build.c

来自「linux 内核源代码」· C语言 代码 · 共 864 行 · 第 1/2 页

/*
 * Copyright (c) International Business Machines Corp., 2006
 * Copyright (c) Nokia Corporation, 2007
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём),
 *         Frank Haverkamp
 */

/*
 * This file includes UBI initialization and building of UBI devices. At the
 * moment UBI devices may only be added while UBI is initialized, but dynamic
 * device add/remove functionality is planned. Also, at the moment we only
 * attach UBI devices by scanning, which will become a bottleneck when flashes
 * reach certain large size. Then one may improve UBI and add other methods.
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/stringify.h>
#include <linux/stat.h>
#include <linux/log2.h>
#include "ubi.h"

/* Maximum length of the 'mtd=' parameter */
#define MTD_PARAM_LEN_MAX 64

/**
 * struct mtd_dev_param - MTD device parameter description data structure.
 * @name: MTD device name or number string
 * @vid_hdr_offs: VID header offset
 * @data_offs: data offset
 */
struct mtd_dev_param
{
	char name[MTD_PARAM_LEN_MAX];
	int vid_hdr_offs;
	int data_offs;
};

/* Numbers of elements set in the @mtd_dev_param array */
static int mtd_devs = 0;

/* MTD devices specification parameters */
static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];

/* Number of UBI devices in system */
int ubi_devices_cnt;

/* All UBI devices in system */
struct ubi_device *ubi_devices[UBI_MAX_DEVICES];

/* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
struct class *ubi_class;

/* "Show" method for files in '/<sysfs>/class/ubi/' */
static ssize_t ubi_version_show(struct class *class, char *buf)
{
	return sprintf(buf, "%d\n", UBI_VERSION);
}

/* UBI version attribute ('/<sysfs>/class/ubi/version') */
static struct class_attribute ubi_version =
	__ATTR(version, S_IRUGO, ubi_version_show, NULL);

static ssize_t dev_attribute_show(struct device *dev,
				  struct device_attribute *attr, char *buf);

/* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
static struct device_attribute dev_eraseblock_size =
	__ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_avail_eraseblocks =
	__ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_total_eraseblocks =
	__ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_volumes_count =
	__ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_max_ec =
	__ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_reserved_for_bad =
	__ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_bad_peb_count =
	__ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_max_vol_count =
	__ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_min_io_size =
	__ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_bgt_enabled =
	__ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);

/* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
static ssize_t dev_attribute_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	const struct ubi_device *ubi;

	ubi = container_of(dev, struct ubi_device, dev);
	if (attr == &dev_eraseblock_size)
		return sprintf(buf, "%d\n", ubi->leb_size);
	else if (attr == &dev_avail_eraseblocks)
		return sprintf(buf, "%d\n", ubi->avail_pebs);
	else if (attr == &dev_total_eraseblocks)
		return sprintf(buf, "%d\n", ubi->good_peb_count);
	else if (attr == &dev_volumes_count)
		return sprintf(buf, "%d\n", ubi->vol_count);
	else if (attr == &dev_max_ec)
		return sprintf(buf, "%d\n", ubi->max_ec);
	else if (attr == &dev_reserved_for_bad)
		return sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
	else if (attr == &dev_bad_peb_count)
		return sprintf(buf, "%d\n", ubi->bad_peb_count);
	else if (attr == &dev_max_vol_count)
		return sprintf(buf, "%d\n", ubi->vtbl_slots);
	else if (attr == &dev_min_io_size)
		return sprintf(buf, "%d\n", ubi->min_io_size);
	else if (attr == &dev_bgt_enabled)
		return sprintf(buf, "%d\n", ubi->thread_enabled);
	else
		BUG();

	return 0;
}

/* Fake "release" method for UBI devices */
static void dev_release(struct device *dev) { }

