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/lmb.h>
  14 #include <asm/firmware.h>
  15 #include <asm/machdep.h>
  16 #include <asm/pSeries_reconfig.h>
  17
  18 static int pseries_remove_memory(struct device_node *np)
  19 {
  20         const char *type;
  21         const unsigned int *regs;
  22         unsigned long base;
  23         unsigned int lmb_size;
  24         u64 start_pfn, start;
  25         struct zone *zone;
  26         int ret = -EINVAL;
  27
  28         /*
  29          * Check to see if we are actually removing memory
  30          */
  31         type = of_get_property(np, "device_type", NULL);
  32         if (type == NULL || strcmp(type, "memory") != 0)
  33                 return 0;
  34
  35         /*
  36          * Find the bae address and size of the lmb
  37          */
  38         regs = of_get_property(np, "reg", NULL);
  39         if (!regs)
  40                 return ret;
  41
  42         base = *(unsigned long *)regs;
  43         lmb_size = regs[3];
  44
  45         start_pfn = base >> PFN_SECTION_SHIFT;
  46         zone = page_zone(pfn_to_page(start_pfn));
  47
  48         /*
  49          * Remove section mappings and sysfs entries for the
  50          * section of the memory we are removing.
  51          *
  52          * NOTE: Ideally, this should be done in generic code like
  53          * remove_memory(). But remove_memory() gets called by writing
  54          * to sysfs "state" file and we can't remove sysfs entries
  55          * while writing to it. So we have to defer it to here.
  56          */
  57         ret = __remove_pages(zone, start_pfn, lmb_size >> PAGE_SHIFT);
  58         if (ret)
  59                 return ret;
  60
  61         /*
  62          * Update memory regions for memory remove
  63          */
  64         lmb_remove(base, lmb_size);
  65
  66         /*
  67          * Remove htab bolted mappings for this section of memory
  68          */
  69         start = (unsigned long)__va(base);
  70         ret = remove_section_mapping(start, start + lmb_size);
  71         return ret;
  72 }
  73
  74 static int pseries_add_memory(struct device_node *np)
  75 {
  76         const char *type;
  77         const unsigned int *regs;
  78         unsigned long base;
  79         unsigned int lmb_size;
  80         u64 start_pfn;
  81         int ret = -EINVAL;
  82
  83         /*
  84          * Check to see if we are actually adding memory
  85          */
  86         type = of_get_property(np, "device_type", NULL);
  87         if (type == NULL || strcmp(type, "memory") != 0)
  88                 return 0;
  89
  90         /*
  91          * Find the base and size of the lmb
  92          */
  93         regs = of_get_property(np, "reg", NULL);
  94         if (!regs)
  95                 return ret;
  96
  97         base = *(unsigned long *)regs;
  98         lmb_size = regs[3];
  99
 100         /*
 101          * Update memory region to represent the memory add
 102          */
 103         lmb_add(base, lmb_size);
 104         return 0;
 105 }
 106
 107 static int pseries_memory_notifier(struct notifier_block *nb,
 108                                 unsigned long action, void *node)
 109 {
 110         int err = NOTIFY_OK;
 111
 112         switch (action) {
 113         case PSERIES_RECONFIG_ADD:
 114                 if (pseries_add_memory(node))
 115                         err = NOTIFY_BAD;
 116                 break;
 117         case PSERIES_RECONFIG_REMOVE:
 118                 if (pseries_remove_memory(node))
 119                         err = NOTIFY_BAD;
 120                 break;
 121         default:
 122                 err = NOTIFY_DONE;
 123                 break;
 124         }
 125         return err;
 126 }
 127
 128 static struct notifier_block pseries_mem_nb = {
 129         .notifier_call = pseries_memory_notifier,
 130 };
 131
 132 static int __init pseries_memory_hotplug_init(void)
 133 {
 134         if (firmware_has_feature(FW_FEATURE_LPAR))
 135                 pSeries_reconfig_notifier_register(&pseries_mem_nb);
 136
 137         return 0;
 138 }
 139 machine_device_initcall(pseries, pseries_memory_hotplug_init);