Linux设备驱动程序学习之设备模型二

/*

 * And the bus type.

 */

struct
 bus_type ldd_bus_type =
 {

    .
name
 =
 "ldd"
,

    .
match =
 ldd_match,

    .uevent 
 = ldd_uevent

,

}
;

static
 int
 __init ldd_bus_init(
void
)

{

    int
 ret;

ret =
 bus_register(
&
ldd_bus_type)
; /*注册总线，在调用这个函数之后ldd_bus_type 
结构体将向内核注册，在/sys/bus中出现ldd文件夹，其中包含两个目录：devices 和 drivers 
*/

    if
 (
ret)

        return
 ret;

    if
 (
bus_create_file(
&
ldd_bus_type,
 &
bus_attr_version)
) /*添加总线属性,将在/sys/bus/ldd目
录中出现version属性文件
*/

        printk(
KERN_NOTICE "Unable to create version attribute ! /n"
)
;

    ret =
 device_register(
&
ldd_bus)
;/*将总线作为设备注册。因为总线也可以是一个设备，比如在S3C2440中SPI
总线控制器相对于ARM920T核心来说，其实就是一个外设。调用此函数后，就会在/sys/devices中出现ldd0目录*/

    if
 (
ret)

        printk(
KERN_NOTICE "Unable to register ldd0 ! /n"
)
;

    

    printk(
KERN_NOTICE "Mount
 lddbus ok !/nBus device is ldd0 !/nYou
 can see me in sys/module/ , sys/devices/ and sys/bus/ !
 /n"
)
;

    

    return
 ret;

}

static
 void
 ldd_bus_exit(
void
)

{

    device_unregister(
&
ldd_bus)
;

    bus_unregister(
&
ldd_bus_type)
;

}

module_init(
ldd_bus_init)
;

module_exit(
ldd_bus_exit)
;

//*******在源码的声明阶段添加如下代码，以增加设备和驱动的结构体*****

struct
 sculld_dev *
sculld_devices;
 /* 
allocated in scull_init_module */

/* Device model stuff */

static
 struct
 ldd_driver sculld_driver =
 {

    .
version =
 "$Revision:
 1.21-tekkamanninja $"
,

    .
module =
 THIS_MODULE,

    .
driver
 =
 {

        .
name =
 "sculld"
,

    }
,

}
;

//**************************************************************

//******
增加设备注册函数和设备号属性********************************

static
 ssize_t sculld_show_dev(
struct
 device *
ddev,
 struct
 device_attribute *
attr ,
 char
 *
buf)

{

    struct
 sculld_dev *
dev =
 ddev-
>
driver_data;

    return
 print_dev_t(
buf,
 dev-
>
cdev.
dev)
;

}

static
 DEVICE_ATTR(
dev,
 S_IRUGO,
 sculld_show_dev,
 NULL
)
;

static
 void
 sculld_register_dev(
struct
 sculld_dev *
dev,
 int
 index)

{

    sprintf
(
dev-
>
devname,
 "sculld%d"
,
 index)
;

    dev-
>
ldev.
name =
 dev-
>
devname;

    dev-
>
ldev.
driver =
 &
sculld_driver;

    dev-
>
ldev.
dev.
driver_data =
 dev;

    register_ldd_device(
&
dev-
>
ldev)
;

    if
 (
device_create_file(
&
dev-
>
ldev.
dev,
 &
dev_attr_dev)
)
 

    printk(
 "Unable to create dev attribute !
 /n"
)
;

}

//*****************************************************************

/*还要在模块的初始化函数和模块清除函数中添加设备和驱动的注册和注销函数
*/

    sculld_register_dev(
sculld_devices +
 i,
 i)
;

    register_ldd_driver(
&
sculld_driver)
;

    unregister_ldd_device(
&
sculld_devices[
i]
.
ldev)
;

    unregister_ldd_driver(
&
sculld_driver)
;

int
 device_register(
struct
 
device *
dev)

{

    device_initialize(
dev)
;

    return
 device_add(
dev)
;

}

void
 device_unregister(
struct
 
device *
 dev)

int
 driver_register(
struct
 
device_driver *
 drv)

void
 driver_unregister(
struct
 
device_driver *
 drv)

[
Tekkaman2440@SBC2440V4]
#
insmod
 /
lib/
modules/
lddbus.
ko

Mount lddbus ok !

Bus device is ldd0 !

You can see me in sys/
module/
 ,
 sys/
devices/
 and
 sys/
bus/
 !

