ubi-user.h 17 KB

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  1. /* SPDX-License-Identifier: GPL-2.0+ */
  2. /*
  3. * Copyright © International Business Machines Corp., 2006
  4. *
  5. * Author: Artem Bityutskiy (Битюцкий Артём)
  6. */
  7. #ifndef __UBI_USER_H__
  8. #define __UBI_USER_H__
  9. #include <linux/types.h>
  10. /*
  11. * UBI device creation (the same as MTD device attachment)
  12. * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  13. *
  14. * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
  15. * control device. The caller has to properly fill and pass
  16. * &struct ubi_attach_req object - UBI will attach the MTD device specified in
  17. * the request and return the newly created UBI device number as the ioctl
  18. * return value.
  19. *
  20. * UBI device deletion (the same as MTD device detachment)
  21. * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  22. *
  23. * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
  24. * control device.
  25. *
  26. * UBI volume creation
  27. * ~~~~~~~~~~~~~~~~~~~
  28. *
  29. * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
  30. * device. A &struct ubi_mkvol_req object has to be properly filled and a
  31. * pointer to it has to be passed to the ioctl.
  32. *
  33. * UBI volume deletion
  34. * ~~~~~~~~~~~~~~~~~~~
  35. *
  36. * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
  37. * device should be used. A pointer to the 32-bit volume ID hast to be passed
  38. * to the ioctl.
  39. *
  40. * UBI volume re-size
  41. * ~~~~~~~~~~~~~~~~~~
  42. *
  43. * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
  44. * device should be used. A &struct ubi_rsvol_req object has to be properly
  45. * filled and a pointer to it has to be passed to the ioctl.
  46. *
  47. * UBI volumes re-name
  48. * ~~~~~~~~~~~~~~~~~~~
  49. *
  50. * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
  51. * of the UBI character device should be used. A &struct ubi_rnvol_req object
  52. * has to be properly filled and a pointer to it has to be passed to the ioctl.
  53. *
  54. * UBI volume update
  55. * ~~~~~~~~~~~~~~~~~
  56. *
  57. * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
  58. * corresponding UBI volume character device. A pointer to a 64-bit update
  59. * size should be passed to the ioctl. After this, UBI expects user to write
  60. * this number of bytes to the volume character device. The update is finished
  61. * when the claimed number of bytes is passed. So, the volume update sequence
  62. * is something like:
  63. *
  64. * fd = open("/dev/my_volume");
  65. * ioctl(fd, UBI_IOCVOLUP, &image_size);
  66. * write(fd, buf, image_size);
  67. * close(fd);
  68. *
  69. * Logical eraseblock erase
  70. * ~~~~~~~~~~~~~~~~~~~~~~~~
  71. *
  72. * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
  73. * corresponding UBI volume character device should be used. This command
  74. * unmaps the requested logical eraseblock, makes sure the corresponding
  75. * physical eraseblock is successfully erased, and returns.
  76. *
  77. * Atomic logical eraseblock change
  78. * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  79. *
  80. * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
  81. * ioctl command of the corresponding UBI volume character device. A pointer to
  82. * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
  83. * user is expected to write the requested amount of bytes (similarly to what
  84. * should be done in case of the "volume update" ioctl).
  85. *
  86. * Logical eraseblock map
  87. * ~~~~~~~~~~~~~~~~~~~~~
  88. *
  89. * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
  90. * ioctl command should be used. A pointer to a &struct ubi_map_req object is
  91. * expected to be passed. The ioctl maps the requested logical eraseblock to
  92. * a physical eraseblock and returns. Only non-mapped logical eraseblocks can
  93. * be mapped. If the logical eraseblock specified in the request is already
  94. * mapped to a physical eraseblock, the ioctl fails and returns error.
  95. *
  96. * Logical eraseblock unmap
  97. * ~~~~~~~~~~~~~~~~~~~~~~~~
  98. *
  99. * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
  100. * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
  101. * schedules corresponding physical eraseblock for erasure, and returns. Unlike
  102. * the "LEB erase" command, it does not wait for the physical eraseblock being
  103. * erased. Note, the side effect of this is that if an unclean reboot happens
  104. * after the unmap ioctl returns, you may find the LEB mapped again to the same
  105. * physical eraseblock after the UBI is run again.
