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/of_address.h>
  14 #include <linux/memblock.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/memory.h>
  17
  18 #include <asm/firmware.h>
  19 #include <asm/machdep.h>
  20 #include <asm/prom.h>
  21 #include <asm/sparsemem.h>
  22
  23 static unsigned long get_memblock_size(void)
  24 {
  25         struct device_node *np;
  26         unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
  27         struct resource r;
  28
  29         np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
  30         if (np) {
  31                 const __be64 *size;
  32
  33                 size = of_get_property(np, "ibm,lmb-size", NULL);
  34                 if (size)
  35                         memblock_size = be64_to_cpup(size);
  36                 of_node_put(np);
  37         } else  if (machine_is(pseries)) {
  38                 /* This fallback really only applies to pseries */
  39                 unsigned int memzero_size = 0;
  40
  41                 np = of_find_node_by_path("/memory@0");
  42                 if (np) {
  43                         if (!of_address_to_resource(np, 0, &r))
  44                                 memzero_size = resource_size(&r);
  45                         of_node_put(np);
  46                 }
  47
  48                 if (memzero_size) {
  49                         /* We now know the size of memory@0, use this to find
  50                          * the first memoryblock and get its size.
  51                          */
  52                         char buf[64];
  53
  54                         sprintf(buf, "/memory@%x", memzero_size);
  55                         np = of_find_node_by_path(buf);
  56                         if (np) {
  57                                 if (!of_address_to_resource(np, 0, &r))
  58                                         memblock_size = resource_size(&r);
  59                                 of_node_put(np);
  60                         }
  61                 }
  62         }
  63         return memblock_size;
  64 }
  65
  66 /* WARNING: This is going to override the generic definition whenever
  67  * pseries is built-in regardless of what platform is active at boot
  68  * time. This is fine for now as this is the only "option" and it
  69  * should work everywhere. If not, we'll have to turn this into a
  70  * ppc_md. callback
  71  */
  72 unsigned long memory_block_size_bytes(void)
  73 {
  74         return get_memblock_size();
  75 }
  76
  77 #ifdef CONFIG_MEMORY_HOTREMOVE
  78 static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
  79 {
  80         unsigned long start, start_pfn;
  81         struct zone *zone;
  82         int ret;
  83         unsigned long section;
  84         unsigned long sections_to_remove;
  85
  86         start_pfn = base >> PAGE_SHIFT;
  87
  88         if (!pfn_valid(start_pfn)) {
  89                 memblock_remove(base, memblock_size);
  90                 return 0;
  91         }
  92
  93         zone = page_zone(pfn_to_page(start_pfn));
  94
  95         /*
  96          * Remove section mappings and sysfs entries for the
  97          * section of the memory we are removing.
  98          *
  99          * NOTE: Ideally, this should be done in generic code like
 100          * remove_memory(). But remove_memory() gets called by writing
 101          * to sysfs "state" file and we can't remove sysfs entries
 102          * while writing to it. So we have to defer it to here.
 103          */
 104         sections_to_remove = (memblock_size >> PAGE_SHIFT) / PAGES_PER_SECTION;
 105         for (section = 0; section < sections_to_remove; section++) {
 106                 unsigned long pfn = start_pfn + section * PAGES_PER_SECTION;
 107                 ret = __remove_pages(zone, pfn, PAGES_PER_SECTION);
 108                 if (ret)
 109                         return ret;
 110         }
 111
 112         /*
 113          * Update memory regions for memory remove
 114          */
 115         memblock_remove(base, memblock_size);
 116
 117         /*
 118          * Remove htab bolted mappings for this section of memory
 119          */
 120         start = (unsigned long)__va(base);
 121         ret = remove_section_mapping(start, start + memblock_size);
 122
 123         /* Ensure all vmalloc mappings are flushed in case they also
 124          * hit that section of memory
 125          */
 126         vm_unmap_aliases();
 127
 128         return ret;
 129 }
 130
 131 static int pseries_remove_memory(struct device_node *np)
 132 {
 133         const char *type;
 134         const unsigned int *regs;
 135         unsigned long base;
 136         unsigned int lmb_size;
 137         int ret = -EINVAL;
 138
 139         /*
 140          * Check to see if we are actually removing memory
 141          */
 142         type = of_get_property(np, "device_type", NULL);
