1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
2 /*
3  * Copyright © International Business Machines Corp., 2006
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_USER_H__
23 #define __UBI_USER_H__
24 
25 #include <linux/types.h>
26 
27 /*
28  * UBI device creation (the same as MTD device attachment)
29  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
30  *
31  * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
32  * control device. The caller has to properly fill and pass
33  * &struct ubi_attach_req object - UBI will attach the MTD device specified in
34  * the request and return the newly created UBI device number as the ioctl
35  * return value.
36  *
37  * UBI device deletion (the same as MTD device detachment)
38  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
39  *
40  * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
41  * control device.
42  *
43  * UBI volume creation
44  * ~~~~~~~~~~~~~~~~~~~
45  *
46  * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
47  * device. A &struct ubi_mkvol_req object has to be properly filled and a
48  * pointer to it has to be passed to the ioctl.
49  *
50  * UBI volume deletion
51  * ~~~~~~~~~~~~~~~~~~~
52  *
53  * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
54  * device should be used. A pointer to the 32-bit volume ID hast to be passed
55  * to the ioctl.
56  *
57  * UBI volume re-size
58  * ~~~~~~~~~~~~~~~~~~
59  *
60  * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
61  * device should be used. A &struct ubi_rsvol_req object has to be properly
62  * filled and a pointer to it has to be passed to the ioctl.
63  *
64  * UBI volumes re-name
65  * ~~~~~~~~~~~~~~~~~~~
66  *
67  * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
68  * of the UBI character device should be used. A &struct ubi_rnvol_req object
69  * has to be properly filled and a pointer to it has to be passed to the ioctl.
70  *
71  * UBI volume update
72  * ~~~~~~~~~~~~~~~~~
73  *
74  * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
75  * corresponding UBI volume character device. A pointer to a 64-bit update
76  * size should be passed to the ioctl. After this, UBI expects user to write
77  * this number of bytes to the volume character device. The update is finished
78  * when the claimed number of bytes is passed. So, the volume update sequence
79  * is something like:
80  *
81  * fd = open("/dev/my_volume");
82  * ioctl(fd, UBI_IOCVOLUP, &image_size);
83  * write(fd, buf, image_size);
84  * close(fd);
85  *
86  * Logical eraseblock erase
87  * ~~~~~~~~~~~~~~~~~~~~~~~~
88  *
89  * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
90  * corresponding UBI volume character device should be used. This command
91  * unmaps the requested logical eraseblock, makes sure the corresponding
92  * physical eraseblock is successfully erased, and returns.
93  *
94  * Atomic logical eraseblock change
95  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
96  *
97  * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
98  * ioctl command of the corresponding UBI volume character device. A pointer to
99  * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
100  * user is expected to write the requested amount of bytes (similarly to what
101  * should be done in case of the "volume update" ioctl).
102  *
103  * Logical eraseblock map
104  * ~~~~~~~~~~~~~~~~~~~~~
105  *
106  * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
107  * ioctl command should be used. A pointer to a &struct ubi_map_req object is
108  * expected to be passed. The ioctl maps the requested logical eraseblock to
109  * a physical eraseblock and returns.  Only non-mapped logical eraseblocks can
110  * be mapped. If the logical eraseblock specified in the request is already
111  * mapped to a physical eraseblock, the ioctl fails and returns error.
112  *
113  * Logical eraseblock unmap
114  * ~~~~~~~~~~~~~~~~~~~~~~~~
115  *
116  * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
117  * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
118  * schedules corresponding physical eraseblock for erasure, and returns. Unlike
119  * the "LEB erase" command, it does not wait for the physical eraseblock being
120  * erased. Note, the side effect of this is that if an unclean reboot happens
121  * after the unmap ioctl returns, you may find the LEB mapped again to the same
122  * physical eraseblock after the UBI is run again.
123  *
124  * Check if logical eraseblock is mapped
125  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
126  *
127  * To check if a logical eraseblock is mapped to a physical eraseblock, the
128  * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
129  * not mapped, and %1 if it is mapped.