/**
 * ubi_sysfs_init - initialize sysfs for an UBI device.
 * @ubi: UBI device description object
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int ubi_sysfs_init(struct ubi_device *ubi)
{
	int err;

	ubi->dev.release = dev_release;
	ubi->dev.devt = MKDEV(ubi->major, 0);
	ubi->dev.class = ubi_class;
	sprintf(&ubi->dev.bus_id[0], UBI_NAME_STR"%d", ubi->ubi_num);
	err = device_register(&ubi->dev);
	if (err)
		goto out;

	err = device_create_file(&ubi->dev, &dev_eraseblock_size);
	if (err)
		goto out_unregister;
	err = device_create_file(&ubi->dev, &dev_avail_eraseblocks);
	if (err)
		goto out_eraseblock_size;
	err = device_create_file(&ubi->dev, &dev_total_eraseblocks);
	if (err)
		goto out_avail_eraseblocks;
	err = device_create_file(&ubi->dev, &dev_volumes_count);
	if (err)
		goto out_total_eraseblocks;
	err = device_create_file(&ubi->dev, &dev_max_ec);
	if (err)
		goto out_volumes_count;
	err = device_create_file(&ubi->dev, &dev_reserved_for_bad);
	if (err)
		goto out_volumes_max_ec;
	err = device_create_file(&ubi->dev, &dev_bad_peb_count);
	if (err)
		goto out_reserved_for_bad;
	err = device_create_file(&ubi->dev, &dev_max_vol_count);
	if (err)
		goto out_bad_peb_count;
	err = device_create_file(&ubi->dev, &dev_min_io_size);
	if (err)
		goto out_max_vol_count;
	err = device_create_file(&ubi->dev, &dev_bgt_enabled);
	if (err)
		goto out_min_io_size;

	return 0;

out_min_io_size:
	device_remove_file(&ubi->dev, &dev_min_io_size);
out_max_vol_count:
	device_remove_file(&ubi->dev, &dev_max_vol_count);
out_bad_peb_count:
	device_remove_file(&ubi->dev, &dev_bad_peb_count);
out_reserved_for_bad:
	device_remove_file(&ubi->dev, &dev_reserved_for_bad);
out_volumes_max_ec:
	device_remove_file(&ubi->dev, &dev_max_ec);
out_volumes_count:
	device_remove_file(&ubi->dev, &dev_volumes_count);
out_total_eraseblocks:
	device_remove_file(&ubi->dev, &dev_total_eraseblocks);
out_avail_eraseblocks:
	device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
out_eraseblock_size:
	device_remove_file(&ubi->dev, &dev_eraseblock_size);
out_unregister:
	device_unregister(&ubi->dev);
out:
	ubi_err("failed to initialize sysfs for %s", ubi->ubi_name);
	return err;
}

/**
 * ubi_sysfs_close - close sysfs for an UBI device.
 * @ubi: UBI device description object
 */
static void ubi_sysfs_close(struct ubi_device *ubi)
{
	device_remove_file(&ubi->dev, &dev_bgt_enabled);
	device_remove_file(&ubi->dev, &dev_min_io_size);
	device_remove_file(&ubi->dev, &dev_max_vol_count);
	device_remove_file(&ubi->dev, &dev_bad_peb_count);
	device_remove_file(&ubi->dev, &dev_reserved_for_bad);
	device_remove_file(&ubi->dev, &dev_max_ec);
	device_remove_file(&ubi->dev, &dev_volumes_count);
	device_remove_file(&ubi->dev, &dev_total_eraseblocks);
	device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
	device_remove_file(&ubi->dev, &dev_eraseblock_size);
	device_unregister(&ubi->dev);
}

/**
 * kill_volumes - destroy all volumes.
 * @ubi: UBI device description object
 */
static void kill_volumes(struct ubi_device *ubi)
{
	int i;

	for (i = 0; i < ubi->vtbl_slots; i++)
		if (ubi->volumes[i])
			ubi_free_volume(ubi, i);
}

/**
 * uif_init - initialize user interfaces for an UBI device.
 * @ubi: UBI device description object
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int uif_init(struct ubi_device *ubi)
{
	int i, err;
	dev_t dev;

	mutex_init(&ubi->vtbl_mutex);
	spin_lock_init(&ubi->volumes_lock);

	sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);

	/*
	 * Major numbers for the UBI character devices are allocated
	 * dynamically. Major numbers of volume character devices are
	 * equivalent to ones of the corresponding UBI character device. Minor
	 * numbers of UBI character devices are 0, while minor numbers of
	 * volume character devices start from 1. Thus, we allocate one major
	 * number and ubi->vtbl_slots + 1 minor numbers.
	 */
	err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
	if (err) {
		ubi_err("cannot register UBI character devices");
		return err;
	}

	cdev_init(&ubi->cdev, &ubi_cdev_operations);
	ubi->major = MAJOR(dev);
	dbg_msg("%s major is %u", ubi->ubi_name, ubi->major);
	ubi->cdev.owner = THIS_MODULE;

