fs: exfat: Import libexfat from fuse-exfat

Import most of libexfat from [1] except for log.c verbatim. The code
does not even compile and further adjustments and integration into
U-Boot filesystem code is in the next patch.

[1] https://github.com/relan/exfat
    0b41c6d3560d ("CI: bump FreeBSD to 13.1.")

Acked-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/fs/exfat/exfatfs.h b/fs/exfat/exfatfs.h
new file mode 100644
index 0000000..3618d4d
--- /dev/null
+++ b/fs/exfat/exfatfs.h
@@ -0,0 +1,181 @@
+/*
+	exfatfs.h (29.08.09)
+	Definitions of structures and constants used in exFAT file system.
+
+	Free exFAT implementation.
+	Copyright (C) 2010-2023  Andrew Nayenko
+
+	This program is free software; you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 2 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License along
+	with this program; if not, write to the Free Software Foundation, Inc.,
+	51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef EXFATFS_H_INCLUDED
+#define EXFATFS_H_INCLUDED
+
+#include "byteorder.h"
+#include "compiler.h"
+
+typedef uint32_t cluster_t;		/* cluster number */
+
+#define EXFAT_FIRST_DATA_CLUSTER 2
+#define EXFAT_LAST_DATA_CLUSTER 0xfffffff6
+
+#define EXFAT_CLUSTER_FREE         0 /* free cluster */
+#define EXFAT_CLUSTER_BAD 0xfffffff7 /* cluster contains bad sector */
+#define EXFAT_CLUSTER_END 0xffffffff /* final cluster of file or directory */
+
+#define EXFAT_STATE_MOUNTED 2
+
+struct exfat_super_block
+{
+	uint8_t jump[3];				/* 0x00 jmp and nop instructions */
+	uint8_t oem_name[8];			/* 0x03 "EXFAT   " */
+	uint8_t	__unused1[53];			/* 0x0B always 0 */
+	le64_t sector_start;			/* 0x40 partition first sector */
+	le64_t sector_count;			/* 0x48 partition sectors count */
+	le32_t fat_sector_start;		/* 0x50 FAT first sector */
+	le32_t fat_sector_count;		/* 0x54 FAT sectors count */
+	le32_t cluster_sector_start;	/* 0x58 first cluster sector */
+	le32_t cluster_count;			/* 0x5C total clusters count */
+	le32_t rootdir_cluster;			/* 0x60 first cluster of the root dir */
+	le32_t volume_serial;			/* 0x64 volume serial number */
+	struct							/* 0x68 FS version */
+	{
+		uint8_t minor;
+		uint8_t major;
+	}
+	version;
+	le16_t volume_state;			/* 0x6A volume state flags */
+	uint8_t sector_bits;			/* 0x6C sector size as (1 << n) */
+	uint8_t spc_bits;				/* 0x6D sectors per cluster as (1 << n) */
+	uint8_t fat_count;				/* 0x6E always 1 */
+	uint8_t drive_no;				/* 0x6F always 0x80 */
+	uint8_t allocated_percent;		/* 0x70 percentage of allocated space */
+	uint8_t __unused2[397];			/* 0x71 always 0 */
+	le16_t boot_signature;			/* the value of 0xAA55 */
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_super_block) == 512);
+
+#define EXFAT_ENTRY_VALID     0x80
+#define EXFAT_ENTRY_CONTINUED 0x40
+#define EXFAT_ENTRY_OPTIONAL  0x20
+
+#define EXFAT_ENTRY_BITMAP    (0x01 | EXFAT_ENTRY_VALID)
+#define EXFAT_ENTRY_UPCASE    (0x02 | EXFAT_ENTRY_VALID)
+#define EXFAT_ENTRY_LABEL     (0x03 | EXFAT_ENTRY_VALID)
+#define EXFAT_ENTRY_FILE      (0x05 | EXFAT_ENTRY_VALID)
+#define EXFAT_ENTRY_FILE_INFO (0x00 | EXFAT_ENTRY_VALID | EXFAT_ENTRY_CONTINUED)
