use module [mmc_block_test] for
example
because the mmc_block_test
already use debugfs, you will see debugfs_create_dir and
debugfs_create_file in the soucrec code. When the module be
installed or be triggered, the debugfs will create a
directory(default in /sys/kernel/debug/) for it.
By using debugfs, we wouldn't need to
write a user application program for testing module functions.
Actual Operation on
DragonBoard
Step1. See current io-scheduler
#cat
/sys/block/mmcblk0/queue/schduler
Step2. Switch io-scheduler and the
relative functions will be mounted in debugfs
#echo test-iosched >
/sys/block/mmcblk0/queue/schduler
Step3. Move to functions folder, in
there we will see /tests/ and /utils/
#cd /sys/kernel/debug/test-iosched/
Step4. Linux use echo command to
trigger .write, and using cat command to trigger .read
in terminal
for example,
#echo 4 >
write_packing_control_test will do 4 cycle of
write_packing_control_test_write
#cat write_packing_control_test
will show what write_packing_control_test_write will do
ref:
Documentation/filesystems/debugfs.txt
