diff options
| -rw-r--r-- | drivers/mtd/ubi/Makefile | 51 | ||||
| -rw-r--r-- | drivers/mtd/ubi/build.c | 1186 | ||||
| -rw-r--r-- | drivers/mtd/ubi/crc32.c | 518 |
3 files changed, 1755 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/Makefile b/drivers/mtd/ubi/Makefile new file mode 100644 index 000000000..8bd82c353 --- /dev/null +++ b/drivers/mtd/ubi/Makefile @@ -0,0 +1,51 @@ +# +# (C) Copyright 2006 +# Wolfgang Denk, DENX Software Engineering, wd@denx.de. +# +# See file CREDITS for list of people who contributed to this +# project. +# +# 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 +# + +include $(TOPDIR)/config.mk + +LIB := $(obj)libubi.a + +ifdef CONFIG_CMD_UBI +COBJS-y += build.o vtbl.o vmt.o upd.o kapi.o eba.o io.o wl.o scan.o crc32.o + +COBJS-y += misc.o +COBJS-y += debug.o +endif + +COBJS := $(COBJS-y) +SRCS := $(COBJS:.o=.c) +OBJS := $(addprefix $(obj),$(COBJS)) + +all: $(LIB) + +$(LIB): $(obj).depend $(OBJS) + $(AR) $(ARFLAGS) $@ $(OBJS) + +######################################################################### + +# defines $(obj).depend target +include $(SRCTREE)/rules.mk + +sinclude $(obj).depend + +######################################################################### diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c new file mode 100644 index 000000000..17cabb2ae --- /dev/null +++ b/drivers/mtd/ubi/build.c @@ -0,0 +1,1186 @@ +/* + * 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. + * + * When UBI is initialized, it attaches all the MTD devices specified as the + * module load parameters or the kernel boot parameters. If MTD devices were + * specified, UBI does not attach any MTD device, but it is possible to do + * later using the "UBI control device". + * + * 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, although it does not seem to be easy to do. + */ + +#ifdef UBI_LINUX +#include <linux/err.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/stringify.h> +#include <linux/stat.h> +#include <linux/miscdevice.h> +#include <linux/log2.h> +#include <linux/kthread.h> +#endif +#include <ubi_uboot.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 + */ +struct mtd_dev_param +{ + char name[MTD_PARAM_LEN_MAX]; + int vid_hdr_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]; + +/* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */ +struct class *ubi_class; + +#ifdef UBI_LINUX +/* Slab cache for wear-leveling entries */ +struct kmem_cache *ubi_wl_entry_slab; + +/* UBI control character device */ +static struct miscdevice ubi_ctrl_cdev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "ubi_ctrl", + .fops = &ubi_ctrl_cdev_operations, +}; +#endif + +/* All UBI devices in system */ +struct ubi_device *ubi_devices[UBI_MAX_DEVICES]; + +#ifdef UBI_LINUX +/* Serializes UBI devices creations and removals */ +DEFINE_MUTEX(ubi_devices_mutex); + +/* Protects @ubi_devices and @ubi->ref_count */ +static DEFINE_SPINLOCK(ubi_devices_lock); + +/* "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); +static struct device_attribute dev_mtd_num = + __ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL); +#endif + +/** + * ubi_get_device - get UBI device. + * @ubi_num: UBI device number + * + * This function returns UBI device description object for UBI device number + * @ubi_num, or %NULL if the device does not exist. This function increases the + * device reference count to prevent removal of the device. In other words, the + * device cannot be removed if its reference count is not zero. + */ +struct ubi_device *ubi_get_device(int ubi_num) +{ + struct ubi_device *ubi; + + spin_lock(&ubi_devices_lock); + ubi = ubi_devices[ubi_num]; + if (ubi) { + ubi_assert(ubi->ref_count >= 0); + ubi->ref_count += 1; + get_device(&ubi->dev); + } + spin_unlock(&ubi_devices_lock); + + return ubi; +} + +/** + * ubi_put_device - drop an UBI device reference. + * @ubi: UBI device description object + */ +void ubi_put_device(struct ubi_device *ubi) +{ + spin_lock(&ubi_devices_lock); + ubi->ref_count -= 1; + put_device(&ubi->dev); + spin_unlock(&ubi_devices_lock); +} + +/** + * ubi_get_by_major - get UBI device description object by character device + * major number. + * @major: major number + * + * This function is similar to 'ubi_get_device()', but it searches the device + * by its major number. + */ +struct ubi_device *ubi_get_by_major(int major) +{ + int i; + struct ubi_device *ubi; + + spin_lock(&ubi_devices_lock); + for (i = 0; i < UBI_MAX_DEVICES; i++) { + ubi = ubi_devices[i]; + if (ubi && MAJOR(ubi->cdev.dev) == major) { + ubi_assert(ubi->ref_count >= 0); + ubi->ref_count += 1; + get_device(&ubi->dev); + spin_unlock(&ubi_devices_lock); + return ubi; + } + } + spin_unlock(&ubi_devices_lock); + + return NULL; +} + +/** + * ubi_major2num - get UBI device number by character device major number. + * @major: major number + * + * This function searches UBI device number object by its major number. If UBI + * device was not found, this function returns -ENODEV, otherwise the UBI device + * number is returned. + */ +int ubi_major2num(int major) +{ + int i, ubi_num = -ENODEV; + + spin_lock(&ubi_devices_lock); + for (i = 0; i < UBI_MAX_DEVICES; i++) { + struct ubi_device *ubi = ubi_devices[i]; + + if (ubi && MAJOR(ubi->cdev.dev) == major) { + ubi_num = ubi->ubi_num; + break; + } + } + spin_unlock(&ubi_devices_lock); + + return ubi_num; +} + +#ifdef UBI_LINUX +/* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */ +static ssize_t dev_attribute_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + ssize_t ret; + struct ubi_device *ubi; + + /* + * The below code looks weird, but it actually makes sense. We get the + * UBI device reference from the contained 'struct ubi_device'. But it + * is unclear if the device was removed or not yet. Indeed, if the + * device was removed before we increased its reference count, + * 'ubi_get_device()' will return -ENODEV and we fail. + * + * Remember, 'struct ubi_device' is freed in the release function, so + * we still can use 'ubi->ubi_num'. + */ + ubi = container_of(dev, struct ubi_device, dev); + ubi = ubi_get_device(ubi->ubi_num); + if (!ubi) + return -ENODEV; + + if (attr == &dev_eraseblock_size) + ret = sprintf(buf, "%d\n", ubi->leb_size); + else if (attr == &dev_avail_eraseblocks) + ret = sprintf(buf, "%d\n", ubi->avail_pebs); + else if (attr == &dev_total_eraseblocks) + ret = sprintf(buf, "%d\n", ubi->good_peb_count); + else if (attr == &dev_volumes_count) + ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT); + else if (attr == &dev_max_ec) + ret = sprintf(buf, "%d\n", ubi->max_ec); + else if (attr == &dev_reserved_for_bad) + ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs); + else if (attr == &dev_bad_peb_count) + ret = sprintf(buf, "%d\n", ubi->bad_peb_count); + else if (attr == &dev_max_vol_count) + ret = sprintf(buf, "%d\n", ubi->vtbl_slots); + else if (attr == &dev_min_io_size) + ret = sprintf(buf, "%d\n", ubi->min_io_size); + else if (attr == &dev_bgt_enabled) + ret = sprintf(buf, "%d\n", ubi->thread_enabled); + else if (attr == &dev_mtd_num) + ret = sprintf(buf, "%d\n", ubi->mtd->index); + else + ret = -EINVAL; + + ubi_put_device(ubi); + return ret; +} + +/* 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 = ubi->cdev.dev; + 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) + return err; + + err = device_create_file(&ubi->dev, &dev_eraseblock_size); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_avail_eraseblocks); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_total_eraseblocks); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_volumes_count); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_max_ec); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_reserved_for_bad); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_bad_peb_count); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_max_vol_count); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_min_io_size); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_bgt_enabled); + if (err) + return err; + err = device_create_file(&ubi->dev, &dev_mtd_num); + 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_mtd_num); + 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); +} +#endif + +/** + * 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, ubi->volumes[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; +#ifdef UBI_LINUX + dev_t dev; +#endif + + 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; + } + + ubi_assert(MINOR(dev) == 0); + cdev_init(&ubi->cdev, &ubi_cdev_operations); + dbg_msg("%s major is %u", ubi->ubi_name, MAJOR(dev)); + ubi->cdev.owner = THIS_MODULE; + + err = cdev_add(&ubi->cdev, dev, 1); + if (err) { + ubi_err("cannot add character device"); + goto out_unreg; + } + + err = ubi_sysfs_init(ubi); + if (err) + goto out_sysfs; + + for (i = 0; i < ubi->vtbl_slots; i++) + if (ubi->volumes[i]) { + err = ubi_add_volume(ubi, ubi->volumes[i]); + if (err) { + ubi_err("cannot add volume %d", i); + goto out_volumes; + } + } + + return 0; + +out_volumes: + kill_volumes(ubi); +out_sysfs: + ubi_sysfs_close(ubi); + cdev_del(&ubi->cdev); +out_unreg: + unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1); + ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err); + 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(ubi->cdev.dev, 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; + } + + if (ubi->vid_hdr_offset < 0) + 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. Note, there is no + * fundamental reason for this assumption. It is just an optimization + * which allows us to avoid costly division operations. + */ + if (!is_power_of_2(ubi->min_io_size)) { + ubi_err("min. I/O unit (%d) is not power of 2", + ubi->min_io_size); + return -EINVAL; + } + + ubi_assert(ubi->hdrs_min_io_size > 0); + ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size); + ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0); + + /* Calculate default aligned sizes of EC and VID headers */ + ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size); + ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size); + + dbg_msg("min_io_size %d", ubi->min_io_size); + dbg_msg("hdrs_min_io_size %d", ubi->hdrs_min_io_size); + dbg_msg("ec_hdr_alsize %d", ubi->ec_hdr_alsize); + dbg_msg("vid_hdr_alsize %d", ubi->vid_hdr_alsize); + + if (ubi->vid_hdr_offset == 0) + /* Default offset */ + ubi->vid_hdr_offset = ubi->vid_hdr_aloffset = + ubi->ec_hdr_alsize; + else { + ubi->vid_hdr_aloffset = ubi->vid_hdr_offset & + ~(ubi->hdrs_min_io_size - 1); + ubi->vid_hdr_shift = ubi->vid_hdr_offset - + ubi->vid_hdr_aloffset; + } + + /* Similar for the data offset */ + ubi->leb_start = ubi->vid_hdr_offset + UBI_EC_HDR_SIZE; + ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size); + + dbg_msg("vid_hdr_offset %d", ubi->vid_hdr_offset); + dbg_msg("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset); + dbg_msg("vid_hdr_shift %d", ubi->vid_hdr_shift); + dbg_msg("leb_start %d", ubi->leb_start); + + /* The shift must be aligned to 32-bit boundary */ + if (ubi->vid_hdr_shift % 4) { + ubi_err("unaligned VID header shift %d", + ubi->vid_hdr_shift); + return -EINVAL; + } + + /* Check sanity */ + if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE || + ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE || + ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE || + ubi->leb_start & (ubi->min_io_size - 1)) { + ubi_err("bad VID header (%d) or data offsets (%d)", + ubi->vid_hdr_offset, ubi->leb_start); + return -EINVAL; + } + + /* + * It may happen that EC and VID headers are situated in one minimal + * I/O unit. In this case we can only accept this UBI image in + * read-only mode. + */ + if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) { + ubi_warn("EC and VID headers are in the same minimal I/O unit, " + "switch to read-only mode"); + ubi->ro_mode = 1; + } + + ubi->leb_size = ubi->peb_size - ubi->leb_start; + + if (!(ubi->mtd->flags & MTD_WRITEABLE)) { + ubi_msg("MTD device %d is write-protected, attach in " + "read-only mode", ubi->mtd->index); + ubi->ro_mode = 1; + } + + ubi_msg("physical eraseblock size: %d bytes (%d KiB)", + ubi->peb_size, ubi->peb_size >> 10); + ubi_msg("logical eraseblock size: %d bytes", ubi->leb_size); + ubi_msg("smallest flash I/O unit: %d", ubi->min_io_size); + if (ubi->hdrs_min_io_size != ubi->min_io_size) + ubi_msg("sub-page size: %d", + ubi->hdrs_min_io_size); + ubi_msg("VID header offset: %d (aligned %d)", + ubi->vid_hdr_offset, ubi->vid_hdr_aloffset); + ubi_msg("data offset: %d", ubi->leb_start); + + /* + * Note, ideally, we have to initialize ubi->bad_peb_count here. But + * unfortunately, MTD does not provide this information. We should loop + * over all physical eraseblocks and invoke mtd->block_is_bad() for + * each physical eraseblock. So, we skip ubi->bad_peb_count + * uninitialized and initialize it after scanning. + */ + + return 0; +} + +/** + * autoresize - re-size the volume which has the "auto-resize" flag set. + * @ubi: UBI device description object + * @vol_id: ID of the volume to re-size + * + * This function re-sizes the volume marked by the @UBI_VTBL_AUTORESIZE_FLG in + * the volume table to the largest possible size. See comments in ubi-header.h + * for more description of the flag. Returns zero in case of success and a + * negative error code in case of failure. + */ +static int autoresize(struct ubi_device *ubi, int vol_id) +{ + struct ubi_volume_desc desc; + struct ubi_volume *vol = ubi->volumes[vol_id]; + int err, old_reserved_pebs = vol->reserved_pebs; + + /* + * Clear the auto-resize flag in the volume in-memory copy of the + * volume table, and 'ubi_resize_volume()' will propogate this change + * to the flash. + */ + ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG; + + if (ubi->avail_pebs == 0) { + struct ubi_vtbl_record vtbl_rec; + + /* + * No avalilable PEBs to re-size the volume, clear the flag on + * flash and exit. + */ + memcpy(&vtbl_rec, &ubi->vtbl[vol_id], + sizeof(struct ubi_vtbl_record)); + err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec); + if (err) + ubi_err("cannot clean auto-resize flag for volume %d", + vol_id); + } else { + desc.vol = vol; + err = ubi_resize_volume(&desc, + old_reserved_pebs + ubi->avail_pebs); + if (err) + ubi_err("cannot auto-resize volume %d", vol_id); + } + + if (err) + return err; + + ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id, + vol->name, old_reserved_pebs, vol->reserved_pebs); + return 0; +} + +/** + * ubi_attach_mtd_dev - attach an MTD device. + * @mtd_dev: MTD device description object + * @ubi_num: number to assign to the new UBI device + * @vid_hdr_offset: VID header offset + * + * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number + * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in + * which case this function finds a vacant device nubert and assings it + * automatically. Returns the new UBI device number in case of success and a + * negative error code in case of failure. + * + * Note, the invocations of this function has to be serialized by the + * @ubi_devices_mutex. + */ +int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset) +{ + struct ubi_device *ubi; + int i, err; + + /* + * Check if we already have the same MTD device attached. + * + * Note, this function assumes that UBI devices creations and deletions + * are serialized, so it does not take the &ubi_devices_lock. + */ + for (i = 0; i < UBI_MAX_DEVICES; i++) { + ubi = ubi_devices[i]; + if (ubi && mtd->index == ubi->mtd->index) { + dbg_err("mtd%d is already attached to ubi%d", + mtd->index, i); + return -EEXIST; + } + } + + /* + * Make sure this MTD device is not emulated on top of an UBI volume + * already. Well, generally this recursion works fine, but there are + * different problems like the UBI module takes a reference to itself + * by attaching (and thus, opening) the emulated MTD device. This + * results in inability to unload the module. And in general it makes + * no sense to attach emulated MTD devices, so we prohibit this. + */ + if (mtd->type == MTD_UBIVOLUME) { + ubi_err("refuse attaching mtd%d - it is already emulated on " + "top of UBI", mtd->index); + return -EINVAL; + } + + if (ubi_num == UBI_DEV_NUM_AUTO) { + /* Search