+#define EXFAT_ENTRY_FILE_NAME (0x01 | EXFAT_ENTRY_VALID | EXFAT_ENTRY_CONTINUED)
+#define EXFAT_ENTRY_FILE_TAIL (0x00 | EXFAT_ENTRY_VALID \
+                                    | EXFAT_ENTRY_CONTINUED \
+                                    | EXFAT_ENTRY_OPTIONAL)
+
+struct exfat_entry					/* common container for all entries */
+{
+	uint8_t type;					/* any of EXFAT_ENTRY_xxx */
+	uint8_t data[31];
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry) == 32);
+
+#define EXFAT_ENAME_MAX 15
+
+struct exfat_entry_bitmap			/* allocated clusters bitmap */
+{
+	uint8_t type;					/* EXFAT_ENTRY_BITMAP */
+	uint8_t __unknown1[19];
+	le32_t start_cluster;
+	le64_t size;					/* in bytes */
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry_bitmap) == 32);
+
+#define EXFAT_UPCASE_CHARS 0x10000
+
+struct exfat_entry_upcase			/* upper case translation table */
+{
+	uint8_t type;					/* EXFAT_ENTRY_UPCASE */
+	uint8_t __unknown1[3];
+	le32_t checksum;
+	uint8_t __unknown2[12];
+	le32_t start_cluster;
+	le64_t size;					/* in bytes */
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry_upcase) == 32);
+
+struct exfat_entry_label			/* volume label */
+{
+	uint8_t type;					/* EXFAT_ENTRY_LABEL */
+	uint8_t length;					/* number of characters */
+	le16_t name[EXFAT_ENAME_MAX];	/* in UTF-16LE */
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry_label) == 32);
+
+#define EXFAT_ATTRIB_RO     0x01
+#define EXFAT_ATTRIB_HIDDEN 0x02
+#define EXFAT_ATTRIB_SYSTEM 0x04
+#define EXFAT_ATTRIB_VOLUME 0x08
+#define EXFAT_ATTRIB_DIR    0x10
+#define EXFAT_ATTRIB_ARCH   0x20
+
+struct exfat_entry_meta1			/* file or directory info (part 1) */
+{
+	uint8_t type;					/* EXFAT_ENTRY_FILE */
+	uint8_t continuations;
+	le16_t checksum;
+	le16_t attrib;					/* combination of EXFAT_ATTRIB_xxx */
+	le16_t __unknown1;
+	le16_t crtime, crdate;			/* creation date and time */
+	le16_t mtime, mdate;			/* latest modification date and time */
+	le16_t atime, adate;			/* latest access date and time */
+	uint8_t crtime_cs;				/* creation time in cs (centiseconds) */
+	uint8_t mtime_cs;				/* latest modification time in cs */
+	uint8_t crtime_tzo, mtime_tzo, atime_tzo;	/* timezone offset encoded */
+	uint8_t __unknown2[7];
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry_meta1) == 32);
+
+#define EXFAT_FLAG_ALWAYS1		(1u << 0)
+#define EXFAT_FLAG_CONTIGUOUS	(1u << 1)
+
+struct exfat_entry_meta2			/* file or directory info (part 2) */
+{
+	uint8_t type;					/* EXFAT_ENTRY_FILE_INFO */
+	uint8_t flags;					/* combination of EXFAT_FLAG_xxx */
+	uint8_t __unknown1;
+	uint8_t name_length;
+	le16_t name_hash;
+	le16_t __unknown2;
+	le64_t valid_size;				/* in bytes, less or equal to size */
+	uint8_t __unknown3[4];
+	le32_t start_cluster;
+	le64_t size;					/* in bytes */
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry_meta2) == 32);
+
+struct exfat_entry_name				/* file or directory name */
+{
+	uint8_t type;					/* EXFAT_ENTRY_FILE_NAME */
+	uint8_t __unknown;
+	le16_t name[EXFAT_ENAME_MAX];	/* in UTF-16LE */
+}
+PACKED;
+STATIC_ASSERT(sizeof(struct exfat_entry_name) == 32);
+
+#endif /* ifndef EXFATFS_H_INCLUDED */