2 * Copyright © International Business Machines Corp., 2006
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 * Author: Artem Bityutskiy (Битюцкий Артём)
21 #ifndef __UBI_USER_H__
22 #define __UBI_USER_H__
25 * UBI device creation (the same as MTD device attachment)
26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
28 * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
29 * control device. The caller has to properly fill and pass
30 * &struct ubi_attach_req object - UBI will attach the MTD device specified in
31 * the request and return the newly created UBI device number as the ioctl
34 * UBI device deletion (the same as MTD device detachment)
35 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
37 * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
43 * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
44 * device. A &struct ubi_mkvol_req object has to be properly filled and a
45 * pointer to it has to be passed to the ioctl.
50 * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
51 * device should be used. A pointer to the 32-bit volume ID hast to be passed
57 * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
58 * device should be used. A &struct ubi_rsvol_req object has to be properly
59 * filled and a pointer to it has to be passed to the ioctl.
64 * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
65 * of the UBI character device should be used. A &struct ubi_rnvol_req object
66 * has to be properly filled and a pointer to it has to be passed to the ioctl.
71 * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
72 * corresponding UBI volume character device. A pointer to a 64-bit update
73 * size should be passed to the ioctl. After this, UBI expects user to write
74 * this number of bytes to the volume character device. The update is finished
75 * when the claimed number of bytes is passed. So, the volume update sequence
78 * fd = open("/dev/my_volume");
79 * ioctl(fd, UBI_IOCVOLUP, &image_size);
80 * write(fd, buf, image_size);
83 * Logical eraseblock erase
84 * ~~~~~~~~~~~~~~~~~~~~~~~~
86 * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
87 * corresponding UBI volume character device should be used. This command
88 * unmaps the requested logical eraseblock, makes sure the corresponding
89 * physical eraseblock is successfully erased, and returns.
91 * Atomic logical eraseblock change
92 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
94 * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
95 * ioctl command of the corresponding UBI volume character device. A pointer to
96 * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
97 * user is expected to write the requested amount of bytes (similarly to what
98 * should be done in case of the "volume update" ioctl).
100 * Logical eraseblock map
101 * ~~~~~~~~~~~~~~~~~~~~~
103 * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
104 * ioctl command should be used. A pointer to a &struct ubi_map_req object is
105 * expected to be passed. The ioctl maps the requested logical eraseblock to
106 * a physical eraseblock and returns. Only non-mapped logical eraseblocks can
107 * be mapped. If the logical eraseblock specified in the request is already
108 * mapped to a physical eraseblock, the ioctl fails and returns error.
110 * Logical eraseblock unmap
111 * ~~~~~~~~~~~~~~~~~~~~~~~~
113 * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
114 * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
115 * schedules corresponding physical eraseblock for erasure, and returns. Unlike
116 * the "LEB erase" command, it does not wait for the physical eraseblock being
117 * erased. Note, the side effect of this is that if an unclean reboot happens
118 * after the unmap ioctl returns, you may find the LEB mapped again to the same
119 * physical eraseblock after the UBI is run again.
121 * Check if logical eraseblock is mapped
122 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
124 * To check if a logical eraseblock is mapped to a physical eraseblock, the
125 * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
126 * not mapped, and %1 if it is mapped.
128 * Set an UBI volume property
129 * ~~~~~~~~~~~~~~~~~~~~~~~~~
131 * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
132 * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
133 * passed. The object describes which property should be set, and to which value
138 * When a new UBI volume or UBI device is created, users may either specify the
139 * volume/device number they want to create or to let UBI automatically assign
140 * the number using these constants.