for an empty slot in the @ubi_devices array */ + for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++) + if (!ubi_devices[ubi_num]) + break; + if (ubi_num == UBI_MAX_DEVICES) { + dbg_err("only %d UBI devices may be created", UBI_MAX_DEVICES); + return -ENFILE; + } + } else { + if (ubi_num >= UBI_MAX_DEVICES) + return -EINVAL; + + /* Make sure ubi_num is not busy */ + if (ubi_devices[ubi_num]) { + dbg_err("ubi%d already exists", ubi_num); + return -EEXIST; + } + } + + ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL); + if (!ubi) + return -ENOMEM; + + ubi->mtd = mtd; + ubi->ubi_num = ubi_num; + ubi->vid_hdr_offset = vid_hdr_offset; + ubi->autoresize_vol_id = -1; + + mutex_init(&ubi->buf_mutex); + mutex_init(&ubi->ckvol_mutex); + mutex_init(&ubi->volumes_mutex); + spin_lock_init(&ubi->volumes_lock); + + ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num); + + err = io_init(ubi); + if (err) + goto out_free; + + ubi->peb_buf1 = vmalloc(ubi->peb_size); + if (!ubi->peb_buf1) + goto out_free; + + ubi->peb_buf2 = vmalloc(ubi->peb_size); + if (!ubi->peb_buf2) + goto out_free; + +#ifdef CONFIG_MTD_UBI_DEBUG + mutex_init(&ubi->dbg_buf_mutex); + ubi->dbg_peb_buf = vmalloc(ubi->peb_size); + if (!ubi->dbg_peb_buf) + goto out_free; +#endif + + err = attach_by_scanning(ubi); + if (err) { + dbg_err("failed to attach by scanning, error %d", err); + goto out_free; + } + + if (ubi->autoresize_vol_id != -1) { + err = autoresize(ubi, ubi->autoresize_vol_id); + if (err) + goto out_detach; + } + + err = uif_init(ubi); + if (err) + goto out_detach; + + ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name); + if (IS_ERR(ubi->bgt_thread)) { + err = PTR_ERR(ubi->bgt_thread); + ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name, + err); + goto out_uif; + } + + ubi_msg("attached mtd%d to ubi%d", mtd->index, ubi_num); + ubi_msg("MTD device name: \"%s\"", mtd->name); + ubi_msg("MTD device size: %llu MiB", ubi->flash_size >> 20); + ubi_msg("number of good PEBs: %d", ubi->good_peb_count); + ubi_msg("number of bad PEBs: %d", ubi->bad_peb_count); + ubi_msg("max. allowed volumes: %d", ubi->vtbl_slots); + ubi_msg("wear-leveling threshold: %d", CONFIG_MTD_UBI_WL_THRESHOLD); + ubi_msg("number of internal volumes: %d", UBI_INT_VOL_COUNT); + ubi_msg("number of user volumes: %d", + ubi->vol_count - UBI_INT_VOL_COUNT); + ubi_msg("available PEBs: %d", ubi->avail_pebs); + ubi_msg("total number of reserved PEBs: %d", ubi->rsvd_pebs); + ubi_msg("number of PEBs reserved for bad PEB handling: %d", + ubi->beb_rsvd_pebs); + ubi_msg("max/mean erase counter: %d/%d", ubi->max_ec, ubi->mean_ec); + + /* Enable the background thread */ + if (!DBG_DISABLE_BGT) { + ubi->thread_enabled = 1; + wake_up_process(ubi->bgt_thread); + } + + ubi_devices[ubi_num] = ubi; + return ubi_num; + +out_uif: + uif_close(ubi); +out_detach: + ubi_eba_close(ubi); + ubi_wl_close(ubi); + vfree(ubi->vtbl); +out_free: + vfree(ubi->peb_buf1); + vfree(ubi->peb_buf2); +#ifdef CONFIG_MTD_UBI_DEBUG + vfree(ubi->dbg_peb_buf); +#endif + kfree(ubi); + return err; +} + +/** + * ubi_detach_mtd_dev - detach an MTD device. + * @ubi_num: UBI device number to detach from + * @anyway: detach MTD even if device reference count is not zero + * + * This function destroys an UBI device number @ubi_num and detaches the + * underlying MTD device. Returns zero in case of success and %-EBUSY if the + * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not + * exist. + * + * Note, the invocations of this function has to be serialized by the + * @ubi_devices_mutex. + */ +int ubi_detach_mtd_dev(int ubi_num, int anyway) +{ + struct ubi_device *ubi; + + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES) + return -EINVAL; + + spin_lock(&ubi_devices_lock); + ubi = ubi_devices[ubi_num]; + if (!ubi) { + spin_unlock(&ubi_devices_lock); + return -EINVAL; + } + + if (ubi->ref_count) { + if (!anyway) { + spin_unlock(&ubi_devices_lock); + return -EBUSY; + } + /* This may only happen if there is a bug */ + ubi_err("%s reference count %d, destroy anyway", + ubi->ubi_name, ubi->ref_count); + } + ubi_devices[ubi_num] = NULL; + spin_unlock(&ubi_devices_lock); + + ubi_assert(ubi_num == ubi->ubi_num); + dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num); + + /* + * Before freeing anything, we have to stop the background thread to + * prevent it from doing anything on this device while we are freeing. + */ + if (ubi->bgt_thread) + kthread_stop(ubi->bgt_thread); + + uif_close(ubi); + ubi_eba_close(ubi); + ubi_wl_close(ubi); + vfree(ubi->vtbl); + put_mtd_device(ubi->mtd); + vfree(ubi->peb_buf1); + vfree(ubi->peb_buf2); +#ifdef CONFIG_MTD_UBI_DEBUG + vfree(ubi->dbg_peb_buf); +#endif + ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num); + kfree(ubi); + return 0; +} + +/** + * find_mtd_device - open an MTD device by its name or number. + * @mtd_dev: name or number of the device + * + * This function tries to open and MTD device described by @mtd_dev string, + * which is first treated as an ASCII number, and if it is not true, it is + * treated as MTD device name. Returns MTD device description object in case of + * success and a negative error code in case of failure. + */ +static struct mtd_info * __init open_mtd_device(const char *mtd_dev) +{ + struct mtd_info *mtd; + int mtd_num; + char *endp; + + mtd_num = simple_strtoul(mtd_dev, &endp, 0); + if (*endp != '\0' || mtd_dev == endp) { + /* + * This does not look like an ASCII integer, probably this is + * MTD device name. + */ + mtd = get_mtd_device_nm(mtd_dev); + } else + mtd = get_mtd_device(NULL, mtd_num); + + return mtd; +} + +int __init ubi_init(void) +{ + int err, i, k; + + /* Ensure that EC and VID headers have correct size */ + BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64); + BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64); + + if (mtd_devs > UBI_MAX_DEVICES) { + ubi_err("too many MTD devices, maximum is %d", UBI_MAX_DEVICES); + return -EINVAL; + } + + /* Create base sysfs directory and sysfs files */ + ubi_class = class_create(THIS_MODULE, UBI_NAME_STR); + if (IS_ERR(ubi_class)) { + err = PTR_ERR(ubi_class); + ubi_err("cannot create UBI class"); + goto out; + } + + err = class_create_file(ubi_class, &ubi_version); + if (err) { + ubi_err("cannot create sysfs file"); + goto out_class; + } + + err = misc_register(&ubi_ctrl_cdev); + if (err) { + ubi_err("cannot register device"); + goto out_version; + } + +#ifdef UBI_LINUX + ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab", + sizeof(struct ubi_wl_entry), + 0, 0, NULL); + if (!ubi_wl_entry_slab) + goto out_dev_unreg; +#endif + + /* Attach MTD devices */ + for (i = 0; i < mtd_devs; i++) { + struct mtd_dev_param *p = &mtd_dev_param[i]; + struct mtd_info *mtd; + + cond_resched(); + + mtd = open_mtd_device(p->name); + if (IS_ERR(mtd)) { + err = PTR_ERR(mtd); + goto out_detach; + } + + mutex_lock(&ubi_devices_mutex); + err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, + p->vid_hdr_offs); + mutex_unlock(&ubi_devices_mutex); + if (err < 0) { + put_mtd_device(mtd); + ubi_err("cannot attach mtd%d", mtd->index); + goto out_detach; + } + } + + return 0; + +out_detach: + for (k = 0; k < i; k++) + if (ubi_devices[k]) { + mutex_lock(&ubi_devices_mutex); + ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1); + mutex_unlock(&ubi_devices_mutex); + } +#ifdef UBI_LINUX + kmem_cache_destroy(ubi_wl_entry_slab); +out_dev_unreg: +#endif + misc_deregister(&ubi_ctrl_cdev); +out_version: + class_remove_file(ubi_class, &ubi_version); +out_class: + class_destroy(ubi_class); +out: + ubi_err("UBI error: cannot initialize UBI, error %d", err); + return err; +} +module_init(ubi_init); + +void __exit ubi_exit(void) +{ + int i; + + for (i = 0; i < UBI_MAX_DEVICES; i++) + if (ubi_devices[i]) { + mutex_lock(&ubi_devices_mutex); + ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1); + mutex_unlock(&ubi_devices_mutex); + } + kmem_cache_destroy(ubi_wl_entry_slab); + misc_deregister(&ubi_ctrl_cdev); + class_remove_file(ubi_class, &ubi_version); + class_destroy(ubi_class); +} +module_exit(ubi_exit); + +/** + * bytes_str_to_int - convert a string representing number of bytes to an + * integer. + * @str: the string to convert + * + * This function returns positive resulting integer in case of success and a + * negative error code in case of failure. + */ +static int __init bytes_str_to_int(const char *str) +{ + char *endp; + unsigned long result; + + result = simple_strtoul(str, &endp, 0); + if (str == endp || result < 0) { + printk(KERN_ERR "UBI error: incorrect bytes count: \"%s\"\n", + str); + return -EINVAL; + } + + switch (*endp) { + case 'G': + result *= 1024; + case 'M': + result *= 1024; + case 'K': + result *= 1024; + if (endp[1] == 'i' && endp[2] == 'B') + endp += 2; + case '\0': + break; + default: + printk(KERN_ERR "UBI error: incorrect bytes count: \"%s\"\n", + str); + return -EINVAL; + } + + return result; +} + +/** + * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter. + * @val: the parameter value to parse + * @kp: not used + * + * This function returns zero in case of success and a negative error code in + * case of error. + */ +int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp) +{ + int i, len; + struct mtd_dev_param *p; + char buf[MTD_PARAM_LEN_MAX]; + char *pbuf = &buf[0]; + char *tokens[2] = {NULL, NULL}; + + if (!val) + return -EINVAL; + + if (mtd_devs == UBI_MAX_DEVICES) { + printk(KERN_ERR "UBI error: too many parameters, max. is %d\n", + UBI_MAX_DEVICES); + return -EINVAL; + } + + len = strnlen(val, MTD_PARAM_LEN_MAX); + if (len == MTD_PARAM_LEN_MAX) { + printk(KERN_ERR "UBI error: parameter \"%s\" is too long, " + "max. is %d\n", val, MTD_PARAM_LEN_MAX); + return -EINVAL; + } + + if (len == 0) { + printk(KERN_WARNING "UBI warning: empty 'mtd=' parameter - " + "ignored\n"); + return 0; + } + + strcpy(buf, val); + + /* Get rid of the final newline */ + if (buf[len - 1] == '\n') + buf[len - 1] = '\0'; + + for (i = 0; i < 2; i++) + tokens[i] = strsep(&pbuf, ","); + + if (pbuf) { + printk(KERN_ERR "UBI error: too many arguments at \"%s\"\n", + val); + return -EINVAL; + } + + p = &mtd_dev_param[mtd_devs]; + strcpy(&p->name[0], tokens[0]); + + if (tokens[1]) + p->vid_hdr_offs = bytes_str_to_int(tokens[1]); + + if (p->vid_hdr_offs < 0) + return p->vid_hdr_offs; + + mtd_devs += 1; + return 0; +} + +module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000); +MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: " + "mtd=<name|num>[,<vid_hdr_offs>].\n" + "Multiple \"mtd\" parameters may be specified.\n" + "MTD devices may be specified by their number or name.\n" + "Optional \"vid_hdr_offs\" parameter specifies UBI VID " + "header position and data starting position to be used " + "by UBI.