fs: exfat: Add U-Boot porting layer

Add U-Boot adjustments to the libexfat code and integrate
the result into U-Boot filesystem layer. This provides full
read-write exfat support for U-Boot available via generic
filesystem interface.

FS_DIRENT_NAME_LEN is increased to 1024 in case exfat is
enabled, because EXFAT can use UTF16 names, which do not
fit into current FS_DIRENT_NAME_LEN. To avoid affecting
every configuration, increase FS_DIRENT_NAME_LEN only in
case EXFAT is enabled.

Example usage via sandbox, assuming disk.img with one exfat partition:

Drive info:
$ ./u-boot -Tc 'host bind 0 ../disk.img ; host info 0'
dev       blocks  blksz label           path
  0       262144    512 0               ../disk.img

List files:
$ ./u-boot -Tc 'host bind 0 ../disk.img ; ls host 0:1 /api'
      475   Kconfig
      230   Makefile
     1873   README
     ...
10 file(s), 0 dir(s)

Load and checksum a file:
$ ./u-boot -Tc 'host bind 0 ../disk.img ; load host 0:1 $loadaddr .config ; \
                crc32 $loadaddr $filesize'
56724 bytes read in 1 ms (54.1 MiB/s)
crc32 for 00000000 ... 0000dd93 ==> b2e847c9

$ crc32 .config
b2e847c9

Load .config file to RAM, store the file into FS as /newconfig,
load the /newconfig into RAM and checksum the file:
$ ./u-boot -Tc 'host bind 0 ../disk.img ; load host 0:1 $loadaddr .config ; \
		save host 0:1 $loadaddr /newconfig $filesize ; \
		load host 0:1 0x10000 /newconfig ; \
		crc32 0x10000 $filesize'
56724 bytes read in 1 ms (54.1 MiB/s)
56724 bytes written in 0 ms
56724 bytes read in 0 ms
crc32 for 00010000 ... 0001dd93 ==> b2e847c9

Remove file 3.txt and create new directory /newdir:
$ ./u-boot -Tc 'host bind 0 ../disk.img ; ls host 0:1 / ; \
                rm host 0:1 3.txt ; mkdir host 0:1 /newdir ; \
		ls host 0:1 /'
...
        0   1.txt
        0   2.txt
        0   3.txt
        0   4.txt
        0   5.txt

7 file(s), 4 dir(s)
...
        0   1.txt
        0   2.txt
            newdir/
        0   4.txt
        0   5.txt

6 file(s), 5 dir(s)

Acked-by: Tom Rini <[email protected]>
Signed-off-by: Marek Vasut <[email protected]>

2 files changed, 26 insertions, 1 deletions

diff --git a/include/exfat.h b/include/exfat.h
new file mode 100644
index 00000000000..7e43beeb348
--- /dev/null
+++ b/include/exfat.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _EXFAT_H_
+#define _EXFAT_H_
+
+struct disk_partition;
+
+int exfat_fs_opendir(const char *filename, struct fs_dir_stream **dirsp);
+int exfat_fs_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
+int exfat_fs_ls(const char *dirname);
+int exfat_fs_probe(struct blk_desc *fs_dev_desc,
+		struct disk_partition *fs_partition);
+int exfat_fs_read(const char *filename, void *buf, loff_t offset,
+	       loff_t len, loff_t *actread);
+int exfat_fs_size(const char *filename, loff_t *size);
+int exfat_fs_exists(const char *filename);
+void exfat_fs_close(void);
+void exfat_fs_closedir(struct fs_dir_stream *dirs);
+
+int exfat_fs_unlink(const char *filename);
+int exfat_fs_mkdir(const char *dirname);
+int exfat_fs_write(const char *filename, void *buf, loff_t offset,
+		   loff_t len, loff_t *actwrite);
+
+#endif /* _EXFAT_H */
diff --git a/include/fs.h b/include/fs.h
index 54449faf2e5..731aaa02637 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -18,6 +18,7 @@ struct cmd_tbl;
 #define FS_TYPE_SQUASHFS 6
 #define FS_TYPE_EROFS   7
 #define FS_TYPE_SEMIHOSTING 8
+#define FS_TYPE_EXFAT   9
 
 struct blk_desc;
 
@@ -173,7 +174,7 @@ int fs_write(const char *filename, ulong addr, loff_t offset, loff_t len,
 #define FS_DT_REG  8         /* regular file */
 #define FS_DT_LNK  10        /* symbolic link */
 
-#define FS_DIRENT_NAME_LEN 256
+#define FS_DIRENT_NAME_LEN	CONFIG_IS_ENABLED(FS_EXFAT, (1024), (256))
 
 /**
  * struct fs_dirent - directory entry