142 #define UBI_VOL_NUM_AUTO (-1)
143 #define UBI_DEV_NUM_AUTO (-1)
145 /* Maximum volume name length */
146 #define UBI_MAX_VOLUME_NAME 127
148 /* ioctl commands of UBI character devices */
150 #define UBI_IOC_MAGIC 'o'
152 /* Create an UBI volume */
153 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
154 /* Remove an UBI volume */
155 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
156 /* Re-size an UBI volume */
157 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
158 /* Re-name volumes */
159 #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
161 /* ioctl commands of the UBI control character device */
163 #define UBI_CTRL_IOC_MAGIC 'o'
165 /* Attach an MTD device */
166 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
167 /* Detach an MTD device */
168 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)
169 #define UBI_IOCFDET _IOW(UBI_CTRL_IOC_MAGIC, 99, int32_t)
171 /* ioctl commands of UBI volume character devices */
173 #define UBI_VOL_IOC_MAGIC 'O'
175 /* Start UBI volume update */
176 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
177 /* LEB erasure command, used for debugging, disabled by default */
178 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
179 /* Atomic LEB change command */
180 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)
181 /* Map LEB command */
182 #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
183 /* Unmap LEB command */
184 #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, int32_t)
185 /* Check if LEB is mapped command */
186 #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, int32_t)
187 /* Set an UBI volume property */
188 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
189 struct ubi_set_vol_prop_req)
191 /* Maximum MTD device name length supported by UBI */
192 #define MAX_UBI_MTD_NAME_LEN 127
194 /* Maximum amount of UBI volumes that can be re-named at one go */
195 #define UBI_MAX_RNVOL 32
198 * UBI volume type constants.
200 * @UBI_DYNAMIC_VOLUME: dynamic volume
201 * @UBI_STATIC_VOLUME: static volume
204 UBI_DYNAMIC_VOLUME
= 3,
205 UBI_STATIC_VOLUME
= 4,
209 * UBI set volume property ioctl constants.
211 * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
212 * user to directly write and erase individual
213 * eraseblocks on dynamic volumes
216 UBI_VOL_PROP_DIRECT_WRITE
= 1,
220 * struct ubi_attach_req - attach MTD device request.
221 * @ubi_num: UBI device number to create
222 * @mtd_num: MTD device number to attach
223 * @vid_hdr_offset: VID header offset (use defaults if %0)
224 * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
225 * @padding: reserved for future, not used, has to be zeroed
227 * This data structure is used to specify MTD device UBI has to attach and the
228 * parameters it has to use. The number which should be assigned to the new UBI
229 * device is passed in @ubi_num. UBI may automatically assign the number if
230 * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
233 * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
234 * offset of the VID header within physical eraseblocks. The default offset is
235 * the next min. I/O unit after the EC header. For example, it will be offset
236 * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
237 * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
239 * But in rare cases, if this optimizes things, the VID header may be placed to
240 * a different offset. For example, the boot-loader might do things faster if
241 * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
242 * As the boot-loader would not normally need to read EC headers (unless it
243 * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
244 * example, but it real-life example. So, in this example, @vid_hdr_offer would
245 * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
246 * aligned, which is OK, as UBI is clever enough to realize this is 4th
247 * sub-page of the first page and add needed padding.
249 * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
250 * UBI device per 1024 eraseblocks. This value is often given in an other form
251 * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
252 * maximum expected bad eraseblocks per 1024 is then:
253 * 1024 * (1 - MinNVB / MaxNVB)
254 * Which gives 20 for most NAND devices. This limit is used in order to derive
255 * amount of eraseblock UBI reserves for handling new bad blocks. If the device
256 * has more bad eraseblocks than this limit, UBI does not reserve any physical
257 * eraseblocks for new bad eraseblocks, but attempts to use available
258 * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
259 * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
261 struct ubi_attach_req
{
264 int32_t vid_hdr_offset
;
265 int16_t max_beb_per1024
;
270 * struct ubi_mkvol_req - volume description data structure used in
271 * volume creation requests.
272 * @vol_id: volume number
273 * @alignment: volume alignment
274 * @bytes: volume size in bytes
275 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
276 * @padding1: reserved for future, not used, has to be zeroed
277 * @name_len: volume name length
278 * @padding2: reserved for future, not used, has to be zeroed
281 * This structure is used by user-space programs when creating new volumes. The
282 * @used_bytes field is only necessary when creating static volumes.
284 * The @alignment field specifies the required alignment of the volume logical
285 * eraseblock. This means, that the size of logical eraseblocks will be aligned
286 * to this number, i.e.,
287 * (UBI device logical eraseblock size) mod (@alignment) = 0.
