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Linux下GPRS撥號功能的實現
第一步：編寫GPRS的內核驅動程序
因為我用的開發板基於ARM920T，linux內核中沒有mc35i的驅動程序，所以自己寫了個驅動程序，重新編譯了內核。驅動程序代碼如下：/**//*
* 作者：龍濤
*/
#define __NO_VERSION__
#include <linux/module.h>
#include <linux/version.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/hardware.h>
#include <asm/uaccess.h>
#undef DEBUG_Mc35i
//#define DEBUG_Mc35i 1
#ifdef DEBUG_Mc35i
#define DBG_Mc35i(fmt, args...) printk(fmt,## args)
#else
#define DBG_Mc35i(fmt, args...)
#endif
static int Mc35i_open(struct inode *, struct file *);
static int Mc35i_close(struct inode *, struct file *);
static int Mc35i_read(struct file *, int *, size_t, loff_t *);
static int Mc35i_write(struct file *, const char *, size_t, loff_t *);
//static void Mc35i_interrupt(int, void *, struct pt_regs *);
static void Mc35i_hardware_init(void);
#define Mc35i_MAJOR 253
#define TRAN_CMD 1
#define TRAN_CMD_DATA 2
#define READ_CMD_DATA 3
/**//* User CMD */
#define CMD_IGT '0'
#define CMD_EMERGOFF '1'
/**//* PC14, PC15, PC5 for Mc35i */
#define MC35_IGT AT91C_PIO_PC14
#define MC35_EMERGOFF AT91C_PIO_PC15
#define MC35_ST AT91C_PIO_PC5
static struct file_operations Mc35i_fops = ...{
open: Mc35i_open,
read: Mc35i_read,
write: Mc35i_write,
release: Mc35i_close,
};
static int input_flag = 0;
static unsigned char input_data = 0xff;
static void Mc35i_hardware_init (void)
...{
DBG_Mc35i("Mc35i_hardware_init ");
AT91_SYS->PIOC_PER |= MC35_IGT | MC35_EMERGOFF|MC35_ST;
AT91_SYS->PIOC_OER |= MC35_IGT | MC35_EMERGOFF;
AT91_SYS->PIOC_ODR |= MC35_ST;
AT91_SYS->PIOC_CODR |= MC35_IGT| MC35_EMERGOFF; //ignition when system init
}
static int Mc35i_open (struct inode *inode, struct file *file)
...{
DBG_Mc35i("Mc35i_open ");
MOD_INC_USE_COUNT;
return 0;
}
static int Mc35i_close (struct inode *inode, struct file *file)
...{
DBG_Mc35i("Mc35i_close ");
MOD_DEC_USE_COUNT;
return 0;
}
static int Mc35i_read (struct file *file, int *buf, size_t count, loff_t *ppos)
...{
unsigned int data;
DBG_Mc35i("Mc35i_read: input_flag %d ", input_flag);
data = AT91_SYS->PIOC_PDSR & MC35_ST;
printk("status of PC5 is %d ", data);
put_user(data, buf);
return count;
}
static int Mc35i_write (struct file *file, const char *buf, size_t count, loff_t *ppos)
...{
unsigned char cmd_type;
DBG_Mc35i("Mc35i_write: %p ", buf);
get_user(cmd_type, buf);
switch (cmd_type) ...{
case CMD_IGT:
AT91_SYS->PIOC_SODR |= MC35_IGT; //enable /IGT
mdelay(10);
AT91_SYS->PIOC_CODR |= MC35_IGT; //disable /IGT
mdelay(100);
AT91_SYS->PIOC_SODR |= MC35_IGT; //enable /IGT
break;
case CMD_EMERGOFF:
AT91_SYS->PIOC_CODR |= MC35_EMERGOFF;
break;
default:
DBG_Mc35i("Mc35i_write: cmd_type = %d error ", cmd_type);
break;
}
return count;
}
static void __init Mc35i_init (void)
...{
//int ret;
Mc35i_hardware_init();
if(register_chrdev(Mc35i_MAJOR, "Mc35i", &Mc35i_fops))...{
DBG_Mc35i("register_chrdev for Mc35i error ");
goto fail_register_chrdev;
}
printk(KERN_INFO __FILE__ ": gprsMc35i for AT91RM9200 ");
return;
fail_register_chrdev:
return;
}
static void __exit Mc35i_cleanup (void)
...{
unregister_chrdev(Mc35i_MAJOR, "Mc35i");
return;
}
module_init(Mc35i_init);
module_exit(Mc35i_cleanup);
編譯內核後，要在文件係統中創建設備，命令如下：mknod Mc35i c 253 0
第二步：移植ppp協議
由於arm-linux上沒有提供使用ppp的pppd, chat應用程序，所以需要向開發板上移植。方法就和普通的應用程序一樣，在pc機上的develop目錄下麵編譯，然後將生成的可執行程序複製到Ramdisk文件係統中，在下次重新下載內核和文件係統時使用新的文件係統，就可以在arm-linux上運行pppd了。具體過程如下：1，在samba.org下載ppp-2.4.3.tar.gz後安如下操作：
