xref: /openbmc/u-boot/drivers/mtd/ubi/ubi.h (revision 4e3349b6)
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 #define ubi_msg(fmt, ...) printk(KERN_NOTICE "UBI: " fmt "\n", ##__VA_ARGS__)
63 /* UBI warning messages */
64 #define ubi_warn(fmt, ...) printk(KERN_WARNING "UBI warning: %s: " fmt "\n", \
65 				  __func__, ##__VA_ARGS__)
66 /* UBI error messages */
67 #define ubi_err(fmt, ...) printk(KERN_ERR "UBI error: %s: " fmt "\n", \
68 				 __func__, ##__VA_ARGS__)
69 
70 /* Lowest number PEBs reserved for bad PEB handling */
71 #define MIN_RESEVED_PEBS 2
72 
73 /* Background thread name pattern */
74 #define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"
75 
76 /* This marker in the EBA table means that the LEB is um-mapped */
77 #define UBI_LEB_UNMAPPED -1
78 
79 /*
80  * In case of errors, UBI tries to repeat the operation several times before
81  * returning error. The below constant defines how many times UBI re-tries.
82  */
83 #define UBI_IO_RETRIES 3
84 
85 /*
86  * Error codes returned by the I/O unit.
87  *
88  * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
89  * 0xFF bytes
90  * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
91  * valid erase counter header, and the rest are %0xFF bytes
92  * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
93  * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
94  * CRC)
95  * UBI_IO_BITFLIPS: bit-flips were detected and corrected
96  */
97 enum {
98 	UBI_IO_PEB_EMPTY = 1,
99 	UBI_IO_PEB_FREE,
100 	UBI_IO_BAD_EC_HDR,
101 	UBI_IO_BAD_VID_HDR,
102 	UBI_IO_BITFLIPS
103 };
104 
105 /**
106  * struct ubi_wl_entry - wear-leveling entry.
107  * @rb: link in the corresponding RB-tree
108  * @ec: erase counter
109  * @pnum: physical eraseblock number
110  *
111  * This data structure is used in the WL unit. Each physical eraseblock has a
112  * corresponding &struct wl_entry object which may be kept in different
113  * RB-trees. See WL unit for details.
114  */
115 struct ubi_wl_entry {
116 	struct rb_node rb;
117 	int ec;
118 	int pnum;
119 };
120 
121 /**
122  * struct ubi_ltree_entry - an entry in the lock tree.
123  * @rb: links RB-tree nodes
124  * @vol_id: volume ID of the locked logical eraseblock
125  * @lnum: locked logical eraseblock number
126  * @users: how many tasks are using this logical eraseblock or wait for it
127  * @mutex: read/write mutex to implement read/write access serialization to
128  *         the (@vol_id, @lnum) logical eraseblock
129  *
130  * This data structure is used in the EBA unit to implement per-LEB locking.
131  * When a logical eraseblock is being locked - corresponding
132  * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
133  * See EBA unit for details.
134  */
135 struct ubi_ltree_entry {
136 	struct rb_node rb;
137 	int vol_id;
138 	int lnum;
139 	int users;
140 	struct rw_semaphore mutex;
141 };
142 
143 struct ubi_volume_desc;
144 
145 /**
146  * struct ubi_volume - UBI volume description data structure.
