198         } else {
 199                 rc = -EINVAL;
 200         }
 201
 202         return rc;
 203 }
 204
 205 static int pseries_memory_notifier(struct notifier_block *nb,
 206                                 unsigned long action, void *node)
 207 {
 208         int err = 0;
 209
 210         switch (action) {
 211         case PSERIES_RECONFIG_ADD:
 212                 err = pseries_add_memory(node);
 213                 break;
 214         case PSERIES_RECONFIG_REMOVE:
 215                 err = pseries_remove_memory(node);
 216                 break;
 217         case PSERIES_DRCONF_MEM_ADD:
 218         case PSERIES_DRCONF_MEM_REMOVE:
 219                 err = pseries_drconf_memory(node, action);
 220                 break;
 221         }
 222         return notifier_from_errno(err);
 223 }
 224
 225 static struct notifier_block pseries_mem_nb = {
 226         .notifier_call = pseries_memory_notifier,
 227 };
 228
 229 static int __init pseries_memory_hotplug_init(void)
 230 {
 231         if (firmware_has_feature(FW_FEATURE_LPAR))
 232                 pSeries_reconfig_notifier_register(&pseries_mem_nb);
 233
 234         return 0;
 235 }
 236 machine_device_initcall(pseries, pseries_memory_hotplug_init);