/*
   * linux/drivers/firmware/memmap.c
   *  Copyright (C) 2008 SUSE LINUX Products GmbH
   *  by Bernhard Walle <bernhard.walle@gmx.de>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License v2.0 as published by
   * the Free Software Foundation
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   */
  
  #include <linux/string.h>
  #include <linux/firmware-map.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/bootmem.h>
  #include <linux/slab.h>
  #include <linux/mm.h>
  
  /*
   * Data types ------------------------------------------------------------------
   */
  
  /*
   * Firmware map entry. Because firmware memory maps are flat and not
   * hierarchical, it's ok to organise them in a linked list. No parent
   * information is necessary as for the resource tree.
   */
  struct firmware_map_entry {
  	/*
  	 * start and end must be u64 rather than resource_size_t, because e820
  	 * resources can lie at addresses above 4G.
  	 */
  	u64			start;	/* start of the memory range */
  	u64			end;	/* end of the memory range (incl.) */
  	const char		*type;	/* type of the memory range */
  	struct list_head	list;	/* entry for the linked list */
  	struct kobject		kobj;   /* kobject for each entry */
  };
  
  /*
   * Forward declarations --------------------------------------------------------
   */
  static ssize_t memmap_attr_show(struct kobject *kobj,
  				struct attribute *attr, char *buf);
  static ssize_t start_show(struct firmware_map_entry *entry, char *buf);
  static ssize_t end_show(struct firmware_map_entry *entry, char *buf);
  static ssize_t type_show(struct firmware_map_entry *entry, char *buf);
  
  static struct firmware_map_entry * __meminit
  firmware_map_find_entry(u64 start, u64 end, const char *type);
  
  /*
   * Static data -----------------------------------------------------------------
   */
  
  struct memmap_attribute {
  	struct attribute attr;
  	ssize_t (*show)(struct firmware_map_entry *entry, char *buf);
  };
  
  static struct memmap_attribute memmap_start_attr = __ATTR_RO(start);
  static struct memmap_attribute memmap_end_attr   = __ATTR_RO(end);
  static struct memmap_attribute memmap_type_attr  = __ATTR_RO(type);
  
  /*
   * These are default attributes that are added for every memmap entry.
   */
  static struct attribute *def_attrs[] = {
  	&memmap_start_attr.attr,
  	&memmap_end_attr.attr,
  	&memmap_type_attr.attr,
  	NULL
  };
  
  static const struct sysfs_ops memmap_attr_ops = {
  	.show = memmap_attr_show,
  };
  
  /* Firmware memory map entries. */
  static LIST_HEAD(map_entries);
  static DEFINE_SPINLOCK(map_entries_lock);
  
  /*
   * For memory hotplug, there is no way to free memory map entries allocated
   * by boot mem after the system is up. So when we hot-remove memory whose
   * map entry is allocated by bootmem, we need to remember the storage and
   * reuse it when the memory is hot-added again.
   */
  static LIST_HEAD(map_entries_bootmem);
  static DEFINE_SPINLOCK(map_entries_bootmem_lock);
  
  
  static inline struct firmware_map_entry *
  to_memmap_entry(struct kobject *kobj)
  {
  	return container_of(kobj, struct firmware_map_entry, kobj);
  }
  
  static void __meminit release_firmware_map_entry(struct kobject *kobj)
  {
  	struct firmware_map_entry *entry = to_memmap_entry(kobj);
  
  	if (PageReserved(virt_to_page(entry))) {
  		/*
  		 * Remember the storage allocated by bootmem, and reuse it when
  		 * the memory is hot-added again. The entry will be added to
  		 * map_entries_bootmem here, and deleted from &map_entries in
  		 * firmware_map_remove_entry().
  		 */
  		spin_lock(&map_entries_bootmem_lock);
  		list_add(&entry->list, &map_entries_bootmem);
  		spin_unlock(&map_entries_bootmem_lock);
  
  		return;
  	}
  
  	kfree(entry);
  }
  
  static struct kobj_type __refdata memmap_ktype = {
  	.release	= release_firmware_map_entry,
  	.sysfs_ops	= &memmap_attr_ops,
  	.default_attrs	= def_attrs,
  };
  