147  * @dev: device object to make use of the the Linux device model
148  * @cdev: character device object to create character device
149  * @ubi: reference to the UBI device description object
150  * @vol_id: volume ID
151  * @ref_count: volume reference count
152  * @readers: number of users holding this volume in read-only mode
153  * @writers: number of users holding this volume in read-write mode
154  * @exclusive: whether somebody holds this volume in exclusive mode
155  *
156  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
157  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
158  * @usable_leb_size: logical eraseblock size without padding
159  * @used_ebs: how many logical eraseblocks in this volume contain data
160  * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
161  * @used_bytes: how many bytes of data this volume contains
162  * @alignment: volume alignment
163  * @data_pad: how many bytes are not used at the end of physical eraseblocks to
164  *            satisfy the requested alignment
165  * @name_len: volume name length
166  * @name: volume name
167  *
168  * @upd_ebs: how many eraseblocks are expected to be updated
169  * @ch_lnum: LEB number which is being changing by the atomic LEB change
170  *           operation
171  * @ch_dtype: data persistency type which is being changing by the atomic LEB
172  *            change operation
173  * @upd_bytes: how many bytes are expected to be received for volume update or
174  *             atomic LEB change
175  * @upd_received: how many bytes were already received for volume update or
176  *                atomic LEB change
177  * @upd_buf: update buffer which is used to collect update data or data for
178  *           atomic LEB change
179  *
180  * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
181  * @checked: %1 if this static volume was checked
182  * @corrupted: %1 if the volume is corrupted (static volumes only)
183  * @upd_marker: %1 if the update marker is set for this volume
184  * @updating: %1 if the volume is being updated
185  * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
186  *
187  * @gluebi_desc: gluebi UBI volume descriptor
188  * @gluebi_refcount: reference count of the gluebi MTD device
189  * @gluebi_mtd: MTD device description object of the gluebi MTD device
190  *
191  * The @corrupted field indicates that the volume's contents is corrupted.
192  * Since UBI protects only static volumes, this field is not relevant to
193  * dynamic volumes - it is user's responsibility to assure their data
194  * integrity.
195  *
196  * The @upd_marker flag indicates that this volume is either being updated at
197  * the moment or is damaged because of an unclean reboot.
198  */
199 struct ubi_volume {
200 	struct device dev;
201 	struct cdev cdev;
202 	struct ubi_device *ubi;
203 	int vol_id;
204 	int ref_count;
205 	int readers;
206 	int writers;
207 	int exclusive;
208 
209 	int reserved_pebs;
210 	int vol_type;
211 	int usable_leb_size;
212 	int used_ebs;
213 	int last_eb_bytes;
214 	long long used_bytes;
215 	int alignment;
216 	int data_pad;
217 	int name_len;
218 	char name[UBI_VOL_NAME_MAX+1];
219 
220 	int upd_ebs;
221 	int ch_lnum;
222 	int ch_dtype;
223 	long long upd_bytes;
224 	long long upd_received;
225 	void *upd_buf;
226 
227 	int *eba_tbl;
228 	unsigned int checked:1;
229 	unsigned int corrupted:1;
230 	unsigned int upd_marker:1;
231 	unsigned int updating:1;
232 	unsigned int changing_leb:1;
233 
234 #ifdef CONFIG_MTD_UBI_GLUEBI
235 	/*
236 	 * Gluebi-related stuff may be compiled out.
237 	 * TODO: this should not be built into UBI but should be a separate
238 	 * ubimtd driver which works on top of UBI and emulates MTD devices.
239 	 */
240 	struct ubi_volume_desc *gluebi_desc;
241 	int gluebi_refcount;
242 	struct mtd_info gluebi_mtd;
243 #endif
244 };
245 
246 /**
247  * struct ubi_volume_desc - descriptor of the UBI volume returned when it is
248  * opened.
