[U-Boot] [PATCH] [UBI] Basic Unsorted Block Image (UBI) support v3 (#5)
Kyungmin Park
kmpark at infradead.org
Tue Oct 28 08:48:09 CET 2008
UBI (Latin: "where?") stands for "Unsorted Block Images". It is a volume management system for flash devices which manages multiple logical volumes on a single physical flash device and spreads the I/O load (i.e, wear-leveling) across the whole flash chip.
In a sense, UBI may be compared to the Logical Volume Manager (LVM). Whereas LVM maps logical sectors to physical sectors, UBI maps logical eraseblocks to physical eraseblocks. But besides the mapping, UBI implements global wear-leveling and I/O errors handling.
For more details, Please visit the following URL.
http://www.linux-mtd.infradead.org/doc/ubi.html
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
---
diff --git a/Makefile b/Makefile
index 9a132f7..93759e4 100644
--- a/Makefile
+++ b/Makefile
@@ -230,6 +230,7 @@ LIBS += drivers/mtd/libmtd.a
LIBS += drivers/mtd/nand/libnand.a
LIBS += drivers/mtd/nand_legacy/libnand_legacy.a
LIBS += drivers/mtd/onenand/libonenand.a
+LIBS += drivers/mtd/ubi/libubi.a
LIBS += drivers/mtd/spi/libspi_flash.a
LIBS += drivers/net/libnet.a
LIBS += drivers/net/phy/libphy.a
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
new file mode 100644
index 0000000..f5224bd
--- /dev/null
+++ b/drivers/mtd/ubi/wl.c
@@ -0,0 +1,1670 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * 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
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
+ */
+
+/*
+ * UBI wear-leveling unit.
+ *
+ * This unit is responsible for wear-leveling. It works in terms of physical
+ * eraseblocks and erase counters and knows nothing about logical eraseblocks,
+ * volumes, etc. From this unit's perspective all physical eraseblocks are of
+ * two types - used and free. Used physical eraseblocks are those that were
+ * "get" by the 'ubi_wl_get_peb()' function, and free physical eraseblocks are
+ * those that were put by the 'ubi_wl_put_peb()' function.
+ *
+ * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
+ * header. The rest of the physical eraseblock contains only 0xFF bytes.
+ *
+ * When physical eraseblocks are returned to the WL unit by means of the
+ * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
+ * done asynchronously in context of the per-UBI device background thread,
+ * which is also managed by the WL unit.
+ *
+ * The wear-leveling is ensured by means of moving the contents of used
+ * physical eraseblocks with low erase counter to free physical eraseblocks
+ * with high erase counter.
+ *
+ * The 'ubi_wl_get_peb()' function accepts data type hints which help to pick
+ * an "optimal" physical eraseblock. For example, when it is known that the
+ * physical eraseblock will be "put" soon because it contains short-term data,
+ * the WL unit may pick a free physical eraseblock with low erase counter, and
+ * so forth.
+ *
+ * If the WL unit fails to erase a physical eraseblock, it marks it as bad.
+ *
+ * This unit is also responsible for scrubbing. If a bit-flip is detected in a
+ * physical eraseblock, it has to be moved. Technically this is the same as
+ * moving it for wear-leveling reasons.
+ *
+ * As it was said, for the UBI unit all physical eraseblocks are either "free"
+ * or "used". Free eraseblock are kept in the @wl->free RB-tree, while used
+ * eraseblocks are kept in a set of different RB-trees: @wl->used,
+ * @wl->prot.pnum, @wl->prot.aec, and @wl->scrub.
+ *
+ * Note, in this implementation, we keep a small in-RAM object for each physical
+ * eraseblock. This is surely not a scalable solution. But it appears to be good
+ * enough for moderately large flashes and it is simple. In future, one may
+ * re-work this unit and make it more scalable.
+ *
+ * At the moment this unit does not utilize the sequence number, which was
+ * introduced relatively recently. But it would be wise to do this because the
+ * sequence number of a logical eraseblock characterizes how old is it. For
+ * example, when we move a PEB with low erase counter, and we need to pick the
+ * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
+ * pick target PEB with an average EC if our PEB is not very "old". This is a
+ * room for future re-works of the WL unit.
+ *
+ * FIXME: looks too complex, should be simplified (later).
+ */
+
+#ifdef UBI_LINUX
+#include <linux/slab.h>
+#include <linux/crc32.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#endif
+
+#include <ubi_uboot.h>
+#include "ubi.h"
+
+/* Number of physical eraseblocks reserved for wear-leveling purposes */
+#define WL_RESERVED_PEBS 1
+
+/*
+ * How many erase cycles are short term, unknown, and long term physical
+ * eraseblocks protected.
+ */
+#define ST_PROTECTION 16
+#define U_PROTECTION 10
+#define LT_PROTECTION 4
+
+/*
+ * Maximum difference between two erase counters. If this threshold is
+ * exceeded, the WL unit starts moving data from used physical eraseblocks with
+ * low erase counter to free physical eraseblocks with high erase counter.
+ */
+#define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
+
+/*
+ * When a physical eraseblock is moved, the WL unit has to pick the target
+ * physical eraseblock to move to. The simplest way would be just to pick the
+ * one with the highest erase counter. But in certain workloads this could lead
+ * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
+ * situation when the picked physical eraseblock is constantly erased after the
+ * data is written to it. So, we have a constant which limits the highest erase
+ * counter of the free physical eraseblock to pick. Namely, the WL unit does
+ * not pick eraseblocks with erase counter greater then the lowest erase
+ * counter plus %WL_FREE_MAX_DIFF.
+ */
+#define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
+
+/*
+ * Maximum number of consecutive background thread failures which is enough to
+ * switch to read-only mode.
+ */
+#define WL_MAX_FAILURES 32
+
+/**
+ * struct ubi_wl_prot_entry - PEB protection entry.
+ * @rb_pnum: link in the @wl->prot.pnum RB-tree
+ * @rb_aec: link in the @wl->prot.aec RB-tree
+ * @abs_ec: the absolute erase counter value when the protection ends
+ * @e: the wear-leveling entry of the physical eraseblock under protection
+ *
+ * When the WL unit returns a physical eraseblock, the physical eraseblock is
+ * protected from being moved for some "time". For this reason, the physical
+ * eraseblock is not directly moved from the @wl->free tree to the @wl->used
+ * tree. There is one more tree in between where this physical eraseblock is
+ * temporarily stored (@wl->prot).
+ *
+ * All this protection stuff is needed because:
+ * o we don't want to move physical eraseblocks just after we have given them
+ * to the user; instead, we first want to let users fill them up with data;
+ *
+ * o there is a chance that the user will put the physical eraseblock very
+ * soon, so it makes sense not to move it for some time, but wait; this is
+ * especially important in case of "short term" physical eraseblocks.
+ *
+ * Physical eraseblocks stay protected only for limited time. But the "time" is
+ * measured in erase cycles in this case. This is implemented with help of the
+ * absolute erase counter (@wl->abs_ec). When it reaches certain value, the
+ * physical eraseblocks are moved from the protection trees (@wl->prot.*) to
+ * the @wl->used tree.
+ *
+ * Protected physical eraseblocks are searched by physical eraseblock number
+ * (when they are put) and by the absolute erase counter (to check if it is
+ * time to move them to the @wl->used tree). So there are actually 2 RB-trees
+ * storing the protected physical eraseblocks: @wl->prot.pnum and
+ * @wl->prot.aec. They are referred to as the "protection" trees. The
+ * first one is indexed by the physical eraseblock number. The second one is
+ * indexed by the absolute erase counter. Both trees store
+ * &struct ubi_wl_prot_entry objects.
+ *
+ * Each physical eraseblock has 2 main states: free and used. The former state
+ * corresponds to the @wl->free tree. The latter state is split up on several
+ * sub-states:
+ * o the WL movement is allowed (@wl->used tree);
+ * o the WL movement is temporarily prohibited (@wl->prot.pnum and
+ * @wl->prot.aec trees);
+ * o scrubbing is needed (@wl->scrub tree).
+ *
+ * Depending on the sub-state, wear-leveling entries of the used physical
+ * eraseblocks may be kept in one of those trees.
+ */
+struct ubi_wl_prot_entry {
+ struct rb_node rb_pnum;
+ struct rb_node rb_aec;
+ unsigned long long abs_ec;
+ struct ubi_wl_entry *e;
+};
+
+/**
+ * struct ubi_work - UBI work description data structure.