tar zxvf ppp-2.4.3.tar.gz
2，由於在ppp根文件夾目錄下麵沒有makefile文件，所以要自己添加：
# PPP top-level Makefile for Linux.
DESTDIR = /usr/local
BINDIR = $(DESTDIR)/sbin
INCDIR = $(DESTDIR)/include
MANDIR = $(DESTDIR)/share/man
ETCDIR = /etc/ppp
# uid 0 = root
INSTALL= install
all:
cd chat; $(MAKE) $(MFLAGS) all
cd pppd/plugins; $(MAKE) $(MFLAGS) all
cd pppd; $(MAKE) $(MFLAGS) all
cd pppstats; $(MAKE) $(MFLAGS) all
cd pppdump; $(MAKE) $(MFLAGS) all
install: $(BINDIR) $(MANDIR)/man8 install-progs install-devel
install-progs:
cd chat; $(MAKE) $(MFLAGS) install
cd pppd/plugins; $(MAKE) $(MFLAGS) install
cd pppd; $(MAKE) $(MFLAGS) install
cd pppstats; $(MAKE) $(MFLAGS) install
cd pppdump; $(MAKE) $(MFLAGS) install
install-etcppp: $(ETCDIR) $(ETCDIR)/options $(ETCDIR)/pap-secrets
$(ETCDIR)/chap-secrets
install-devel:
cd pppd; $(MAKE) $(MFLAGS) install-devel
$(ETCDIR)/options:
$(INSTALL) -c -m 644 etc.ppp/options $@
$(ETCDIR)/pap-secrets:
$(INSTALL) -c -m 600 etc.ppp/pap-secrets $@
$(ETCDIR)/chap-secrets:
$(INSTALL) -c -m 600 etc.ppp/chap-secrets $@
$(BINDIR):
$(INSTALL) -d -m 755 $@
$(MANDIR)/man8:
$(INSTALL) -d -m 755 $@
$(ETCDIR):
$(INSTALL) -d -m 755 $@
clean:
rm -f `find . -name '*.[oas]' -print`
rm -f `find . -name 'core' -print`
rm -f `find . -name '*~' -print`
cd chat; $(MAKE) clean
cd pppd/plugins; $(MAKE) clean
cd pppd; $(MAKE) clean
cd pppstats; $(MAKE) clean
cd pppdump; $(MAKE) clean
dist-clean: clean
rm -f Makefile `find . -name Makefile -print`
#kernel:
# cd linux; ./kinstall.sh
# no tests yet, one day...
installcheck:
true
至於其他目錄下的makefile可以複製該目錄下的makefile.linux即可。交叉編譯後得到chat、pppd、pppstats、pppdump四個應用程序，拷貝到嵌入式係統的文件係統ramdisk/target/usr/sbin目錄下，權限改成755即可。
然後在ramdisk/target/dev目錄下建立ppp節點：
mknod ppp -c 108,0
運行PPPD看看， 若說segment fault, 則是內核沒有配置mmap, 或者把剛才的Makefile中的 HAVE_MMAP改為FALSE, 因為pppd中調用了mmap().
PPP撥號腳本有ppp-on:
#!/bin/sh
#
# Script to initiate a ppp connection. This is the first part of the
# pair of scripts. This is not a secure pair of scripts as the codes
# are visible with the 'ps' command. However, it is simple.
#
# These are the parameters. Change as needed.
TELEPHONE=*99***1# # The telephone number for the connection
ACCOUNT= # The account name for logon (as in 'George Burns')
PASSWORD= # The password for this account (and 'Gracie Allen')