289 * To put it differently, the logical eraseblock of this volume may be slightly
290 * shortened in order to make it properly aligned. The alignment has to be
291 * multiple of the flash minimal input/output unit, or %1 to utilize the entire
292 * available space of logical eraseblocks.
294 * The @alignment field may be useful, for example, when one wants to maintain
295 * a block device on top of an UBI volume. In this case, it is desirable to fit
296 * an integer number of blocks in logical eraseblocks of this UBI volume. With
297 * alignment it is possible to update this volume using plane UBI volume image
298 * BLOBs, without caring about how to properly align them.
300 struct ubi_mkvol_req
{
308 char name
[UBI_MAX_VOLUME_NAME
+ 1];
309 } __attribute__((packed
));
312 * struct ubi_rsvol_req - a data structure used in volume re-size requests.
313 * @vol_id: ID of the volume to re-size
314 * @bytes: new size of the volume in bytes
316 * Re-sizing is possible for both dynamic and static volumes. But while dynamic
317 * volumes may be re-sized arbitrarily, static volumes cannot be made to be
318 * smaller than the number of bytes they bear. To arbitrarily shrink a static
319 * volume, it must be wiped out first (by means of volume update operation with
320 * zero number of bytes).
322 struct ubi_rsvol_req
{
325 } __attribute__((packed
));
328 * struct ubi_rnvol_req - volumes re-name request.
329 * @count: count of volumes to re-name
330 * @padding1: reserved for future, not used, has to be zeroed
331 * @vol_id: ID of the volume to re-name
332 * @name_len: name length
333 * @padding2: reserved for future, not used, has to be zeroed
334 * @name: new volume name
336 * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
337 * re-name is specified in the @count field. The ID of the volumes to re-name
338 * and the new names are specified in the @vol_id and @name fields.
340 * The UBI volume re-name operation is atomic, which means that should power cut
341 * happen, the volumes will have either old name or new name. So the possible
342 * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
343 * A and B one may create temporary volumes %A1 and %B1 with the new contents,
344 * then atomically re-name A1->A and B1->B, in which case old %A and %B will
347 * If it is not desirable to remove old A and B, the re-name request has to
348 * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
349 * become A and B, and old A and B will become A1 and B1.
351 * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
352 * and B1 become A and B, and old A and B become X and Y.
354 * In other words, in case of re-naming into an existing volume name, the
355 * existing volume is removed, unless it is re-named as well at the same
358 struct ubi_rnvol_req
{
365 char name
[UBI_MAX_VOLUME_NAME
+ 1];
366 } ents
[UBI_MAX_RNVOL
];
367 } __attribute__((packed
));
370 * struct ubi_leb_change_req - a data structure used in atomic LEB change
372 * @lnum: logical eraseblock number to change
373 * @bytes: how many bytes will be written to the logical eraseblock
374 * @dtype: pass "3" for better compatibility with old kernels
375 * @padding: reserved for future, not used, has to be zeroed
377 * The @dtype field used to inform UBI about what kind of data will be written
378 * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
379 * UBI tried to pick a PEB with lower erase counter for short term data and a
380 * PEB with higher erase counter for long term data. But this was not really
381 * used because users usually do not know this and could easily mislead UBI. We
382 * removed this feature in May 2012. UBI currently just ignores the @dtype
383 * field. But for better compatibility with older kernels it is recommended to
384 * set @dtype to 3 (unknown).
386 struct ubi_leb_change_req
{
389 int8_t dtype
; /* obsolete, do not use! */
391 } __attribute__((packed
));
394 * struct ubi_map_req - a data structure used in map LEB requests.
395 * @dtype: pass "3" for better compatibility with old kernels
396 * @lnum: logical eraseblock number to unmap
397 * @padding: reserved for future, not used, has to be zeroed
401 int8_t dtype
; /* obsolete, do not use! */
403 } __attribute__((packed
));
407 * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
409 * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
410 * @padding: reserved for future, not used, has to be zeroed
411 * @value: value to set
413 struct ubi_set_vol_prop_req
{
417 } __attribute__((packed
));
419 #endif /* __UBI_USER_H__ */