驱动入门hello world

首先mkdir hello1文件夹，在下面编写hello.c

vi hello.c 

1. #include <linux/init.h>  
2. #include <linux/module.h>  
3. MODULE_LICENSE("Dual BSD/GPL");  
4.    
5. static int hello_init(void)  
6. {  
7.     printk(KERN_ALERT "Hello, fanmaolin\n");  
8.     return 0;  
9. }  
10.    
11.    
12.    
13. static void hello_exit(void)  
14. {  
15.     printk(KERN_ALERT "Goodbye, fanmaolin\n");  
16. }  
17.    
18.    
19. module_init(hello_init);  
20. module_exit(hello_exit);  

在该路径下编写Makefile

vim Makefile

然后make

生成的hello.ko传到开发板上进行编译

tftp -gr hello.ko 192.168.1.2  
insmod hello.ko       安装驱动模块
dmesg              查看printk信息
lsmod               列出模块
rmmod hello     删除

>: tftp -gr hello.ko 192.168.1.2
hello.ko             100% |*******************************| 24436   0:00:00 ETA
>: insmod hello.ko 
Hello, fanmaolin
>: dmesg
Linux version 3.0.0 (fanmaolin@Centeros.ocaldomain) (gcc version 4.5.4 (Buildroot 2012.08) ) #16 Fri Mar 24 16:53:14 CST 2017
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: SMDK2440
Memory policy: ECC disabled, Data cache writeback
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, Copyright 2004 Simtec Electronics
S3C244X: core 405.600 MHz, memory 101.400 MHz, peripheral 50.700 MHz
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on
On node 0 totalpages: 16384
free_area_init_node: node 0, pgdat c04b5e30, node_mem_map c04ea000
  Normal zone: 128 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 16256 pages, LIFO batch:3
pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
pcpu-alloc: [0] 0 
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256
Kernel command line: console=ttyS0,115200 mem=64M ubi.mtd=2 root=ubi0:rootfs rootwait rootfstype=ubifs rw
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 64MB = 64MB total
Memory: 59880k/59880k available, 5656k reserved, 0K highmem
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
    DMA     : 0xffc00000 - 0xffe00000   (   2 MB)
    vmalloc : 0xc4800000 - 0xf6000000   ( 792 MB)
    lowmem  : 0xc0000000 - 0xc4000000   (  64 MB)
    modules : 0xbf000000 - 0xc0000000   (  16 MB)
      .init : 0xc0008000 - 0xc0027000   ( 124 kB)
      .text : 0xc0027000 - 0xc0491298   (4521 kB)
      .data : 0xc0492000 - 0xc04b6660   ( 146 kB)
       .bss : 0xc04b6684 - 0xc04e985c   ( 205 kB)
SLUB: Genslabs=13, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS:85
irq: clearing subpending status 00000003
irq: clearing subpending status 00000002
timer tcon=00500000, tcnt a509, tcfg 00000200,00000000, usec 00001e4c
Console: colour dummy device 80x30
console [ttyS0] enabled
Calibrating delay loop... 202.54 BogoMIPS (lpj=506368)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
gpiochip_add: gpios 288..303 (GPIOK) failed to register
gpiochip_add: gpios 320..334 (GPIOL) failed to register
gpiochip_add: gpios 352..353 (GPIOM) failed to register
NET: Registered protocol family 16
S3C Power Management, Copyright 2004 Simtec Electronics
S3C2440: Initialising architecture
S3C2440: IRQ Support
S3C244X: Clock Support, DVS off
bio: create slab <bio-0> at 0
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
s3c-i2c s3c2440-i2c: slave address 0x10
s3c-i2c s3c2440-i2c: bus frequency set to 99 KHz
s3c-i2c s3c2440-i2c: i2c-0: S3C I2C adapter
Advanced Linux Sound Architecture Driver Version 1.0.24.
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 2048 (order: 2, 16384 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 2048 bind 2048)
TCP reno registered
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
NTFS driver 2.1.30 [Flags: R/W].
JFFS2 version 2.2. (NAND) ? 2001-2006 Red Hat, Inc.
msgmni has been set to 116
io scheduler noop registered
