linux txt

 

1.Ubuntu-10.04(LTS) :Vmware  vmare player
2.minicom : serial terminal target shell
3.tftp server: target board(bootloader)HW
 copy the kernel image(in host-pc) to RAM, and boot the kernel(down load to tftp server)
4.nfs server: target board (Linux)HW
  mount HOST file system by network(执行类似本地文件)

 (USB RDNIS)
 adb push driver file directory
5.cross compiler : ARM GCC ,kernel source compile, driver source compile(SW)
 [ way to test hello module:minicom  (in minicom)

#cd /mnt/nfs/el2440-driver/sample-src/hello module
 #insmod hello_module.ko
 #lsmod
 #rmmod hello_module

step in studying device driver

1. character driver : major number device file(oplication ?)
2. LDM (Linux Driver Model) : bus/device/driver  (it is the key and very important)
3. LDM : class (every device must be belong to a class) USB FB MDP

1.open VMware player -> file -> open a virtual file(add ubuntu)-> ex
alt + ctrl + enter
google use 10.04 for android(newly is 13.04)
2.virtual machine for setting(ctrl + D) : option + shared folders -> always enable
  => add => next => browse => select el2440-lab2 => rename "Shared"
  then select Places => Floppy Drive ,we can see Shared
 then run Terminal,enter minicom,then press "reset key" in the board
terminal-> enter "minicom" -> set com1 -> connect

root => cd / => etc

//
AUTO.txt
[Target-BD:minicom]
tftp 30c00000 zImage
tftp 30800000 ramdisk.gz
go linux

mount -t nfs 192.168.100.2:/tftpboot /mnt/nfs

mount -t jffs2 /dev/mtdblock3 /mnt/mtd3

[Host-PC:ubuntu]
ifconfig eth1 192.168.100.2 up
/etc/init.d/xinetd restart        second,then "ifconfig"
/etc/init.d/nfs-kernel-server restart

another command:
 1. first : ifconfig eth1 192.168.100.2 up
  2. second: /etc/init.d/xinetd restart       input "ifconfig"

quit command
minicom => tftp 30c00000 zImage
//

PM1:
target board PA map
[1] ROM : 0x0
[2] RAM : 0x30000000 ~ 0x33FFFFFF[64MB]
[3] SFR : 0x40000000 [AHB] map for momery
   0x50000000 [APB]

*linux 使用虚拟空间 linux va map : 32 bit [4GB]  linux space
linux kernel[1G](0xFFFFFFFF ~ 0XC0000000 start(this can be lower but can not be above as 0xBF000000 in ARM)) shared memory
linux user [3G](0xBFFFFFFF ~ 0X0)  not a shared memory
momery.h  TASK_SIZE
lsmod can find hello_module 1088 0 - Live 0xbf000000(start point addr)

in file linux-2.6.24-el2440-v2.0,we can see system.map (by search initcall)
init.h  main.c(do_initcall)int /init/

 

makefile in hello_module
# EL-2440 kernel 2.6 driver Makefile

obj-m  := hello_module.o

KDIR  := /usr/src/elayer/linux-2.6.24-el2440-v2.0
PWD    := $(shell pwd)

default:
 $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
  
clean : 
 rm -rf *.ko
 rm -rf *.mod.*
 rm -rf .*.cmd
 rm -rf *.o

PM2:
[way to test mydrv : minicom]
1.#cd /mnt/nfs/el2440-driver/sample-src/mydrv
  #mkbod /dev/mydrv c 240 0  (creat node )
  #insmod mydrv.ko
  #lsmod
  #cat /proc/devices

 

commad:
cat /proc/cpuinfo/
ls /proc/
cat /proc/devices

unsmod?

*File System   ~/include/linux/fs.h       struct file_operations{}函数指针fp
[1]struct inode (very important)
 has the infomation of a file in the disk
 dev_t i_rdev : [(high 12bit)12bit(major number) | 20bit (minor number)]
 mknod /dev/mydrv c 240 0   (it is device file,can not use like a real file,is a fake file)
 (if the num is not in the rang,the driver fun will not be called,as we set 243)
 insmod mydrv.ko ==> register file_operations(many function) to 240  in driver table,other driver can not use this number
unistd.h  (can not change the num,just can use the system call num)

<application> : can access to H/W with standard and abstraction way.
int fd = open("/dev/mydrv",O_RDWR); (open virtual function)             (int fd = open("hello.txt",O_RDWR);use in normal function)
int fd = open("/dev/video0",O_RDWR);//operation call , open camera device
         //but the name is not important,open("/dev/video0",O_RDWR) can use "/dev/aaa"  ?(first we should change mknod /dev/aaa c 240 0 )
//"swi 5"-->(sytem call,only way to change into kernel)-->kernel mode -->sys_open():get major number,(has two nums)
 create file objecter ,get 240 file_operations,save it to file object-->mydrv_open()  in mydry.c
 //MAJOR(inode->i_rdev);和file *file 的区别是？

 read(fd,buf_in,MAX_BUFFER);
//"swi 3"-->kernel_mode--sytem_read()-->mydrv_read()will be call
 write(fd,buf_out,)
//"swi 4"-->kernel_mode--sytem_write()-->mydrv_write()will be call(unsitd.h)
 close(fd)  locate below framework(dinamic),like JNI,NDK(C,C++)  HAL is a lib(***.so),in HAL use ioctl, deliver command to device driver
//"swi 6"-->kernel_mode--sytem_close()-->mydrv_release()-->sys_close:delete file object
 camera device(video0) can not write, just read

[2]struct file : dinamic
  created when calling open()
  removed when calling close()
         created in memory,can be created many times
one device must be belong to a class

command:
strace
strace xterm(root@elayer will go sleep)

 

<linux/time.h> compile  I can not use the function of localtime()