[
Tekkaman2440@SBC2440V4]
#
tree -
AC /
sys/
module/
lddbus/
 /
sys/
devices/
ldd0/
 /
sys/
bus/
ldd/

/
sys/
module/
lddbus/

├── holders

├── initstate

├── refcnt

└── 
sections

    ├── __ksymtab

    └── __ksymtab_strings

/
sys/
devices/
ldd0/

├── power

│ └── wakeup

└──
 uevent

/
sys/
bus/
ldd/

├── 
devices

├── drivers

├── drivers_autoprobe

├── drivers_probe

└──
 version

5 directories,
 9 files

[
Tekkaman2440@SBC2440V4]
#
cat /
sys/
bus/
ldd/
version

Revision:
 1.
9-
tekkamanninja

[
Tekkaman2440@SBC2440V4]
#
rmmod lddbus

The LDD bus device

 ldd_bus_release :
 lddbus 

[
Tekkaman2440@SBC2440V4]
#
ls
 /
sys/
module /
sys/
devices /
sys/
bus

/
sys/
bus:

i2c 
ide mmc platform serio spi usb

/
sys/
devices:

platform system

/
sys/
module:

8250 loop rd snd_seq usbnet

atkbd
 mac80211 redboot snd_seq_oss v4l1_compat

cdrom mousedev rfd_ftl 
snd_soc_core vt

dm9000 nfs rtc_ds1307 snd_timer yaffs

hid ohci_hcd
 s3c2410_wdt spidev zc0301

ide_cd printk snd sunrpc

keyboard 
psmouse snd_pcm tcp_cubic

lockd rcupdate snd_pcm_oss usbcore

[
Tekkaman2440@SBC2440V4]
#
insmod /
lib/
modules/
sculld.
ko

sculld:
 Unknown symbol 
register_ldd_device

sculld:
 Unknown symbol register_ldd_driver

sculld:
 Unknown symbol unregister_ldd_driver

sculld:
 Unknown symbol 
unregister_ldd_device

insmod:
 cannot insert '/lib/modules/sculld.ko'
:
 Unknown symbol in module (
-
1)
:
 No such file
 or
 directory

[
Tekkaman2440@SBC2440V4]
#
insmod /
lib/
modules/
lddbus.
ko

Mount
 lddbus ok !

Bus device 
is ldd0 !

You can see me 
in sys/
module/
 ,
 sys/
devices/
 and
 sys/
bus/
 !

[
Tekkaman2440@SBC2440V4]
#
insmod /
lib/
modules/
sculld.
ko

[
Tekkaman2440@SBC2440V4]
#
tree -
AC /
sys/
module/
lddbus/
 /
sys/
devices/
ldd0/
 /
sys/
bus/
ldd/
 /
sys/
module/
sculld/

/
sys/
module/
lddbus/

├── holders

│ └── sculld -
>
 .
.
/
.
.
/
.
.
/
module/
sculld

├── initstate

├── refcnt

└── sections

    ├──
 __ksymtab

    └── __ksymtab_strings

/
sys/
devices/
ldd0/

├── power

│ └── wakeup

├── sculld0

│ ├── 
bus -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ 
├── dev

│ ├── driver -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd/
drivers/
sculld

│ ├── power

│ │ └──
 wakeup

│ ├── subsystem -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ └── uevent

├── sculld1

│ ├── bus -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ 
├── dev

│ ├── driver -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd/
drivers/
sculld

│ ├── power

│ │ └──
 wakeup

│ ├── subsystem -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ └── uevent

├── sculld2

│ ├── bus -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ 
├── dev

│ ├── driver -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd/
drivers/
sculld

│ ├── power

│ │ └──
 wakeup

│ ├── subsystem -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ └── uevent

├── sculld3

│ ├── bus -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ 
├── dev

│ ├── driver -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd/
drivers/
sculld

│ ├── power

│ │ └──
 wakeup

│ ├── subsystem -
>
 .
.
/
.
.
/
.
.
/
bus/
ldd

│ └── uevent

└── uevent

/
sys/
bus/
ldd/

├── devices

│ ├── sculld0 -
>
 .
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld0

│ ├── sculld1 -
>
 .
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld1

│ ├── sculld2 -
>
 .
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld2

│ └── sculld3 -
>
 .
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld3

├── drivers

│ └── sculld

│ ├── bind

│ ├── sculld0 -
>
 .
.
/
.
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld0

│ ├── sculld1 -
>
 .
.
/
.
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld1

│ ├── sculld2 -
>
 .
.
/
.
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld2

│ ├── sculld3 -
>
 .
.
/
.
.
/
.
.
/
.
.
/
devices/
ldd0/
sculld3

│ ├── unbind

│ └──
 version

├── drivers_autoprobe

├── drivers_probe

└── version

/
sys/
module/
sculld/

├── holders

├── initstate

├── parameters

│ 
├── scull_major

│ ├── scull_minor

│ ├── scull_nr_devs

│ ├── 
scull_qset

│ └── scull_quantum

├── refcnt

└── sections

    ├──
 __ex_table

    └── __param

38 directories,
 33 files

[
Tekkaman2440@SBC2440V4]
#
cat /
sys/
bus/
ldd/
version /
sys/
devices/
ldd0/
sculld*
/
dev /
sys/
bus/
ldd/
drivers/
sculld/
version

Revision:
 1.
9-
tekkamanninja

252:
0

252:
1

252:
2

252:
3

$Revision:
 1.
21-
tekkamanninja
 $

[
Tekkaman2440@SBC2440V4]
#
rmmod sculld

[
Tekkaman2440@SBC2440V4]
#
tree -
ACd /
sys/
module/
lddbus/
 /
sys/
devices/
ldd0/
 /
sys/
bus/
ldd/
 /
sys/
module/