130  *
131  * Set an UBI volume property
132  * ~~~~~~~~~~~~~~~~~~~~~~~~~
133  *
134  * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
135  * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
136  * passed. The object describes which property should be set, and to which value
137  * it should be set.
138  *
139  * Block devices on UBI volumes
140  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
141  *
142  * To create a R/O block device on top of an UBI volume the %UBI_IOCVOLCRBLK
143  * should be used. A pointer to a &struct ubi_blkcreate_req object is expected
144  * to be passed, which is not used and reserved for future usage.
145  *
146  * Conversely, to remove a block device the %UBI_IOCVOLRMBLK should be used,
147  * which takes no arguments.
148  */
149 
150 /*
151  * When a new UBI volume or UBI device is created, users may either specify the
152  * volume/device number they want to create or to let UBI automatically assign
153  * the number using these constants.
154  */
155 #define UBI_VOL_NUM_AUTO (-1)
156 #define UBI_DEV_NUM_AUTO (-1)
157 
158 /* Maximum volume name length */
159 #define UBI_MAX_VOLUME_NAME 127
160 
161 /* ioctl commands of UBI character devices */
162 
163 #define UBI_IOC_MAGIC 'o'
164 
165 /* Create an UBI volume */
166 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
167 /* Remove an UBI volume */
168 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
169 /* Re-size an UBI volume */
170 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
171 /* Re-name volumes */
172 #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
173 
174 /* ioctl commands of the UBI control character device */
175 
176 #define UBI_CTRL_IOC_MAGIC 'o'
177 
178 /* Attach an MTD device */
179 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
180 /* Detach an MTD device */
181 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
182 
183 /* ioctl commands of UBI volume character devices */
184 
185 #define UBI_VOL_IOC_MAGIC 'O'
186 
187 /* Start UBI volume update
188  * Note: This actually takes a pointer (__s64*), but we can't change
189  *       that without breaking the ABI on 32bit systems
190  */
191 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
192 /* LEB erasure command, used for debugging, disabled by default */
193 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
194 /* Atomic LEB change command */
195 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
196 /* Map LEB command */
197 #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
198 /* Unmap LEB command */
199 #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
200 /* Check if LEB is mapped command */
201 #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
202 /* Set an UBI volume property */
203 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
204 			       struct ubi_set_vol_prop_req)
205 /* Create a R/O block device on top of an UBI volume */
206 #define UBI_IOCVOLCRBLK _IOW(UBI_VOL_IOC_MAGIC, 7, struct ubi_blkcreate_req)
207 /* Remove the R/O block device */
208 #define UBI_IOCVOLRMBLK _IO(UBI_VOL_IOC_MAGIC, 8)
209 
210 /* Maximum MTD device name length supported by UBI */
211 #define MAX_UBI_MTD_NAME_LEN 127
212 
213 /* Maximum amount of UBI volumes that can be re-named at one go */
214 #define UBI_MAX_RNVOL 32
215 
216 /*
217  * UBI volume type constants.
218  *
219  * @UBI_DYNAMIC_VOLUME: dynamic volume
220  * @UBI_STATIC_VOLUME:  static volume
221  */
222 enum {
223 	UBI_DYNAMIC_VOLUME = 3,
224 	UBI_STATIC_VOLUME  = 4,
225 };
226 
227 /*
228  * UBI set volume property ioctl constants.
229  *
230  * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
231  *                             user to directly write and erase individual
232  *                             eraseblocks on dynamic volumes
233  */
234 enum {
235 	UBI_VOL_PROP_DIRECT_WRITE = 1,
236 };
237 
238 /**
239  * struct ubi_attach_req - attach MTD device request.
240  * @ubi_num: UBI device number to create
241  * @mtd_num: MTD device number to attach
242  * @vid_hdr_offset: VID header offset (use defaults if %0)
243  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
244  * @padding: reserved for future, not used, has to be zeroed
245  *
246  * This data structure is used to specify MTD device UBI has to attach and the
247  * parameters it has to use. The number which should be assigned to the new UBI
248  * device is passed in @ubi_num. UBI may automatically assign the number if
249  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
250  * @ubi_num.
