[PATCH 09/10] Add support for VMUFAT filesystem

Adrian McMenamin
2026-04-10T15:07:06Z

vmufat.h provides constants and common data structures to inode.c and super.c as well as a wrapper around calls to sb_read

Signed-off-by: Adrian McMenamin <adrianmcmenamin@gmail.com>

fs/vmufat/vmufat.h | 126 ++++

---

--- /dev/null
+++ b/fs/vmufat/vmufat.h
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Header file for VMUFAT filesystem */
+#ifndef _VMUFAT_H_
+#define _VMUFAT_H_
+
+/* maximum length of file name */
+#define VMUFAT_NAMELEN 12
+
+/* Some GNU utils might not list files with inode num 0 */
+#define VMUFAT_ZEROBLOCK 0x10000
+#define VMU_BLK_SZ 0x200
+#define VMU_BLK_SZ16 0x100
+#define VMU_PHYS_SZ 0x100
+
+/* file allocation table markers */
+#define VMUFAT_FILE_END 0xFFFA
+#define VMUFAT_UNALLOCATED 0xFFFC
+#define VMUFAT_ERROR 0xFFFF
+
+/* parameters for possible VMU volume sizes */
+#define VMUFAT_MIN_BLK 0x04
+#define VMUFAT_MAX_BLK 0x10000
+
+/* specifcations for directory entries */
+#define VMU_DIR_RECORD_LEN 0x20
+#define VMU_DIR_RECORD_LEN16 0x10
+#define VMU_DIR_ENTRIES_PER_BLOCK 0x10
+#define VMUFAT_NAME_OFFSET 0x04
+#define VMUFAT_FIRSTBLOCK_OFFSET16 0x01
+#define VMUFAT_START_OFFSET16 0x01
+#define VMUFAT_SIZE_OFFSET16 0x0C
+#define VMUFAT_HEADER_OFFSET16 0x0D
+
+/* File types used in directory */
+#define VMU_GAME 0xCC
+#define VMU_DATA 0x33
+
+/* filesystem locations marked in the root block */
+#define VMU_LOCATION_FAT 0x23
+#define VMU_LOCATION_FATLEN 0x24
+#define VMU_LOCATION_DIR 0x25
+#define VMU_LOCATION_DIRLEN 0x26
+#define VMU_LOCATION_USRLEN 0x28 /* set to 200 by real hardware */
+
+/* date offsets */
+#define VMUFAT_SB_DATEOFFSET 0x30
+#define VMUFAT_FILE_DATEOFFSET 0x10
+
+#define EXEC 0111
+#define NOCOPY 0xFF
+#define CANCOPY 0x00
+
+u16 vmufat_get_fat(struct super_block *sb, long block);
+void vmufat_save_bcd(struct inode *in, char *bh, int index_to_dir);
+struct inode *vmufat_get_inode(struct super_block *sb, long ino);
+int vmufat_list_blocks(struct inode *in);
+
+enum vmufat_date {
+ VMUFAT_DIR_CENT = 0x10,
+ VMUFAT_DIR_YEAR,
+ VMUFAT_DIR_MONTH,
+ VMUFAT_DIR_DAY,
+ VMUFAT_DIR_HOUR,
+ VMUFAT_DIR_MIN,
+ VMUFAT_DIR_SEC,
+ VMUFAT_DIR_DOW
+};
+
+/* constants for BCD conversion */
+#define SECONDS_PER_DAY 86400
+#define DAYS_PER_YEAR 365
+#define SECONDS_PER_HOUR 3600
+#define HOURS_PER_DAY 24
+#define SIXTY_MINS_OR_SECS 60
+#define FEB28 59
+#define DAYS_PER_WEEK 7
+#define START_OF_EPOCH 70
+#define CENTURY21 30
+#define CENTURY22 130
+
+struct memcard {
+ unsigned int sb_bnum;
+ unsigned int fat_bnum;
+ unsigned int fat_len;
+ unsigned int dir_bnum;
+ unsigned int dir_len;
+ unsigned int numblocks;
+ struct mutex mutex;
+};
+
+struct vmufat_block {
+ struct list_head b_list;
+ int bno;
+};
+
+struct vmufat_inode {
+ struct list_head blocks;
+ unsigned int nblcks;
+ enum vmufat_file_type {
+ GAME = 1,
+ DATA = 2
+ } ft;
+ struct inode vfs_inode;
+};
+
+static inline struct vmufat_inode *VMUFAT_I(struct inode *in)
+{
+ return container_of(in, struct vmufat_inode, vfs_inode);
+}
+
+struct vmufat_file_info {
+ u8 ftype;
+ int fblk;
+ char fname[VMUFAT_NAMELEN];
+};
+
+static struct buffer_head *vmufat_sb_bread(struct super_block *sb,
+ sector_t block)
+{
+ if (!sb)
+ return NULL;
+ return sb_bread(sb, block);
+}
+
+int vmufat_count_files(struct super_block *sb);
+#endif