\n" + "Example: mtd=content,1984 mtd=4 - attach MTD device" + "with name \"content\" using VID header offset 1984, and " + "MTD device number 4 with default VID header offset."); + +MODULE_VERSION(__stringify(UBI_VERSION)); +MODULE_DESCRIPTION("UBI - Unsorted Block Images"); +MODULE_AUTHOR("Artem Bityutskiy"); +MODULE_LICENSE("GPL"); diff --git a/drivers/mtd/ubi/crc32.c b/drivers/mtd/ubi/crc32.c new file mode 100644 index 000000000..5273ca3e0 --- /dev/null +++ b/drivers/mtd/ubi/crc32.c @@ -0,0 +1,518 @@ +/* + * Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com> + * Nicer crc32 functions/docs submitted by linux@horizon.com. Thanks! + * Code was from the public domain, copyright abandoned. Code was + * subsequently included in the kernel, thus was re-licensed under the + * GNU GPL v2. + * + * Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com> + * Same crc32 function was used in 5 other places in the kernel. + * I made one version, and deleted the others. + * There are various incantations of crc32(). Some use a seed of 0 or ~0. + * Some xor at the end with ~0. The generic crc32() function takes + * seed as an argument, and doesn't xor at the end. Then individual + * users can do whatever they need. + * drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0. + * fs/jffs2 uses seed 0, doesn't xor with ~0. + * fs/partitions/efi.c uses seed ~0, xor's with ~0. + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#ifdef UBI_LINUX +#include <linux/crc32.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/compiler.h> +#endif +#include <linux/types.h> + +#include <asm/byteorder.h> + +#ifdef UBI_LINUX +#include <linux/slab.h> +#include <linux/init.h> +#include <asm/atomic.h> +#endif +#include "crc32defs.h" +#define CRC_LE_BITS 8 + +# define __force +#ifndef __constant_cpu_to_le32 +#define __constant_cpu_to_le32(x) ((__force __le32)(__u32)(x)) +#endif +#ifndef __constant_le32_to_cpu +#define __constant_le32_to_cpu(x) ((__force __u32)(__le32)(x)) +#endif + +#if CRC_LE_BITS == 8 +#define tole(x) __constant_cpu_to_le32(x) +#define tobe(x) __constant_cpu_to_be32(x) +#else +#define tole(x) (x) +#define tobe(x) (x) +#endif +#include "crc32table.h" +#ifdef UBI_LINUX +MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>"); +MODULE_DESCRIPTION("Ethernet CRC32 calculations"); +MODULE_LICENSE("GPL"); +#endif +/** + * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32 + * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for + * other uses, or the previous crc32 value if computing incrementally. + * @p: pointer to buffer over which CRC is run + * @len: length of buffer @p + */ +u32 crc32_le(u32 crc, unsigned char const *p, size_t len); + +#if CRC_LE_BITS == 1 +/* + * In fact, the table-based code will work in this case, but it can be + * simplified by inlining the table in ?: form. + */ + +u32 crc32_le(u32 crc, unsigned char const *p, size_t len) +{ + int i; + while (len--) { + crc ^= *p++; + for (i = 0; i < 8; i++) + crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0); + } + return crc; +} +#else /* Table-based approach */ + +u32 crc32_le(u32 crc, unsigned char const *p, size_t len) +{ +# if CRC_LE_BITS == 8 + const u32 *b =(u32 *)p; + const u32 *tab = crc32table_le; + +# ifdef __LITTLE_ENDIAN +# define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8) +# else +# define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8) +# endif + //printf("Crc32_le crc=%x\n",crc); + crc = __cpu_to_le32(crc); + /* Align it */ + if((((long)b)&3 && len)){ + do { + u8 *p = (u8 *)b; + DO_CRC(*p++); + b = (void *)p; + } while ((--len) && ((long)b)&3 ); + } + if((len >= 4)){ + /* load data 32 bits wide, xor data 32 bits wide. */ + size_t save_len = len & 3; + len = len >> 2; + --b; /* use pre increment below(*++b) for speed */ + do { + crc ^= *++b; + DO_CRC(0); + DO_CRC(0); + DO_CRC(0); + DO_CRC(0); + } while (--len); + b++; /* point to next byte(s) */ + len = save_len; + } + /* And the last few bytes */ + if(len){ + do { + u8 *p = (u8 *)b; + DO_CRC(*p++); + b = (void *)p; + } while (--len); + } + + return __le32_to_cpu(crc); +#undef ENDIAN_SHIFT +#undef DO_CRC + +# elif CRC_LE_BITS == 4 + while (len--) { + crc ^= *p++; + crc = (crc >> 4) ^ crc32table_le[crc & 15]; + crc = (crc >> 4) ^ crc32table_le[crc & 15]; + } + return crc; +# elif CRC_LE_BITS == 2 + while (len--) { + crc ^= *p++; + crc = (crc >> 2) ^ crc32table_le[crc & 3]; + crc = (crc >> 2) ^ crc32table_le[crc & 3]; + crc = (crc >> 2) ^ crc32table_le[crc & 3]; + crc = (crc >> 2) ^ crc32table_le[crc & 3]; + } + return crc; +# endif +} +#endif +#ifdef UBI_LINUX +/** + * crc32_be() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32 + * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for + * other uses, or the previous crc32 value if computing incrementally. + * @p: pointer to buffer over which CRC is run + * @len: length of buffer @p + */ +u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len); + +#if CRC_BE_BITS == 1 +/* + * In fact, the table-based code will work in this case, but it can be + * simplified by inlining the table in ?: form. + */ + +u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len) +{ + int i; + while (len--) { + crc ^= *p++ << 24; + for (i = 0; i < 8; i++) + crc = + (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : + 0); + } + return crc; +} + +#else /* Table-based approach */ +u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len) +{ +# if CRC_BE_BITS == 8 + const u32 *b =(u32 *)p; + const u32 *tab = crc32table_be; + +# ifdef __LITTLE_ENDIAN +# define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8) +# else +# define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8) +# endif + + crc = __cpu_to_be32(crc); + /* Align it */ + if(unlikely(((long)b)&3 && len)){ + do { + u8 *p = (u8 *)b; + DO_CRC(*p++); + b = (u32 *)p; + } while ((--len) && ((long)b)&3 ); + } + if(likely(len >= 4)){ + /* load data 32 bits wide, xor data 32 bits wide. */ + size_t save_len = len & 3; + len = len >> 2; + --b; /* use pre increment below(*++b) for speed */ + do { + crc ^= *++b; + DO_CRC(0); + DO_CRC(0); + DO_CRC(0); + DO_CRC(0); + } while (--len); + b++; /* point to next byte(s) */ + len = save_len; + } + /* And the last few bytes */ + if(len){ + do { + u8 *p = (u8 *)b; + DO_CRC(*p++); + b = (void *)p; + } while (--len); + } + return __be32_to_cpu(crc); +#undef ENDIAN_SHIFT +#undef DO_CRC + +# elif CRC_BE_BITS == 4 + while (len--) { + crc ^= *p++ << 24; + crc = (crc << 4) ^ crc32table_be[crc >> 28]; + crc = (crc << 4) ^ crc32table_be[crc >> 28]; + } + return crc; +# elif CRC_BE_BITS == 2 + while (len--) { + crc ^= *p++ << 24; + crc = (crc << 2) ^ crc32table_be[crc >> 30]; + crc = (crc << 2) ^ crc32table_be[crc >> 30]; + crc = (crc << 2) ^ crc32table_be[crc >> 30]; + crc = (crc << 2) ^ crc32table_be[crc >> 30]; + } + return crc; +# endif +} +#endif + +EXPORT_SYMBOL(crc32_le); +EXPORT_SYMBOL(crc32_be); +#endif +/* + * A brief CRC tutorial. + * + * A CRC is a long-division remainder. You add the CRC to the message, + * and the whole thing (message+CRC) is a multiple of the given + * CRC polynomial. To check the CRC, you can either check that the + * CRC matches the recomputed value, *or* you can check that the + * remainder computed on the message+CRC is 0. This latter approach + * is used by a lot of hardware implementations, and is why so many + * protocols put the end-of-frame flag after the CRC. + * + * It's actually the same long division you learned in school, except that + * - We're working in binary, so the digits are only 0 and 1, and + * - When dividing polynomials, there are no carries. Rather than add and + * subtract, we just xor. Thus, we tend to get a bit sloppy about + * the difference between adding and subtracting. + * + * A 32-bit CRC polynomial is actually 33 bits long. But since it's + * 33 bits long, bit 32 is always going to be set, so usually the CRC + * is written in hex with the most significant bit omitted. (If you're + * familiar with the IEEE 754 floating-point format, it's the same idea.) + * + * Note that a CRC is computed over a string of *bits*, so you have + * to decide on the endianness of the bits within each byte. To get + * the best error-detecting properties, this should correspond to the + * order they're actually sent. For example, standard RS-232 serial is + * little-endian; the most significant bit (sometimes used for parity) + * is sent last. And when appending a CRC word to a message, you should + * do it in the right order, matching the endianness. + * + * Just like with ordinary division, the remainder is always smaller than + * the divisor (the CRC polynomial) you're dividing by. Each step of the + * division, you take one more digit (bit) of the dividend and append it + * to the current remainder. Then you figure out the appropriate multiple + * of the divisor to subtract to being the remainder back into range. + * In binary, it's easy - it has to be either 0 or 1, and to make the + * XOR cancel, it's just a copy of bit 32 of the remainder. + * + * When computing a CRC, we don't care about the quotient, so we can + * throw the quotient bit away, but subtract the appropriate multiple of + * the polynomial from the remainder and we're back to where we started, + * ready to process the next bit. + * + * A big-endian CRC written this way would be coded like: + * for (i = 0; i < input_bits; i++) { + * multiple = remainder & 0x80000000 ? CRCPOLY : 0; + * remainder = (remainder << 1 | next_input_bit()) ^ multiple; + * } + * Notice how, to get at bit 32 of the shifted remainder, we look + * at bit 31 of the remainder *before* shifting it. + * + * But also notice how the next_input_bit() bits we're shifting into + * the remainder don't actually affect any decision-making until + * 32 bits later. Thus, the first 32 cycles of this are pretty boring. + * Also, to add the CRC to a message, we need a 32-bit-long hole for it at + * the end, so we have to add 32 extra cycles shifting in zeros at the + * end of every message, + * + * So the standard trick is to rearrage merging in the next_input_bit() + * until the moment it's needed. Then the first 32 cycles can be precomputed, + * and merging in the final 32 zero bits to make room for the CRC can be + * skipped entirely. + * This changes the code to: + * for (i = 0; i < input_bits; i++) { + * remainder ^= next_input_bit() << 31; + * multiple = (remainder & 0x80000000) ? CRCPOLY : 0; + * remainder = (remainder << 1) ^ multiple; + * } + * With this optimization, the little-endian code is simpler: + * for (i = 0; i < input_bits; i++) { + * remainder ^= next_input_bit(); + * multiple = (remainder & 1) ? CRCPOLY : 0; + * remainder = (remainder >> 1) ^ multiple; + * } + * + * Note that the other details of endianness have been hidden in CRCPOLY + * (which must be bit-reversed) and next_input_bit(). + * + * However, as