249  * @vol: reference to the corresponding volume description object
250  * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
251  */
252 struct ubi_volume_desc {
253 	struct ubi_volume *vol;
254 	int mode;
255 };
256 
257 struct ubi_wl_entry;
258 
259 /**
260  * struct ubi_device - UBI device description structure
261  * @dev: UBI device object to use the the Linux device model
262  * @cdev: character device object to create character device
263  * @ubi_num: UBI device number
264  * @ubi_name: UBI device name
265  * @vol_count: number of volumes in this UBI device
266  * @volumes: volumes of this UBI device
267  * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
268  *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
269  *                @vol->readers, @vol->writers, @vol->exclusive,
270  *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
271  * @ref_count: count of references on the UBI device
272  *
273  * @rsvd_pebs: count of reserved physical eraseblocks
274  * @avail_pebs: count of available physical eraseblocks
275  * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
276  *                 handling
277  * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
278  *
279  * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
280  *                     of UBI ititializetion
281  * @vtbl_slots: how many slots are available in the volume table
282  * @vtbl_size: size of the volume table in bytes
283  * @vtbl: in-RAM volume table copy
284  * @volumes_mutex: protects on-flash volume table and serializes volume
285  *                 changes, like creation, deletion, update, resize
286  *
287  * @max_ec: current highest erase counter value
288  * @mean_ec: current mean erase counter value
289  *
290  * @global_sqnum: global sequence number
291  * @ltree_lock: protects the lock tree and @global_sqnum
292  * @ltree: the lock tree
293  * @alc_mutex: serializes "atomic LEB change" operations
294  *
295  * @used: RB-tree of used physical eraseblocks
296  * @free: RB-tree of free physical eraseblocks
297  * @scrub: RB-tree of physical eraseblocks which need scrubbing
298  * @prot: protection trees
299  * @prot.pnum: protection tree indexed by physical eraseblock numbers
300  * @prot.aec: protection tree indexed by absolute erase counter value
301  * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
302  *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
303  *           fields
304  * @move_mutex: serializes eraseblock moves
305  * @wl_scheduled: non-zero if the wear-leveling was scheduled
306  * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
307  *             physical eraseblock
308  * @abs_ec: absolute erase counter
309  * @move_from: physical eraseblock from where the data is being moved
310  * @move_to: physical eraseblock where the data is being moved to
311  * @move_to_put: if the "to" PEB was put
312  * @works: list of pending works
313  * @works_count: count of pending works
314  * @bgt_thread: background thread description object
315  * @thread_enabled: if the background thread is enabled
316  * @bgt_name: background thread name
317  *
318  * @flash_size: underlying MTD device size (in bytes)
319  * @peb_count: count of physical eraseblocks on the MTD device
320  * @peb_size: physical eraseblock size
321  * @bad_peb_count: count of bad physical eraseblocks
322  * @good_peb_count: count of good physical eraseblocks
323  * @min_io_size: minimal input/output unit size of the underlying MTD device
324  * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
325  * @ro_mode: if the UBI device is in read-only mode
326  * @leb_size: logical eraseblock size
327  * @leb_start: starting offset of logical eraseblocks within physical
328  * eraseblocks
329  * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
330  * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
331  * @vid_hdr_offset: starting offset of the volume identifier header (might be
332  * unaligned)
333  * @vid_hdr_aloffset: starting offset of the VID header aligned to
334  * @hdrs_min_io_size
335  * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
336  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
337  *               not
338  * @mtd: MTD device descriptor
339  *
340  * @peb_buf1: a buffer of PEB size used for different purposes
341  * @peb_buf2: another buffer of PEB size used for different purposes
342  * @buf_mutex: proptects @peb_buf1 and @peb_buf2
343  * @dbg_peb_buf: buffer of PEB size used for debugging
344  * @dbg_buf_mutex: proptects @dbg_peb_buf
345  */
346 struct ubi_device {
347 	struct cdev cdev;
348 	struct device dev;
349 	int ubi_num;
350 	char ubi_name[sizeof(UBI_NAME_STR)+5];
351 	int vol_count;
352 	struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
353 	spinlock_t volumes_lock;
354 	int ref_count;
355 
356 	int rsvd_pebs;
357 	int avail_pebs;
358 	int beb_rsvd_pebs;
359 	int beb_rsvd_level;
360 
361 	int autoresize_vol_id;
362 	int vtbl_slots;
363 	int vtbl_size;
364 	struct ubi_vtbl_record *vtbl;
365 	struct mutex volumes_mutex;
366 
367 	int max_ec;
368 	/* TODO: mean_ec is not updated run-time, fix */
369 	int mean_ec;
370 
371 	/* EBA unit's stuff */
372 	unsigned long long global_sqnum;
373 	spinlock_t ltree_lock;
374 	struct rb_root ltree;
375 	struct mutex alc_mutex;
376 
377 	/* Wear-leveling unit's stuff */
378 	struct rb_root used;
379 	struct rb_root free;