  106. *
  107. * Check if logical eraseblock is mapped
  108. * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  109. *
  110. * To check if a logical eraseblock is mapped to a physical eraseblock, the
  111. * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
  112. * not mapped, and %1 if it is mapped.
  113. *
  114. * Set an UBI volume property
  115. * ~~~~~~~~~~~~~~~~~~~~~~~~~
  116. *
  117. * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
  118. * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
  119. * passed. The object describes which property should be set, and to which value
  120. * it should be set.
  121. *
  122. * Block devices on UBI volumes
  123. * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  124. *
  125. * To create a R/O block device on top of an UBI volume the %UBI_IOCVOLCRBLK
  126. * should be used. A pointer to a &struct ubi_blkcreate_req object is expected
  127. * to be passed, which is not used and reserved for future usage.
  128. *
  129. * Conversely, to remove a block device the %UBI_IOCVOLRMBLK should be used,
  130. * which takes no arguments.
  131. */
  132. /*
  133. * When a new UBI volume or UBI device is created, users may either specify the
  134. * volume/device number they want to create or to let UBI automatically assign
  135. * the number using these constants.
  136. */
  137. #define UBI_VOL_NUM_AUTO (-1)
  138. #define UBI_DEV_NUM_AUTO (-1)
  139. /* Maximum volume name length */
  140. #define UBI_MAX_VOLUME_NAME 127
  141. /* ioctl commands of UBI character devices */
  142. #define UBI_IOC_MAGIC 'o'
  143. /* Create an UBI volume */
  144. #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
  145. /* Remove an UBI volume */
  146. #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
  147. /* Re-size an UBI volume */
  148. #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
  149. /* Re-name volumes */
  150. #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
  151. /* ioctl commands of the UBI control character device */
  152. #define UBI_CTRL_IOC_MAGIC 'o'
  153. /* Attach an MTD device */
  154. #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
  155. /* Detach an MTD device */
  156. #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
  157. /* ioctl commands of UBI volume character devices */
  158. #define UBI_VOL_IOC_MAGIC 'O'
  159. /* Start UBI volume update
  160. * Note: This actually takes a pointer (__s64*), but we can't change
  161. * that without breaking the ABI on 32bit systems
  162. */
  163. #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
  164. /* LEB erasure command, used for debugging, disabled by default */
  165. #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
  166. /* Atomic LEB change command */
  167. #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
  168. /* Map LEB command */
  169. #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
  170. /* Unmap LEB command */
  171. #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
  172. /* Check if LEB is mapped command */
  173. #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
  174. /* Set an UBI volume property */
  175. #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
  176. struct ubi_set_vol_prop_req)
  177. /* Create a R/O block device on top of an UBI volume */
  178. #define UBI_IOCVOLCRBLK _IOW(UBI_VOL_IOC_MAGIC, 7, struct ubi_blkcreate_req)
  179. /* Remove the R/O block device */
  180. #define UBI_IOCVOLRMBLK _IO(UBI_VOL_IOC_MAGIC, 8)
  181. /* Maximum MTD device name length supported by UBI */
  182. #define MAX_UBI_MTD_NAME_LEN 127
  183. /* Maximum amount of UBI volumes that can be re-named at one go */
  184. #define UBI_MAX_RNVOL 32
  185. /*
  186. * UBI volume type constants.
  187. *
  188. * @UBI_DYNAMIC_VOLUME: dynamic volume
  189. * @UBI_STATIC_VOLUME: static volume
  190. */
  191. enum {
  192. UBI_DYNAMIC_VOLUME = 3,
  193. UBI_STATIC_VOLUME = 4,
  194. };
  195. /*
  196. * UBI set volume property ioctl constants.
  197. *
  198. * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
  199. * user to directly write and erase individual
  200. * eraseblocks on dynamic volumes
  201. */
  202. enum {
  203. UBI_VOL_PROP_DIRECT_WRITE = 1,
  204. };
  205. /**
  206. * struct ubi_attach_req - attach MTD device request.
  207. * @ubi_num: UBI device number to create
  208. * @mtd_num: MTD device number to attach
  209. * @vid_hdr_offset: VID header offset (use defaults if %0)
  210. * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
  211. * @padding: reserved for future, not used, has to be zeroed
  212. *
  213. * This data structure is used to specify MTD device UBI has to attach and the
  214. * parameters it has to use. The number which should be assigned to the new UBI
  215. * device is passed in @ubi_num. UBI may automatically assign the number if
  216. * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
  217. * @ubi_num.