251  *
252  * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
253  * offset of the VID header within physical eraseblocks. The default offset is
254  * the next min. I/O unit after the EC header. For example, it will be offset
255  * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
256  * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
257  *
258  * But in rare cases, if this optimizes things, the VID header may be placed to
259  * a different offset. For example, the boot-loader might do things faster if
260  * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
261  * As the boot-loader would not normally need to read EC headers (unless it
262  * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
263  * example, but it real-life example. So, in this example, @vid_hdr_offer would
264  * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
265  * aligned, which is OK, as UBI is clever enough to realize this is 4th
266  * sub-page of the first page and add needed padding.
267  *
268  * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
269  * UBI device per 1024 eraseblocks.  This value is often given in an other form
270  * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
271  * maximum expected bad eraseblocks per 1024 is then:
272  *    1024 * (1 - MinNVB / MaxNVB)
273  * Which gives 20 for most NAND devices.  This limit is used in order to derive
274  * amount of eraseblock UBI reserves for handling new bad blocks. If the device
275  * has more bad eraseblocks than this limit, UBI does not reserve any physical
276  * eraseblocks for new bad eraseblocks, but attempts to use available
277  * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
278  * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
279  */
280 struct ubi_attach_req {
281 	__s32 ubi_num;
282 	__s32 mtd_num;
283 	__s32 vid_hdr_offset;
284 	__s16 max_beb_per1024;
285 	__s8 padding[10];
286 };
287 
288 /*
289  * UBI volume flags.
290  *
291  * @UBI_VOL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at
292  *				open time. Only valid for static volumes and
293  *				should only be used if the volume user has a
294  *				way to verify data integrity
295  */
296 enum {
297 	UBI_VOL_SKIP_CRC_CHECK_FLG = 0x1,
298 };
299 
300 #define UBI_VOL_VALID_FLGS	(UBI_VOL_SKIP_CRC_CHECK_FLG)
301 
302 /**
303  * struct ubi_mkvol_req - volume description data structure used in
304  *                        volume creation requests.
305  * @vol_id: volume number
306  * @alignment: volume alignment
307  * @bytes: volume size in bytes
308  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
309  * @flags: volume flags (%UBI_VOL_SKIP_CRC_CHECK_FLG)
310  * @name_len: volume name length
311  * @padding2: reserved for future, not used, has to be zeroed
312  * @name: volume name
313  *
314  * This structure is used by user-space programs when creating new volumes. The
315  * @used_bytes field is only necessary when creating static volumes.
316  *
317  * The @alignment field specifies the required alignment of the volume logical
318  * eraseblock. This means, that the size of logical eraseblocks will be aligned
319  * to this number, i.e.,
320  *	(UBI device logical eraseblock size) mod (@alignment) = 0.
321  *
322  * To put it differently, the logical eraseblock of this volume may be slightly
323  * shortened in order to make it properly aligned. The alignment has to be
324  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
325  * available space of logical eraseblocks.
326  *
327  * The @alignment field may be useful, for example, when one wants to maintain
328  * a block device on top of an UBI volume. In this case, it is desirable to fit
329  * an integer number of blocks in logical eraseblocks of this UBI volume. With
330  * alignment it is possible to update this volume using plane UBI volume image
331  * BLOBs, without caring about how to properly align them.
332  */
333 struct ubi_mkvol_req {
334 	__s32 vol_id;
335 	__s32 alignment;
336 	__s64 bytes;
337 	__s8 vol_type;
338 	__u8 flags;
339 	__s16 name_len;
340 	__s8 padding2[4];
341 	char name[UBI_MAX_VOLUME_NAME + 1];
342 } __packed;
343 
344 /**
345  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
346  * @vol_id: ID of the volume to re-size
347  * @bytes: new size of the volume in bytes
348  *
349  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
350  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
351  * smaller than the number of bytes they bear. To arbitrarily shrink a static
352  * volume, it must be wiped out first (by means of volume update operation with
353  * zero number of bytes).