380 	struct rb_root scrub;
381 	struct {
382 		struct rb_root pnum;
383 		struct rb_root aec;
384 	} prot;
385 	spinlock_t wl_lock;
386 	struct mutex move_mutex;
387 	struct rw_semaphore work_sem;
388 	int wl_scheduled;
389 	struct ubi_wl_entry **lookuptbl;
390 	unsigned long long abs_ec;
391 	struct ubi_wl_entry *move_from;
392 	struct ubi_wl_entry *move_to;
393 	int move_to_put;
394 	struct list_head works;
395 	int works_count;
396 	struct task_struct *bgt_thread;
397 	int thread_enabled;
398 	char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
399 
400 	/* I/O unit's stuff */
401 	long long flash_size;
402 	int peb_count;
403 	int peb_size;
404 	int bad_peb_count;
405 	int good_peb_count;
406 	int min_io_size;
407 	int hdrs_min_io_size;
408 	int ro_mode;
409 	int leb_size;
410 	int leb_start;
411 	int ec_hdr_alsize;
412 	int vid_hdr_alsize;
413 	int vid_hdr_offset;
414 	int vid_hdr_aloffset;
415 	int vid_hdr_shift;
416 	int bad_allowed;
417 	struct mtd_info *mtd;
418 
419 	void *peb_buf1;
420 	void *peb_buf2;
421 	struct mutex buf_mutex;
422 	struct mutex ckvol_mutex;
423 #ifdef CONFIG_MTD_UBI_DEBUG
424 	void *dbg_peb_buf;
425 	struct mutex dbg_buf_mutex;
426 #endif
427 };
428 
429 extern struct kmem_cache *ubi_wl_entry_slab;
430 extern struct file_operations ubi_ctrl_cdev_operations;
431 extern struct file_operations ubi_cdev_operations;
432 extern struct file_operations ubi_vol_cdev_operations;
433 extern struct class *ubi_class;
434 extern struct mutex ubi_devices_mutex;
435 
436 /* vtbl.c */
437 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
438 			   struct ubi_vtbl_record *vtbl_rec);
439 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
440 
441 /* vmt.c */
442 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
443 int ubi_remove_volume(struct ubi_volume_desc *desc);
444 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
445 int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
446 void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
447 
448 /* upd.c */
449 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
450 		     long long bytes);
451 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
452 			 const void __user *buf, int count);
453 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
454 			 const struct ubi_leb_change_req *req);
455 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
456 			     const void __user *buf, int count);
457 
458 /* misc.c */
459 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, int length);
460 int ubi_check_volume(struct ubi_device *ubi, int vol_id);
461 void ubi_calculate_reserved(struct ubi_device *ubi);
462 
463 /* gluebi.c */
464 #ifdef CONFIG_MTD_UBI_GLUEBI
465 int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
466 int ubi_destroy_gluebi(struct ubi_volume *vol);
467 void ubi_gluebi_updated(struct ubi_volume *vol);
468 #else
469 #define ubi_create_gluebi(ubi, vol) 0
470 
471 static inline int ubi_destroy_gluebi(struct ubi_volume *vol)
472 {
473 	return 0;
474 }
475 
476 #define ubi_gluebi_updated(vol)
477 #endif
478 
479 /* eba.c */
480 int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
481 		      int lnum);
482 int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
483 		     void *buf, int offset, int len, int check);
484 int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
485 		      const void *buf, int offset, int len, int dtype);
486 int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
487 			 int lnum, const void *buf, int len, int dtype,
488 			 int used_ebs);
489 int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
490 			      int lnum, const void *buf, int len, int dtype);
491 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
492 		     struct ubi_vid_hdr *vid_hdr);
493 int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
494 void ubi_eba_close(const struct ubi_device *ubi);
495 
496 /* wl.c */
497 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
498 int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
499 int ubi_wl_flush(struct ubi_device *ubi);
500 int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
501 int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
502 void ubi_wl_close(struct ubi_device *ubi);
503 int ubi_thread(void *u);
504 
505 /* io.c */
506 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
507 		int len);
508 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
509 		 int len);
510 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
511 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
512 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
513 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
514 		       struct ubi_ec_hdr *ec_hdr, int verbose);
515 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
516 			struct ubi_ec_hdr *ec_hdr);
517 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
518 			struct ubi_vid_hdr *vid_hdr, int verbose);
519 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
520 			 struct ubi_vid_hdr *vid_hdr);
521 
522 /* build.c */
523 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
524 int ubi_detach_mtd_dev(int ubi_num, int anyway);
525 struct ubi_device *ubi_get_device(int ubi_num);
526 void ubi_put_device(struct ubi_device *ubi);
527 struct ubi_device *ubi_get_by_major(int major);
528 int ubi_major2num(int major);
529 
530 /*
531  * ubi_rb_for_each_entry - walk an RB-tree.