io scheduler deadline registered
io scheduler cfq registered (default)
Console: switching to colour frame buffer device 60x53
fb0: s3c2410fb frame buffer device
s3c2440-uart.0: ttyS0 at MMIO 0x50000000 (irq = 70) is a S3C2440
s3c2440-uart.1: ttyS1 at MMIO 0x50004000 (irq = 73) is a S3C2440
s3c2440-uart.2: ttyS2 at MMIO 0x50008000 (irq = 76) is a S3C2440
brd: module loaded
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c24xx-nand s3c2440-nand: Tacls=3, 29ns Twrph0=7 69ns, Twrph1=3 29ns
s3c24xx-nand s3c2440-nand: NAND soft ECC
NAND device: Manufacturer ID: 0xec, Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-bit)
Scanning device for bad blocks
Bad eraseblock 651 at 0x000005160000
Bad eraseblock 825 at 0x000006720000
Bad eraseblock 1667 at 0x00000d060000
Bad eraseblock 1787 at 0x00000df60000
Bad eraseblock 1879 at 0x00000eae0000
Creating 5 MTD partitions on "NAND":
0x000000000000-0x000000100000 : "bootloader"
0x000000100000-0x000001000000 : "linux"
0x000001000000-0x000003800000 : "rootfs"
0x000003800000-0x000009c00000 : "apps"
0x000000000000-0x000010000000 : "data"
UBI: attaching mtd2 to ubi0
UBI: physical eraseblock size:   131072 bytes (128 KiB)
UBI: logical eraseblock size:    129024 bytes
UBI: smallest flash I/O unit:    2048
UBI: sub-page size:              512
UBI: VID header offset:          512 (aligned 512)
UBI: data offset:                2048
UBI: max. sequence number:       0
UBI: volume 0 ("rootfs") re-sized from 313 to 313 LEBs
UBI: attached mtd2 to ubi0
UBI: MTD device name:            "rootfs"
UBI: MTD device size:            40 MiB
UBI: number of good PEBs:        320
UBI: number of bad PEBs:         0
UBI: number of corrupted PEBs:   0
UBI: max. allowed volumes:       128
UBI: wear-leveling threshold:    4096
UBI: number of internal volumes: 1
UBI: number of user volumes:     1
UBI: available PEBs:             0
UBI: total number of reserved PEBs: 320
UBI: number of PEBs reserved for bad PEB handling: 3
UBI: max/mean erase counter: 1/0
UBI: image sequence number:  1869742398
UBI: background thread "ubi_bgt0d" started, PID 673
dm9000 Ethernet Driver, V1.31
eth0: dm9000a at c48a6300,c48a8304 IRQ 51 MAC: 08:00:3e:26:0a:5b (chip)
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
s3c2410-ohci s3c2410-ohci: S3C24XX OHCI
s3c2410-ohci s3c2410-ohci: new USB bus registered, assigned bus number 1
s3c2410-ohci s3c2410-ohci: irq 42, io mem 0x49000000
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
usbcore: registered new interface driver libusual
mousedev: PS/2 mouse device common for all mice
S3C24XX RTC, (c) 2004,2006 Simtec Electronics
i2c /dev entries driver
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq enabled
cpuidle: using governor ladder
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
ALSA device list:
  No soundcards found.
TCP cubic registered
NET: Registered protocol family 17
Registering the dns_resolver key type
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
UBIFS: mounted UBI device 0, volume 0, name "rootfs"
UBIFS: file system size:   39094272 bytes (38178 KiB, 37 MiB, 303 LEBs)
UBIFS: journal size:       5419008 bytes (5292 KiB, 5 MiB, 42 LEBs)
UBIFS: media format:       w4/r0 (latest is w4/r0)
UBIFS: default compressor: lzo
UBIFS: reserved for root:  0 bytes (0 KiB)
VFS: Mounted root (ubifs filesystem) on device 0:13.
Freeing init memory: 124K
usb 1-1: new full speed USB device number 2 using s3c2410-ohci
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
dm9000 dm9000: eth0: link down
dm9000 dm9000: eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1
Hello, fanmaolin
>: lsmod
hello 660 0 - Live 0xbf004000
>: rmmod hello
Goodbye, fanmaolin
>: 

