1 /*
2  * Copyright © International Business Machines Corp., 2006
3  *
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.
8  *
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.
13  *
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
17  *
18  * Author: Artem Bityutskiy (Битюцкий Артём)
19  */
20 
21 #ifndef __UBI_USER_H__
22 #define __UBI_USER_H__
23 
24 #include <linux/types.h>
25 
26 /*
27  * UBI device creation (the same as MTD device attachment)
28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
29  *
30  * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
31  * control device. The caller has to properly fill and pass
32  * &struct ubi_attach_req object - UBI will attach the MTD device specified in
33  * the request and return the newly created UBI device number as the ioctl
34  * return value.
35  *
36  * UBI device deletion (the same as MTD device detachment)
37  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
38  *
39  * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
40  * control device.
41  *
42  * UBI volume creation
43  * ~~~~~~~~~~~~~~~~~~~
44  *
45  * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
46  * device. A &struct ubi_mkvol_req object has to be properly filled and a
47  * pointer to it has to be passed to the ioctl.
48  *
49  * UBI volume deletion
50  * ~~~~~~~~~~~~~~~~~~~
51  *
52  * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
53  * device should be used. A pointer to the 32-bit volume ID hast to be passed
54  * to the ioctl.
55  *
56  * UBI volume re-size
57  * ~~~~~~~~~~~~~~~~~~
58  *
59  * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
60  * device should be used. A &struct ubi_rsvol_req object has to be properly
61  * filled and a pointer to it has to be passed to the ioctl.
62  *
63  * UBI volumes re-name
64  * ~~~~~~~~~~~~~~~~~~~
65  *
66  * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
67  * of the UBI character device should be used. A &struct ubi_rnvol_req object
68  * has to be properly filled and a pointer to it has to be passed to the ioctl.
69  *
70  * UBI volume update
71  * ~~~~~~~~~~~~~~~~~
72  *
73  * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
74  * corresponding UBI volume character device. A pointer to a 64-bit update
75  * size should be passed to the ioctl. After this, UBI expects user to write
76  * this number of bytes to the volume character device. The update is finished
77  * when the claimed number of bytes is passed. So, the volume update sequence
78  * is something like:
79  *
80  * fd = open("/dev/my_volume");
81  * ioctl(fd, UBI_IOCVOLUP, &image_size);
82  * write(fd, buf, image_size);
83  * close(fd);
84  *
85  * Logical eraseblock erase
86  * ~~~~~~~~~~~~~~~~~~~~~~~~
87  *
88  * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
89  * corresponding UBI volume character device should be used. This command
90  * unmaps the requested logical eraseblock, makes sure the corresponding
91  * physical eraseblock is successfully erased, and returns.
92  *
93  * Atomic logical eraseblock change
94  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
95  *
96  * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
97  * ioctl command of the corresponding UBI volume character device. A pointer to
98  * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
99  * user is expected to write the requested amount of bytes (similarly to what
100  * should be done in case of the "volume update" ioctl).
101  *
102  * Logical eraseblock map
103  * ~~~~~~~~~~~~~~~~~~~~~
104  *
105  * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
106  * ioctl command should be used. A pointer to a &struct ubi_map_req object is
107  * expected to be passed. The ioctl maps the requested logical eraseblock to
108  * a physical eraseblock and returns.  Only non-mapped logical eraseblocks can
109  * be mapped. If the logical eraseblock specified in the request is already
110  * mapped to a physical eraseblock, the ioctl fails and returns error.
111  *
112  * Logical eraseblock unmap
113  * ~~~~~~~~~~~~~~~~~~~~~~~~
114  *
115  * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
116  * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
117  * schedules corresponding physical eraseblock for erasure, and returns. Unlike
118  * the "LEB erase" command, it does not wait for the physical eraseblock being
119  * erased. Note, the side effect of this is that if an unclean reboot happens
120  * after the unmap ioctl returns, you may find the LEB mapped again to the same
121  * physical eraseblock after the UBI is run again.
