1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Copyright (c) International Business Machines Corp., 2006
4 *
5 * Author: Artem Bityutskiy (Битюцкий Артём)
6 */
7
8 #ifndef __LINUX_UBI_H__
9 #define __LINUX_UBI_H__
10
11 #include <linux/ioctl.h>
12 #include <linux/types.h>
13 #include <linux/scatterlist.h>
14 #include <mtd/ubi-user.h>
15
16 /* All voumes/LEBs */
17 #define UBI_ALL -1
18
19 /*
20 * Maximum number of scatter gather list entries,
21 * we use only 64 to have a lower memory foot print.
22 */
23 #define UBI_MAX_SG_COUNT 64
24
25 /*
26 * enum ubi_open_mode - UBI volume open mode constants.
27 *
28 * UBI_READONLY: read-only mode
29 * UBI_READWRITE: read-write mode
30 * UBI_EXCLUSIVE: exclusive mode
31 * UBI_METAONLY: modify only the volume meta-data,
32 * i.e. the data stored in the volume table, but not in any of volume LEBs.
33 */
34 enum {
35 UBI_READONLY = 1,
36 UBI_READWRITE,
37 UBI_EXCLUSIVE,
38 UBI_METAONLY
39 };
40
41 /**
42 * struct ubi_volume_info - UBI volume description data structure.
43 * @vol_id: volume ID
44 * @ubi_num: UBI device number this volume belongs to
45 * @size: how many physical eraseblocks are reserved for this volume
46 * @used_bytes: how many bytes of data this volume contains
47 * @used_ebs: how many physical eraseblocks of this volume actually contain any
48 * data
49 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
50 * @corrupted: non-zero if the volume is corrupted (static volumes only)
51 * @upd_marker: non-zero if the volume has update marker set
52 * @alignment: volume alignment
53 * @usable_leb_size: how many bytes are available in logical eraseblocks of
54 * this volume
55 * @name_len: volume name length
56 * @name: volume name
57 * @cdev: UBI volume character device major and minor numbers
58 *
59 * The @corrupted flag is only relevant to static volumes and is always zero
60 * for dynamic ones. This is because UBI does not care about dynamic volume
61 * data protection and only cares about protecting static volume data.
62 *
63 * The @upd_marker flag is set if the volume update operation was interrupted.
64 * Before touching the volume data during the update operation, UBI first sets
65 * the update marker flag for this volume. If the volume update operation was
66 * further interrupted, the update marker indicates this. If the update marker
67 * is set, the contents of the volume is certainly damaged and a new volume
68 * update operation has to be started.
69 *
70 * To put it differently, @corrupted and @upd_marker fields have different
71 * semantics:
72 * o the @corrupted flag means that this static volume is corrupted for some
73 * reasons, but not because an interrupted volume update
74 * o the @upd_marker field means that the volume is damaged because of an
75 * interrupted update operation.
76 *
77 * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
78 *
79 * The @used_bytes and @used_ebs fields are only really needed for static
80 * volumes and contain the number of bytes stored in this static volume and how
81 * many eraseblock this data occupies. In case of dynamic volumes, the
82 * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
83 * field is equivalent to @size.
84 *
85 * In general, logical eraseblock size is a property of the UBI device, not
86 * of the UBI volume. Indeed, the logical eraseblock size depends on the
87 * physical eraseblock size and on how much bytes UBI headers consume. But
88 * because of the volume alignment (@alignment), the usable size of logical
89 * eraseblocks if a volume may be less. The following equation is true:
90 * @usable_leb_size = LEB size - (LEB size mod @alignment),
91 * where LEB size is the logical eraseblock size defined by the UBI device.
92 *
93 * The alignment is multiple to the minimal flash input/output unit size or %1
94 * if all the available space is used.
95 *
96 * To put this differently, alignment may be considered is a way to change
97 * volume logical eraseblock sizes.
98 */
99 struct ubi_volume_info {
100 int ubi_num;
101 int vol_id;
102 int size;
103 long long used_bytes;
104 int used_ebs;
105 int vol_type;
106 int corrupted;
107 int upd_marker;
108 int alignment;
109 int usable_leb_size;
110 int name_len;
111 const char *name;
112 dev_t cdev;
113 };
114
115 /**
116 * struct ubi_sgl - UBI scatter gather list data structure.
117 * @list_pos: current position in @sg[]
118 * @page_pos: current position in @sg[@list_pos]
119 * @sg: the scatter gather list itself
120 *
121 * ubi_sgl is a wrapper around a scatter list which keeps track of the
122 * current position in the list and the current list item such that
123 * it can be used across multiple ubi_leb_read_sg() calls.
