drivers/firmware/memmap.c

   1 /*
   2  * linux/drivers/firmware/memmap.c
   3  *  Copyright (C) 2008 SUSE LINUX Products GmbH
   4  *  by Bernhard Walle <bwalle@suse.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         resource_size_t         start;  /* start of the memory range */
  35         resource_size_t         end;    /* end of the memory range (incl.) */
  36         const char              *type;  /* type of the memory range */
  37         struct list_head        list;   /* entry for the linked list */
  38         struct kobject          kobj;   /* kobject for each entry */
  39 };
  40
  41 /*
  42  * Forward declarations --------------------------------------------------------
  43  */
  44 static ssize_t memmap_attr_show(struct kobject *kobj,
  45                                 struct attribute *attr, char *buf);
  46 static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
  47 static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
  48 static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
  49
  50 /*
  51  * Static data -----------------------------------------------------------------
  52  */
  53
  54 struct memmap_attribute {
  55         struct attribute attr;
  56         ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
  57 };
  58
  59 struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
  60 struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
  61 struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);
  62
  63 /*
  64  * These are default attributes that are added for every memmap entry.
  65  */
  66 static struct attribute *def_attrs[] = {
  67         &memmap_start_attr.attr,
  68         &memmap_end_attr.attr,
  69         &memmap_type_attr.attr,
  70         NULL
  71 };
  72
  73 static struct sysfs_ops memmap_attr_ops = {
  74         .show = memmap_attr_show,
  75 };
  76
  77 static struct kobj_type memmap_ktype = {
  78         .sysfs_ops      = &memmap_attr_ops,
  79         .default_attrs  = def_attrs,
  80 };
  81
  82 /*
  83  * Registration functions ------------------------------------------------------
  84  */
  85
  86 /*
  87  * Firmware memory map entries. No locking is needed because the
  88  * firmware_map_add() and firmware_map_add_early() functions are called
  89  * in firmware initialisation code in one single thread of execution.
  90  */
  91 static LIST_HEAD(map_entries);
  92
  93 /**
  94  * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
  95  * @start: Start of the memory range.
  96  * @end:   End of the memory range (inclusive).
  97  * @type:  Type of the memory range.
  98  * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
  99  *         entry.
 100  *
 101  * Common implementation of firmware_map_add() and firmware_map_add_early()
 102  * which expects a pre-allocated struct firmware_map_entry.
 103  **/
 104 static int firmware_map_add_entry(resource_size_t start, resource_size_t end,
 105                                   const char *type,
 106                                   struct firmware_map_entry *entry)
 107 {
 108         BUG_ON(start > end);
 109
 110         entry->start = start;
 111         entry->end = end;
 112         entry->type = type;
 113         INIT_LIST_HEAD(&entry->list);
 114         kobject_init(&entry->kobj, &memmap_ktype);
 115
 116         list_add_tail(&entry->list, &map_entries);
 117
 118         return 0;
 119 }
 120
 121 /**
 122  * firmware_map_add() - Adds a firmware mapping entry.
 123  * @start: Start of the memory range.
 124  * @end:   End of the memory range (inclusive).
 125  * @type:  Type of the memory range.
 126  *
 127  * This function uses kmalloc() for memory
 128  * allocation. Use firmware_map_add_early() if you want to use the bootmem
 129  * allocator.
 130  *
 131  * That function must be called before late_initcall.
 132  *
 133  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 134  **/
 135 int firmware_map_add(resource_size_t start, resource_size_t end,
 136                      const char *type)
 137 {
 138         struct firmware_map_entry *entry;
 139
 140         entry = kmalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
 141         if (!entry)
 142                 return -ENOMEM;
 143
 144         return firmware_map_add_entry(start, end, type, entry);
 145 }
 146
 147 /**
 148  * firmware_map_add_early() - Adds a firmware mapping entry.
 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 uses the bootmem allocator
 154  * for memory allocation. Use firmware_map_add() if you want to use kmalloc().
 155  *
 156  * That function must be called before late_initcall.
 157  *
 158  * Returns 0 on success, or -ENOMEM if no memory could be allocated.
 159  **/
 160 int __init firmware_map_add_early(resource_size_t start, resource_size_t end,
 161                                   const char *type)
 162 {
 163         struct firmware_map_entry *entry;
 164
 165         entry = alloc_bootmem_low(sizeof(struct firmware_map_entry));
 166         if (WARN_ON(!entry))
 167                 return -ENOMEM;
 168
 169         return firmware_map_add_entry(start, end, type, entry);
 170 }
 171
 172 /*
 173  * Sysfs functions -------------------------------------------------------------
 174  */
 175
 176 static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
 177 {
 178         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 179                 (unsigned long long)entry->start);
 180 }
 181
 182 static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
 183 {
 184         return snprintf(buf, PAGE_SIZE, "0x%llx\n",
 185                 (unsigned long long)entry->end);
 186 }
 187
 188 static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
 189 {
 190         return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 191 }
 192
 193 #define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
 194 #define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)
 195
 196 static ssize_t memmap_attr_show(struct kobject *kobj,
 197                                 struct attribute *attr, char *buf)
 198 {
 199         struct firmware_map_entry *entry = to_memmap_entry(kobj);
 200         struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
 201
 202         return memmap_attr->show(entry, buf);
 203 }
 204
 205 /*
 206  * Initialises stuff and adds the entries in the map_entries list to
 207  * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
 208  * must be called before late_initcall. That's just because that function
 209  * is called as late_initcall() function, which means that if you call
 210  * firmware_map_add() or firmware_map_add_early() afterwards, the entries
 211  * are not added to sysfs.
 212  */
 213 static int __init memmap_init(void)
 214 {
 215         int i = 0;
 216         struct firmware_map_entry *entry;
 217         struct kset *memmap_kset;
 218
 219         memmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
 220         if (WARN_ON(!memmap_kset))
 221                 return -ENOMEM;
 222
 223         list_for_each_entry(entry, &map_entries, list) {
 224                 entry->kobj.kset = memmap_kset;
 225                 if (kobject_add(&entry->kobj, NULL, "%d", i++))
 226                         kobject_put(&entry->kobj);
 227         }
 228
 229         return 0;
 230 }
 231 late_initcall(memmap_init);
 232