xref: /openbmc/u-boot/drivers/mtd/ubi/ubi.h (revision d6208a3c)
1 /*
2  * Copyright (c) International Business Machines Corp., 2006
3  * Copyright (c) Nokia Corporation, 2006, 2007
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13  * the GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * Author: Artem Bityutskiy (Битюцкий Артём)
20  */
21 
22 #ifndef __UBI_UBI_H__
23 #define __UBI_UBI_H__
24 
25 #ifdef UBI_LINUX
26 #include <linux/init.h>
27 #include <linux/types.h>
28 #include <linux/list.h>
29 #include <linux/rbtree.h>
30 #include <linux/sched.h>
31 #include <linux/wait.h>
32 #include <linux/mutex.h>
33 #include <linux/rwsem.h>
34 #include <linux/spinlock.h>
35 #include <linux/fs.h>
36 #include <linux/cdev.h>
37 #include <linux/device.h>
38 #include <linux/string.h>
39 #include <linux/vmalloc.h>
40 #include <linux/mtd/mtd.h>
41 #include <linux/mtd/ubi.h>
42 #endif
43 
44 #include <linux/types.h>
45 #include <linux/list.h>
46 #include <linux/rbtree.h>
47 #include <linux/string.h>
48 #include <linux/mtd/mtd.h>
49 #include <linux/mtd/ubi.h>
50 
51 #include "ubi-media.h"
52 #include "scan.h"
53 #include "debug.h"
54 
55 /* Maximum number of supported UBI devices */
56 #define UBI_MAX_DEVICES 32
57 
58 /* UBI name used for character devices, sysfs, etc */
59 #define UBI_NAME_STR "ubi"
60 
61 /* Normal UBI messages */
62 #ifdef CONFIG_UBI_SILENCE_MSG
63 #define ubi_msg(fmt, ...)
64 #else
65 #define ubi_msg(fmt, ...) printk(KERN_NOTICE "UBI: " fmt "\n", ##__VA_ARGS__)
66 #endif
67 /* UBI warning messages */
68 #define ubi_warn(fmt, ...) printk(KERN_WARNING "UBI warning: %s: " fmt "\n", \
69 				  __func__, ##__VA_ARGS__)
70 /* UBI error messages */
71 #define ubi_err(fmt, ...) printk(KERN_ERR "UBI error: %s: " fmt "\n", \
72 				 __func__, ##__VA_ARGS__)
73 
74 /* Lowest number PEBs reserved for bad PEB handling */
75 #define MIN_RESEVED_PEBS 2
76 
77 /* Background thread name pattern */
78 #define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"
79 
80 /* This marker in the EBA table means that the LEB is um-mapped */
81 #define UBI_LEB_UNMAPPED -1
82 
83 /*
84  * In case of errors, UBI tries to repeat the operation several times before
85  * returning error. The below constant defines how many times UBI re-tries.
86  */
87 #define UBI_IO_RETRIES 3
88 
89 /*
90  * Error codes returned by the I/O unit.
91  *
92  * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
93  * 0xFF bytes
94  * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
95  * valid erase counter header, and the rest are %0xFF bytes
96  * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
97  * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
98  * CRC)
99  * UBI_IO_BITFLIPS: bit-flips were detected and corrected
100  */
101 enum {
102 	UBI_IO_PEB_EMPTY = 1,
103 	UBI_IO_PEB_FREE,
104 	UBI_IO_BAD_EC_HDR,
105 	UBI_IO_BAD_VID_HDR,
106 	UBI_IO_BITFLIPS
107 };
108 
109 /**
110  * struct ubi_wl_entry - wear-leveling entry.
111  * @rb: link in the corresponding RB-tree
112  * @ec: erase counter
113  * @pnum: physical eraseblock number
114  *
115  * This data structure is used in the WL unit. Each physical eraseblock has a
116  * corresponding &struct wl_entry object which may be kept in different
117  * RB-trees. See WL unit for details.
118  */
119 struct ubi_wl_entry {
120 	struct rb_node rb;
121 	int ec;
122 	int pnum;
123 };
124 
125 /**
126  * struct ubi_ltree_entry - an entry in the lock tree.
127  * @rb: links RB-tree nodes
128  * @vol_id: volume ID of the locked logical eraseblock
129  * @lnum: locked logical eraseblock number
130  * @users: how many tasks are using this logical eraseblock or wait for it
131  * @mutex: read/write mutex to implement read/write access serialization to
132  *         the (@vol_id, @lnum) logical eraseblock
133  *
134  * This data structure is used in the EBA unit to implement per-LEB locking.