+ * @list: a link in the list of pending works
+ * @func: worker function
+ * @priv: private data of the worker function
+ *
+ * @e: physical eraseblock to erase
+ * @torture: if the physical eraseblock has to be tortured
+ *
+ * The @func pointer points to the worker function. If the @cancel argument is
+ * not zero, the worker has to free the resources and exit immediately. The
+ * worker has to return zero in case of success and a negative error code in
+ * case of failure.
+ */
+struct ubi_work {
+ struct list_head list;
+ int (*func)(struct ubi_device *ubi, struct ubi_work *wrk, int cancel);
+ /* The below fields are only relevant to erasure works */
+ struct ubi_wl_entry *e;
+ int torture;
+};
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec);
+static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
+ struct rb_root *root);
+#else
+#define paranoid_check_ec(ubi, pnum, ec) 0
+#define paranoid_check_in_wl_tree(e, root)
+#endif
+
+/**
+ * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
+ * @e: the wear-leveling entry to add
+ * @root: the root of the tree
+ *
+ * Note, we use (erase counter, physical eraseblock number) pairs as keys in
+ * the @ubi->used and @ubi->free RB-trees.
+ */
+static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
+{
+ struct rb_node **p, *parent = NULL;
+
+ p = &root->rb_node;
+ while (*p) {
+ struct ubi_wl_entry *e1;
+
+ parent = *p;
+ e1 = rb_entry(parent, struct ubi_wl_entry, rb);
+
+ if (e->ec < e1->ec)
+ p = &(*p)->rb_left;
+ else if (e->ec > e1->ec)
+ p = &(*p)->rb_right;
+ else {
+ ubi_assert(e->pnum != e1->pnum);
+ if (e->pnum < e1->pnum)
+ p = &(*p)->rb_left;
+ else
+ p = &(*p)->rb_right;
+ }
+ }
+
+ rb_link_node(&e->rb, parent, p);
+ rb_insert_color(&e->rb, root);
+}
+
+/**
+ * do_work - do one pending work.
+ * @ubi: UBI device description object
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int do_work(struct ubi_device *ubi)
+{
+ int err;
+ struct ubi_work *wrk;
+
+ cond_resched();
+
+ /*
+ * @ubi->work_sem is used to synchronize with the workers. Workers take
+ * it in read mode, so many of them may be doing works at a time. But
+ * the queue flush code has to be sure the whole queue of works is
+ * done, and it takes the mutex in write mode.
+ */
+ down_read(&ubi->work_sem);
+ spin_lock(&ubi->wl_lock);
+ if (list_empty(&ubi->works)) {
+ spin_unlock(&ubi->wl_lock);
+ up_read(&ubi->work_sem);
+ return 0;
+ }
+
+ wrk = list_entry(ubi->works.next, struct ubi_work, list);
+ list_del(&wrk->list);
+ ubi->works_count -= 1;
+ ubi_assert(ubi->works_count >= 0);
+ spin_unlock(&ubi->wl_lock);
+
+ /*
+ * Call the worker function. Do not touch the work structure
+ * after this call as it will have been freed or reused by that
+ * time by the worker function.
+ */
+ err = wrk->func(ubi, wrk, 0);
+ if (err)
+ ubi_err("work failed with error code %d", err);
+ up_read(&ubi->work_sem);
+
+ return err;
+}
+
+/**
+ * produce_free_peb - produce a free physical eraseblock.
+ * @ubi: UBI device description object
+ *
+ * This function tries to make a free PEB by means of synchronous execution of
+ * pending works. This may be needed if, for example the background thread is
+ * disabled. Returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+static int produce_free_peb(struct ubi_device *ubi)
+{
+ int err;
+
+ spin_lock(&ubi->wl_lock);
+ while (!ubi->free.rb_node) {
+ spin_unlock(&ubi->wl_lock);
+
+ dbg_wl("do one work synchronously");
+ err = do_work(ubi);
+ if (err)
+ return err;
+
+ spin_lock(&ubi->wl_lock);
+ }
+ spin_unlock(&ubi->wl_lock);
+
+ return 0;
+}
+
+/**
+ * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree.
+ * @e: the wear-leveling entry to check
+ * @root: the root of the tree
+ *
+ * This function returns non-zero if @e is in the @root RB-tree and zero if it
+ * is not.
+ */
+static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
+{
+ struct rb_node *p;
+
+ p = root->rb_node;
+ while (p) {
+ struct ubi_wl_entry *e1;
+
+ e1 = rb_entry(p, struct ubi_wl_entry, rb);
+
+ if (e->pnum == e1->pnum) {
+ ubi_assert(e == e1);
+ return 1;
+ }
+
+ if (e->ec < e1->ec)
+ p = p->rb_left;
+ else if (e->ec > e1->ec)
+ p = p->rb_right;
+ else {
+ ubi_assert(e->pnum != e1->pnum);
+ if (e->pnum < e1->pnum)
+ p = p->rb_left;
+ else
+ p = p->rb_right;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * prot_tree_add - add physical eraseblock to protection trees.
+ * @ubi: UBI device description object
+ * @e: the physical eraseblock to add
+ * @pe: protection entry object to use
+ * @abs_ec: absolute erase counter value when this physical eraseblock has
+ * to be removed from the protection trees.
+ *
+ * @wl->lock has to be locked.
+ */
+static void prot_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e,
+ struct ubi_wl_prot_entry *pe, int abs_ec)
+{
+ struct rb_node **p, *parent = NULL;
+ struct ubi_wl_prot_entry *pe1;
+
+ pe->e = e;
+ pe->abs_ec = ubi->abs_ec + abs_ec;
+
+ p = &ubi->prot.pnum.rb_node;
+ while (*p) {
+ parent = *p;
+ pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_pnum);
+
+ if (e->pnum < pe1->e->pnum)
+ p = &(*p)->rb_left;
+ else
+ p = &(*p)->rb_right;
+ }
+ rb_link_node(&pe->rb_pnum, parent, p);
+ rb_insert_color(&pe->rb_pnum, &ubi->prot.pnum);
+
+ p = &ubi->prot.aec.rb_node;
+ parent = NULL;
+ while (*p) {
+ parent = *p;
+ pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_aec);
+
+ if (pe->abs_ec < pe1->abs_ec)
+ p = &(*p)->rb_left;
+ else
+ p = &(*p)->rb_right;
+ }
+ rb_link_node(&pe->rb_aec, parent, p);
+ rb_insert_color(&pe->rb_aec, &ubi->prot.aec);
+}
+
+/**
+ * find_wl_entry - find wear-leveling entry closest to certain erase counter.
+ * @root: the RB-tree where to look for
+ * @max: highest possible erase counter
+ *
+ * This function looks for a wear leveling entry with erase counter closest to
+ * @max and less then @max.
+ */
+static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max)
+{
+ struct rb_node *p;
+ struct ubi_wl_entry *e;
+
+ e = rb_entry(rb_first(root), struct ubi_wl_entry, rb);
+ max += e->ec;
+
+ p = root->rb_node;
+ while (p) {
+ struct ubi_wl_entry *e1;
+
+ e1 = rb_entry(p, struct ubi_wl_entry, rb);
+ if (e1->ec >= max)
+ p = p->rb_left;
+ else {
+ p = p->rb_right;
+ e = e1;
+ }
+ }
+
+ return e;
+}
+
+/**
+ * ubi_wl_get_peb - get a physical eraseblock.
+ * @ubi: UBI device description object
+ * @dtype: type of data which will be stored in this physical eraseblock
+ *
+ * This function returns a physical eraseblock in case of success and a
+ * negative error code in case of failure. Might sleep.
+ */
+int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
+{
+ int err, protect, medium_ec;
+ struct ubi_wl_entry *e, *first, *last;
+ struct ubi_wl_prot_entry *pe;
+
+ ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
+ dtype == UBI_UNKNOWN);
+
+ pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
+ if (!pe)
+ return -ENOMEM;
+
+retry:
+ spin_lock(&ubi->wl_lock);
+ if (!ubi->free.rb_node) {
+ if (ubi->works_count == 0) {
+ ubi_assert(list_empty(&ubi->works));
+ ubi_err("no free eraseblocks");
+ spin_unlock(&ubi->wl_lock);
+ kfree(pe);
+ return -ENOSPC;
+ }
+ spin_unlock(&ubi->wl_lock);
+
+ err = produce_free_peb(ubi);
+ if (err < 0) {
+ kfree(pe);
+ return err;
+ }
+ goto retry;
+ }
+
+ switch (dtype) {
+ case UBI_LONGTERM:
+ /*
+ * For long term data we pick a physical eraseblock
+ * with high erase counter. But the highest erase
+ * counter we can pick is bounded by the the lowest
+ * erase counter plus %WL_FREE_MAX_DIFF.