  /*
   * Registration functions ------------------------------------------------------
   */
  
  /**
   * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
   * @start: Start of the memory range.
   * @end:   End of the memory range (exclusive).
   * @type:  Type of the memory range.
   * @entry: Pre-allocated (either kmalloc() or bootmem allocator), uninitialised
   *         entry.
   *
   * Common implementation of firmware_map_add() and firmware_map_add_early()
   * which expects a pre-allocated struct firmware_map_entry.
   **/
  static int firmware_map_add_entry(u64 start, u64 end,
  				  const char *type,
  				  struct firmware_map_entry *entry)
  {
  	BUG_ON(start > end);
  
  	entry->start = start;
  	entry->end = end - 1;
  	entry->type = type;
  	INIT_LIST_HEAD(&entry->list);
  	kobject_init(&entry->kobj, &memmap_ktype);
  
  	spin_lock(&map_entries_lock);
  	list_add_tail(&entry->list, &map_entries);
  	spin_unlock(&map_entries_lock);
  
  	return 0;
  }
  
  /**
   * firmware_map_remove_entry() - Does the real work to remove a firmware
   * memmap entry.
   * @entry: removed entry.
   *
   * The caller must hold map_entries_lock, and release it properly.
   **/
  static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)
  {
  	list_del(&entry->list);
  }
  
  /*
   * Add memmap entry on sysfs
   */
  static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
  {
  	static int map_entries_nr;
  	static struct kset *mmap_kset;
  
  	if (!mmap_kset) {
  		mmap_kset = kset_create_and_add("memmap", NULL, firmware_kobj);
  		if (!mmap_kset)
  			return -ENOMEM;
  	}
  
  	entry->kobj.kset = mmap_kset;
  	if (kobject_add(&entry->kobj, NULL, "%d", map_entries_nr++))
  		kobject_put(&entry->kobj);
  
  	return 0;
  }
  
  /*
   * Remove memmap entry on sysfs
   */
  static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)
  {
  	kobject_put(&entry->kobj);
  }
  
  /*
   * firmware_map_find_entry_in_list() - Search memmap entry in a given list.
   * @start: Start of the memory range.
   * @end:   End of the memory range (exclusive).
   * @type:  Type of the memory range.
   * @list:  In which to find the entry.
   *
   * This function is to find the memmap entey of a given memory range in a
   * given list. The caller must hold map_entries_lock, and must not release
   * the lock until the processing of the returned entry has completed.
   *
   * Return: Pointer to the entry to be found on success, or NULL on failure.
   */
  static struct firmware_map_entry * __meminit
  firmware_map_find_entry_in_list(u64 start, u64 end, const char *type,
  				struct list_head *list)
  {
  	struct firmware_map_entry *entry;
  
  	list_for_each_entry(entry, list, list)
  		if ((entry->start == start) && (entry->end == end) &&
  		    (!strcmp(entry->type, type))) {
  			return entry;
  		}
  
  	return NULL;
  }
  
  /*
   * firmware_map_find_entry() - Search memmap entry in map_entries.
   * @start: Start of the memory range.
   * @end:   End of the memory range (exclusive).
   * @type:  Type of the memory range.
   *
   * This function is to find the memmap entey of a given memory range.
   * The caller must hold map_entries_lock, and must not release the lock
   * until the processing of the returned entry has completed.
   *
   * Return: Pointer to the entry to be found on success, or NULL on failure.
   */
  static struct firmware_map_entry * __meminit
  firmware_map_find_entry(u64 start, u64 end, const char *type)
  {
  	return firmware_map_find_entry_in_list(start, end, type, &map_entries);
  }
  
  /*
   * firmware_map_find_entry_bootmem() - Search memmap entry in map_entries_bootmem.
   * @start: Start of the memory range.
   * @end:   End of the memory range (exclusive).
   * @type:  Type of the memory range.
   *
   * This function is similar to firmware_map_find_entry except that it find the
   * given entry in map_entries_bootmem.
   *
   * Return: Pointer to the entry to be found on success, or NULL on failure.
   */
  static struct firmware_map_entry * __meminit
  firmware_map_find_entry_bootmem(u64 start, u64 end, const char *type)
  {
  	return firmware_map_find_entry_in_list(start, end, type,
  					       &map_entries_bootmem);
  }
  
