1. test_app.c 라즈베리파이에서 작업
test_app.c : 디바이스 드라이버를 사용하는 애플리케이션
# app Makefile
CC = gcc
OBJECT = test_app.o
TARGET = test_app
CFLAGS = -g -Wall
$(TARGET) : $(OBJECT)
$(CC) -o $(TARGET) $(OBJECT)
clean:
rm -f $(OBJECT) $(TARGET)
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
int main(int argc,char *argv[])
{
int fd;
char val;
if(argc < 2 ){
printf("usage: %s [no] \n",*argv);
return 1;
}
fd = open("/dev/testdev",O_RDWR); //장치를 RW 권한으로 오픈. R:4 W:2 X:1 / test_dev에 구조체 file_operations test_fops= 의 open 과 연결되어있뜸
if(fd < 0){
perror("open failed...");
return 1;
}
//시스템콜
val = atoi(argv[1]);
write(fd, &val, sizeof(val));
read(fd, &val, sizeof(val));
printf("App val: %d\n",val);
close(fd);
return 0;
}2. test_dev.c 우분투에서 작업
#include <linux/module.h>
#include <linux/init.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#define MAJOR_NUM 256
static char data;
int test_open(struct inode *inode, struct file *filp)
{
printk("Dev test_open() call\n");
return 0;
}
int test_release(struct inode *inode, struct file *filp)
{
printk("Dev test_close() call\n");
return 0;
}
int test_write(struct file *filp, const char *buf, size_t count, loff_t *f_pos)
{
printk("Dev test_write() call\n");
data = *buf; //data 라는 변수에 저장됨
return count;
}
int test_read(struct file *filp, char *buf, size_t count, loff_t *f_pos)
{
printk("Dev test_read() call\n");
*buf = data +10;
return count;
}
struct file_operations test_fops=
{
owner: THIS_MODULE,
open :test_open,
release :test_release,
write :test_write,
read :test_read
};
static int __init test_init(void)
{
int result;
printk("Dev test_init() call\n");
result=register_chrdev(MAJOR_NUM, "testdev",&test_fops);
return 0;
}
static void __exit test_exit(void)
{
printk("Dev test_exit() call\n");
unregister_chrdev(MAJOR_NUM, "testdev");
}
module_init(test_init);
module_exit(test_exit);
MODULE_LICENSE("GPL");
#linux kernel source
KDIR = /home/sss/linux
obj-m := test_dev.o
default:
$(MAKE) ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -C $(KDIR) M=$$PWD modules
clean:
$(MAKE) -C $(KDIR) M=$$PWD clean
pi@raspberrypi:~/work/test_dev $ ls -l /dev/testdev
crw-r--r-- 1 root root 256, 0 Dec 18 09:58 /dev/testdev
pi@raspberrypi:~/work/test_dev $ cat /proc/devices
Character devices:
1 mem
4 /dev/vc/0
4 tty
5 /dev/tty
5 /dev/console
5 /dev/ptmx
5 ttyprintk
7 vcs
10 misc
13 input
14 sound
29 fb
81 video4linux
89 i2c
116 alsa
128 ptm
136 pts
153 spi
162 raw
180 usb
189 usb_device
204 ttyAMA
216 rfcomm
226 drm
235 cec
236 media
237 rpivid-vp9mem
238 rpivid-h264mem
239 rpivid-intcmem
240 rpivid-hevcmem
241 uio
242 vcsm
243 vchiq
244 hidraw
245 rpmb
246 bcm2835-gpiomem
247 vcio
248 vc-mem
249 bsg
250 watchdog
251 BaseRemoteCtl
252 rtc
253 dma_heap
254 gpiochip
Block devices:
1 ramdisk
7 loop
8 sd
65 sd
66 sd
67 sd
68 sd
69 sd
70 sd
71 sd
128 sd
129 sd
130 sd
131 sd
132 sd
133 sd
134 sd
135 sd
179 mmc
259 blkext
