1 /*
2  * JFFS -- Journaling Flash File System, Linux implementation.
3  *
4  * Copyright (C) 1999, 2000  Axis Communications AB.
5  *
6  * Created by Finn Hakansson <finn@axis.com>.
7  *
8  * This is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * $Id: jffs_fm.h,v 1.13 2001/01/11 12:03:25 dwmw2 Exp $
14  *
15  * Ported to Linux 2.3.x and MTD:
16  * Copyright (C) 2000  Alexander Larsson (alex@cendio.se), Cendio Systems AB
17  *
18  */
19 
20 #ifndef __LINUX_JFFS_FM_H__
21 #define __LINUX_JFFS_FM_H__
22 
23 #include <linux/types.h>
24 #include <linux/jffs.h>
25 #include <linux/mtd/mtd.h>
26 #include <linux/config.h>
27 
28 /* The alignment between two nodes in the flash memory.  */
29 #define JFFS_ALIGN_SIZE 4
30 
31 /* Mark the on-flash space as obsolete when appropriate.  */
32 #define JFFS_MARK_OBSOLETE 0
33 
34 #ifndef CONFIG_JFFS_FS_VERBOSE
35 #define CONFIG_JFFS_FS_VERBOSE 1
36 #endif
37 
38 #if CONFIG_JFFS_FS_VERBOSE > 0
39 #define D(x) x
40 #define D1(x) D(x)
41 #else
42 #define D(x)
43 #define D1(x)
44 #endif
45 
46 #if CONFIG_JFFS_FS_VERBOSE > 1
47 #define D2(x) D(x)
48 #else
49 #define D2(x)
50 #endif
51 
52 #if CONFIG_JFFS_FS_VERBOSE > 2
53 #define D3(x) D(x)
54 #else
55 #define D3(x)
56 #endif
57 
58 #define ASSERT(x) x
59 
60 /* How many padding bytes should be inserted between two chunks of data
61    on the flash?  */
62 #define JFFS_GET_PAD_BYTES(size) ( (JFFS_ALIGN_SIZE-1) & -(__u32)(size) )
63 #define JFFS_PAD(size) ( (size + (JFFS_ALIGN_SIZE-1)) & ~(JFFS_ALIGN_SIZE-1) )
64 
65 
66 
67 void jffs_free_fm(struct jffs_fm *n);
68 struct jffs_fm *jffs_alloc_fm(void);
69 
70 
71 struct jffs_node_ref
72 {
73 	struct jffs_node *node;
74 	struct jffs_node_ref *next;
75 };
76 
77 
78 /* The struct jffs_fm represents a chunk of data in the flash memory.  */
79 struct jffs_fm
80 {
81 	__u32 offset;
82 	__u32 size;
83 	struct jffs_fm *prev;
84 	struct jffs_fm *next;
85 	struct jffs_node_ref *nodes; /* USED if != 0.  */
86 };
87 
88 struct jffs_fmcontrol
89 {
90 	__u32 flash_size;
91 	__u32 used_size;
92 	__u32 dirty_size;
93 	__u32 free_size;
94 	__u32 sector_size;
95 	__u32 min_free_size;  /* The minimum free space needed to be able
96 				 to perform garbage collections.  */
97 	__u32 max_chunk_size; /* The maximum size of a chunk of data.  */
98 	struct mtd_info *mtd;
99 	struct jffs_control *c;
100 	struct jffs_fm *head;
101 	struct jffs_fm *tail;
102 	struct jffs_fm *head_extra;
103 	struct jffs_fm *tail_extra;
104 	struct semaphore biglock;
105 };
106 
107 /* Notice the two members head_extra and tail_extra in the jffs_control
108    structure above. Those are only used during the scanning of the flash
109    memory; while the file system is being built. If the data in the flash
110    memory is organized like
111 
112       +----------------+------------------+----------------+
113       |  USED / DIRTY  |       FREE       |  USED / DIRTY  |
114       +----------------+------------------+----------------+
115 
116    then the scan is split in two parts. The first scanned part of the
117    flash memory is organized through the members head and tail. The
118    second scanned part is organized with head_extra and tail_extra. When
119    the scan is completed, the two lists are merged together. The jffs_fm
120    struct that head_extra references is the logical beginning of the
121    flash memory so it will be referenced by the head member.  */
122 
123 
124 
125 struct jffs_fmcontrol *jffs_build_begin(struct jffs_control *c, kdev_t dev);
126 void jffs_build_end(struct jffs_fmcontrol *fmc);
127 void jffs_cleanup_fmcontrol(struct jffs_fmcontrol *fmc);
128 
129 int jffs_fmalloc(struct jffs_fmcontrol *fmc, __u32 size,
130 		 struct jffs_node *node, struct jffs_fm **result);
131 int jffs_fmfree(struct jffs_fmcontrol *fmc, struct jffs_fm *fm,
132 		struct jffs_node *node);
133 
134 __u32 jffs_free_size1(struct jffs_fmcontrol *fmc);
135 __u32 jffs_free_size2(struct jffs_fmcontrol *fmc);
136 void jffs_sync_erase(struct jffs_fmcontrol *fmc, int erased_size);
137 struct jffs_fm *jffs_cut_node(struct jffs_fmcontrol *fmc, __u32 size);
138 struct jffs_node *jffs_get_oldest_node(struct jffs_fmcontrol *fmc);
139 long jffs_erasable_size(struct jffs_fmcontrol *fmc);
140 struct jffs_fm *jffs_fmalloced(struct jffs_fmcontrol *fmc, __u32 offset,
141 			       __u32 size, struct jffs_node *node);
142 int jffs_add_node(struct jffs_node *node);
143 void jffs_fmfree_partly(struct jffs_fmcontrol *fmc, struct jffs_fm *fm,
144 			__u32 size);
145 
146 void jffs_print_fmcontrol(struct jffs_fmcontrol *fmc);
147 void jffs_print_fm(struct jffs_fm *fm);
148 void jffs_print_node_ref(struct jffs_node_ref *ref);
149 
150 #endif /* __LINUX_JFFS_FM_H__  */
151