+ */
+ e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+ protect = LT_PROTECTION;
+ break;
+ case UBI_UNKNOWN:
+ /*
+ * For unknown data we pick a physical eraseblock with
+ * medium erase counter. But we by no means can pick a
+ * physical eraseblock with erase counter greater or
+ * equivalent than the lowest erase counter plus
+ * %WL_FREE_MAX_DIFF.
+ */
+ first = rb_entry(rb_first(&ubi->free),
+ struct ubi_wl_entry, rb);
+ last = rb_entry(rb_last(&ubi->free),
+ struct ubi_wl_entry, rb);
+
+ if (last->ec - first->ec < WL_FREE_MAX_DIFF)
+ e = rb_entry(ubi->free.rb_node,
+ struct ubi_wl_entry, rb);
+ else {
+ medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2;
+ e = find_wl_entry(&ubi->free, medium_ec);
+ }
+ protect = U_PROTECTION;
+ break;
+ case UBI_SHORTTERM:
+ /*
+ * For short term data we pick a physical eraseblock
+ * with the lowest erase counter as we expect it will
+ * be erased soon.
+ */
+ e = rb_entry(rb_first(&ubi->free),
+ struct ubi_wl_entry, rb);
+ protect = ST_PROTECTION;
+ break;
+ default:
+ protect = 0;
+ e = NULL;
+ BUG();
+ }
+
+ /*
+ * Move the physical eraseblock to the protection trees where it will
+ * be protected from being moved for some time.
+ */
+ paranoid_check_in_wl_tree(e, &ubi->free);
+ rb_erase(&e->rb, &ubi->free);
+ prot_tree_add(ubi, e, pe, protect);
+
+ dbg_wl("PEB %d EC %d, protection %d", e->pnum, e->ec, protect);
+ spin_unlock(&ubi->wl_lock);
+
+ return e->pnum;
+}
+
+/**
+ * prot_tree_del - remove a physical eraseblock from the protection trees
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock to remove
+ *
+ * This function returns PEB @pnum from the protection trees and returns zero
+ * in case of success and %-ENODEV if the PEB was not found in the protection
+ * trees.
+ */
+static int prot_tree_del(struct ubi_device *ubi, int pnum)
+{
+ struct rb_node *p;
+ struct ubi_wl_prot_entry *pe = NULL;
+
+ p = ubi->prot.pnum.rb_node;
+ while (p) {
+
+ pe = rb_entry(p, struct ubi_wl_prot_entry, rb_pnum);
+
+ if (pnum == pe->e->pnum)
+ goto found;
+
+ if (pnum < pe->e->pnum)
+ p = p->rb_left;
+ else
+ p = p->rb_right;
+ }
+
+ return -ENODEV;
+
+found:
+ ubi_assert(pe->e->pnum == pnum);
+ rb_erase(&pe->rb_aec, &ubi->prot.aec);
+ rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
+ kfree(pe);
+ return 0;
+}
+
+/**
+ * sync_erase - synchronously erase a physical eraseblock.
+ * @ubi: UBI device description object
+ * @e: the the physical eraseblock to erase
+ * @torture: if the physical eraseblock has to be tortured
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int torture)
+{
+ int err;
+ struct ubi_ec_hdr *ec_hdr;
+ unsigned long long ec = e->ec;
+
+ dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec);
+
+ err = paranoid_check_ec(ubi, e->pnum, e->ec);
+ if (err > 0)
+ return -EINVAL;
+
+ ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
+ if (!ec_hdr)
+ return -ENOMEM;
+
+ err = ubi_io_sync_erase(ubi, e->pnum, torture);
+ if (err < 0)
+ goto out_free;
+
+ ec += err;
+ if (ec > UBI_MAX_ERASECOUNTER) {
+ /*
+ * Erase counter overflow. Upgrade UBI and use 64-bit
+ * erase counters internally.
+ */
+ ubi_err("erase counter overflow at PEB %d, EC %llu",
+ e->pnum, ec);
+ err = -EINVAL;
+ goto out_free;
+ }
+
+ dbg_wl("erased PEB %d, new EC %llu", e->pnum, ec);
+
+ ec_hdr->ec = cpu_to_be64(ec);
+
+ err = ubi_io_write_ec_hdr(ubi, e->pnum, ec_hdr);
+ if (err)
+ goto out_free;
+
+ e->ec = ec;
+ spin_lock(&ubi->wl_lock);
+ if (e->ec > ubi->max_ec)
+ ubi->max_ec = e->ec;
+ spin_unlock(&ubi->wl_lock);
+
+out_free:
+ kfree(ec_hdr);
+ return err;
+}
+
+/**
+ * check_protection_over - check if it is time to stop protecting some
+ * physical eraseblocks.
+ * @ubi: UBI device description object
+ *
+ * This function is called after each erase operation, when the absolute erase
+ * counter is incremented, to check if some physical eraseblock have not to be
+ * protected any longer. These physical eraseblocks are moved from the
+ * protection trees to the used tree.
+ */
+static void check_protection_over(struct ubi_device *ubi)
+{
+ struct ubi_wl_prot_entry *pe;
+
+ /*
+ * There may be several protected physical eraseblock to remove,
+ * process them all.
+ */
+ while (1) {
+ spin_lock(&ubi->wl_lock);
+ if (!ubi->prot.aec.rb_node) {
+ spin_unlock(&ubi->wl_lock);
+ break;
+ }
+
+ pe = rb_entry(rb_first(&ubi->prot.aec),
+ struct ubi_wl_prot_entry, rb_aec);
+
+ if (pe->abs_ec > ubi->abs_ec) {
+ spin_unlock(&ubi->wl_lock);
+ break;
+ }
+
+ dbg_wl("PEB %d protection over, abs_ec %llu, PEB abs_ec %llu",
+ pe->e->pnum, ubi->abs_ec, pe->abs_ec);
+ rb_erase(&pe->rb_aec, &ubi->prot.aec);
+ rb_erase(&pe->rb_pnum, &ubi->prot.pnum);
+ wl_tree_add(pe->e, &ubi->used);
+ spin_unlock(&ubi->wl_lock);
+
+ kfree(pe);
+ cond_resched();
+ }
+}
+
+/**
+ * schedule_ubi_work - schedule a work.
+ * @ubi: UBI device description object
+ * @wrk: the work to schedule
+ *
+ * This function enqueues a work defined by @wrk to the tail of the pending
+ * works list.
+ */
+static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
+{
+ spin_lock(&ubi->wl_lock);
+ list_add_tail(&wrk->list, &ubi->works);
+ ubi_assert(ubi->works_count >= 0);
+ ubi->works_count += 1;
+ if (ubi->thread_enabled)
+ wake_up_process(ubi->bgt_thread);
+ spin_unlock(&ubi->wl_lock);
+}
+
+static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
+ int cancel);
+
+/**
+ * schedule_erase - schedule an erase work.
+ * @ubi: UBI device description object
+ * @e: the WL entry of the physical eraseblock to erase
+ * @torture: if the physical eraseblock has to be tortured
+ *
+ * This function returns zero in case of success and a %-ENOMEM in case of
+ * failure.
+ */
+static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
+ int torture)
+{
+ struct ubi_work *wl_wrk;
+
+ dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
+ e->pnum, e->ec, torture);
+
+ wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+ if (!wl_wrk)
+ return -ENOMEM;
+
+ wl_wrk->func = &erase_worker;
+ wl_wrk->e = e;
+ wl_wrk->torture = torture;
+
+ schedule_ubi_work(ubi, wl_wrk);
+ return 0;
+}
+
+/**
+ * wear_leveling_worker - wear-leveling worker function.
+ * @ubi: UBI device description object
+ * @wrk: the work object
+ * @cancel: non-zero if the worker has to free memory and exit
+ *
+ * This function copies a more worn out physical eraseblock to a less worn out
+ * one. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
+ int cancel)
+{
+ int err, put = 0, scrubbing = 0, protect = 0;
+ struct ubi_wl_prot_entry *uninitialized_var(pe);
+ struct ubi_wl_entry *e1, *e2;
+ struct ubi_vid_hdr *vid_hdr;
+
+ kfree(wrk);
+
+ if (cancel)
+ return 0;
+
+ vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
+ if (!vid_hdr)
+ return -ENOMEM;
+
+ mutex_lock(&ubi->move_mutex);
+ spin_lock(&ubi->wl_lock);
+ ubi_assert(!ubi->move_from && !ubi->move_to);
+ ubi_assert(!ubi->move_to_put);
+
+ if (!ubi->free.rb_node ||
+ (!ubi->used.rb_node && !ubi->scrub.rb_node)) {
+ /*
+ * No free physical eraseblocks? Well, they must be waiting in
+ * the queue to be erased. Cancel movement - it will be
+ * triggered again when a free physical eraseblock appears.