long as next_input_bit is returning the bits in a sensible + * order, we can actually do the merging 8 or more bits at a time rather + * than one bit at a time: + * for (i = 0; i < input_bytes; i++) { + * remainder ^= next_input_byte() << 24; + * for (j = 0; j < 8; j++) { + * multiple = (remainder & 0x80000000) ? CRCPOLY : 0; + * remainder = (remainder << 1) ^ multiple; + * } + * } + * Or in little-endian: + * for (i = 0; i < input_bytes; i++) { + * remainder ^= next_input_byte(); + * for (j = 0; j < 8; j++) { + * multiple = (remainder & 1) ? CRCPOLY : 0; + * remainder = (remainder << 1) ^ multiple; + * } + * } + * If the input is a multiple of 32 bits, you can even XOR in a 32-bit + * word at a time and increase the inner loop count to 32. + * + * You can also mix and match the two loop styles, for example doing the + * bulk of a message byte-at-a-time and adding bit-at-a-time processing + * for any fractional bytes at the end. + * + * The only remaining optimization is to the byte-at-a-time table method. + * Here, rather than just shifting one bit of the remainder to decide + * in the correct multiple to subtract, we can shift a byte at a time. + * This produces a 40-bit (rather than a 33-bit) intermediate remainder, + * but again the multiple of the polynomial to subtract depends only on + * the high bits, the high 8 bits in this case. + * + * The multile we need in that case is the low 32 bits of a 40-bit + * value whose high 8 bits are given, and which is a multiple of the + * generator polynomial. This is simply the CRC-32 of the given + * one-byte message. + * + * Two more details: normally, appending zero bits to a message which + * is already a multiple of a polynomial produces a larger multiple of that + * polynomial. To enable a CRC to detect this condition, it's common to + * invert the CRC before appending it. This makes the remainder of the + * message+crc come out not as zero, but some fixed non-zero value. + * + * The same problem applies to zero bits prepended to the message, and + * a similar solution is used. Instead of starting with a remainder of + * 0, an initial remainder of all ones is used. As long as you start + * the same way on decoding, it doesn't make a difference. + */ + +#ifdef UNITTEST + +#include <stdlib.h> +#include <stdio.h> + +#ifdef UBI_LINUX /*Not used at present */ +static void +buf_dump(char const *prefix, unsigned char const *buf, size_t len) +{ + fputs(prefix, stdout); + while (len--) + printf(" %02x", *buf++); + putchar('\n'); + +} +#endif + +static void bytereverse(unsigned char *buf, size_t len) +{ + while (len--) { + unsigned char x = bitrev8(*buf); + *buf++ = x; + } +} + +static void random_garbage(unsigned char *buf, size_t len) +{ + while (len--) + *buf++ = (unsigned char) random(); +} + +#ifdef UBI_LINUX /* Not used at present */ +static void store_le(u32 x, unsigned char *buf) +{ + buf[0] = (unsigned char) x; + buf[1] = (unsigned char) (x >> 8); + buf[2] = (unsigned char) (x >> 16); + buf[3] = (unsigned char) (x >> 24); +} +#endif + +static void store_be(u32 x, unsigned char *buf) +{ + buf[0] = (unsigned char) (x >> 24); + buf[1] = (unsigned char) (x >> 16); + buf[2] = (unsigned char) (x >> 8); + buf[3] = (unsigned char) x; +} + +/* + * This checks that CRC(buf + CRC(buf)) = 0, and that + * CRC commutes with bit-reversal. This has the side effect + * of bytewise bit-reversing the input buffer, and returns + * the CRC of the reversed buffer. + */ +static u32 test_step(u32 init, unsigned char *buf, size_t len) +{ + u32 crc1, crc2; + size_t i; + + crc1 = crc32_be(init, buf, len); + store_be(crc1, buf + len); + crc2 = crc32_be(init, buf, len + 4); + if (crc2) + printf("\nCRC cancellation fail: 0x%08x should be 0\n", + crc2); + + for (i = 0; i <= len + 4; i++) { + crc2 = crc32_be(init, buf, i); + crc2 = crc32_be(crc2, buf + i, len + 4 - i); + if (crc2) + printf("\nCRC split fail: 0x%08x\n", crc2); + } + + /* Now swap it around for the other test */ + + bytereverse(buf, len + 4); + init = bitrev32(init); + crc2 = bitrev32(crc1); + if (crc1 != bitrev32(crc2)) + printf("\nBit reversal fail: 0x%08x -> 0x%08x -> 0x%08x\n", + crc1, crc2, bitrev32(crc2)); + crc1 = crc32_le(init, buf, len); + if (crc1 != crc2) + printf("\nCRC endianness fail: 0x%08x != 0x%08x\n", crc1, + crc2); + crc2 = crc32_le(init, buf, len + 4); + if (crc2) + printf("\nCRC cancellation fail: 0x%08x should be 0\n", + crc2); + + for (i = 0; i <= len + 4; i++) { + crc2 = crc32_le(init, buf, i); + crc2 = crc32_le(crc2, buf + i, len + 4 - i); + if (crc2) + printf("\nCRC split fail: 0x%08x\n", crc2); + } + + return crc1; +} + +#define SIZE 64 +#define INIT1 0 +#define INIT2 0 + +int main(void) +{ + unsigned char buf1[SIZE + 4]; + unsigned char buf2[SIZE + 4]; + unsigned char buf3[SIZE + 4]; + int i, j; + u32 crc1, crc2, crc3; + + for (i = 0; i <= SIZE; i++) { + printf("\rTesting length %d...", i); + fflush(stdout); + random_garbage(buf1, i); + random_garbage(buf2, i); + for (j = 0; j < i; j++) + buf3[j] = buf1[j] ^ buf2[j]; + + crc1 = test_step(INIT1, buf1, i); + crc2 = test_step(INIT2, buf2, i); + /* Now check that CRC(buf1 ^ buf2) = CRC(buf1) ^ CRC(buf2) */ + crc3 = test_step(INIT1 ^ INIT2, buf3, i); + if (crc3 != (crc1 ^ crc2)) + printf("CRC XOR fail: 0x%08x != 0x%08x ^ 0x%08x\n", + crc3, crc1, crc2); + } + printf("\nAll test complete. No failures expected.\n"); + return 0; +} + +#endif /* UNITTEST */ |