122  *
123  * Check if logical eraseblock is mapped
124  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
125  *
126  * To check if a logical eraseblock is mapped to a physical eraseblock, the
127  * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
128  * not mapped, and %1 if it is mapped.
129  *
130  * Set an UBI volume property
131  * ~~~~~~~~~~~~~~~~~~~~~~~~~
132  *
133  * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
134  * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
135  * passed. The object describes which property should be set, and to which value
136  * it should be set.
137  *
138  * Block devices on UBI volumes
139  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
140  *
141  * To create a R/O block device on top of an UBI volume the %UBI_IOCVOLCRBLK
142  * should be used. A pointer to a &struct ubi_blkcreate_req object is expected
143  * to be passed, which is not used and reserved for future usage.
144  *
145  * Conversely, to remove a block device the %UBI_IOCVOLRMBLK should be used,
146  * which takes no arguments.
147  */
148 
149 /*
150  * When a new UBI volume or UBI device is created, users may either specify the
151  * volume/device number they want to create or to let UBI automatically assign
152  * the number using these constants.
153  */
154 #define UBI_VOL_NUM_AUTO (-1)
155 #define UBI_DEV_NUM_AUTO (-1)
156 
157 /* Maximum volume name length */
158 #define UBI_MAX_VOLUME_NAME 127
159 
160 /* ioctl commands of UBI character devices */
161 
162 #define UBI_IOC_MAGIC 'o'
163 
164 /* Create an UBI volume */
165 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
166 /* Remove an UBI volume */
167 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
168 /* Re-size an UBI volume */
169 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
170 /* Re-name volumes */
171 #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
172 
173 /* ioctl commands of the UBI control character device */
174 
175 #define UBI_CTRL_IOC_MAGIC 'o'
176 
177 /* Attach an MTD device */
178 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
179 /* Detach an MTD device */
180 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
181 
182 /* ioctl commands of UBI volume character devices */
183 
184 #define UBI_VOL_IOC_MAGIC 'O'
185 
186 /* Start UBI volume update
187  * Note: This actually takes a pointer (__s64*), but we can't change
188  *       that without breaking the ABI on 32bit systems
189  */
190 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
191 /* LEB erasure command, used for debugging, disabled by default */
192 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
193 /* Atomic LEB change command */
194 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
195 /* Map LEB command */
196 #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
197 /* Unmap LEB command */
198 #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
199 /* Check if LEB is mapped command */
200 #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
201 /* Set an UBI volume property */
202 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
203 			       struct ubi_set_vol_prop_req)
204 /* Create a R/O block device on top of an UBI volume */
205 #define UBI_IOCVOLCRBLK _IOW(UBI_VOL_IOC_MAGIC, 7, struct ubi_blkcreate_req)
206 /* Remove the R/O block device */
207 #define UBI_IOCVOLRMBLK _IO(UBI_VOL_IOC_MAGIC, 8)
208 
209 /* Maximum MTD device name length supported by UBI */
210 #define MAX_UBI_MTD_NAME_LEN 127
211 
212 /* Maximum amount of UBI volumes that can be re-named at one go */
213 #define UBI_MAX_RNVOL 32
214 
215 /*
216  * UBI volume type constants.
217  *
218  * @UBI_DYNAMIC_VOLUME: dynamic volume
219  * @UBI_STATIC_VOLUME:  static volume
220  */
221 enum {
222 	UBI_DYNAMIC_VOLUME = 3,
223 	UBI_STATIC_VOLUME  = 4,
224 };
225 
226 /*
227  * UBI set volume property ioctl constants.
228  *
229  * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
230  *                             user to directly write and erase individual
231  *                             eraseblocks on dynamic volumes
232  */
233 enum {
234 	UBI_VOL_PROP_DIRECT_WRITE = 1,
235 };
236 
237 /**
238  * struct ubi_attach_req - attach MTD device request.