+ *
+ * No used physical eraseblocks? They must be temporarily
+ * protected from being moved. They will be moved to the
+ * @ubi->used tree later and the wear-leveling will be
+ * triggered again.
+ */
+ dbg_wl("cancel WL, a list is empty: free %d, used %d",
+ !ubi->free.rb_node, !ubi->used.rb_node);
+ goto out_cancel;
+ }
+
+ if (!ubi->scrub.rb_node) {
+ /*
+ * Now pick the least worn-out used physical eraseblock and a
+ * highly worn-out free physical eraseblock. If the erase
+ * counters differ much enough, start wear-leveling.
+ */
+ e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb);
+ e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+
+ if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
+ dbg_wl("no WL needed: min used EC %d, max free EC %d",
+ e1->ec, e2->ec);
+ goto out_cancel;
+ }
+ paranoid_check_in_wl_tree(e1, &ubi->used);
+ rb_erase(&e1->rb, &ubi->used);
+ dbg_wl("move PEB %d EC %d to PEB %d EC %d",
+ e1->pnum, e1->ec, e2->pnum, e2->ec);
+ } else {
+ /* Perform scrubbing */
+ scrubbing = 1;
+ e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, rb);
+ e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+ paranoid_check_in_wl_tree(e1, &ubi->scrub);
+ rb_erase(&e1->rb, &ubi->scrub);
+ dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
+ }
+
+ paranoid_check_in_wl_tree(e2, &ubi->free);
+ rb_erase(&e2->rb, &ubi->free);
+ ubi->move_from = e1;
+ ubi->move_to = e2;
+ spin_unlock(&ubi->wl_lock);
+
+ /*
+ * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum.
+ * We so far do not know which logical eraseblock our physical
+ * eraseblock (@e1) belongs to. We have to read the volume identifier
+ * header first.
+ *
+ * Note, we are protected from this PEB being unmapped and erased. The
+ * 'ubi_wl_put_peb()' would wait for moving to be finished if the PEB
+ * which is being moved was unmapped.
+ */
+
+ err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);
+ if (err && err != UBI_IO_BITFLIPS) {
+ if (err == UBI_IO_PEB_FREE) {
+ /*
+ * We are trying to move PEB without a VID header. UBI
+ * always write VID headers shortly after the PEB was
+ * given, so we have a situation when it did not have
+ * chance to write it down because it was preempted.
+ * Just re-schedule the work, so that next time it will
+ * likely have the VID header in place.
+ */
+ dbg_wl("PEB %d has no VID header", e1->pnum);
+ goto out_not_moved;
+ }
+
+ ubi_err("error %d while reading VID header from PEB %d",
+ err, e1->pnum);
+ if (err > 0)
+ err = -EIO;
+ goto out_error;
+ }
+
+ err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
+ if (err) {
+
+ if (err < 0)
+ goto out_error;
+ if (err == 1)
+ goto out_not_moved;
+
+ /*
+ * For some reason the LEB was not moved - it might be because
+ * the volume is being deleted. We should prevent this PEB from
+ * being selected for wear-levelling movement for some "time",
+ * so put it to the protection tree.
+ */
+
+ dbg_wl("cancelled moving PEB %d", e1->pnum);
+ pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
+ if (!pe) {
+ err = -ENOMEM;
+ goto out_error;
+ }
+
+ protect = 1;
+ }
+
+ ubi_free_vid_hdr(ubi, vid_hdr);
+ spin_lock(&ubi->wl_lock);
+ if (protect)
+ prot_tree_add(ubi, e1, pe, protect);
+ if (!ubi->move_to_put)
+ wl_tree_add(e2, &ubi->used);
+ else
+ put = 1;
+ ubi->move_from = ubi->move_to = NULL;
+ ubi->move_to_put = ubi->wl_scheduled = 0;
+ spin_unlock(&ubi->wl_lock);
+
+ if (put) {
+ /*
+ * Well, the target PEB was put meanwhile, schedule it for
+ * erasure.
+ */
+ dbg_wl("PEB %d was put meanwhile, erase", e2->pnum);
+ err = schedule_erase(ubi, e2, 0);
+ if (err)
+ goto out_error;
+ }
+
+ if (!protect) {
+ err = schedule_erase(ubi, e1, 0);
+ if (err)
+ goto out_error;
+ }
+
+
+ dbg_wl("done");
+ mutex_unlock(&ubi->move_mutex);
+ return 0;
+
+ /*
+ * For some reasons the LEB was not moved, might be an error, might be
+ * something else. @e1 was not changed, so return it back. @e2 might
+ * be changed, schedule it for erasure.
+ */
+out_not_moved:
+ ubi_free_vid_hdr(ubi, vid_hdr);
+ spin_lock(&ubi->wl_lock);
+ if (scrubbing)
+ wl_tree_add(e1, &ubi->scrub);
+ else
+ wl_tree_add(e1, &ubi->used);
+ ubi->move_from = ubi->move_to = NULL;
+ ubi->move_to_put = ubi->wl_scheduled = 0;
+ spin_unlock(&ubi->wl_lock);
+
+ err = schedule_erase(ubi, e2, 0);
+ if (err)
+ goto out_error;
+
+ mutex_unlock(&ubi->move_mutex);
+ return 0;
+
+out_error:
+ ubi_err("error %d while moving PEB %d to PEB %d",
+ err, e1->pnum, e2->pnum);
+
+ ubi_free_vid_hdr(ubi, vid_hdr);
+ spin_lock(&ubi->wl_lock);
+ ubi->move_from = ubi->move_to = NULL;
+ ubi->move_to_put = ubi->wl_scheduled = 0;
+ spin_unlock(&ubi->wl_lock);
+
+ kmem_cache_free(ubi_wl_entry_slab, e1);
+ kmem_cache_free(ubi_wl_entry_slab, e2);
+ ubi_ro_mode(ubi);
+
+ mutex_unlock(&ubi->move_mutex);
+ return err;
+
+out_cancel:
+ ubi->wl_scheduled = 0;
+ spin_unlock(&ubi->wl_lock);
+ mutex_unlock(&ubi->move_mutex);
+ ubi_free_vid_hdr(ubi, vid_hdr);
+ return 0;
+}
+
+/**
+ * ensure_wear_leveling - schedule wear-leveling if it is needed.
+ * @ubi: UBI device description object
+ *
+ * This function checks if it is time to start wear-leveling and schedules it
+ * if yes. This function returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+static int ensure_wear_leveling(struct ubi_device *ubi)
+{
+ int err = 0;
+ struct ubi_wl_entry *e1;
+ struct ubi_wl_entry *e2;
+ struct ubi_work *wrk;
+
+ spin_lock(&ubi->wl_lock);
+ if (ubi->wl_scheduled)
+ /* Wear-leveling is already in the work queue */
+ goto out_unlock;
+
+ /*
+ * If the ubi->scrub tree is not empty, scrubbing is needed, and the
+ * the WL worker has to be scheduled anyway.
+ */
+ if (!ubi->scrub.rb_node) {
+ if (!ubi->used.rb_node || !ubi->free.rb_node)
+ /* No physical eraseblocks - no deal */
+ goto out_unlock;
+
+ /*
+ * We schedule wear-leveling only if the difference between the
+ * lowest erase counter of used physical eraseblocks and a high
+ * erase counter of free physical eraseblocks is greater then
+ * %UBI_WL_THRESHOLD.
+ */
+ e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb);
+ e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+
+ if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
+ goto out_unlock;
+ dbg_wl("schedule wear-leveling");
+ } else
+ dbg_wl("schedule scrubbing");
+
+ ubi->wl_scheduled = 1;
+ spin_unlock(&ubi->wl_lock);
+
+ wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+ if (!wrk) {
+ err = -ENOMEM;
+ goto out_cancel;
+ }
+
+ wrk->func = &wear_leveling_worker;
+ schedule_ubi_work(ubi, wrk);
+ return err;
+
+out_cancel:
+ spin_lock(&ubi->wl_lock);
+ ubi->wl_scheduled = 0;
+out_unlock:
+ spin_unlock(&ubi->wl_lock);
+ return err;
+}
+
+/**
+ * erase_worker - physical eraseblock erase worker function.
