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  */
ubi_sgl_init(struct ubi_sgl * usgl)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  */
ubi_read(struct ubi_volume_desc * desc,int lnum,char * buf,int offset,int len)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  */
ubi_read_sg(struct ubi_volume_desc * desc,int lnum,struct ubi_sgl * sgl,int offset,int len)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__ */
272