debugfs 생성 ( /sys/kernel/debug/)

다음과 같은 경로에 read/write 가능한 debug fs를 생성한다

cat /sys/kernel/debug/rpi_debug/val

 

아래의 코드를 module로 생성하여 빌드한다.

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <asm/setup.h>
#include <linux/input.h>
#include <linux/debugfs.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/slub_def.h>
#include <linux/uaccess.h>
#include <asm/memory.h>

uint32_t my_debug_state = 0x1000;
static struct dentry *my_debugfs_root;

static int my_stat_get(void *data, u64 *val)
{
    *val = my_debug_state;
    return 0;
}

static int my_stat_set(void *data, u64 val)
{
    my_debug_state = (uint32_t)val;
    return 0;
}


DEFINE_SIMPLE_ATTRIBUTE(my_stat_fops, my_stat_get, my_stat_set, "%llu\n");

static int my_debugfs_driver_probe(struct platform_device *pdev)
{
    return 0;
}

static struct platform_driver my_debugfs_driver = {
    .probe      = my_debugfs_driver_probe,
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = "my_debug",
    },
};

static int __init my_debugfs_init(void)
{
    my_debugfs_root = debugfs_create_dir("my_debug", NULL);
    debugfs_create_file("val", S_IRUGO, my_debugfs_root, NULL, &my_stat_fops);

    return platform_driver_register(&my_debugfs_driver);
}
late_initcall(my_debugfs_init);

MODULE_LICENSE("GPL");

.