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 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  * firmware_map_add() - Adds a firmware mapping entry.
 127  * @start: Start of the memory range.
 128  * @end:   End of the memory range (inclusive).
 129  * @type:  Type of the memory range.
 130  *
 131  * This function uses kmalloc() for memory
 132  * allocation. Use firmware_map_add_early() if you want to use the bootmem
 133  * allocator.
 134  *
 135  * That function must be called before late_initcall.
 136  *
 137  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 138  **/
 139 int firmware_map_add(u64 start, u64 end, const char *type)
 140 {
 141         struct firmware_map_entry *entry;
 142
 143         entry = kmalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 144         if (!entry)
 145                 return -ENOMEM;
 146
 147         return firmware_map_add_entry(start, end, type, entry);
 148 }
 149
 150 /**
 151  * firmware_map_add_early() - Adds a firmware mapping entry.
 152  * @start: Start of the memory range.
 153  * @end:   End of the memory range (inclusive).
 154  * @type:  Type of the memory range.
 155  *
 156  * Adds a firmware mapping entry. This function uses the bootmem allocator
 157  * for memory allocation. Use firmware_map_add() if you want to use kmalloc().
 158  *
 159  * That function must be called before late_initcall.
 160  *
 161  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 162  **/
 163 int __init firmware_map_add_early(u64 start, u64 end, const char *type)
 164 {
 165         struct firmware_map_entry *entry;
 166
 167         entry = alloc_bootmem_low(sizeof(struct firmware_map_entry));
 168         if (WARN_ON(!entry))
 169                 return -ENOMEM;
 170
 171         return firmware_map_add_entry(start, end, type, entry);
 172 }
 173
 174 /*
 175  * Sysfs functions -------------------------------------------------------------
 176  */
 177
 178 static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 179 {
 180         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 181                 (unsigned long long)entry->start);
 182 }
 183
 184 static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 185 {
 186         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 187                 (unsigned long long)entry->end);
 188 }
 189
 190 static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 191 {
 192         return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 193 }
 194
 195 #define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
 196 #define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)
 197
 198 static ssize_t memmap_attr_show(struct kobject *kobj,
 199                                 struct attribute *attr, char *buf)
 200 {
 201         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 202         struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 203
 204         return memmap_attr->show(entry, buf);
 205 }
 206
 207 /*
 208  * Initialises stuff and adds the entries in the map_entries list to
 209  * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 210  * must be called before late_initcall. That's just because that function
 211  * is called as late_initcall() function, which means that if you call
 212  * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 213  * are not added to sysfs.
 214  */
 215 static int __init memmap_init(void)
 216 {
 217         int i = 0;
 218         struct firmware_map_entry *entry;
 219         struct kset *memmap_kset;
 220
 221         memmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
 222         if (WARN_ON(!memmap_kset))
 223                 return -ENOMEM;
 224
 225         list_for_each_entry(entry, &map_entries, list) {
 226                 entry->kobj.kset = memmap_kset;
 227                 if (kobject_add(&entry->kobj, NULL, "%d", i++))
 228                         kobject_put(&entry->kobj);
 229         }
 230
 231         return 0;
 232 }
 233 late_initcall(memmap_init);
 234