  /**
   * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
   * memory hotplug.
   * @start: Start of the memory range.
   * @end:   End of the memory range (exclusive)
   * @type:  Type of the memory range.
   *
   * Adds a firmware mapping entry. This function is for memory hotplug, it is
   * similar to function firmware_map_add_early(). The only difference is that
   * it will create the syfs entry dynamically.
   *
   * Returns 0 on success, or -ENOMEM if no memory could be allocated.
   **/
  int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
  {
  	struct firmware_map_entry *entry;
  
  	entry = firmware_map_find_entry_bootmem(start, end, type);
  	if (!entry) {
  		entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
  		if (!entry)
  			return -ENOMEM;
  	} else {
  		/* Reuse storage allocated by bootmem. */
  		spin_lock(&map_entries_bootmem_lock);
  		list_del(&entry->list);
  		spin_unlock(&map_entries_bootmem_lock);
  
  		memset(entry, 0, sizeof(*entry));
  	}
  
  	firmware_map_add_entry(start, end, type, entry);
  	/* create the memmap entry */
  	add_sysfs_fw_map_entry(entry);
  
  	return 0;
  }
  
  /**
   * firmware_map_add_early() - Adds a firmware mapping entry.
   * @start: Start of the memory range.
   * @end:   End of the memory range.
   * @type:  Type of the memory range.
   *
   * Adds a firmware mapping entry. This function uses the bootmem allocator
   * for memory allocation.
   *
   * That function must be called before late_initcall.
   *
   * Returns 0 on success, or -ENOMEM if no memory could be allocated.
   **/
  int __init firmware_map_add_early(u64 start, u64 end, const char *type)
  {
  	struct firmware_map_entry *entry;
  
  	entry = memblock_virt_alloc(sizeof(struct firmware_map_entry), 0);
  	if (WARN_ON(!entry))
  		return -ENOMEM;
  
  	return firmware_map_add_entry(start, end, type, entry);
  }
  
  /**
   * firmware_map_remove() - remove a firmware mapping entry
   * @start: Start of the memory range.
   * @end:   End of the memory range.
   * @type:  Type of the memory range.
   *
   * removes a firmware mapping entry.
   *
   * Returns 0 on success, or -EINVAL if no entry.
   **/
  int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
  {
  	struct firmware_map_entry *entry;
  
  	spin_lock(&map_entries_lock);
  	entry = firmware_map_find_entry(start, end - 1, type);
  	if (!entry) {
  		spin_unlock(&map_entries_lock);
  		return -EINVAL;
  	}
  
  	firmware_map_remove_entry(entry);
  	spin_unlock(&map_entries_lock);
  
  	/* remove the memmap entry */
  	remove_sysfs_fw_map_entry(entry);
  
  	return 0;
  }
  
  /*
   * Sysfs functions -------------------------------------------------------------
   */
  
  static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "0x%llx
  ",
  		(unsigned long long)entry->start);
  }
  
  static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "0x%llx
  ",
  		(unsigned long long)entry->end);
  }
  
  static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%s
  ", entry->type);
  }
  
  static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
  {
  	return container_of(attr, struct memmap_attribute, attr);
  }
  
  static ssize_t memmap_attr_show(struct kobject *kobj,
  				struct attribute *attr, char *buf)
  {
  	struct firmware_map_entry *entry = to_memmap_entry(kobj);
  	struct memmap_attribute *memmap_attr = to_memmap_attr(attr);
  
  	return memmap_attr->show(entry, buf);
  }
  
  /*
   * Initialises stuff and adds the entries in the map_entries list to
   * sysfs. Important is that firmware_map_add() and firmware_map_add_early()
   * must be called before late_initcall. That's just because that function
   * is called as late_initcall() function, which means that if you call
   * firmware_map_add() or firmware_map_add_early() afterwards, the entries
   * are not added to sysfs.
   */
  static int __init firmware_memmap_init(void)
  {
  	struct firmware_map_entry *entry;
  
  	list_for_each_entry(entry, &map_entries, list)
  		add_sysfs_fw_map_entry(entry);
  
  	return 0;
  }
  late_initcall(firmware_memmap_init);