1 /*
2  * Copyright (c) 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 __LINUX_UBI_H__
22 #define __LINUX_UBI_H__
23 
24 #include <linux/ioctl.h>
25 #include <linux/types.h>
26 #include <linux/scatterlist.h>
27 #include <mtd/ubi-user.h>
28 
29 /* All voumes/LEBs */
30 #define UBI_ALL -1
31 
32 /*
33  * Maximum number of scatter gather list entries,
34  * we use only 64 to have a lower memory foot print.
35  */
36 #define UBI_MAX_SG_COUNT 64
37 
38 /*
39  * enum ubi_open_mode - UBI volume open mode constants.
40  *
41  * UBI_READONLY: read-only mode
42  * UBI_READWRITE: read-write mode
43  * UBI_EXCLUSIVE: exclusive mode
44  * UBI_METAONLY: modify only the volume meta-data,
45  *  i.e. the data stored in the volume table, but not in any of volume LEBs.
46  */
47 enum {
48 	UBI_READONLY = 1,
49 	UBI_READWRITE,
50 	UBI_EXCLUSIVE,
51 	UBI_METAONLY
52 };
53 
54 /**
55  * struct ubi_volume_info - UBI volume description data structure.
56  * @vol_id: volume ID
57  * @ubi_num: UBI device number this volume belongs to
58  * @size: how many physical eraseblocks are reserved for this volume
59  * @used_bytes: how many bytes of data this volume contains
60  * @used_ebs: how many physical eraseblocks of this volume actually contain any
61  *            data
62  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
63  * @corrupted: non-zero if the volume is corrupted (static volumes only)
64  * @upd_marker: non-zero if the volume has update marker set
65  * @alignment: volume alignment
66  * @usable_leb_size: how many bytes are available in logical eraseblocks of
67  *                   this volume
68  * @name_len: volume name length
69  * @name: volume name
70  * @cdev: UBI volume character device major and minor numbers
71  *
72  * The @corrupted flag is only relevant to static volumes and is always zero
73  * for dynamic ones. This is because UBI does not care about dynamic volume
74  * data protection and only cares about protecting static volume data.
75  *
76  * The @upd_marker flag is set if the volume update operation was interrupted.
77  * Before touching the volume data during the update operation, UBI first sets
78  * the update marker flag for this volume. If the volume update operation was
79  * further interrupted, the update marker indicates this. If the update marker
80  * is set, the contents of the volume is certainly damaged and a new volume
81  * update operation has to be started.
82  *
83  * To put it differently, @corrupted and @upd_marker fields have different
84  * semantics:
85  *     o the @corrupted flag means that this static volume is corrupted for some
86  *       reasons, but not because an interrupted volume update
87  *     o the @upd_marker field means that the volume is damaged because of an
88  *       interrupted update operation.
89  *
90  * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
91  *
92  * The @used_bytes and @used_ebs fields are only really needed for static
93  * volumes and contain the number of bytes stored in this static volume and how
94  * many eraseblock this data occupies. In case of dynamic volumes, the
95  * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
96  * field is equivalent to @size.
97  *
98  * In general, logical eraseblock size is a property of the UBI device, not
99  * of the UBI volume. Indeed, the logical eraseblock size depends on the
100  * physical eraseblock size and on how much bytes UBI headers consume. But
101  * because of the volume alignment (@alignment), the usable size of logical
102  * eraseblocks if a volume may be less. The following equation is true:
103  *	@usable_leb_size = LEB size - (LEB size mod @alignment),
104  * where LEB size is the logical eraseblock size defined by the UBI device.
105  *
106  * The alignment is multiple to the minimal flash input/output unit size or %1
107  * if all the available space is used.
108  *
109  * To put this differently, alignment may be considered is a way to change
110  * volume logical eraseblock sizes.
111  */
112 struct ubi_volume_info {
113 	int ubi_num;
114 	int vol_id;
115 	int size;
116 	long long used_bytes;
117 	int used_ebs;
118 	int vol_type;
119 	int corrupted;
120 	int upd_marker;
121 	int alignment;
122 	int usable_leb_size;
123 	int name_len;
124 	const char *name;
125 	dev_t cdev;
126 };
127 
128 /**
129  * struct ubi_sgl - UBI scatter gather list data structure.
130  * @list_pos: current position in @sg[]
131  * @page_pos: current position in @sg[@list_pos]
132  * @sg: the scatter gather list itself
133  *
134  * ubi_sgl is a wrapper around a scatter list which keeps track of the
135  * current position in the list and the current list item such that
136  * it can be used across multiple ubi_leb_read_sg() calls.
137  */
138 struct ubi_sgl {
139 	int list_pos;
140 	int page_pos;
141 	struct scatterlist sg[UBI_MAX_SG_COUNT];
142 };
143 
144 /**
145  * ubi_sgl_init - initialize an UBI scatter gather list data structure.