532  * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
533  * @pos: a pointer to RB-tree entry type to use as a loop counter
534  * @root: RB-tree's root
535  * @member: the name of the 'struct rb_node' within the RB-tree entry
536  */
537 #define ubi_rb_for_each_entry(rb, pos, root, member)                         \
538 	for (rb = rb_first(root),                                            \
539 	     pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
540 	     rb;                                                             \
541 	     rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
542 
543 /**
544  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
545  * @ubi: UBI device description object
546  * @gfp_flags: GFP flags to allocate with
547  *
548  * This function returns a pointer to the newly allocated and zero-filled
549  * volume identifier header object in case of success and %NULL in case of
550  * failure.
551  */
552 static inline struct ubi_vid_hdr *
553 ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
554 {
555 	void *vid_hdr;
556 
557 	vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
558 	if (!vid_hdr)
559 		return NULL;
560 
561 	/*
562 	 * VID headers may be stored at un-aligned flash offsets, so we shift
563 	 * the pointer.
564 	 */
565 	return vid_hdr + ubi->vid_hdr_shift;
566 }
567 
568 /**
569  * ubi_free_vid_hdr - free a volume identifier header object.
570  * @ubi: UBI device description object
571  * @vid_hdr: the object to free
572  */
573 static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
574 				    struct ubi_vid_hdr *vid_hdr)
575 {
576 	void *p = vid_hdr;
577 
578 	if (!p)
579 		return;
580 
581 	kfree(p - ubi->vid_hdr_shift);
582 }
583 
584 /*
585  * This function is equivalent to 'ubi_io_read()', but @offset is relative to
586  * the beginning of the logical eraseblock, not to the beginning of the
587  * physical eraseblock.
588  */
589 static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
590 				   int pnum, int offset, int len)
591 {
592 	ubi_assert(offset >= 0);
593 	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
594 }
595 
596 /*
597  * This function is equivalent to 'ubi_io_write()', but @offset is relative to
598  * the beginning of the logical eraseblock, not to the beginning of the
599  * physical eraseblock.
600  */
601 static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
602 				    int pnum, int offset, int len)
603 {
604 	ubi_assert(offset >= 0);
605 	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
606 }
607 
608 /**
609  * ubi_ro_mode - switch to read-only mode.
610  * @ubi: UBI device description object
611  */
612 static inline void ubi_ro_mode(struct ubi_device *ubi)
613 {
614 	if (!ubi->ro_mode) {
615 		ubi->ro_mode = 1;
616 		ubi_warn("switch to read-only mode");
617 	}
618 }
619 
620 /**
621  * vol_id2idx - get table index by volume ID.
622  * @ubi: UBI device description object
623  * @vol_id: volume ID
624  */
625 static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
626 {
627 	if (vol_id >= UBI_INTERNAL_VOL_START)
628 		return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
629 	else
630 		return vol_id;
631 }
632 
633 /**
634  * idx2vol_id - get volume ID by table index.
635  * @ubi: UBI device description object
636  * @idx: table index
637  */
638 static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
639 {
640 	if (idx >= ubi->vtbl_slots)
641 		return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
642 	else
643 		return idx;
644 }
645 
646 #endif /* !__UBI_UBI_H__ */
647