pi@raspberrypi:~/work/test_dev $ sudo insmod test_dev.ko
pi@raspberrypi:~/work/test_dev $ lsmod
Module Size Used by
test_dev 16384 0
cmac 16384 1
rfcomm 49152 4
bnep 20480 2
hci_uart 40960 1
btbcm 16384 1 hci_uart
bluetooth 372736 29 hci_uart,bnep,btbcm,rfcomm
ecdh_generic 16384 2 bluetooth
ecc 40960 1 ecdh_generic
8021q 32768 0
garp 16384 1 8021q
stp 16384 1 garp
llc 16384 2 garp,stp
spidev 20480 0
brcmfmac 319488 0
brcmutil 20480 1 brcmfmac
sha256_generic 16384 0
libsha256 20480 1 sha256_generic
vc4 241664 0
cec 49152 1 vc4
cfg80211 692224 1 brcmfmac
v3d 69632 0
drm_kms_helper 184320 2 vc4
gpu_sched 36864 1 v3d
rfkill 28672 6 bluetooth,cfg80211
bcm2835_codec 36864 0
drm 466944 5 v3d,vc4,gpu_sched,drm_kms_helper
v4l2_mem2mem 32768 1 bcm2835_codec
raspberrypi_hwmon 16384 0
bcm2835_v4l2 49152 0
bcm2835_isp 32768 0
bcm2835_mmal_vchiq 28672 3 bcm2835_isp,bcm2835_codec,bcm2835_v4l2
videobuf2_dma_contig 20480 2 bcm2835_isp,bcm2835_codec
videobuf2_vmalloc 16384 1 bcm2835_v4l2
videobuf2_memops 16384 2 videobuf2_dma_contig,videobuf2_vmalloc
drm_panel_orientation_quirks 16384 1 drm
videobuf2_v4l2 28672 4 bcm2835_isp,bcm2835_codec,bcm2835_v4l2,v4l2_mem2mem
videobuf2_common 57344 5 bcm2835_isp,bcm2835_codec,bcm2835_v4l2,v4l2_mem2mem,videobuf2_v4l2
spi_bcm2835 24576 0
videodev 237568 6 bcm2835_isp,bcm2835_codec,videobuf2_common,bcm2835_v4l2,v4l2_mem2mem,videobuf2_v4l2
snd_soc_core 200704 1 vc4
mc 40960 6 bcm2835_isp,bcm2835_codec,videobuf2_common,videodev,v4l2_mem2mem,videobuf2_v4l2
snd_bcm2835 28672 1
snd_compress 20480 1 snd_soc_core
snd_pcm_dmaengine 16384 1 snd_soc_core
vc_sm_cma 32768 2 bcm2835_isp,bcm2835_mmal_vchiq
snd_pcm 98304 4 vc4,snd_pcm_dmaengine,snd_bcm2835,snd_soc_core
snd_timer 32768 1 snd_pcm
rpivid_mem 16384 0
snd 73728 7 snd_compress,snd_timer,snd_bcm2835,snd_soc_core,snd_pcm
syscopyarea 16384 1 drm_kms_helper
sysfillrect 16384 1 drm_kms_helper
sysimgblt 16384 1 drm_kms_helper
fb_sys_fops 16384 1 drm_kms_helper
uio_pdrv_genirq 16384 0
uio 20480 1 uio_pdrv_genirq
i2c_dev 20480 0
ip_tables 28672 0
x_tables 32768 1 ip_tables
ipv6 466944 32
pi@raspberrypi:~/work/test_dev $ cat /proc/devices
Character devices:
1 mem
4 /dev/vc/0
4 tty
5 /dev/tty
5 /dev/console
5 /dev/ptmx
5 ttyprintk
7 vcs
10 misc
13 input
14 sound
29 fb
81 video4linux
89 i2c
116 alsa
128 ptm
136 pts
153 spi
162 raw
180 usb
189 usb_device
204 ttyAMA
216 rfcomm
226 drm
235 cec
236 media
237 rpivid-vp9mem
238 rpivid-h264mem
239 rpivid-intcmem
240 rpivid-hevcmem
241 uio
242 vcsm
243 vchiq
244 hidraw
245 rpmb
246 bcm2835-gpiomem
247 vcio
248 vc-mem
249 bsg
250 watchdog
251 BaseRemoteCtl
252 rtc
253 dma_heap
254 gpiochip
256 testdev
Block devices:
1 ramdisk
7 loop
8 sd
65 sd
66 sd
67 sd
68 sd
69 sd
70 sd
71 sd
128 sd
129 sd
130 sd
131 sd
132 sd
133 sd
134 sd
135 sd
179 mmc
259 blkext
pi@raspberrypi:~/work/test_dev $
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