memmap.c

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/*
 * linux/drivers/firmware/memmap.c
 *  Copyright (C) 2008 SUSE LINUX Products GmbH
 *  by Bernhard Walle <[email protected]>
 *
 * 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>

/*
 * 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 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,
};

static struct kobj_type memmap_ktype = {
    .sysfs_ops  = &memmap_attr_ops,
    .default_attrs  = def_attrs,
};

/*
 * Registration functions ------------------------------------------------------
 */

/*
 * Firmware memory map entries. No locking is needed because the
 * firmware_map_add() and firmware_map_add_early() functions are called
 * in firmware initialisation code in one single thread of execution.
 */
static LIST_HEAD(map_entries);

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);

    list_add_tail(&entry->list, &map_entries);

    return 0;
}

/*
 * 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;
}

int __meminit firmware_map_add_hotplug(u64 start, u64 end, const char *type)
{
    struct firmware_map_entry *entry;

    entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
    if (!entry)
        return -ENOMEM;

    firmware_map_add_entry(start, end, type, entry);
    /* create the memmap entry */
    add_sysfs_fw_map_entry(entry);

    return 0;
}

int __init firmware_map_add_early(u64 start, u64 end, const char *type)
{
    struct firmware_map_entry *entry;

    entry = alloc_bootmem(sizeof(struct firmware_map_entry));
    if (WARN_ON(!entry))
        return -ENOMEM;

    return firmware_map_add_entry(start, end, type, entry);
}

/*
 * Sysfs functions -------------------------------------------------------------
 */

static ssize_t start_show(struct firmware_map_entry *entry, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "0x%llx\n",
        (unsigned long long)entry->start);
}

static ssize_t end_show(struct firmware_map_entry *entry, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "0x%llx\n",
        (unsigned long long)entry->end);
}

static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
}

#define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
#define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)

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);