135  * When a logical eraseblock is being locked - corresponding
136  * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
137  * See EBA unit for details.
138  */
139 struct ubi_ltree_entry {
140 	struct rb_node rb;
141 	int vol_id;
142 	int lnum;
143 	int users;
144 	struct rw_semaphore mutex;
145 };
146 
147 struct ubi_volume_desc;
148 
149 /**
150  * struct ubi_volume - UBI volume description data structure.
151  * @dev: device object to make use of the the Linux device model
152  * @cdev: character device object to create character device
153  * @ubi: reference to the UBI device description object
154  * @vol_id: volume ID
155  * @ref_count: volume reference count
156  * @readers: number of users holding this volume in read-only mode
157  * @writers: number of users holding this volume in read-write mode
158  * @exclusive: whether somebody holds this volume in exclusive mode
159  *
160  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
161  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
162  * @usable_leb_size: logical eraseblock size without padding
163  * @used_ebs: how many logical eraseblocks in this volume contain data
164  * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
165  * @used_bytes: how many bytes of data this volume contains
166  * @alignment: volume alignment
167  * @data_pad: how many bytes are not used at the end of physical eraseblocks to
168  *            satisfy the requested alignment
169  * @name_len: volume name length
170  * @name: volume name
171  *
172  * @upd_ebs: how many eraseblocks are expected to be updated
173  * @ch_lnum: LEB number which is being changing by the atomic LEB change
174  *           operation
175  * @ch_dtype: data persistency type which is being changing by the atomic LEB
176  *            change operation
177  * @upd_bytes: how many bytes are expected to be received for volume update or
178  *             atomic LEB change
179  * @upd_received: how many bytes were already received for volume update or
180  *                atomic LEB change
181  * @upd_buf: update buffer which is used to collect update data or data for
182  *           atomic LEB change
183  *
184  * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
185  * @checked: %1 if this static volume was checked
186  * @corrupted: %1 if the volume is corrupted (static volumes only)
187  * @upd_marker: %1 if the update marker is set for this volume
188  * @updating: %1 if the volume is being updated
189  * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
190  *
191  * @gluebi_desc: gluebi UBI volume descriptor
192  * @gluebi_refcount: reference count of the gluebi MTD device
193  * @gluebi_mtd: MTD device description object of the gluebi MTD device
194  *
195  * The @corrupted field indicates that the volume's contents is corrupted.
196  * Since UBI protects only static volumes, this field is not relevant to
197  * dynamic volumes - it is user's responsibility to assure their data
198  * integrity.
199  *
200  * The @upd_marker flag indicates that this volume is either being updated at
201  * the moment or is damaged because of an unclean reboot.
202  */
203 struct ubi_volume {
204 	struct device dev;
205 	struct cdev cdev;
206 	struct ubi_device *ubi;
207 	int vol_id;
208 	int ref_count;
209 	int readers;
210 	int writers;
211 	int exclusive;
212 
213 	int reserved_pebs;
214 	int vol_type;
215 	int usable_leb_size;
216 	int used_ebs;
217 	int last_eb_bytes;
218 	long long used_bytes;
219 	int alignment;
220 	int data_pad;
221 	int name_len;
222 	char name[UBI_VOL_NAME_MAX+1];
223 
224 	int upd_ebs;
225 	int ch_lnum;
226 	int ch_dtype;
227 	long long upd_bytes;
228 	long long upd_received;
229 	void *upd_buf;
230 
231 	int *eba_tbl;
232 	unsigned int checked:1;
233 	unsigned int corrupted:1;
234 	unsigned int upd_marker:1;
235 	unsigned int updating:1;
236 	unsigned int changing_leb:1;
237 
238 #ifdef CONFIG_MTD_UBI_GLUEBI
239 	/*
240 	 * Gluebi-related stuff may be compiled out.
241 	 * TODO: this should not be built into UBI but should be a separate
242 	 * ubimtd driver which works on top of UBI and emulates MTD devices.
243 	 */
244 	struct ubi_volume_desc *gluebi_desc;
245 	int gluebi_refcount;
246 	struct mtd_info gluebi_mtd;
247 #endif
248 };
249 
250 /**
251  * struct ubi_volume_desc - descriptor of the UBI volume returned when it is
252  * opened.