124 */
125 struct ubi_sgl {
126 int list_pos;
127 int page_pos;
128 struct scatterlist sg[UBI_MAX_SG_COUNT];
129 };
130
131 /**
132 * ubi_sgl_init - initialize an UBI scatter gather list data structure.
133 * @usgl: the UBI scatter gather struct itself
134 *
135 * Please note that you still have to use sg_init_table() or any adequate
136 * function to initialize the unterlaying struct scatterlist.
137 */
138 static inline void ubi_sgl_init(struct ubi_sgl *usgl)
139 {
140 usgl->list_pos = 0;
141 usgl->page_pos = 0;
142 }
143
144 /**
145 * struct ubi_device_info - UBI device description data structure.
146 * @ubi_num: ubi device number
147 * @leb_size: logical eraseblock size on this UBI device
148 * @leb_start: starting offset of logical eraseblocks within physical
149 * eraseblocks
150 * @min_io_size: minimal I/O unit size
151 * @max_write_size: maximum amount of bytes the underlying flash can write at a
152 * time (MTD write buffer size)
153 * @ro_mode: if this device is in read-only mode
154 * @cdev: UBI character device major and minor numbers
155 *
156 * Note, @leb_size is the logical eraseblock size offered by the UBI device.
157 * Volumes of this UBI device may have smaller logical eraseblock size if their
158 * alignment is not equivalent to %1.
159 *
160 * The @max_write_size field describes flash write maximum write unit. For
161 * example, NOR flash allows for changing individual bytes, so @min_io_size is
162 * %1. However, it does not mean than NOR flash has to write data byte-by-byte.
163 * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
164 * writing large chunks of data, they write 64-bytes at a time. Obviously, this
165 * improves write throughput.
166 *
167 * Also, the MTD device may have N interleaved (striped) flash chips
168 * underneath, in which case @min_io_size can be physical min. I/O size of
169 * single flash chip, while @max_write_size can be N * @min_io_size.
170 *
171 * The @max_write_size field is always greater or equivalent to @min_io_size.
172 * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
173 * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
174 * page size.
175 */
176 struct ubi_device_info {
177 int ubi_num;
178 int leb_size;
179 int leb_start;
180 int min_io_size;
181 int max_write_size;
182 int ro_mode;
183 dev_t cdev;
184 };
185
186 /*
187 * Volume notification types.
188 * @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
189 * volume was created)
190 * @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
191 * or a volume was removed)
192 * @UBI_VOLUME_RESIZED: a volume has been re-sized
193 * @UBI_VOLUME_RENAMED: a volume has been re-named
194 * @UBI_VOLUME_UPDATED: data has been written to a volume
195 *
196 * These constants define which type of event has happened when a volume
197 * notification function is invoked.
198 */
199 enum {
200 UBI_VOLUME_ADDED,
201 UBI_VOLUME_REMOVED,
202 UBI_VOLUME_RESIZED,
203 UBI_VOLUME_RENAMED,
204 UBI_VOLUME_UPDATED,
205 };
206
207 /*
208 * struct ubi_notification - UBI notification description structure.
209 * @di: UBI device description object
210 * @vi: UBI volume description object
211 *
212 * UBI notifiers are called with a pointer to an object of this type. The
213 * object describes the notification. Namely, it provides a description of the
214 * UBI device and UBI volume the notification informs about.
215 */
216 struct ubi_notification {
217 struct ubi_device_info di;
218 struct ubi_volume_info vi;
219 };
220
221 /* UBI descriptor given to users when they open UBI volumes */
222 struct ubi_volume_desc;
223
224 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
225 void ubi_get_volume_info(struct ubi_volume_desc *desc,
226 struct ubi_volume_info *vi);
227 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
228 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
229 int mode);
230 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
231
232 int ubi_register_volume_notifier(struct notifier_block *nb,
233 int ignore_existing);
234 int ubi_unregister_volume_notifier(struct notifier_block *nb);
235
236 void ubi_close_volume(struct ubi_volume_desc *desc);
237 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
238 int len, int check);
239 int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
240 int offset, int len, int check);
241 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
242 int offset, int len);
243 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
244 int len);
245 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
246 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
247 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum);
248 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
249 int ubi_sync(int ubi_num);
250 int ubi_flush(int ubi_num, int vol_id, int lnum);
251
252 /*
253 * This function is the same as the 'ubi_leb_read()' function, but it does not
254 * provide the checking capability.
255 */
256 static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
257 int offset, int len)
258 {
259 return ubi_leb_read(desc, lnum, buf, offset, len, 0);
260 }
261
262 /*
263 * This function is the same as the 'ubi_leb_read_sg()' function, but it does
264 * not provide the checking capability.
265 */
266 static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum,
267 struct ubi_sgl *sgl, int offset, int len)
268 {
269 return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0);
270 }
271 #endif /* !__LINUX_UBI_H__ */