146  * @usgl: the UBI scatter gather struct itself
147  *
148  * Please note that you still have to use sg_init_table() or any adequate
149  * function to initialize the unterlaying struct scatterlist.
150  */
ubi_sgl_init(struct ubi_sgl * usgl)151 static inline void ubi_sgl_init(struct ubi_sgl *usgl)
152 {
153 	usgl->list_pos = 0;
154 	usgl->page_pos = 0;
155 }
156 
157 /**
158  * struct ubi_device_info - UBI device description data structure.
159  * @ubi_num: ubi device number
160  * @leb_size: logical eraseblock size on this UBI device
161  * @leb_start: starting offset of logical eraseblocks within physical
162  *             eraseblocks
163  * @min_io_size: minimal I/O unit size
164  * @max_write_size: maximum amount of bytes the underlying flash can write at a
165  *                  time (MTD write buffer size)
166  * @ro_mode: if this device is in read-only mode
167  * @cdev: UBI character device major and minor numbers
168  *
169  * Note, @leb_size is the logical eraseblock size offered by the UBI device.
170  * Volumes of this UBI device may have smaller logical eraseblock size if their
171  * alignment is not equivalent to %1.
172  *
173  * The @max_write_size field describes flash write maximum write unit. For
174  * example, NOR flash allows for changing individual bytes, so @min_io_size is
175  * %1. However, it does not mean than NOR flash has to write data byte-by-byte.
176  * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
177  * writing large chunks of data, they write 64-bytes at a time. Obviously, this
178  * improves write throughput.
179  *
180  * Also, the MTD device may have N interleaved (striped) flash chips
181  * underneath, in which case @min_io_size can be physical min. I/O size of
182  * single flash chip, while @max_write_size can be N * @min_io_size.
183  *
184  * The @max_write_size field is always greater or equivalent to @min_io_size.
185  * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
186  * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
187  * page size.
188  */
189 struct ubi_device_info {
190 	int ubi_num;
191 	int leb_size;
192 	int leb_start;
193 	int min_io_size;
194 	int max_write_size;
195 	int ro_mode;
196 	dev_t cdev;
197 };
198 
199 /*
200  * Volume notification types.
201  * @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
202  *                    volume was created)
203  * @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
204  *			or a volume was removed)
205  * @UBI_VOLUME_RESIZED: a volume has been re-sized
206  * @UBI_VOLUME_RENAMED: a volume has been re-named
207  * @UBI_VOLUME_UPDATED: data has been written to a volume
208  *
209  * These constants define which type of event has happened when a volume
210  * notification function is invoked.
211  */
212 enum {
213 	UBI_VOLUME_ADDED,
214 	UBI_VOLUME_REMOVED,
215 	UBI_VOLUME_RESIZED,
216 	UBI_VOLUME_RENAMED,
217 	UBI_VOLUME_UPDATED,
218 };
219 
220 /*
221  * struct ubi_notification - UBI notification description structure.
222  * @di: UBI device description object
223  * @vi: UBI volume description object
224  *
225  * UBI notifiers are called with a pointer to an object of this type. The
226  * object describes the notification. Namely, it provides a description of the
227  * UBI device and UBI volume the notification informs about.
228  */
229 struct ubi_notification {
230 	struct ubi_device_info di;
231 	struct ubi_volume_info vi;
232 };
233 
234 /* UBI descriptor given to users when they open UBI volumes */
235 struct ubi_volume_desc;
236 
237 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
238 void ubi_get_volume_info(struct ubi_volume_desc *desc,
239 			 struct ubi_volume_info *vi);
240 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
241 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
242 					   int mode);
243 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
244 
245 int ubi_register_volume_notifier(struct notifier_block *nb,
246 				 int ignore_existing);
247 int ubi_unregister_volume_notifier(struct notifier_block *nb);
248 
249 void ubi_close_volume(struct ubi_volume_desc *desc);
250 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
251 		 int len, int check);
252 int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
253 		   int offset, int len, int check);
254 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
255 		  int offset, int len);
256 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
257 		   int len);
258 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
259 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
260 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum);
261 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
262 int ubi_sync(int ubi_num);
263 int ubi_flush(int ubi_num, int vol_id, int lnum);
264 
265 /*
266  * This function is the same as the 'ubi_leb_read()' function, but it does not
267  * provide the checking capability.
268  */
ubi_read(struct ubi_volume_desc * desc,int lnum,char * buf,int offset,int len)269 static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
270 			   int offset, int len)
271 {
272 	return ubi_leb_read(desc, lnum, buf, offset, len, 0);
273 }
274 
275 /*
276  * This function is the same as the 'ubi_leb_read_sg()' function, but it does
277  * not provide the checking capability.
278  */
ubi_read_sg(struct ubi_volume_desc * desc,int lnum,struct ubi_sgl * sgl,int offset,int len)279 static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum,
280 			      struct ubi_sgl *sgl, int offset, int len)
281 {
282 	return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0);
283 }
284 #endif /* !__LINUX_UBI_H__ */
285