linux/drivers/firmware/memmap.c
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   1/*
   2 * linux/drivers/firmware/memmap.c
   3 *  Copyright (C) 2008 SUSE LINUX Products GmbH
   4 *  by Bernhard Walle <bernhard.walle@gmx.de>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License v2.0 as published by
   8 * the Free Software Foundation
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 */
  16
  17#include <linux/string.h>
  18#include <linux/firmware-map.h>
  19#include <linux/kernel.h>
  20#include <linux/module.h>
  21#include <linux/types.h>
  22#include <linux/bootmem.h>
  23#include <linux/slab.h>
  24
  25/*
  26 * Data types ------------------------------------------------------------------
  27 */
  28
  29/*
  30 * Firmware map entry. Because firmware memory maps are flat and not
  31 * hierarchical, it's ok to organise them in a linked list. No parent
  32 * information is necessary as for the resource tree.
  33 */
  34struct firmware_map_entry {
  35        /*
  36         * start and end must be u64 rather than resource_size_t, because e820
  37         * resources can lie at addresses above 4G.
  38         */
  39        u64                     start;  /* start of the memory range */
  40        u64                     end;    /* end of the memory range (incl.) */
  41        const char              *type;  /* type of the memory range */
  42        struct list_head        list;   /* entry for the linked list */
  43        struct kobject          kobj;   /* kobject for each entry */
  44};
  45
  46/*
  47 * Forward declarations --------------------------------------------------------
  48 */
  49static ssize_t memmap_attr_show(struct kobject *kobj,
  50                                struct attribute *attr, char *buf);
  51static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
  52static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
  53static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
  54
  55/*
  56 * Static data -----------------------------------------------------------------
  57 */
  58
  59struct memmap_attribute {
  60        struct attribute attr;
  61        ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
  62};
  63
  64static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
  65static struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
  66static struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);
  67
  68/*
  69 * These are default attributes that are added for every memmap entry.
  70 */
  71static struct attribute *def_attrs[] = {
  72        &memmap_start_attr.attr,
  73        &memmap_end_attr.attr,
  74        &memmap_type_attr.attr,
  75        NULL
  76};
  77
  78static const struct sysfs_ops memmap_attr_ops = {
  79        .show = memmap_attr_show,
  80};
  81
  82static struct kobj_type memmap_ktype = {
  83        .sysfs_ops      = &memmap_attr_ops,
  84        .default_attrs  = def_attrs,
  85};
  86
  87/*
  88 * Registration functions ------------------------------------------------------
  89 */
  90
  91/*
  92 * Firmware memory map entries. No locking is needed because the
  93 * firmware_map_add() and firmware_map_add_early() functions are called
  94 * in firmware initialisation code in one single thread of execution.
  95 */
  96static LIST_HEAD(map_entries);
  97
  98/**
  99 * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
 100 * @start: Start of the memory range.
 101 * @end:   End of the memory range (exclusive).
 102 * @type:  Type of the memory range.
 103 * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
 104 *         entry.
 105 *
 106 * Common implementation of firmware_map_add() and firmware_map_add_early()
 107 * which expects a pre-allocated struct firmware_map_entry.
 108 **/
 109static int firmware_map_add_entry(u64 start, u64 end,
 110                                  const char *type,
 111                                  struct firmware_map_entry *entry)
 112{
 113        BUG_ON(start > end);
 114
 115        entry->start = start;
 116        entry->end = end - 1;
 117        entry->type = type;
 118        INIT_LIST_HEAD(&entry->list);
 119        kobject_init(&entry->kobj, &memmap_ktype);
 120
 121        list_add_tail(&entry->list, &map_entries);
 122
 123        return 0;
 124}
 125
 126/*
 127 * Add memmap entry on sysfs
 128 */
 129static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 130{
 131        static int map_entries_nr;
 132        static struct kset *mmap_kset;
 133
 134        if (!mmap_kset) {
 135                mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
 136                if (!mmap_kset)
 137                        return -ENOMEM;
 138        }
 139
 140        entry->kobj.kset = mmap_kset;
 141        if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))
 142                kobject_put(&entry->kobj);
 143
 144        return 0;
 145}
 146
 147/**
 148 * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
 149 * memory hotplug.
 150 * @start: Start of the memory range.
 151 * @end:   End of the memory range (exclusive)
 152 * @type:  Type of the memory range.
 153 *
 154 * Adds a firmware mapping entry. This function is for memory hotplug, it is
 155 * similar to function firmware_map_add_early(). The only difference is that
 156 * it will create the syfs entry dynamically.
 157 *
 158 * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 159 **/
 160int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 161{
 162        struct firmware_map_entry *entry;
 163
 164        entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 165        if (!entry)
 166                return -ENOMEM;
 167
 168        firmware_map_add_entry(start, end, type, entry);
 169        /* create the memmap entry */
 170        add_sysfs_fw_map_entry(entry);
 171
 172        return 0;
 173}
 174
 175/**
 176 * firmware_map_add_early() - Adds a firmware mapping entry.
 177 * @start: Start of the memory range.
 178 * @end:   End of the memory range.
 179 * @type:  Type of the memory range.
 180 *
 181 * Adds a firmware mapping entry. This function uses the bootmem allocator
 182 * for memory allocation.
 183 *
 184 * That function must be called before late_initcall.
 185 *
 186 * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 187 **/
 188int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 189{
 190        struct firmware_map_entry *entry;
 191
 192        entry = alloc_bootmem(sizeof(struct firmware_map_entry));
 193        if (WARN_ON(!entry))
 194                return -ENOMEM;
 195
 196        return firmware_map_add_entry(start, end, type, entry);
 197}
 198
 199/*
 200 * Sysfs functions -------------------------------------------------------------
 201 */
 202
 203static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 204{
 205        return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 206                (unsigned long long)entry->start);
 207}
 208
 209static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 210{
 211        return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 212                (unsigned long long)entry->end);
 213}
 214
 215static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 216{
 217        return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 218}
 219
 220#define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
 221#define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)
 222
 223static ssize_t memmap_attr_show(struct kobject *kobj,
 224                                struct attribute *attr, char *buf)
 225{
 226        struct firmware_map_entry *entry = to_memmap_entry(kobj);
 227        struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 228
 229        return memmap_attr->show(entry, buf);
 230}
 231
 232/*
 233 * Initialises stuff and adds the entries in the map_entries list to
 234 * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 235 * must be called before late_initcall. That's just because that function
 236 * is called as late_initcall() function, which means that if you call
 237 * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 238 * are not added to sysfs.
 239 */
 240static int __init memmap_init(void)
 241{
 242        struct firmware_map_entry *entry;
 243
 244        list_for_each_entry(entry, &map_entries, list)
 245                add_sysfs_fw_map_entry(entry);
 246
 247        return 0;
 248}
 249late_initcall(memmap_init);
 250
 251
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