253  * @vol: reference to the corresponding volume description object
254  * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
255  */
256 struct ubi_volume_desc {
257 	struct ubi_volume *vol;
258 	int mode;
259 };
260 
261 struct ubi_wl_entry;
262 
263 /**
264  * struct ubi_device - UBI device description structure
265  * @dev: UBI device object to use the the Linux device model
266  * @cdev: character device object to create character device
267  * @ubi_num: UBI device number
268  * @ubi_name: UBI device name
269  * @vol_count: number of volumes in this UBI device
270  * @volumes: volumes of this UBI device
271  * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
272  *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
273  *                @vol->readers, @vol->writers, @vol->exclusive,
274  *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
275  * @ref_count: count of references on the UBI device
276  *
277  * @rsvd_pebs: count of reserved physical eraseblocks
278  * @avail_pebs: count of available physical eraseblocks
279  * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
280  *                 handling
281  * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
282  *
283  * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
284  *                     of UBI ititializetion
285  * @vtbl_slots: how many slots are available in the volume table
286  * @vtbl_size: size of the volume table in bytes
287  * @vtbl: in-RAM volume table copy
288  * @volumes_mutex: protects on-flash volume table and serializes volume
289  *                 changes, like creation, deletion, update, resize
290  *
291  * @max_ec: current highest erase counter value
292  * @mean_ec: current mean erase counter value
293  *
294  * @global_sqnum: global sequence number
295  * @ltree_lock: protects the lock tree and @global_sqnum
296  * @ltree: the lock tree
297  * @alc_mutex: serializes "atomic LEB change" operations
298  *
299  * @used: RB-tree of used physical eraseblocks
300  * @free: RB-tree of free physical eraseblocks
301  * @scrub: RB-tree of physical eraseblocks which need scrubbing
302  * @prot: protection trees
303  * @prot.pnum: protection tree indexed by physical eraseblock numbers
304  * @prot.aec: protection tree indexed by absolute erase counter value
305  * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
306  *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
307  *           fields
308  * @move_mutex: serializes eraseblock moves
309  * @wl_scheduled: non-zero if the wear-leveling was scheduled
310  * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
311  *             physical eraseblock
312  * @abs_ec: absolute erase counter
313  * @move_from: physical eraseblock from where the data is being moved
314  * @move_to: physical eraseblock where the data is being moved to
315  * @move_to_put: if the "to" PEB was put
316  * @works: list of pending works
317  * @works_count: count of pending works
318  * @bgt_thread: background thread description object
319  * @thread_enabled: if the background thread is enabled
320  * @bgt_name: background thread name
321  *
322  * @flash_size: underlying MTD device size (in bytes)
323  * @peb_count: count of physical eraseblocks on the MTD device
324  * @peb_size: physical eraseblock size
325  * @bad_peb_count: count of bad physical eraseblocks
326  * @good_peb_count: count of good physical eraseblocks
327  * @min_io_size: minimal input/output unit size of the underlying MTD device
328  * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
329  * @ro_mode: if the UBI device is in read-only mode
330  * @leb_size: logical eraseblock size
331  * @leb_start: starting offset of logical eraseblocks within physical
332  * eraseblocks
333  * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
334  * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
335  * @vid_hdr_offset: starting offset of the volume identifier header (might be
336  * unaligned)
337  * @vid_hdr_aloffset: starting offset of the VID header aligned to
338  * @hdrs_min_io_size
339  * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
340  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
341  *               not
342  * @mtd: MTD device descriptor
343  *
344  * @peb_buf1: a buffer of PEB size used for different purposes
345  * @peb_buf2: another buffer of PEB size used for different purposes
346  * @buf_mutex: proptects @peb_buf1 and @peb_buf2
347  * @dbg_peb_buf: buffer of PEB size used for debugging
348  * @dbg_buf_mutex: proptects @dbg_peb_buf
349  */
350 struct ubi_device {
351 	struct cdev cdev;
352 	struct device dev;
353 	int ubi_num;
354 	char ubi_name[sizeof(UBI_NAME_STR)+5];
355 	int vol_count;
356 	struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
357 	spinlock_t volumes_lock;
358 	int ref_count;
359 
360 	int rsvd_pebs;
361 	int avail_pebs;
362 	int beb_rsvd_pebs;
363 	int beb_rsvd_level;
364 
365 	int autoresize_vol_id;
366 	int vtbl_slots;
367 	int vtbl_size;
368 	struct ubi_vtbl_record *vtbl;
369 	struct mutex volumes_mutex;
370 
371 	int max_ec;
372 	/* TODO: mean_ec is not updated run-time, fix */
373 	int mean_ec;
374 
375 	/* EBA unit's stuff */
376 	unsigned long long global_sqnum;
377 	spinlock_t ltree_lock;
378 	struct rb_root ltree;
379 	struct mutex alc_mutex;
380 
381 	/* Wear-leveling unit's stuff */
382 	struct rb_root used;
383 	struct rb_root free;