	dev = MKDEV(ubi->major, 0);
	err = cdev_add(&ubi->cdev, dev, 1);
	if (err) {
		ubi_err("cannot add character device %s", ubi->ubi_name);
		goto out_unreg;
	}

	err = ubi_sysfs_init(ubi);
	if (err)
		goto out_cdev;

	for (i = 0; i < ubi->vtbl_slots; i++)
		if (ubi->volumes[i]) {
			err = ubi_add_volume(ubi, i);
			if (err)
				goto out_volumes;
		}

	return 0;

out_volumes:
	kill_volumes(ubi);
	ubi_sysfs_close(ubi);
out_cdev:
	cdev_del(&ubi->cdev);
out_unreg:
	unregister_chrdev_region(MKDEV(ubi->major, 0),
				 ubi->vtbl_slots + 1);
	return err;
}

/**
 * uif_close - close user interfaces for an UBI device.
 * @ubi: UBI device description object
 */
static void uif_close(struct ubi_device *ubi)
{
	kill_volumes(ubi);
	ubi_sysfs_close(ubi);
	cdev_del(&ubi->cdev);
	unregister_chrdev_region(MKDEV(ubi->major, 0), ubi->vtbl_slots + 1);
}

/**
 * attach_by_scanning - attach an MTD device using scanning method.
 * @ubi: UBI device descriptor
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 *
 * Note, currently this is the only method to attach UBI devices. Hopefully in
 * the future we'll have more scalable attaching methods and avoid full media
 * scanning. But even in this case scanning will be needed as a fall-back
 * attaching method if there are some on-flash table corruptions.
 */
static int attach_by_scanning(struct ubi_device *ubi)
{
	int err;
	struct ubi_scan_info *si;

	si = ubi_scan(ubi);
	if (IS_ERR(si))
		return PTR_ERR(si);

	ubi->bad_peb_count = si->bad_peb_count;
	ubi->good_peb_count = ubi->peb_count - ubi->bad_peb_count;
	ubi->max_ec = si->max_ec;
	ubi->mean_ec = si->mean_ec;

	err = ubi_read_volume_table(ubi, si);
	if (err)
		goto out_si;

	err = ubi_wl_init_scan(ubi, si);
	if (err)
		goto out_vtbl;

	err = ubi_eba_init_scan(ubi, si);
	if (err)
		goto out_wl;

	ubi_scan_destroy_si(si);
	return 0;

out_wl:
	ubi_wl_close(ubi);
out_vtbl:
	vfree(ubi->vtbl);
out_si:
	ubi_scan_destroy_si(si);
	return err;
}

/**
 * io_init - initialize I/O unit for a given UBI device.
 * @ubi: UBI device description object
 *
 * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
 * assumed:
 *   o EC header is always at offset zero - this cannot be changed;
 *   o VID header starts just after the EC header at the closest address
 *   aligned to @io->@hdrs_min_io_size;
 *   o data starts just after the VID header at the closest address aligned to
 *     @io->@min_io_size
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int io_init(struct ubi_device *ubi)
{
	if (ubi->mtd->numeraseregions != 0) {
		/*
		 * Some flashes have several erase regions. Different regions
		 * may have different eraseblock size and other
		 * characteristics. It looks like mostly multi-region flashes
		 * have one "main" region and one or more small regions to
		 * store boot loader code or boot parameters or whatever. I
		 * guess we should just pick the largest region. But this is
		 * not implemented.
		 */
		ubi_err("multiple regions, not implemented");
		return -EINVAL;
	}

	/*
	 * Note, in this implementation we support MTD devices with 0x7FFFFFFF
	 * physical eraseblocks maximum.
	 */

	ubi->peb_size   = ubi->mtd->erasesize;
	ubi->peb_count  = ubi->mtd->size / ubi->mtd->erasesize;
	ubi->flash_size = ubi->mtd->size;

	if (ubi->mtd->block_isbad && ubi->mtd->block_markbad)
		ubi->bad_allowed = 1;

	ubi->min_io_size = ubi->mtd->writesize;
	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;

	/* Make sure minimal I/O unit is power of 2 */
	if (!is_power_of_2(ubi->min_io_size)) {
		ubi_err("bad min. I/O unit");
		return -EINVAL;
	}

	ubi_assert(ubi->hdrs_min_io_size > 0);
	ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);