drivers/firmware/memmap.c

   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  */
  34 struct 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  */
  49 static ssize_t memmap_attr_show(struct kobject *kobj,
  50                                 struct attribute *attr, char *buf);
  51 static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
  52 static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
  53 static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
  54
  55 /*
  56  * Static data -----------------------------------------------------------------
  57  */
  58
  59 struct memmap_attribute {
  60         struct attribute attr;
  61         ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
  62 };
  63
  64 static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
  65 static struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
  66 static struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);
  67
  68 /*
  69  * These are default attributes that are added for every memmap entry.
  70  */
  71 static struct attribute *def_attrs[] = {
  72         &memmap_start_attr.attr,
  73         &memmap_end_attr.attr,
  74         &memmap_type_attr.attr,
  75         NULL
  76 };
  77
  78 static const struct sysfs_ops memmap_attr_ops = {
  79         .show = memmap_attr_show,
  80 };
  81
  82 static 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  */
  96 static 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  **/
 109 static 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  */
 129 static 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  **/
 160 int __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  **/
 188 int __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
 203 static 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
 209 static 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
 215 static 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
 223 static 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  */
 240 static 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 }
 249 late_initcall(memmap_init);
 250