+ * @ubi: UBI device description object
+ * @wl_wrk: the work object
+ * @cancel: non-zero if the worker has to free memory and exit
+ *
+ * This function erases a physical eraseblock and perform torture testing if
+ * needed. It also takes care about marking the physical eraseblock bad if
+ * needed. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
+ int cancel)
+{
+ struct ubi_wl_entry *e = wl_wrk->e;
+ int pnum = e->pnum, err, need;
+
+ if (cancel) {
+ dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
+ kfree(wl_wrk);
+ kmem_cache_free(ubi_wl_entry_slab, e);
+ return 0;
+ }
+
+ dbg_wl("erase PEB %d EC %d", pnum, e->ec);
+
+ err = sync_erase(ubi, e, wl_wrk->torture);
+ if (!err) {
+ /* Fine, we've erased it successfully */
+ kfree(wl_wrk);
+
+ spin_lock(&ubi->wl_lock);
+ ubi->abs_ec += 1;
+ wl_tree_add(e, &ubi->free);
+ spin_unlock(&ubi->wl_lock);
+
+ /*
+ * One more erase operation has happened, take care about protected
+ * physical eraseblocks.
+ */
+ check_protection_over(ubi);
+
+ /* And take care about wear-leveling */
+ err = ensure_wear_leveling(ubi);
+ return err;
+ }
+
+ ubi_err("failed to erase PEB %d, error %d", pnum, err);
+ kfree(wl_wrk);
+ kmem_cache_free(ubi_wl_entry_slab, e);
+
+ if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
+ err == -EBUSY) {
+ int err1;
+
+ /* Re-schedule the LEB for erasure */
+ err1 = schedule_erase(ubi, e, 0);
+ if (err1) {
+ err = err1;
+ goto out_ro;
+ }
+ return err;
+ } else if (err != -EIO) {
+ /*
+ * If this is not %-EIO, we have no idea what to do. Scheduling
+ * this physical eraseblock for erasure again would cause
+ * errors again and again. Well, lets switch to RO mode.
+ */
+ goto out_ro;
+ }
+
+ /* It is %-EIO, the PEB went bad */
+
+ if (!ubi->bad_allowed) {
+ ubi_err("bad physical eraseblock %d detected", pnum);
+ goto out_ro;
+ }
+
+ spin_lock(&ubi->volumes_lock);
+ need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs + 1;
+ if (need > 0) {
+ need = ubi->avail_pebs >= need ? need : ubi->avail_pebs;
+ ubi->avail_pebs -= need;
+ ubi->rsvd_pebs += need;
+ ubi->beb_rsvd_pebs += need;
+ if (need > 0)
+ ubi_msg("reserve more %d PEBs", need);
+ }
+
+ if (ubi->beb_rsvd_pebs == 0) {
+ spin_unlock(&ubi->volumes_lock);
+ ubi_err("no reserved physical eraseblocks");
+ goto out_ro;
+ }
+
+ spin_unlock(&ubi->volumes_lock);
+ ubi_msg("mark PEB %d as bad", pnum);
+
+ err = ubi_io_mark_bad(ubi, pnum);
+ if (err)
+ goto out_ro;
+
+ spin_lock(&ubi->volumes_lock);
+ ubi->beb_rsvd_pebs -= 1;
+ ubi->bad_peb_count += 1;
+ ubi->good_peb_count -= 1;
+ ubi_calculate_reserved(ubi);
+ if (ubi->beb_rsvd_pebs == 0)
+ ubi_warn("last PEB from the reserved pool was used");
+ spin_unlock(&ubi->volumes_lock);
+
+ return err;
+
+out_ro:
+ ubi_ro_mode(ubi);
+ return err;
+}
+
+/**
+ * ubi_wl_put_peb - return a physical eraseblock to the wear-leveling unit.
+ * @ubi: UBI device description object
+ * @pnum: physical eraseblock to return
+ * @torture: if this physical eraseblock has to be tortured
+ *
+ * This function is called to return physical eraseblock @pnum to the pool of
+ * free physical eraseblocks. The @torture flag has to be set if an I/O error
+ * occurred to this @pnum and it has to be tested. This function returns zero
+ * in case of success, and a negative error code in case of failure.
+ */
+int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture)
+{
+ int err;
+ struct ubi_wl_entry *e;
+
+ dbg_wl("PEB %d", pnum);
+ ubi_assert(pnum >= 0);
+ ubi_assert(pnum < ubi->peb_count);
+
+retry:
+ spin_lock(&ubi->wl_lock);
+ e = ubi->lookuptbl[pnum];
+ if (e == ubi->move_from) {
+ /*
+ * User is putting the physical eraseblock which was selected to
+ * be moved. It will be scheduled for erasure in the
+ * wear-leveling worker.
+ */
+ dbg_wl("PEB %d is being moved, wait", pnum);
+ spin_unlock(&ubi->wl_lock);
+
+ /* Wait for the WL worker by taking the @ubi->move_mutex */
+ mutex_lock(&ubi->move_mutex);
+ mutex_unlock(&ubi->move_mutex);
+ goto retry;
+ } else if (e == ubi->move_to) {
+ /*
+ * User is putting the physical eraseblock which was selected
+ * as the target the data is moved to. It may happen if the EBA
+ * unit already re-mapped the LEB in 'ubi_eba_copy_leb()' but
+ * the WL unit has not put the PEB to the "used" tree yet, but
+ * it is about to do this. So we just set a flag which will
+ * tell the WL worker that the PEB is not needed anymore and
+ * should be scheduled for erasure.
+ */
+ dbg_wl("PEB %d is the target of data moving", pnum);
+ ubi_assert(!ubi->move_to_put);
+ ubi->move_to_put = 1;
+ spin_unlock(&ubi->wl_lock);
+ return 0;
+ } else {
+ if (in_wl_tree(e, &ubi->used)) {
+ paranoid_check_in_wl_tree(e, &ubi->used);
+ rb_erase(&e->rb, &ubi->used);
+ } else if (in_wl_tree(e, &ubi->scrub)) {
+ paranoid_check_in_wl_tree(e, &ubi->scrub);
+ rb_erase(&e->rb, &ubi->scrub);
+ } else {
+ err = prot_tree_del(ubi, e->pnum);
+ if (err) {
+ ubi_err("PEB %d not found", pnum);
+ ubi_ro_mode(ubi);
+ spin_unlock(&ubi->wl_lock);
+ return err;
+ }
+ }
+ }
+ spin_unlock(&ubi->wl_lock);
+
+ err = schedule_erase(ubi, e, torture);
+ if (err) {
+ spin_lock(&ubi->wl_lock);
+ wl_tree_add(e, &ubi->used);
+ spin_unlock(&ubi->wl_lock);
+ }
+
+ return err;
+}
+
+/**
+ * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock to schedule
+ *
+ * If a bit-flip in a physical eraseblock is detected, this physical eraseblock
+ * needs scrubbing. This function schedules a physical eraseblock for
+ * scrubbing which is done in background. This function returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
+{
+ struct ubi_wl_entry *e;
+
+ ubi_msg("schedule PEB %d for scrubbing", pnum);
+
+retry:
+ spin_lock(&ubi->wl_lock);
+ e = ubi->lookuptbl[pnum];
+ if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub)) {
+ spin_unlock(&ubi->wl_lock);
+ return 0;
+ }
+
+ if (e == ubi->move_to) {
+ /*
+ * This physical eraseblock was used to move data to. The data
+ * was moved but the PEB was not yet inserted to the proper
+ * tree. We should just wait a little and let the WL worker
+ * proceed.
+ */
+ spin_unlock(&ubi->wl_lock);
+ dbg_wl("the PEB %d is not in proper tree, retry", pnum);
+ yield();
+ goto retry;
+ }
+
+ if (in_wl_tree(e, &ubi->used)) {
+ paranoid_check_in_wl_tree(e, &ubi->used);
+ rb_erase(&e->rb, &ubi->used);
+ } else {
+ int err;
+
+ err = prot_tree_del(ubi, e->pnum);
+ if (err) {
+ ubi_err("PEB %d not found", pnum);
+ ubi_ro_mode(ubi);
+ spin_unlock(&ubi->wl_lock);
+ return err;
+ }
+ }
+
+ wl_tree_add(e, &ubi->scrub);
+ spin_unlock(&ubi->wl_lock);
+
+ /*
+ * Technically scrubbing is the same as wear-leveling, so it is done
+ * by the WL worker.
+ */
+ return ensure_wear_leveling(ubi);
+}
+
+/**
+ * ubi_wl_flush - flush all pending works.
+ * @ubi: UBI device description object
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+int ubi_wl_flush(struct ubi_device *ubi)
+{
+ int err;
+
+ /*
+ * Erase while the pending works queue is not empty, but not more then
+ * the number of currently pending works.