239  * @ubi_num: UBI device number to create
240  * @mtd_num: MTD device number to attach
241  * @vid_hdr_offset: VID header offset (use defaults if %0)
242  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
243  * @padding: reserved for future, not used, has to be zeroed
244  *
245  * This data structure is used to specify MTD device UBI has to attach and the
246  * parameters it has to use. The number which should be assigned to the new UBI
247  * device is passed in @ubi_num. UBI may automatically assign the number if
248  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
249  * @ubi_num.
250  *
251  * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
252  * offset of the VID header within physical eraseblocks. The default offset is
253  * the next min. I/O unit after the EC header. For example, it will be offset
254  * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
255  * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
256  *
257  * But in rare cases, if this optimizes things, the VID header may be placed to
258  * a different offset. For example, the boot-loader might do things faster if
259  * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
260  * As the boot-loader would not normally need to read EC headers (unless it
261  * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
262  * example, but it real-life example. So, in this example, @vid_hdr_offer would
263  * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
264  * aligned, which is OK, as UBI is clever enough to realize this is 4th
265  * sub-page of the first page and add needed padding.
266  *
267  * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
268  * UBI device per 1024 eraseblocks.  This value is often given in an other form
269  * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
270  * maximum expected bad eraseblocks per 1024 is then:
271  *    1024 * (1 - MinNVB / MaxNVB)
272  * Which gives 20 for most NAND devices.  This limit is used in order to derive
273  * amount of eraseblock UBI reserves for handling new bad blocks. If the device
274  * has more bad eraseblocks than this limit, UBI does not reserve any physical
275  * eraseblocks for new bad eraseblocks, but attempts to use available
276  * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
277  * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
278  */
279 struct ubi_attach_req {
280 	__s32 ubi_num;
281 	__s32 mtd_num;
282 	__s32 vid_hdr_offset;
283 	__s16 max_beb_per1024;
284 	__s8 padding[10];
285 };
286 
287 /**
288  * struct ubi_mkvol_req - volume description data structure used in
289  *                        volume creation requests.
290  * @vol_id: volume number
291  * @alignment: volume alignment
292  * @bytes: volume size in bytes
293  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
294  * @padding1: reserved for future, not used, has to be zeroed
295  * @name_len: volume name length
296  * @padding2: reserved for future, not used, has to be zeroed
297  * @name: volume name
298  *
299  * This structure is used by user-space programs when creating new volumes. The
300  * @used_bytes field is only necessary when creating static volumes.
301  *
302  * The @alignment field specifies the required alignment of the volume logical
303  * eraseblock. This means, that the size of logical eraseblocks will be aligned
304  * to this number, i.e.,
305  *	(UBI device logical eraseblock size) mod (@alignment) = 0.
306  *
307  * To put it differently, the logical eraseblock of this volume may be slightly
308  * shortened in order to make it properly aligned. The alignment has to be
309  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
310  * available space of logical eraseblocks.
311  *
312  * The @alignment field may be useful, for example, when one wants to maintain
313  * a block device on top of an UBI volume. In this case, it is desirable to fit
314  * an integer number of blocks in logical eraseblocks of this UBI volume. With
315  * alignment it is possible to update this volume using plane UBI volume image
316  * BLOBs, without caring about how to properly align them.
317  */
318 struct ubi_mkvol_req {
319 	__s32 vol_id;
320 	__s32 alignment;
321 	__s64 bytes;
322 	__s8 vol_type;
323 	__s8 padding1;
324 	__s16 name_len;
325 	__s8 padding2[4];
326 	char name[UBI_MAX_VOLUME_NAME + 1];
327 } __packed;
328 
329 /**
330  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
331  * @vol_id: ID of the volume to re-size
332  * @bytes: new size of the volume in bytes
333  *
334  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
335  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
336  * smaller than the number of bytes they bear. To arbitrarily shrink a static
337  * volume, it must be wiped out first (by means of volume update operation with
338  * zero number of bytes).