/
sys/
module/
lddbus/

├── holders

└── sections

/
sys/
devices/
ldd0/

└── power

/
sys/
bus/
ldd/

├── devices

└── drivers

/
sys/
module/

├──
 8250

│ └── parameters

├── atkbd

│ └── drivers

│ └── serio:
atkbd -
>
 .
.
/
.
.
/
.
.
/
bus/
serio/
drivers/
atkbd

├──
 cdrom

├── dm9000

│ └── parameters

├── hid

│ └── parameters

├──
 ide_cd

│ └── parameters

├── keyboard

│ └── parameters

├── 
lddbus

│ ├── holders

│ └── sections

├── lockd

│ └── 
parameters

├── loop

├── mac80211

│ └── parameters

├── 
mousedev

│ └── parameters

├── nfs

│ └── parameters

├── 
ohci_hcd

├── printk

│ └── parameters

├── psmouse

│ ├── 
drivers

│ │ └── serio:
psmouse
 -
>
 .
.
/
.
.
/
.
.
/
bus/
serio/
drivers/
psmouse

│ └── parameters

├── rcupdate

├──
 rd

├── redboot

├── rfd_ftl

├── rtc_ds1307

├── s3c2410_wdt

├──
 snd

│ └── parameters

├── snd_pcm

│ └── parameters

├── 
snd_pcm_oss

│ └── parameters

├── snd_seq

│ └── parameters

├──
 snd_seq_oss

│ └── parameters

├── snd_soc_core

├── snd_timer

│
 └── parameters

├── spidev

│ └── parameters

├── sunrpc

│ └──
 parameters

├── tcp_cubic

│ └── parameters

├── usbcore

│ ├──
 drivers

│ │ ├── usb:
hub -
>
 .
.
/
.
.
/
.
.
/
bus/
usb/
drivers/
hub

│ │ └── usb:
usbfs -
>
 .
.
/
.
.
/
.
.
/
bus/
usb/
drivers/
usbfs

│ └── parameters

├──
 usbnet

├── v4l1_compat

│ └── parameters

├── vt

│ └── 
parameters

├── yaffs

│ └── parameters

└── zc0301

    ├── 
drivers

    │ └── usb:
zc0301
 -
>
 .
.
/
.
.
/
.
.
/
bus/
usb/
drivers/
zc0301

    └── parameters

79 directories

[
Tekkaman2440@SBC2440V4]
#
insmod /
lib/
modules/
sculld.
ko

[
Tekkaman2440@SBC2440V4]
#
rmmod lddbus

rmmod:
 lddbus:
 Resource 
temporarily unavailable

[
Tekkaman2440@SBC2440V4]
#
rmmod sculld

[
Tekkaman2440@SBC2440V4]
#
rmmod lddbus

The LDD bus device

 ldd_bus_release :
 lddbus 

[
Tekkaman2440@SBC2440V4]
#

#
挂载/
sys
为sysfs文件系统

    echo "----------mount
 /sys as sysfs"

    /
bin/
mount -
t tmpfs mdev /
dev
 

    /
bin/
mount -
t sysfs sysfs /
sys

    echo
 "----------Starting mdev......"

    /
bin/
echo /
sbin
/
mdev >
 /
proc/
sys/
kernel/
hotplug

    mdev -
s

sculld[
0-
1]
 0:
0 666 *
 echo tekkaman >
 /
tmp/
mdev

#
include
 <
linux/
firmware.
h>

int
 request_firmware(
const
 struct
 
firmware *
*
fw,

const
 char
 *
name, /* name 为固件文件名*/

struct
 device *
device)
;

/*要求用户空间定位并提供一个固件映象给内核；若成功加载, 返回值是 0(否则返回错误码)*/

/*因为 request_firmware 需要用户空间的操作, 
所以返回前将保持休眠。若驱动必须使用固件而不能进入休眠时,可使用以下异步函数:*/

int
 request_firmware_nowait(

    struct
 module *
module,
 /* = THIS_MODULE*/

    int
 uevent,

    const
 char
 *
name,
 

    struct
 device *
device,
 

    void
 *
context,
/*不由固件子系统使用的私有数据指针*/

    void
 (
*
cont)
(
const
 struct
 firmware *
fw,
 void
 *
context)
)
;

/*如果一切正常，request_firmware_nowait 开始固件加载过程并返回 0. 
过了一段时间后（默认10秒）,将用加载的结果(若加载失败, fw 为 NULL)作为参数调用 cont。*/

/* fw 参数指向以下结构体:*/

struct
 firmware {

    size_t
 size;

    u8
 *
data;

}
;

/*那个结构包含实际的固件, 
它现在可被下载到设备中.但是请注意：在发送它到硬件之前，必须检查这个文件以确保它是正确的固件映象（设备固件常常包含标识字符串、 校验和等等）*/

/*当固件已经发送到设备后，应当释放 firmware 结构体, 使用:*/

void
 release_firmware(
struct
 firmware *
fw)
;