  218. *
  219. * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
  220. * offset of the VID header within physical eraseblocks. The default offset is
  221. * the next min. I/O unit after the EC header. For example, it will be offset
  222. * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
  223. * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
  224. *
  225. * But in rare cases, if this optimizes things, the VID header may be placed to
  226. * a different offset. For example, the boot-loader might do things faster if
  227. * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
  228. * As the boot-loader would not normally need to read EC headers (unless it
  229. * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
  230. * example, but it real-life example. So, in this example, @vid_hdr_offer would
  231. * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
  232. * aligned, which is OK, as UBI is clever enough to realize this is 4th
  233. * sub-page of the first page and add needed padding.
  234. *
  235. * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
  236. * UBI device per 1024 eraseblocks. This value is often given in an other form
  237. * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
  238. * maximum expected bad eraseblocks per 1024 is then:
  239. * 1024 * (1 - MinNVB / MaxNVB)
  240. * Which gives 20 for most NAND devices. This limit is used in order to derive
  241. * amount of eraseblock UBI reserves for handling new bad blocks. If the device
  242. * has more bad eraseblocks than this limit, UBI does not reserve any physical
  243. * eraseblocks for new bad eraseblocks, but attempts to use available
  244. * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
  245. * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
  246. */
  247. struct ubi_attach_req {
  248. __s32 ubi_num;
  249. __s32 mtd_num;
  250. __s32 vid_hdr_offset;
  251. __s16 max_beb_per1024;
  252. __s8 padding[10];
  253. };
  254. /*
  255. * UBI volume flags.
  256. *
  257. * @UBI_VOL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at
  258. * open time. Only valid for static volumes and
  259. * should only be used if the volume user has a
  260. * way to verify data integrity
  261. */
  262. enum {
  263. UBI_VOL_SKIP_CRC_CHECK_FLG = 0x1,
  264. };
  265. #define UBI_VOL_VALID_FLGS (UBI_VOL_SKIP_CRC_CHECK_FLG)
  266. /**
  267. * struct ubi_mkvol_req - volume description data structure used in
  268. * volume creation requests.
  269. * @vol_id: volume number
  270. * @alignment: volume alignment
  271. * @bytes: volume size in bytes
  272. * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
  273. * @flags: volume flags (%UBI_VOL_SKIP_CRC_CHECK_FLG)
  274. * @name_len: volume name length
  275. * @padding2: reserved for future, not used, has to be zeroed
  276. * @name: volume name
  277. *
  278. * This structure is used by user-space programs when creating new volumes. The
  279. * @used_bytes field is only necessary when creating static volumes.
  280. *
  281. * The @alignment field specifies the required alignment of the volume logical
  282. * eraseblock. This means, that the size of logical eraseblocks will be aligned
  283. * to this number, i.e.,
  284. * (UBI device logical eraseblock size) mod (@alignment) = 0.
  285. *
  286. * To put it differently, the logical eraseblock of this volume may be slightly
  287. * shortened in order to make it properly aligned. The alignment has to be
  288. * multiple of the flash minimal input/output unit, or %1 to utilize the entire
  289. * available space of logical eraseblocks.
  290. *
  291. * The @alignment field may be useful, for example, when one wants to maintain
  292. * a block device on top of an UBI volume. In this case, it is desirable to fit
  293. * an integer number of blocks in logical eraseblocks of this UBI volume. With
  294. * alignment it is possible to update this volume using plane UBI volume image
  295. * BLOBs, without caring about how to properly align them.
  296. */
  297. struct ubi_mkvol_req {
  298. __s32 vol_id;
  299. __s32 alignment;
  300. __s64 bytes;
  301. __s8 vol_type;
  302. __u8 flags;
  303. __s16 name_len;
  304. __s8 padding2[4];
  305. char name[UBI_MAX_VOLUME_NAME + 1];
  306. } __packed;
  307. /**
  308. * struct ubi_rsvol_req - a data structure used in volume re-size requests.
