4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
35 * \author Francesco Sacchi <batt@develer.com>
37 * \brief BattFS: a filesystem for embedded platforms (interface).
38 * TODO: Add detailed filesystem description.
44 #include <cfg/compiler.h> // uintXX_t; STATIC_ASSERT
45 #include <cpu/types.h> // CPU_BITS_PER_CHAR
46 #include <algo/rotating_hash.h>
47 #include <mware/list.h>
48 #include <kern/kfile.h>
50 typedef uint16_t fill_t;
51 typedef fill_t pgaddr_t;
52 typedef uint16_t pgoff_t;
53 typedef uint32_t mark_t;
54 typedef uint8_t mark_roll_t;
55 typedef uint8_t inode_t;
56 typedef uint8_t seq_t;
57 typedef rotating_t fcs_t;
60 * Size required for free block allocation is at least 1 bit more
61 * than page addressing.
63 STATIC_ASSERT(sizeof(mark_t) > sizeof(pgaddr_t));
66 * BattFS page header, used to represent a page
68 * To see how this is stored on disk:
72 typedef struct BattFsPageHeader
74 inode_t inode; ///< File inode (file identifier).
75 seq_t seq; ///< Page sequence number.
76 fill_t fill; ///< Filled bytes in page.
77 pgoff_t pgoff; ///< Page offset inside file.
78 mark_t mark; ///< Marker used to keep trace of free/used pages.
81 * FCS (Frame Check Sequence) of the page header once the page
82 * as been marked as free.
87 * FCS (Frame Check Sequence) of the page header.
93 * Size of the header once saved on disk.
97 #define BATTFS_HEADER_LEN 12
100 * Marks for valid pages.
101 * Simply set to 1 all field bits.
104 #define MARK_PAGE_VALID ((1 << (CPU_BITS_PER_CHAR * sizeof(pgaddr_t) + 1)) - 1)
105 #define FCS_FREE_VALID ((1 << (CPU_BITS_PER_CHAR * sizeof(fcs_t))) - 1)
110 * Half-size of free page marker.
111 * Used to keep trace of free marker wrap-arounds.
113 #define MARK_HALF_SIZE (1 << (CPU_BITS_PER_CHAR * sizeof(pgaddr_t) + 1))
116 * Maximum page address.
118 #define MAX_PAGE_ADDR ((1 << (CPU_BITS_PER_CHAR * sizeof(pgaddr_t))) - 1)
121 * Max number of files.
123 #define BATTFS_MAX_FILES (1 << (CPU_BITS_PER_CHAR * sizeof(inode_t)))
129 * Type for disk page addressing.
131 typedef uint16_t pgcnt_t;
134 * Sentinel used to keep trace of unset pages in disk->page_array.
136 #define PAGE_UNSET_SENTINEL ((1 << (CPU_BITS_PER_CHAR * sizeof(pgcnt_t))) - 1)
139 * Type interface for disk init function.
140 * \return true if all is ok, false otherwise.
142 typedef bool (*disk_open_t) (struct BattFsSuper *d);
145 * Type interface for disk page read function.
146 * \a page is the page address, \a addr the address inside the page,
147 * \a size the lenght to be read.
148 * \return the number of bytes read.
150 typedef size_t (*disk_page_read_t) (struct BattFsSuper *d, pgcnt_t page, pgaddr_t addr, void *buf, size_t);
153 * Type interface for disk page write function.
154 * \a page is the page address, \a addr the address inside the page,
155 * \a size the lenght to be written.
156 * \return the number of bytes written.
158 typedef size_t (*disk_page_write_t) (struct BattFsSuper *d, pgcnt_t page, pgaddr_t addr, const void *buf, size_t);
161 * Type interface for disk page erase function.
162 * \a page is the page address.
163 * \return true if all is ok, false otherwise.
165 typedef bool (*disk_page_erase_t) (struct BattFsSuper *d, pgcnt_t page);
168 * Type interface for disk deinit function.
169 * \return true if all is ok, false otherwise.
171 typedef bool (*disk_close_t) (struct BattFsSuper *d);
174 typedef uint32_t disk_size_t; ///< Type for disk sizes.
177 * Context used to describe a disk.
178 * This context structure will be used to access disk.
179 * Must be initialized by hw memory driver.
181 typedef struct BattFsSuper
183 disk_open_t open; ///< Disk init.
184 disk_page_read_t read; ///< Page read.
185 disk_page_write_t write; ///< Page write.
186 disk_page_erase_t erase; ///< Page erase.
187 disk_close_t close; ///< Disk deinit.
189 pgaddr_t page_size; ///< Size of a disk page, in bytes.
190 pgcnt_t page_count; ///< Number of pages on disk.
193 * Page allocation array.
194 * This array must be allocated somewhere and
195 * must have enough space for page_count elements.
196 * Is used by the filesystem to represent
197 * the entire disk in memory.
202 * Lowest free page counter.
203 * This is the counter of the first availble free page.
208 * Highest free page counter.
209 * This value is the next to be used to mark a block as free.
213 disk_size_t disk_size; ///< Size of the disk, in bytes (page_count * page_size).
214 disk_size_t free_bytes; ///< Free space on the disk.
216 List file_opened_list; ///< List used to keep trace of open files.
217 /* TODO add other fields. */
220 typedef uint8_t filemode_t; ///< Type for file open.
223 * Describe a BattFs file usign a KFile.
225 typedef struct KFileBattFs
227 KFile fd; ///< KFile context
228 Node link; ///< Link for inserting in opened file list
229 inode_t inode; ///< inode of the opened file
230 BattFsSuper *disk; ///< Disk context
231 filemode_t mode; ///< File open mode
234 INLINE KFileBattFs * KFILEBATTFS(KFile *fd)
236 ASSERT(fd->_type == KFT_BATTFS);
237 return (KFileBattFs *)fd;
240 bool battfs_init(struct BattFsSuper *d);
241 bool battfs_close(struct BattFsSuper *disk);
243 bool battfs_fileopen(BattFsSuper *disk, KFileBattFs *fd, inode_t inode, filemode_t mode);
245 bool battfs_writeTestBlock(struct BattFsSuper *disk, pgcnt_t page, inode_t inode, seq_t seq, fill_t fill, pgoff_t pgoff, mark_t mark);
247 #endif /* FS_BATTFS_H */