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
  24 /*
  25  * Data types ------------------------------------------------------------------
  26  */
  27
  28 /*
  29  * Firmware map entry. Because firmware memory maps are flat and not
  30  * hierarchical, it's ok to organise them in a linked list. No parent
  31  * information is necessary as for the resource tree.
  32  */
  33 struct firmware_map_entry {
  34         /*
  35          * start and end must be u64 rather than resource_size_t, because e820
  36          * resources can lie at addresses above 4G.
  37          */
  38         u64                     start;  /* start of the memory range */
  39         u64                     end;    /* end of the memory range (incl.) */
  40         const char              *type;  /* type of the memory range */
  41         struct list_head        list;   /* entry for the linked list */
  42         struct kobject          kobj;   /* kobject for each entry */
  43 };
  44
  45 /*
  46  * Forward declarations --------------------------------------------------------
  47  */
  48 static ssize_t memmap_attr_show(struct kobject *kobj,
  49                                 struct attribute *attr, char *buf);
  50 static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
  51 static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
  52 static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
  53
  54 /*
  55  * Static data -----------------------------------------------------------------
  56  */
  57
  58 struct memmap_attribute {
  59         struct attribute attr;
  60         ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
  61 };
  62
  63 static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
  64 static struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
  65 static struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);
  66
  67 /*
  68  * These are default attributes that are added for every memmap entry.
  69  */
  70 static struct attribute *def_attrs[] = {
  71         &memmap_start_attr.attr,
  72         &memmap_end_attr.attr,
  73         &memmap_type_attr.attr,
  74         NULL
  75 };
  76
  77 static const struct sysfs_ops memmap_attr_ops = {
  78         .show = memmap_attr_show,
  79 };
  80
  81 static struct kobj_type memmap_ktype = {
  82         .sysfs_ops      = &memmap_attr_ops,
  83         .default_attrs  = def_attrs,
  84 };
  85
  86 /*
  87  * Registration functions ------------------------------------------------------
  88  */
  89
  90 /*
  91  * Firmware memory map entries. No locking is needed because the
  92  * firmware_map_add() and firmware_map_add_early() functions are called
  93  * in firmware initialisation code in one single thread of execution.
  94  */
  95 static LIST_HEAD(map_entries);
  96
  97 /**
  98  * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
  99  * @start: Start of the memory range.
 100  * @end:   End of the memory range (inclusive).
 101  * @type:  Type of the memory range.
 102  * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
 103  *         entry.
 104  *
 105  * Common implementation of firmware_map_add() and firmware_map_add_early()
 106  * which expects a pre-allocated struct firmware_map_entry.
 107  **/
 108 static int firmware_map_add_entry(u64 start, u64 end,
 109                                   const char *type,
 110                                   struct firmware_map_entry *entry)
 111 {
 112         BUG_ON(start > end);
 113
 114         entry->start = start;
 115         entry->end = end;
 116         entry->type = type;
 117         INIT_LIST_HEAD(&entry->list);
 118         kobject_init(&entry->kobj, &memmap_ktype);
 119
 120         list_add_tail(&entry->list, &map_entries);
 121
 122         return 0;
 123 }
 124
 125 /*
 126  * Add memmap entry on sysfs
 127  */
 128 static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
 129 {
 130         static int map_entries_nr;
 131         static struct kset *mmap_kset;
 132
 133         if (!mmap_kset) {
 134                 mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
 135                 if (!mmap_kset)
 136                         return -ENOMEM;
 137         }
 138
 139         entry->kobj.kset = mmap_kset;
 140         if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))
 141                 kobject_put(&entry->kobj);
 142
 143         return 0;
 144 }
 145
 146 /**
 147  * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
 148  * memory hotplug.
 149  * @start: Start of the memory range.
 150  * @end:   End of the memory range (inclusive).
 151  * @type:  Type of the memory range.
 152  *
 153  * Adds a firmware mapping entry. This function is for memory hotplug, it is
 154  * similar to function firmware_map_add_early(). The only difference is that
 155  * it will create the syfs entry dynamically.
 156  *
 157  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 158  **/
 159 int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
 160 {
 161         struct firmware_map_entry *entry;
 162
 163         entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 164         if (!entry)
 165                 return -ENOMEM;
 166
 167         firmware_map_add_entry(start, end, type, entry);
 168         /* create the memmap entry */
 169         add_sysfs_fw_map_entry(entry);
 170
 171         return 0;
 172 }
 173
 174 /**
 175  * firmware_map_add_early() - Adds a firmware mapping entry.
 176  * @start: Start of the memory range.
 177  * @end:   End of the memory range (inclusive).
 178  * @type:  Type of the memory range.
 179  *
 180  * Adds a firmware mapping entry. This function uses the bootmem allocator
 181  * for memory allocation.
 182  *
 183  * That function must be called before late_initcall.
 184  *
 185  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 186  **/
 187 int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 188 {
 189         struct firmware_map_entry *entry;
 190
 191         entry = alloc_bootmem(sizeof(struct firmware_map_entry));
 192         if (WARN_ON(!entry))
 193                 return -ENOMEM;
 194
 195         return firmware_map_add_entry(start, end, type, entry);
 196 }
 197
 198 /*
 199  * Sysfs functions -------------------------------------------------------------
 200  */
 201
 202 static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 203 {
 204         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 205                 (unsigned long long)entry->start);
 206 }
 207
 208 static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 209 {
 210         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 211                 (unsigned long long)entry->end);
 212 }
 213
 214 static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 215 {
 216         return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 217 }
 218
 219 #define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
 220 #define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)
 221
 222 static ssize_t memmap_attr_show(struct kobject *kobj,
 223                                 struct attribute *attr, char *buf)
 224 {
 225         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 226         struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 227
 228         return memmap_attr->show(entry, buf);
 229 }
 230
 231 /*
 232  * Initialises stuff and adds the entries in the map_entries list to
 233  * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 234  * must be called before late_initcall. That's just because that function
 235  * is called as late_initcall() function, which means that if you call
 236  * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 237  * are not added to sysfs.
 238  */
 239 static int __init memmap_init(void)
 240 {
 241         struct firmware_map_entry *entry;
 242
 243         list_for_each_entry(entry, &map_entries, list)
 244                 add_sysfs_fw_map_entry(entry);
 245
 246         return 0;
 247 }
 248 late_initcall(memmap_init);
 249