384 	struct rb_root scrub;
385 	struct {
386 		struct rb_root pnum;
387 		struct rb_root aec;
388 	} prot;
389 	spinlock_t wl_lock;
390 	struct mutex move_mutex;
391 	struct rw_semaphore work_sem;
392 	int wl_scheduled;
393 	struct ubi_wl_entry **lookuptbl;
394 	unsigned long long abs_ec;
395 	struct ubi_wl_entry *move_from;
396 	struct ubi_wl_entry *move_to;
397 	int move_to_put;
398 	struct list_head works;
399 	int works_count;
400 	struct task_struct *bgt_thread;
401 	int thread_enabled;
402 	char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
403 
404 	/* I/O unit's stuff */
405 	long long flash_size;
406 	int peb_count;
407 	int peb_size;
408 	int bad_peb_count;
409 	int good_peb_count;
410 	int min_io_size;
411 	int hdrs_min_io_size;
412 	int ro_mode;
413 	int leb_size;
414 	int leb_start;
415 	int ec_hdr_alsize;
416 	int vid_hdr_alsize;
417 	int vid_hdr_offset;
418 	int vid_hdr_aloffset;
419 	int vid_hdr_shift;
420 	int bad_allowed;
421 	struct mtd_info *mtd;
422 
423 	void *peb_buf1;
424 	void *peb_buf2;
425 	struct mutex buf_mutex;
426 	struct mutex ckvol_mutex;
427 #ifdef CONFIG_MTD_UBI_DEBUG
428 	void *dbg_peb_buf;
429 	struct mutex dbg_buf_mutex;
430 #endif
431 };
432 
433 extern struct kmem_cache *ubi_wl_entry_slab;
434 extern struct file_operations ubi_ctrl_cdev_operations;
435 extern struct file_operations ubi_cdev_operations;
436 extern struct file_operations ubi_vol_cdev_operations;
437 extern struct class *ubi_class;
438 extern struct mutex ubi_devices_mutex;
439 
440 /* vtbl.c */
441 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
442 			   struct ubi_vtbl_record *vtbl_rec);
443 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
444 
445 /* vmt.c */
446 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
447 int ubi_remove_volume(struct ubi_volume_desc *desc);
448 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
449 int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
450 void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
451 
452 /* upd.c */
453 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
454 		     long long bytes);
455 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
456 			 const void __user *buf, int count);
457 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
458 			 const struct ubi_leb_change_req *req);
459 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
460 			     const void __user *buf, int count);
461 
462 /* misc.c */
463 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, int length);
464 int ubi_check_volume(struct ubi_device *ubi, int vol_id);
465 void ubi_calculate_reserved(struct ubi_device *ubi);
466 
467 /* gluebi.c */
468 #ifdef CONFIG_MTD_UBI_GLUEBI
469 int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
470 int ubi_destroy_gluebi(struct ubi_volume *vol);
471 void ubi_gluebi_updated(struct ubi_volume *vol);
472 #else
473 #define ubi_create_gluebi(ubi, vol) 0
474 
475 static inline int ubi_destroy_gluebi(struct ubi_volume *vol)
476 {
477 	return 0;
478 }
479 
480 #define ubi_gluebi_updated(vol)
481 #endif
482 
483 /* eba.c */
484 int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
485 		      int lnum);
486 int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
487 		     void *buf, int offset, int len, int check);
488 int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
489 		      const void *buf, int offset, int len, int dtype);
490 int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
491 			 int lnum, const void *buf, int len, int dtype,
492 			 int used_ebs);
493 int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
494 			      int lnum, const void *buf, int len, int dtype);
495 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
496 		     struct ubi_vid_hdr *vid_hdr);
497 int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
498 void ubi_eba_close(const struct ubi_device *ubi);
499 
500 /* wl.c */
501 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
502 int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
503 int ubi_wl_flush(struct ubi_device *ubi);
504 int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
505 int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
506 void ubi_wl_close(struct ubi_device *ubi);
507 int ubi_thread(void *u);
508 
509 /* io.c */
510 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
511 		int len);
512 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
513 		 int len);
514 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
515 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
516 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
517 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
518 		       struct ubi_ec_hdr *ec_hdr, int verbose);
519 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
520 			struct ubi_ec_hdr *ec_hdr);
521 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
522 			struct ubi_vid_hdr *vid_hdr, int verbose);
523 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
524 			 struct ubi_vid_hdr *vid_hdr);
525 
526 /* build.c */
527 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
528 int ubi_detach_mtd_dev(int ubi_num, int anyway);
529 struct ubi_device *ubi_get_device(int ubi_num);
530 void ubi_put_device(struct ubi_device *ubi);
531 struct ubi_device *ubi_get_by_major(int major);
532 int ubi_major2num(int major);
533 
534 /*
535  * ubi_rb_for_each_entry - walk an RB-tree.
