Merge pull request RIOT-OS#16800 from chrysn-pull-requests/vfs-fat-us…

…ability

Small fatfs usability fixes

examples/filesystem/README.md

@@ -76,3 +76,47 @@ Hello World!
 cat /const/hello-riot
 Hello RIOT!
 ```
+
+## Example on `native` with `fatfs`
+
+- Unpack the provided image proviced in the `pkg_fatfs` test:
+
+```
+$ tar vxjf ../../tests/pkg_fatfs/riot_fatfs_disk.tar.bz2
+riot_fatfs_disk.img
+```
+
+- Configure the application to use the file and the right geometry by adding
+  these to the Makefile:
+
+```
+CFLAGS += -DMTD_NATIVE_FILENAME=\"riot_fatfs_disk.img\"
+CFLAGS += -DMTD_PAGE_SIZE=512
+CFLAGS += -DMTD_SECTOR_SIZE=512
+CFLAGS += -DMTD_SECTOR_NUM=262144
+```
+
+- In the Makefile, comment the `littlefs2` USEMODULE line, and enable the
+  `fatfs_vfs` line instead.
+
+- Build and run the `filesystem` example application on the `native` target as above.
+
+- Mount the external file system:
+
+```
+> mount
+mount
+/sda successfully mounted
+```
+
+- List the available files in the FAT partition:
+
+```
+> ls /sda
+ls /sda
+TEST.TXT
+total 1 files
+```
+
+- You can also use the writing commands now to create and modify files; run
+  `vfs` for instructions.

tests/pkg_fatfs/Makefile

@@ -45,10 +45,11 @@ USEMODULE += mtd_sdcard
 endif
 
 image:
-	@tar -xjf riot_fatfs_disk.tar.gz -C ./bin/
+	${Q}mkdir -p bin
+	${Q}tar -xjf riot_fatfs_disk.tar.bz2 -C ./bin/
 
 #this generates a compressed fat image file that can be used by the fat driver on native
 compressed-image:
-	@./create_fat_image_file.sh $(FATFS_IMAGE_FILE_SIZE_MIB)
+	${Q}./create_fat_image_file.sh $(FATFS_IMAGE_FILE_SIZE_MIB)
 
 include $(RIOTBASE)/Makefile.include

tests/pkg_fatfs/create_fat_image_file.sh

@@ -13,5 +13,5 @@ sudo mount -o loop,umask=000 riot_fatfs_disk.img /media/riot_fatfs_disk
 touch /media/riot_fatfs_disk/test.txt
 echo "the test file content 123 abc" | tr '\n' '\0' >> /media/riot_fatfs_disk/test.txt
 sudo umount /media/riot_fatfs_disk
-tar -cjf riot_fatfs_disk.tar.gz riot_fatfs_disk.img
+tar -cjf riot_fatfs_disk.tar.bz2 riot_fatfs_disk.img
 rm riot_fatfs_disk.img