 143         if (type == NULL || strcmp(type, "memory") != 0)
 144                 return 0;
 145
 146         /*
 147          * Find the bae address and size of the memblock
 148          */
 149         regs = of_get_property(np, "reg", NULL);
 150         if (!regs)
 151                 return ret;
 152
 153         base = *(unsigned long *)regs;
 154         lmb_size = regs[3];
 155
 156         ret = pseries_remove_memblock(base, lmb_size);
 157         return ret;
 158 }
 159 #else
 160 static inline int pseries_remove_memblock(unsigned long base,
 161                                           unsigned int memblock_size)
 162 {
 163         return -EOPNOTSUPP;
 164 }
 165 static inline int pseries_remove_memory(struct device_node *np)
 166 {
 167         return -EOPNOTSUPP;
 168 }
 169 #endif /* CONFIG_MEMORY_HOTREMOVE */
 170
 171 static int pseries_add_memory(struct device_node *np)
 172 {
 173         const char *type;
 174         const unsigned int *regs;
 175         unsigned long base;
 176         unsigned int lmb_size;
 177         int ret = -EINVAL;
 178
 179         /*
 180          * Check to see if we are actually adding memory
 181          */
 182         type = of_get_property(np, "device_type", NULL);
 183         if (type == NULL || strcmp(type, "memory") != 0)
 184                 return 0;
 185
 186         /*
 187          * Find the base and size of the memblock
 188          */
 189         regs = of_get_property(np, "reg", NULL);
 190         if (!regs)
 191                 return ret;
 192
 193         base = *(unsigned long *)regs;
 194         lmb_size = regs[3];
 195
 196         /*
 197          * Update memory region to represent the memory add
 198          */
 199         ret = memblock_add(base, lmb_size);
 200         return (ret < 0) ? -EINVAL : 0;
 201 }
 202
 203 static int pseries_update_drconf_memory(struct of_prop_reconfig *pr)
 204 {
 205         struct of_drconf_cell *new_drmem, *old_drmem;
 206         unsigned long memblock_size;
 207         u32 entries;
 208         u32 *p;
 209         int i, rc = -EINVAL;
 210
 211         memblock_size = get_memblock_size();
 212         if (!memblock_size)
 213                 return -EINVAL;
 214
 215         p = (u32 *)of_get_property(pr->dn, "ibm,dynamic-memory", NULL);
 216         if (!p)
 217                 return -EINVAL;
 218
 219         /* The first int of the property is the number of lmb's described
 220          * by the property. This is followed by an array of of_drconf_cell
 221          * entries. Get the niumber of entries and skip to the array of
 222          * of_drconf_cell's.
 223          */
 224         entries = *p++;
 225         old_drmem = (struct of_drconf_cell *)p;
 226
 227         p = (u32 *)pr->prop->value;
 228         p++;
 229         new_drmem = (struct of_drconf_cell *)p;
 230
 231         for (i = 0; i < entries; i++) {
 232                 if ((old_drmem[i].flags & DRCONF_MEM_ASSIGNED) &&
 233                     (!(new_drmem[i].flags & DRCONF_MEM_ASSIGNED))) {
 234                         rc = pseries_remove_memblock(old_drmem[i].base_addr,
 235                                                      memblock_size);
 236                         break;
 237                 } else if ((!(old_drmem[i].flags & DRCONF_MEM_ASSIGNED)) &&
 238                            (new_drmem[i].flags & DRCONF_MEM_ASSIGNED)) {
 239                         rc = memblock_add(old_drmem[i].base_addr,
 240                                           memblock_size);
 241                         rc = (rc < 0) ? -EINVAL : 0;
 242                         break;
 243                 }
 244         }
 245
 246         return rc;
 247 }
 248
 249 static int pseries_memory_notifier(struct notifier_block *nb,
 250                                    unsigned long action, void *node)
 251 {
 252         struct of_prop_reconfig *pr;
 253         int err = 0;
 254
 255         switch (action) {
 256         case OF_RECONFIG_ATTACH_NODE:
 257                 err = pseries_add_memory(node);
 258                 break;
 259         case OF_RECONFIG_DETACH_NODE:
 260                 err = pseries_remove_memory(node);
 261                 break;
 262         case OF_RECONFIG_UPDATE_PROPERTY:
 263                 pr = (struct of_prop_reconfig *)node;
 264                 if (!strcmp(pr->prop->name, "ibm,dynamic-memory"))
 265                         err = pseries_update_drconf_memory(pr);
 266                 break;
 267         }
 268         return notifier_from_errno(err);
 269 }
 270
 271 static struct notifier_block pseries_mem_nb = {
 272         .notifier_call = pseries_memory_notifier,
 273 };
 274
 275 static int __init pseries_memory_hotplug_init(void)
 276 {
 277         if (firmware_has_feature(FW_FEATURE_LPAR))
 278                 of_reconfig_notifier_register(&pseries_mem_nb);
 279
 280         return 0;
 281 }
 282 machine_device_initcall(pseries, pseries_memory_hotplug_init);