536  * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
537  * @pos: a pointer to RB-tree entry type to use as a loop counter
538  * @root: RB-tree's root
539  * @member: the name of the 'struct rb_node' within the RB-tree entry
540  */
541 #define ubi_rb_for_each_entry(rb, pos, root, member)                         \
542 	for (rb = rb_first(root),                                            \
543 	     pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
544 	     rb;                                                             \
545 	     rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
546 
547 /**
548  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
549  * @ubi: UBI device description object
550  * @gfp_flags: GFP flags to allocate with
551  *
552  * This function returns a pointer to the newly allocated and zero-filled
553  * volume identifier header object in case of success and %NULL in case of
554  * failure.
555  */
556 static inline struct ubi_vid_hdr *
557 ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
558 {
559 	void *vid_hdr;
560 
561 	vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
562 	if (!vid_hdr)
563 		return NULL;
564 
565 	/*
566 	 * VID headers may be stored at un-aligned flash offsets, so we shift
567 	 * the pointer.
568 	 */
569 	return vid_hdr + ubi->vid_hdr_shift;
570 }
571 
572 /**
573  * ubi_free_vid_hdr - free a volume identifier header object.
574  * @ubi: UBI device description object
575  * @vid_hdr: the object to free
576  */
577 static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
578 				    struct ubi_vid_hdr *vid_hdr)
579 {
580 	void *p = vid_hdr;
581 
582 	if (!p)
583 		return;
584 
585 	kfree(p - ubi->vid_hdr_shift);
586 }
587 
588 /*
589  * This function is equivalent to 'ubi_io_read()', but @offset is relative to
590  * the beginning of the logical eraseblock, not to the beginning of the
591  * physical eraseblock.
592  */
593 static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
594 				   int pnum, int offset, int len)
595 {
596 	ubi_assert(offset >= 0);
597 	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
598 }
599 
600 /*
601  * This function is equivalent to 'ubi_io_write()', but @offset is relative to
602  * the beginning of the logical eraseblock, not to the beginning of the
603  * physical eraseblock.
604  */
605 static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
606 				    int pnum, int offset, int len)
607 {
608 	ubi_assert(offset >= 0);
609 	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
610 }
611 
612 /**
613  * ubi_ro_mode - switch to read-only mode.
614  * @ubi: UBI device description object
615  */
616 static inline void ubi_ro_mode(struct ubi_device *ubi)
617 {
618 	if (!ubi->ro_mode) {
619 		ubi->ro_mode = 1;
620 		ubi_warn("switch to read-only mode");
621 	}
622 }
623 
624 /**
625  * vol_id2idx - get table index by volume ID.
626  * @ubi: UBI device description object
627  * @vol_id: volume ID
628  */
629 static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
630 {
631 	if (vol_id >= UBI_INTERNAL_VOL_START)
632 		return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
633 	else
634 		return vol_id;
635 }
636 
637 /**
638  * idx2vol_id - get volume ID by table index.
639  * @ubi: UBI device description object
640  * @idx: table index
641  */
642 static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
643 {
644 	if (idx >= ubi->vtbl_slots)
645 		return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
646 	else
647 		return idx;
648 }
649 
650 #endif /* !__UBI_UBI_H__ */
651