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