+ */
+ dbg_wl("flush (%d pending works)", ubi->works_count);
+ while (ubi->works_count) {
+ err = do_work(ubi);
+ if (err)
+ return err;
+ }
+
+ /*
+ * Make sure all the works which have been done in parallel are
+ * finished.
+ */
+ down_write(&ubi->work_sem);
+ up_write(&ubi->work_sem);
+
+ /*
+ * And in case last was the WL worker and it cancelled the LEB
+ * movement, flush again.
+ */
+ while (ubi->works_count) {
+ dbg_wl("flush more (%d pending works)", ubi->works_count);
+ err = do_work(ubi);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * tree_destroy - destroy an RB-tree.
+ * @root: the root of the tree to destroy
+ */
+static void tree_destroy(struct rb_root *root)
+{
+ struct rb_node *rb;
+ struct ubi_wl_entry *e;
+
+ rb = root->rb_node;
+ while (rb) {
+ if (rb->rb_left)
+ rb = rb->rb_left;
+ else if (rb->rb_right)
+ rb = rb->rb_right;
+ else {
+ e = rb_entry(rb, struct ubi_wl_entry, rb);
+
+ rb = rb_parent(rb);
+ if (rb) {
+ if (rb->rb_left == &e->rb)
+ rb->rb_left = NULL;
+ else
+ rb->rb_right = NULL;
+ }
+
+ kmem_cache_free(ubi_wl_entry_slab, e);
+ }
+ }
+}
+
+/**
+ * ubi_thread - UBI background thread.
+ * @u: the UBI device description object pointer
+ */
+int ubi_thread(void *u)
+{
+ int failures = 0;
+ struct ubi_device *ubi = u;
+
+ ubi_msg("background thread \"%s\" started, PID %d",
+ ubi->bgt_name, task_pid_nr(current));
+
+ set_freezable();
+ for (;;) {
+ int err;
+
+ if (kthread_should_stop())
+ break;
+
+ if (try_to_freeze())
+ continue;
+
+ spin_lock(&ubi->wl_lock);
+ if (list_empty(&ubi->works) || ubi->ro_mode ||
+ !ubi->thread_enabled) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ spin_unlock(&ubi->wl_lock);
+ schedule();
+ continue;
+ }
+ spin_unlock(&ubi->wl_lock);
+
+ err = do_work(ubi);
+ if (err) {
+ ubi_err("%s: work failed with error code %d",
+ ubi->bgt_name, err);
+ if (failures++ > WL_MAX_FAILURES) {
+ /*
+ * Too many failures, disable the thread and
+ * switch to read-only mode.
+ */
+ ubi_msg("%s: %d consecutive failures",
+ ubi->bgt_name, WL_MAX_FAILURES);
+ ubi_ro_mode(ubi);
+ break;
+ }
+ } else
+ failures = 0;
+
+ cond_resched();
+ }
+
+ dbg_wl("background thread \"%s\" is killed", ubi->bgt_name);
+ return 0;
+}
+
+/**
+ * cancel_pending - cancel all pending works.
+ * @ubi: UBI device description object
+ */
+static void cancel_pending(struct ubi_device *ubi)
+{
+ while (!list_empty(&ubi->works)) {
+ struct ubi_work *wrk;
+
+ wrk = list_entry(ubi->works.next, struct ubi_work, list);
+ list_del(&wrk->list);
+ wrk->func(ubi, wrk, 1);
+ ubi->works_count -= 1;
+ ubi_assert(ubi->works_count >= 0);
+ }
+}
+
+/**
+ * ubi_wl_init_scan - initialize the wear-leveling unit using scanning
+ * information.
+ * @ubi: UBI device description object
+ * @si: scanning information
+ *
+ * This function returns zero in case of success, and a negative error code in
+ * case of failure.
+ */
+int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
+{
+ int err;
+ struct rb_node *rb1, *rb2;
+ struct ubi_scan_volume *sv;
+ struct ubi_scan_leb *seb, *tmp;
+ struct ubi_wl_entry *e;
+
+
+ ubi->used = ubi->free = ubi->scrub = RB_ROOT;
+ ubi->prot.pnum = ubi->prot.aec = RB_ROOT;
+ spin_lock_init(&ubi->wl_lock);
+ mutex_init(&ubi->move_mutex);
+ init_rwsem(&ubi->work_sem);
+ ubi->max_ec = si->max_ec;
+ INIT_LIST_HEAD(&ubi->works);
+
+ sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
+
+ err = -ENOMEM;
+ ubi->lookuptbl = kzalloc(ubi->peb_count * sizeof(void *), GFP_KERNEL);
+ if (!ubi->lookuptbl)
+ return err;
+
+ list_for_each_entry_safe(seb, tmp, &si->erase, u.list) {
+ cond_resched();
+
+ e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
+ if (!e)
+ goto out_free;
+
+ e->pnum = seb->pnum;
+ e->ec = seb->ec;
+ ubi->lookuptbl[e->pnum] = e;
+ if (schedule_erase(ubi, e, 0)) {
+ kmem_cache_free(ubi_wl_entry_slab, e);
+ goto out_free;
+ }
+ }
+
+ list_for_each_entry(seb, &si->free, u.list) {
+ cond_resched();
+
+ e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
+ if (!e)
+ goto out_free;
+
+ e->pnum = seb->pnum;
+ e->ec = seb->ec;
+ ubi_assert(e->ec >= 0);
+ wl_tree_add(e, &ubi->free);
+ ubi->lookuptbl[e->pnum] = e;
+ }
+
+ list_for_each_entry(seb, &si->corr, u.list) {
+ cond_resched();
+
+ e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
+ if (!e)
+ goto out_free;
+
+ e->pnum = seb->pnum;
+ e->ec = seb->ec;
+ ubi->lookuptbl[e->pnum] = e;
+ if (schedule_erase(ubi, e, 0)) {
+ kmem_cache_free(ubi_wl_entry_slab, e);
+ goto out_free;
+ }
+ }
+
+ ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) {
+ ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) {
+ cond_resched();
+
+ e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
+ if (!e)
+ goto out_free;
+
+ e->pnum = seb->pnum;
+ e->ec = seb->ec;
+ ubi->lookuptbl[e->pnum] = e;
+ if (!seb->scrub) {
+ dbg_wl("add PEB %d EC %d to the used tree",
+ e->pnum, e->ec);
+ wl_tree_add(e, &ubi->used);
+ } else {
+ dbg_wl("add PEB %d EC %d to the scrub tree",
+ e->pnum, e->ec);
+ wl_tree_add(e, &ubi->scrub);
+ }
+ }
+ }
+
+ if (ubi->avail_pebs < WL_RESERVED_PEBS) {
+ ubi_err("no enough physical eraseblocks (%d, need %d)",
+ ubi->avail_pebs, WL_RESERVED_PEBS);
+ goto out_free;
+ }
+ ubi->avail_pebs -= WL_RESERVED_PEBS;
+ ubi->rsvd_pebs += WL_RESERVED_PEBS;
+
+ /* Schedule wear-leveling if needed */
+ err = ensure_wear_leveling(ubi);
+ if (err)
+ goto out_free;
+
+ return 0;
+
+out_free:
+ cancel_pending(ubi);
+ tree_destroy(&ubi->used);
+ tree_destroy(&ubi->free);
+ tree_destroy(&ubi->scrub);
+ kfree(ubi->lookuptbl);
+ return err;
+}
+
+/**
+ * protection_trees_destroy - destroy the protection RB-trees.
+ * @ubi: UBI device description object
+ */
+static void protection_trees_destroy(struct ubi_device *ubi)
+{
+ struct rb_node *rb;
+ struct ubi_wl_prot_entry *pe;
+
+ rb = ubi->prot.aec.rb_node;
+ while (rb) {
+ if (rb->rb_left)
+ rb = rb->rb_left;
+ else if (rb->rb_right)
+ rb = rb->rb_right;
+ else {
+ pe = rb_entry(rb, struct ubi_wl_prot_entry, rb_aec);
+
+ rb = rb_parent(rb);
+ if (rb) {
+ if (rb->rb_left == &pe->rb_aec)
+ rb->rb_left = NULL;
+ else
+ rb->rb_right = NULL;
+ }
+
+ kmem_cache_free(ubi_wl_entry_slab, pe->e);
+ kfree(pe);
+ }
+ }
+}
+
+/**
+ * ubi_wl_close - close the wear-leveling unit.