问题及解决：

没有网卡，安装dm9000网卡

>: tftp -gr hello.ko 192.168.1.2
hello.ko             100% |*******************************| 24436   0:00:00 ETA
>: insmod hello.ko 
Hello, fanmaolin
>: dmesg
Linux version 3.0.0 (fanmaolin@Centeros.ocaldomain) (gcc version 4.5.4 (Buildroot 2012.08) ) #16 Fri Mar 24 16:53:14 CST 2017
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: SMDK2440
Memory policy: ECC disabled, Data cache writeback
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, Copyright 2004 Simtec Electronics
S3C244X: core 405.600 MHz, memory 101.400 MHz, peripheral 50.700 MHz
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on
On node 0 totalpages: 16384
free_area_init_node: node 0, pgdat c04b5e30, node_mem_map c04ea000
  Normal zone: 128 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 16256 pages, LIFO batch:3
pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
pcpu-alloc: [0] 0 
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256
Kernel command line: console=ttyS0,115200 mem=64M ubi.mtd=2 root=ubi0:rootfs rootwait rootfstype=ubifs rw
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 64MB = 64MB total
Memory: 59880k/59880k available, 5656k reserved, 0K highmem
Virtual kernel memory layout:
    vector  : 0xffff0000 - 0xffff1000   (   4 kB)
    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
    DMA     : 0xffc00000 - 0xffe00000   (   2 MB)
    vmalloc : 0xc4800000 - 0xf6000000   ( 792 MB)
    lowmem  : 0xc0000000 - 0xc4000000   (  64 MB)
    modules : 0xbf000000 - 0xc0000000   (  16 MB)
      .init : 0xc0008000 - 0xc0027000   ( 124 kB)
      .text : 0xc0027000 - 0xc0491298   (4521 kB)
      .data : 0xc0492000 - 0xc04b6660   ( 146 kB)
       .bss : 0xc04b6684 - 0xc04e985c   ( 205 kB)
SLUB: Genslabs=13, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS:85
irq: clearing subpending status 00000003
irq: clearing subpending status 00000002
timer tcon=00500000, tcnt a509, tcfg 00000200,00000000, usec 00001e4c
Console: colour dummy device 80x30
console [ttyS0] enabled
Calibrating delay loop... 202.54 BogoMIPS (lpj=506368)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
gpiochip_add: gpios 288..303 (GPIOK) failed to register
gpiochip_add: gpios 320..334 (GPIOL) failed to register
gpiochip_add: gpios 352..353 (GPIOM) failed to register
NET: Registered protocol family 16
S3C Power Management, Copyright 2004 Simtec Electronics
S3C2440: Initialising architecture
S3C2440: IRQ Support
S3C244X: Clock Support, DVS off
bio: create slab <bio-0> at 0
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
s3c-i2c s3c2440-i2c: slave address 0x10
s3c-i2c s3c2440-i2c: bus frequency set to 99 KHz
s3c-i2c s3c2440-i2c: i2c-0: S3C I2C adapter
Advanced Linux Sound Architecture Driver Version 1.0.24.
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 2048 (order: 2, 16384 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
TCP: Hash tables configured (established 2048 bind 2048)
TCP reno registered
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
NTFS driver 2.1.30 [Flags: R/W].
JFFS2 version 2.2. (NAND) ? 2001-2006 Red Hat, Inc.
msgmni has been set to 116
io scheduler noop registered
io scheduler deadline registered
io scheduler cfq registered (default)
Console: switching to colour frame buffer device 60x53
fb0: s3c2410fb frame buffer device
s3c2440-uart.0: ttyS0 at MMIO 0x50000000 (irq = 70) is a S3C2440
s3c2440-uart.1: ttyS1 at MMIO 0x50004000 (irq = 73) is a S3C2440
s3c2440-uart.2: ttyS2 at MMIO 0x50008000 (irq = 76) is a S3C2440
brd: module loaded
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c24xx-nand s3c2440-nand: Tacls=3, 29ns Twrph0=7 69ns, Twrph1=3 29ns