354  */
355 struct ubi_rsvol_req {
356 	__s64 bytes;
357 	__s32 vol_id;
358 } __packed;
359 
360 /**
361  * struct ubi_rnvol_req - volumes re-name request.
362  * @count: count of volumes to re-name
363  * @padding1:  reserved for future, not used, has to be zeroed
364  * @vol_id: ID of the volume to re-name
365  * @name_len: name length
366  * @padding2:  reserved for future, not used, has to be zeroed
367  * @name: new volume name
368  *
369  * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
370  * re-name is specified in the @count field. The ID of the volumes to re-name
371  * and the new names are specified in the @vol_id and @name fields.
372  *
373  * The UBI volume re-name operation is atomic, which means that should power cut
374  * happen, the volumes will have either old name or new name. So the possible
375  * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
376  * A and B one may create temporary volumes %A1 and %B1 with the new contents,
377  * then atomically re-name A1->A and B1->B, in which case old %A and %B will
378  * be removed.
379  *
380  * If it is not desirable to remove old A and B, the re-name request has to
381  * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
382  * become A and B, and old A and B will become A1 and B1.
383  *
384  * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
385  * and B1 become A and B, and old A and B become X and Y.
386  *
387  * In other words, in case of re-naming into an existing volume name, the
388  * existing volume is removed, unless it is re-named as well at the same
389  * re-name request.
390  */
391 struct ubi_rnvol_req {
392 	__s32 count;
393 	__s8 padding1[12];
394 	struct {
395 		__s32 vol_id;
396 		__s16 name_len;
397 		__s8  padding2[2];
398 		char    name[UBI_MAX_VOLUME_NAME + 1];
399 	} ents[UBI_MAX_RNVOL];
400 } __packed;
401 
402 /**
403  * struct ubi_leb_change_req - a data structure used in atomic LEB change
404  *                             requests.
405  * @lnum: logical eraseblock number to change
406  * @bytes: how many bytes will be written to the logical eraseblock
407  * @dtype: pass "3" for better compatibility with old kernels
408  * @padding: reserved for future, not used, has to be zeroed
409  *
410  * The @dtype field used to inform UBI about what kind of data will be written
411  * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
412  * UBI tried to pick a PEB with lower erase counter for short term data and a
413  * PEB with higher erase counter for long term data. But this was not really
414  * used because users usually do not know this and could easily mislead UBI. We
415  * removed this feature in May 2012. UBI currently just ignores the @dtype
416  * field. But for better compatibility with older kernels it is recommended to
417  * set @dtype to 3 (unknown).
418  */
419 struct ubi_leb_change_req {
420 	__s32 lnum;
421 	__s32 bytes;
422 	__s8  dtype; /* obsolete, do not use! */
423 	__s8  padding[7];
424 } __packed;
425 
426 /**
427  * struct ubi_map_req - a data structure used in map LEB requests.
428  * @dtype: pass "3" for better compatibility with old kernels
429  * @lnum: logical eraseblock number to unmap
430  * @padding: reserved for future, not used, has to be zeroed
431  */
432 struct ubi_map_req {
433 	__s32 lnum;
434 	__s8  dtype; /* obsolete, do not use! */
435 	__s8  padding[3];
436 } __packed;
437 
438 
439 /**
440  * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
441  *                               property.
442  * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
443  * @padding: reserved for future, not used, has to be zeroed
444  * @value: value to set
445  */
446 struct ubi_set_vol_prop_req {
447 	__u8  property;
448 	__u8  padding[7];
449 	__u64 value;
450 }  __packed;
451 
452 /**
453  * struct ubi_blkcreate_req - a data structure used in block creation requests.
454  * @padding: reserved for future, not used, has to be zeroed
455  */
456 struct ubi_blkcreate_req {
457 	__s8  padding[128];
458 }  __packed;
459 
460 #endif /* __UBI_USER_H__ */
461