  309. * @vol_id: ID of the volume to re-size
  310. * @bytes: new size of the volume in bytes
  311. *
  312. * Re-sizing is possible for both dynamic and static volumes. But while dynamic
  313. * volumes may be re-sized arbitrarily, static volumes cannot be made to be
  314. * smaller than the number of bytes they bear. To arbitrarily shrink a static
  315. * volume, it must be wiped out first (by means of volume update operation with
  316. * zero number of bytes).
  317. */
  318. struct ubi_rsvol_req {
  319. __s64 bytes;
  320. __s32 vol_id;
  321. } __packed;
  322. /**
  323. * struct ubi_rnvol_req - volumes re-name request.
  324. * @count: count of volumes to re-name
  325. * @padding1: reserved for future, not used, has to be zeroed
  326. * @vol_id: ID of the volume to re-name
  327. * @name_len: name length
  328. * @padding2: reserved for future, not used, has to be zeroed
  329. * @name: new volume name
  330. *
  331. * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
  332. * re-name is specified in the @count field. The ID of the volumes to re-name
  333. * and the new names are specified in the @vol_id and @name fields.
  334. *
  335. * The UBI volume re-name operation is atomic, which means that should power cut
  336. * happen, the volumes will have either old name or new name. So the possible
  337. * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
  338. * A and B one may create temporary volumes %A1 and %B1 with the new contents,
  339. * then atomically re-name A1->A and B1->B, in which case old %A and %B will
  340. * be removed.
  341. *
  342. * If it is not desirable to remove old A and B, the re-name request has to
  343. * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
  344. * become A and B, and old A and B will become A1 and B1.
  345. *
  346. * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
  347. * and B1 become A and B, and old A and B become X and Y.
  348. *
  349. * In other words, in case of re-naming into an existing volume name, the
  350. * existing volume is removed, unless it is re-named as well at the same
  351. * re-name request.
  352. */
  353. struct ubi_rnvol_req {
  354. __s32 count;
  355. __s8 padding1[12];
  356. struct {
  357. __s32 vol_id;
  358. __s16 name_len;
  359. __s8 padding2[2];
  360. char name[UBI_MAX_VOLUME_NAME + 1];
  361. } ents[UBI_MAX_RNVOL];
  362. } __packed;
  363. /**
  364. * struct ubi_leb_change_req - a data structure used in atomic LEB change
  365. * requests.
  366. * @lnum: logical eraseblock number to change
  367. * @bytes: how many bytes will be written to the logical eraseblock
  368. * @dtype: pass "3" for better compatibility with old kernels
  369. * @padding: reserved for future, not used, has to be zeroed
  370. *
  371. * The @dtype field used to inform UBI about what kind of data will be written
  372. * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
  373. * UBI tried to pick a PEB with lower erase counter for short term data and a
  374. * PEB with higher erase counter for long term data. But this was not really
  375. * used because users usually do not know this and could easily mislead UBI. We
  376. * removed this feature in May 2012. UBI currently just ignores the @dtype
  377. * field. But for better compatibility with older kernels it is recommended to
  378. * set @dtype to 3 (unknown).
  379. */
  380. struct ubi_leb_change_req {
  381. __s32 lnum;
  382. __s32 bytes;
  383. __s8 dtype; /* obsolete, do not use! */
  384. __s8 padding[7];
  385. } __packed;
  386. /**
  387. * struct ubi_map_req - a data structure used in map LEB requests.
  388. * @dtype: pass "3" for better compatibility with old kernels
  389. * @lnum: logical eraseblock number to unmap
  390. * @padding: reserved for future, not used, has to be zeroed
  391. */
  392. struct ubi_map_req {
  393. __s32 lnum;
  394. __s8 dtype; /* obsolete, do not use! */
  395. __s8 padding[3];
  396. } __packed;
  397. /**
  398. * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
  399. * property.
  400. * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
  401. * @padding: reserved for future, not used, has to be zeroed
  402. * @value: value to set
  403. */
  404. struct ubi_set_vol_prop_req {
  405. __u8 property;
  406. __u8 padding[7];
  407. __u64 value;
  408. } __packed;
  409. /**
  410. * struct ubi_blkcreate_req - a data structure used in block creation requests.
  411. * @padding: reserved for future, not used, has to be zeroed
  412. */
  413. struct ubi_blkcreate_req {
  414. __s8 padding[128];
  415. } __packed;
  416. #endif /* __UBI_USER_H__ */