+ * @ubi: UBI device description object
+ */
+void ubi_wl_close(struct ubi_device *ubi)
+{
+ dbg_wl("close the UBI wear-leveling unit");
+
+ cancel_pending(ubi);
+ protection_trees_destroy(ubi);
+ tree_destroy(&ubi->used);
+ tree_destroy(&ubi->free);
+ tree_destroy(&ubi->scrub);
+ kfree(ubi->lookuptbl);
+}
+
+#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
+
+/**
+ * paranoid_check_ec - make sure that the erase counter of a physical eraseblock
+ * is correct.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to check
+ * @ec: the erase counter to check
+ *
+ * This function returns zero if the erase counter of physical eraseblock @pnum
+ * is equivalent to @ec, %1 if not, and a negative error code if an error
+ * occurred.
+ */
+static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec)
+{
+ int err;
+ long long read_ec;
+ struct ubi_ec_hdr *ec_hdr;
+
+ ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
+ if (!ec_hdr)
+ return -ENOMEM;
+
+ err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
+ if (err && err != UBI_IO_BITFLIPS) {
+ /* The header does not have to exist */
+ err = 0;
+ goto out_free;
+ }
+
+ read_ec = be64_to_cpu(ec_hdr->ec);
+ if (ec != read_ec) {
+ ubi_err("paranoid check failed for PEB %d", pnum);
+ ubi_err("read EC is %lld, should be %d", read_ec, ec);
+ ubi_dbg_dump_stack();
+ err = 1;
+ } else
+ err = 0;
+
+out_free:
+ kfree(ec_hdr);
+ return err;
+}
+
+/**
+ * paranoid_check_in_wl_tree - make sure that a wear-leveling entry is present
+ * in a WL RB-tree.
+ * @e: the wear-leveling entry to check
+ * @root: the root of the tree
+ *
+ * This function returns zero if @e is in the @root RB-tree and %1 if it
+ * is not.
+ */
+static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e,
+ struct rb_root *root)
+{
+ if (in_wl_tree(e, root))
+ return 0;
+
+ ubi_err("paranoid check failed for PEB %d, EC %d, RB-tree %p ",
+ e->pnum, e->ec, root);
+ ubi_dbg_dump_stack();
+ return 1;
+}
+
+#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */
diff --git a/include/linux/crc32.h b/include/linux/crc32.h
new file mode 100644
index 0000000..ac4aed1
--- /dev/null
+++ b/include/linux/crc32.h
@@ -0,0 +1,27 @@
+/*
+ * crc32.h
+ * See linux/lib/crc32.c for license and changes
+ */
+#ifndef _LINUX_CRC32_H
+#define _LINUX_CRC32_H
+
+#include <linux/types.h>
+/* #include <linux/bitrev.h> */
+
+extern u32 crc32_le(u32 crc, unsigned char const *p, size_t len);
+/* extern u32 crc32_be(u32 crc, unsigned char const *p, size_t len); */
+
+#define crc32(seed, data, length) crc32_le(seed, (unsigned char const *)data, length)
+
+/*
+ * Helpers for hash table generation of ethernet nics:
+ *
+ * Ethernet sends the least significant bit of a byte first, thus crc32_le
+ * is used. The output of crc32_le is bit reversed [most significant bit
+ * is in bit nr 0], thus it must be reversed before use. Except for
+ * nics that bit swap the result internally...
+ */
+/* #define ether_crc(length, data) bitrev32(crc32_le(~0, data, length)) */
+/* #define ether_crc_le(length, data) crc32_le(~0, data, length) */
+
+#endif /* _LINUX_CRC32_H */
diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h
new file mode 100644
index 0000000..43d9b38
--- /dev/null
+++ b/include/linux/mtd/ubi.h
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * 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)
+ */
+
+#ifndef __LINUX_UBI_H__
+#define __LINUX_UBI_H__
+
+/* #include <asm/ioctl.h> */
+#include <linux/types.h>
+#include <mtd/ubi-user.h>
+
+/*
+ * enum ubi_open_mode - UBI volume open mode constants.
+ *
+ * UBI_READONLY: read-only mode
+ * UBI_READWRITE: read-write mode
+ * UBI_EXCLUSIVE: exclusive mode
+ */
+enum {
+ UBI_READONLY = 1,
+ UBI_READWRITE,
+ UBI_EXCLUSIVE
+};
+
+/**
+ * struct ubi_volume_info - UBI volume description data structure.
+ * @vol_id: volume ID
+ * @ubi_num: UBI device number this volume belongs to
+ * @size: how many physical eraseblocks are reserved for this volume
+ * @used_bytes: how many bytes of data this volume contains
+ * @used_ebs: how many physical eraseblocks of this volume actually contain any
+ * data
+ * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
+ * @corrupted: non-zero if the volume is corrupted (static volumes only)
+ * @upd_marker: non-zero if the volume has update marker set
+ * @alignment: volume alignment
+ * @usable_leb_size: how many bytes are available in logical eraseblocks of
+ * this volume
+ * @name_len: volume name length
+ * @name: volume name
+ * @cdev: UBI volume character device major and minor numbers
+ *
+ * The @corrupted flag is only relevant to static volumes and is always zero
+ * for dynamic ones. This is because UBI does not care about dynamic volume
+ * data protection and only cares about protecting static volume data.
+ *
+ * The @upd_marker flag is set if the volume update operation was interrupted.
+ * Before touching the volume data during the update operation, UBI first sets
+ * the update marker flag for this volume. If the volume update operation was
+ * further interrupted, the update marker indicates this. If the update marker
+ * is set, the contents of the volume is certainly damaged and a new volume
+ * update operation has to be started.
+ *
+ * To put it differently, @corrupted and @upd_marker fields have different
+ * semantics:
+ * o the @corrupted flag means that this static volume is corrupted for some
+ * reasons, but not because an interrupted volume update
+ * o the @upd_marker field means that the volume is damaged because of an
+ * interrupted update operation.
+ *
+ * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
+ *
+ * The @used_bytes and @used_ebs fields are only really needed for static
+ * volumes and contain the number of bytes stored in this static volume and how
+ * many eraseblock this data occupies. In case of dynamic volumes, the
+ * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
+ * field is equivalent to @size.
+ *
+ * In general, logical eraseblock size is a property of the UBI device, not
+ * of the UBI volume. Indeed, the logical eraseblock size depends on the
+ * physical eraseblock size and on how much bytes UBI headers consume. But
+ * because of the volume alignment (@alignment), the usable size of logical
+ * eraseblocks if a volume may be less. The following equation is true:
+ * @usable_leb_size = LEB size - (LEB size mod @alignment),
+ * where LEB size is the logical eraseblock size defined by the UBI device.
+ *
+ * The alignment is multiple to the minimal flash input/output unit size or %1
+ * if all the available space is used.
+ *
+ * To put this differently, alignment may be considered is a way to change
+ * volume logical eraseblock sizes.
+ */
+struct ubi_volume_info {
+ int ubi_num;
+ int vol_id;
+ int size;
+ long long used_bytes;
+ int used_ebs;
+ int vol_type;
+ int corrupted;
+ int upd_marker;
+ int alignment;
+ int usable_leb_size;
+ int name_len;
+ const char *name;
+ dev_t cdev;
+};
+
+/**
+ * struct ubi_device_info - UBI device description data structure.
+ * @ubi_num: ubi device number
+ * @leb_size: logical eraseblock size on this UBI device
+ * @min_io_size: minimal I/O unit size
+ * @ro_mode: if this device is in read-only mode
+ * @cdev: UBI character device major and minor numbers
+ *
+ * Note, @leb_size is the logical eraseblock size offered by the UBI device.
+ * Volumes of this UBI device may have smaller logical eraseblock size if their
+ * alignment is not equivalent to %1.
+ */
+struct ubi_device_info {
+ int ubi_num;
+ int leb_size;
+ int min_io_size;
+ int ro_mode;
+ dev_t cdev;
+};
+
+/* UBI descriptor given to users when they open UBI volumes */
+struct ubi_volume_desc;
+
+int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
+void ubi_get_volume_info(struct ubi_volume_desc *desc,
+ struct ubi_volume_info *vi);
+struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
+struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
+ int mode);
+void ubi_close_volume(struct ubi_volume_desc *desc);
+int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
+ int len, int check);
+int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
+ int offset, int len, int dtype);
+int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
+ int len, int dtype);
+int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
+int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
+int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype);
+int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
+
+/*
+ * This function is the same as the 'ubi_leb_read()' function, but it does not
+ * provide the checking capability.
+ */
+static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
+ int offset, int len)
+{
+ return ubi_leb_read(desc, lnum, buf, offset, len, 0);
+}
+
+/*
+ * This function is the same as the 'ubi_leb_write()' functions, but it does
+ * not have the data type argument.