s3c24xx-nand s3c2440-nand: NAND soft ECC
NAND device: Manufacturer ID: 0xec, Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-bit)
Scanning device for bad blocks
Bad eraseblock 651 at 0x000005160000
Bad eraseblock 825 at 0x000006720000
Bad eraseblock 1667 at 0x00000d060000
Bad eraseblock 1787 at 0x00000df60000
Bad eraseblock 1879 at 0x00000eae0000
Creating 5 MTD partitions on "NAND":
0x000000000000-0x000000100000 : "bootloader"
0x000000100000-0x000001000000 : "linux"
0x000001000000-0x000003800000 : "rootfs"
0x000003800000-0x000009c00000 : "apps"
0x000000000000-0x000010000000 : "data"
UBI: attaching mtd2 to ubi0
UBI: physical eraseblock size:   131072 bytes (128 KiB)
UBI: logical eraseblock size:    129024 bytes
UBI: smallest flash I/O unit:    2048
UBI: sub-page size:              512
UBI: VID header offset:          512 (aligned 512)
UBI: data offset:                2048
UBI: max. sequence number:       0
UBI: volume 0 ("rootfs") re-sized from 313 to 313 LEBs
UBI: attached mtd2 to ubi0
UBI: MTD device name:            "rootfs"
UBI: MTD device size:            40 MiB
UBI: number of good PEBs:        320
UBI: number of bad PEBs:         0
UBI: number of corrupted PEBs:   0
UBI: max. allowed volumes:       128
UBI: wear-leveling threshold:    4096
UBI: number of internal volumes: 1
UBI: number of user volumes:     1
UBI: available PEBs:             0
UBI: total number of reserved PEBs: 320
UBI: number of PEBs reserved for bad PEB handling: 3
UBI: max/mean erase counter: 1/0
UBI: image sequence number:  1869742398
UBI: background thread "ubi_bgt0d" started, PID 673
dm9000 Ethernet Driver, V1.31
eth0: dm9000a at c48a6300,c48a8304 IRQ 51 MAC: 08:00:3e:26:0a:5b (chip)
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
s3c2410-ohci s3c2410-ohci: S3C24XX OHCI
s3c2410-ohci s3c2410-ohci: new USB bus registered, assigned bus number 1
s3c2410-ohci s3c2410-ohci: irq 42, io mem 0x49000000
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
usbcore: registered new interface driver libusual
mousedev: PS/2 mouse device common for all mice
S3C24XX RTC, (c) 2004,2006 Simtec Electronics
i2c /dev entries driver
S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics
s3c2410-wdt s3c2410-wdt: watchdog inactive, reset disabled, irq enabled
cpuidle: using governor ladder
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
ALSA device list:
  No soundcards found.
TCP cubic registered
NET: Registered protocol family 17
Registering the dns_resolver key type
drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
UBIFS: mounted UBI device 0, volume 0, name "rootfs"
UBIFS: file system size:   39094272 bytes (38178 KiB, 37 MiB, 303 LEBs)
UBIFS: journal size:       5419008 bytes (5292 KiB, 5 MiB, 42 LEBs)
UBIFS: media format:       w4/r0 (latest is w4/r0)
UBIFS: default compressor: lzo
UBIFS: reserved for root:  0 bytes (0 KiB)
VFS: Mounted root (ubifs filesystem) on device 0:13.
Freeing init memory: 124K
usb 1-1: new full speed USB device number 2 using s3c2410-ohci
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
dm9000 dm9000: eth0: link down
dm9000 dm9000: eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1
Welcome to Lingyun IOT System Lab.
Official Website: www.iot-yun.com
Wow! It's very good and I have learn much from it, thanks!
Hello, fanmaolin
>: lsmod
hello 660 0 - Live 0xbf004000
>: rmmod hello
Goodbye, fanmaolin
>: 

完成

问题：

1、没有安装dm9000网卡，下一篇写在内核安装方法。

2、Makefile 路径错误，改正后Ok

3、insmod: can't insert 'hello.ko': invalid module format  解决办法参考http://blog.youkuaiyun.com/zengxianyang/article/details/50505998（他人博客）