339  */
340 struct ubi_rsvol_req {
341 	__s64 bytes;
342 	__s32 vol_id;
343 } __packed;
344 
345 /**
346  * struct ubi_rnvol_req - volumes re-name request.
347  * @count: count of volumes to re-name
348  * @padding1:  reserved for future, not used, has to be zeroed
349  * @vol_id: ID of the volume to re-name
350  * @name_len: name length
351  * @padding2:  reserved for future, not used, has to be zeroed
352  * @name: new volume name
353  *
354  * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
355  * re-name is specified in the @count field. The ID of the volumes to re-name
356  * and the new names are specified in the @vol_id and @name fields.
357  *
358  * The UBI volume re-name operation is atomic, which means that should power cut
359  * happen, the volumes will have either old name or new name. So the possible
360  * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
361  * A and B one may create temporary volumes %A1 and %B1 with the new contents,
362  * then atomically re-name A1->A and B1->B, in which case old %A and %B will
363  * be removed.
364  *
365  * If it is not desirable to remove old A and B, the re-name request has to
366  * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
367  * become A and B, and old A and B will become A1 and B1.
368  *
369  * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
370  * and B1 become A and B, and old A and B become X and Y.
371  *
372  * In other words, in case of re-naming into an existing volume name, the
373  * existing volume is removed, unless it is re-named as well at the same
374  * re-name request.
375  */
376 struct ubi_rnvol_req {
377 	__s32 count;
378 	__s8 padding1[12];
379 	struct {
380 		__s32 vol_id;
381 		__s16 name_len;
382 		__s8  padding2[2];
383 		char    name[UBI_MAX_VOLUME_NAME + 1];
384 	} ents[UBI_MAX_RNVOL];
385 } __packed;
386 
387 /**
388  * struct ubi_leb_change_req - a data structure used in atomic LEB change
389  *                             requests.
390  * @lnum: logical eraseblock number to change
391  * @bytes: how many bytes will be written to the logical eraseblock
392  * @dtype: pass "3" for better compatibility with old kernels
393  * @padding: reserved for future, not used, has to be zeroed
394  *
395  * The @dtype field used to inform UBI about what kind of data will be written
396  * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
397  * UBI tried to pick a PEB with lower erase counter for short term data and a
398  * PEB with higher erase counter for long term data. But this was not really
399  * used because users usually do not know this and could easily mislead UBI. We
400  * removed this feature in May 2012. UBI currently just ignores the @dtype
401  * field. But for better compatibility with older kernels it is recommended to
402  * set @dtype to 3 (unknown).
403  */
404 struct ubi_leb_change_req {
405 	__s32 lnum;
406 	__s32 bytes;
407 	__s8  dtype; /* obsolete, do not use! */
408 	__s8  padding[7];
409 } __packed;
410 
411 /**
412  * struct ubi_map_req - a data structure used in map LEB requests.
413  * @dtype: pass "3" for better compatibility with old kernels
414  * @lnum: logical eraseblock number to unmap
415  * @padding: reserved for future, not used, has to be zeroed
416  */
417 struct ubi_map_req {
418 	__s32 lnum;
419 	__s8  dtype; /* obsolete, do not use! */
420 	__s8  padding[3];
421 } __packed;
422 
423 
424 /**
425  * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
426  *                               property.
427  * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
428  * @padding: reserved for future, not used, has to be zeroed
429  * @value: value to set
430  */
431 struct ubi_set_vol_prop_req {
432 	__u8  property;
433 	__u8  padding[7];
434 	__u64 value;
435 }  __packed;
436 
437 /**
438  * struct ubi_blkcreate_req - a data structure used in block creation requests.
439  * @padding: reserved for future, not used, has to be zeroed
440  */
441 struct ubi_blkcreate_req {
442 	__s8  padding[128];
443 }  __packed;
444 
445 #endif /* __UBI_USER_H__ */
446