+ */
+static inline int ubi_write(struct ubi_volume_desc *desc, int lnum,
+ const void *buf, int offset, int len)
+{
+ return ubi_leb_write(desc, lnum, buf, offset, len, UBI_UNKNOWN);
+}
+
+/*
+ * This function is the same as the 'ubi_leb_change()' functions, but it does
+ * not have the data type argument.
+ */
+static inline int ubi_change(struct ubi_volume_desc *desc, int lnum,
+ const void *buf, int len)
+{
+ return ubi_leb_change(desc, lnum, buf, len, UBI_UNKNOWN);
+}
+
+#endif /* !__LINUX_UBI_H__ */
diff --git a/include/linux/types.h b/include/linux/types.h
index df4808f..1b0b4a4 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -119,6 +119,30 @@ typedef __s64 int64_t;
* Below are truly Linux-specific types that should never collide with
* any application/library that wants linux/types.h.
*/
+#ifdef __CHECKER__
+#define __bitwise__ __attribute__((bitwise))
+#else
+#define __bitwise__
+#endif
+#ifdef __CHECK_ENDIAN__
+#define __bitwise __bitwise__
+#else
+#define __bitwise
+#endif
+
+typedef __u16 __bitwise __le16;
+typedef __u16 __bitwise __be16;
+typedef __u32 __bitwise __le32;
+typedef __u32 __bitwise __be32;
+#if defined(__GNUC__)
+typedef __u64 __bitwise __le64;
+typedef __u64 __bitwise __be64;
+#endif
+typedef __u16 __bitwise __sum16;
+typedef __u32 __bitwise __wsum;
+
+
+typedef unsigned __bitwise__ gfp_t;
struct ustat {
__kernel_daddr_t f_tfree;
diff --git a/include/ubi_uboot.h b/include/ubi_uboot.h
new file mode 100644
index 0000000..b4b2fa2
--- /dev/null
+++ b/include/ubi_uboot.h
@@ -0,0 +1,218 @@
+/*
+ * Header file for UBI support for U-Boot
+ *
+ * Adaptation from kernel to U-Boot
+ *
+ * Copyright (C) 2005-2007 Samsung Electronics
+ * Kyungmin Park <kyungmin.park at samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __UBOOT_UBI_H
+#define __UBOOT_UBI_H
+
+#include <common.h>
+#include <malloc.h>
+#include <div64.h>
+#include <linux/crc32.h>
+#include <linux/mtd/mtd.h>
+
+#ifdef CONFIG_CMD_ONENAND
+#include <onenand_uboot.h>
+#endif
+
+#include <asm/errno.h>
+
+#define DPRINTK(format, args...) \
+do { \
+ printf("%s[%d]: " format "\n", __func__, __LINE__, ##args); \
+} while (0)
+
+/* configurable */
+#define CONFIG_MTD_UBI_WL_THRESHOLD 4096
+#define CONFIG_MTD_UBI_BEB_RESERVE 1
+#define UBI_IO_DEBUG 0
+
+/* #define CONFIG_MTD_UBI_DEBUG */
+/* #define CONFIG_MTD_UBI_DEBUG_PARANOID */
+
+#define CONFIG_MTD_UBI_DEBUG_DISABLE_BGT
+/* #define CONFIG_MTD_UBI_DEBUG_MSG */
+/* #define CONFIG_MTD_UBI_DEBUG_MSG_EBA */
+/* #define CONFIG_MTD_UBI_DEBUG_MSG_WL */
+/* #define CONFIG_MTD_UBI_DEBUG_MSG_IO */
+/* #define CONFIG_MTD_UBI_DEBUG_MSG_BLD */
+
+/* compiler options */
+#define uninitialized_var(x) x = x
+
+/* build.c */
+#define get_device(...)
+#define put_device(...)
+#define ubi_sysfs_init(...) 0
+#define ubi_sysfs_close(...) do { } while (0)
+static inline int is_power_of_2(unsigned long n)
+{
+ return n != 0 && ((n & (n - 1)) == 0);
+}
+
+/* FIXME */
+#define MKDEV(...) 0
+#define MAJOR(dev) 0
+#define MINOR(dev) 0
+
+#define alloc_chrdev_region(...) 0
+#define unregister_chrdev_region(...)
+
+#define class_create(...) __builtin_return_address(0)
+#define class_create_file(...) 0
+#define class_remove_file(...)
+#define class_destroy(...)
+#define misc_register(...) 0
+#define misc_deregister(...)
+
+
+/* vmt.c */
+#define device_register(...) 0
+#define volume_sysfs_init(...) 0
+#define volume_sysfs_close(...) do { } while (0)
+
+/* kapi.c */
+
+/* eba.c */
+
+/* io.c */
+#define init_waitqueue_head(...) do { } while (0)
+#define wait_event_interruptible(...) 0
+#define wake_up_interruptible(...) do { } while (0)
+#define print_hex_dump(...) do { } while (0)
+#define dump_stack(...) do { } while (0)
+
+/* wl.c */
+#define task_pid_nr(x) 0
+#define set_freezable(...) do { } while (0)
+#define try_to_freeze(...) 0
+#define set_current_state(...) do { } while (0)
+#define kthread_should_stop(...) 0
+#define schedule() do { } while (0)
+
+/* upd.c */
+#define copy_from_user(dest, src, count) ({ \
+ int __ret = 0; \
+ memcpy(dest, src, count); \
+ __ret; \
+})
+
+/* common */
+typedef int spinlock_t;
+typedef int wait_queue_head_t;
+#define spin_lock_init(...)
+#define spin_lock(...)
+#define spin_unlock(...)
+
+#define mutex_init(...)
+#define mutex_lock(...)
+#define mutex_unlock(...)
+
+#define init_rwsem(...) do { } while (0)
+#define down_read(...) do { } while (0)
+#define down_write(...) do { } while (0)
+#define down_write_trylock(...) 0
+#define up_read(...) do { } while (0)
+#define up_write(...) do { } while (0)
+
+struct kmem_cache { int i; };
+#define kmem_cache_create(...) 1
+#define kmem_cache_alloc(obj, gfp) malloc(sizeof(struct ubi_wl_entry))
+#define kmem_cache_free(obj, size) free(size)
+#define kmem_cache_destroy(...)
+
+#define cond_resched() do { } while (0)
+#define yield() do { } while (0)
+
+#define KERN_WARNING
+#define KERN_ERR
+#define KERN_NOTICE
+#define KERN_DEBUG
+
+#define GFP_KERNEL 0
+#define GFP_NOFS 1
+
+#define __user
+#define __init
+#define __exit
+
+#define kthread_create(...) __builtin_return_address(0)
+#define kthread_stop(...) do { } while (0)
+#define wake_up_process(...) do { } while (0)
+
+struct rw_semaphore { int i; };
+struct device {
+ struct device *parent;
+ struct class *class;
+ dev_t devt;
+ int bus_id[20];
+ void (*release)(struct device *dev);
+};
+struct mutex { int i; };
+struct kernel_param { int i; };
+
+struct cdev {
+ int owner;
+ dev_t dev;
+};
+#define cdev_init(...) do { } while (0)
+#define cdev_add(...) 0
+#define cdev_del(...) do { } while (0)
+
+#define MAX_ERRNO 4095
+#define IS_ERR_VALUE(x) ((x) >= (unsigned long)-MAX_ERRNO)
+
+static inline void *ERR_PTR(long error)
+{
+ return (void *) error;
+}
+
+static inline long PTR_ERR(const void *ptr)
+{
+ return (long) ptr;
+}
+
+static inline long IS_ERR(const void *ptr)
+{
+ return IS_ERR_VALUE((unsigned long)ptr);
+}
+
+/* Force a compilation error if condition is true */
+#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
+
+/* module */
+#define THIS_MODULE 0
+#define try_module_get(...) 0
+#define module_put(...) do { } while (0)
+#define module_init(...)
+#define module_exit(...)
+#define EXPORT_SYMBOL(...)
+#define EXPORT_SYMBOL_GPL(...)
+#define module_param_call(...)
+#define MODULE_PARM_DESC(...)
+#define MODULE_VERSION(...)
+#define MODULE_DESCRIPTION(...)
+#define MODULE_AUTHOR(...)
+#define MODULE_LICENSE(...)
+
+#include "../drivers/mtd/ubi/ubi.h"
+
+/* functions */
+extern int ubi_mtd_param_parse(const char *val, struct kernel_param *kp);
+extern int ubi_init(void);
+
+extern struct ubi_device *ubi_devices[];
+
+/* Board specific functions */
+extern int ubi_board_scan(void);
+
+#endif
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