LOCAL_IP=0.0.0.0 # Local IP address if known. Dynamic = 0.0.0.0
REMOTE_IP=0.0.0.0 # Remote IP address if desired. Normally 0.0.0.0
NETMASK=255.255.255.0 # The proper netmask if needed
#
# Export them so that they will be available at 'ppp-on-dialer' time.
export TELEPHONE ACCOUNT PASSWORD
#
# This is the location of the script which dials the phone and logs
# in. Please use the absolute file name as the $PATH variable is not
# used on the connect option. (To do so on a 'root' account would be
# a security hole so don't ask.)
#
DIALER_SCRIPT=/mnt/ppp-on-dialer #這裏改成自己文件所在的路徑
#
# Initiate the connection
#
# I put most of the common options on this command. Please, don't
# forget the 'lock' option or some programs such as mgetty will not
# work. The asyncmap and escape will permit the PPP link to work with
# a telnet or rlogin connection. You are welcome to make any changes
# as desired. Don't use the 'defaultroute' option if you currently
# have a default route to an ethernet gateway.
#
exec /usr/sbin/pppd debug lock modem /dev/ttyS1 19200
asyncmap 20A0000 escape FF kdebug 0 $LOCAL_IP:$REMOTE_IP
noipdefault netmask $NETMASK defaultroute connect $DIALER_SCRIPT
如果是Modem撥號，ppp-on為：
#!/bin/sh
#
# Script to initiate a ppp connection. This is the first part of the
# pair of scripts. This is not a secure pair of scripts as the codes
# are visible with the 'ps' command. However, it is simple.
#
# These are the parameters. Change as needed.
TELEPHONE=016300 # The telephone number for the connection
ACCOUNT=163 # The account name for logon (as in 'George Burns')
PASSWORD=163 # The password for this account (and 'Gracie Allen')
LOCAL_IP=0.0.0.0 # Local IP address if known. Dynamic = 0.0.0.0
REMOTE_IP=0.0.0.0 # Remote IP address if desired. Normally 0.0.0.0
NETMASK=255.255.255.0 # The proper netmask if needed
#
# Export them so that they will be available at 'ppp-on-dialer' time.
export TELEPHONE ACCOUNT PASSWORD
#
# This is the location of the script which dials the phone and logs
# in. Please use the absolute file name as the $PATH variable is not
# used on the connect option. (To do so on a 'root' account would be
# a security hole so don't ask.)
#
DIALER_SCRIPT=/mnt/ppp-on-dialer-modem
#
# Initiate the connection
#
# I put most of the common options on this command. Please, don't
# forget the 'lock' option or some programs such as mgetty will not
# work. The asyncmap and escape will permit the PPP link to work with
# a telnet or rlogin connection. You are welcome to make any changes
# as desired. Don't use the 'defaultroute' option if you currently
# have a default route to an ethernet gateway.
#
exec /usr/sbin/pppd debug lock modem crtscts /dev/ttyS1 115200
asyncmap 20A0000 escape FF kdebug 0 $LOCAL_IP:$REMOTE_IP
noipdefault netmask $NETMASK defaultroute connect $DIALER_SCRIPT
GPRS的ppp-on-dialer腳本如下：
#!/bin/sh
#
# This is part 2 of the ppp-on script. It will perform the connection
# protocol for the desired connection.
#
exec chat -v
TIMEOUT 3
ABORT ' BUSY '
ABORT ' NO ANSWER '
ABORT ' RINGING RINGING '
'' AT
TIMEOUT 30
OK AT+CMEE=1
OK AT+CGDCONT=1,"ip","cmnet"
OK AT+CGATT=1
OK ATDT*99***1#
CONNECT
Modem的ppp-on-dialer如下：
#!/bin/sh
#
# This is part 2 of the ppp-on script. It will perform the connection
# protocol for the desired connection.
#
exec chat -v
TIMEOUT 3
ABORT ' BUSY '
ABORT ' NO ANSWER '
ABORT ' RINGING RINGING '
'' AT
TIMEOUT 30
OK ATDT$TELEPHONE
sername:--sername: $ACCOUNT
assword: $PASSWORD
第三步：C程序的實現
//GPRS初始化
int InitGPRS(char *IP)
{
FILE *ppp0;
int status;
char buf[100];
int nIndex = 0;
char *ch=NULL,*nlch=NULL;
//判斷是否存在IP
status = system("ifconfig ppp0>/ppp0");
if(status == 127||status == -1||status != 0)
{
//打開設備
if(confData->WorkType == TYPE_GPRS)
{
if ((mc35i = open("/dev/Mc35i",O_RDWR|O_NOCTTY))<0)
{
printf("Warning:Open GPRS Mc35i failed! ");
return -1;
}
else
{
printf("OK:Open GPRS is ok! ");
}
while(1)
{
nIndex++;
if(nIndex > 30)
return -1;
if (!GPRSPowerIsOn())
{
printf("Warning:gprs power is not on! ");
write(mc35i,"0",1); //ignition mc35i
sleep(2);
}
else
break;
}
}
//執行ppp撥號程序
if (!vfork())
{
//GPRS方式
if(confData->WorkType == TYPE_GPRS)
{
printf("Exec GPRS ppp-on...... ");
if(execl("./ppp-on","ppp-on",NULL)<0)
//if (execvp("pppd",pppdScript)<0)
{
printf("Exec ppp-on error:%s! ",strerror(errno));
return -1;
}
}
//MODEM方式
else
{
printf("Exec MODEM ppp-on...... ");
if(execl("./ppp-on-modem","ppp-on",NULL)<0)
{
printf("Exec ppp-on error:%s! ",strerror(errno));
return -1;
}
}
}
sleep(40);
//獲取分配的IP地址
printf("Exec ifconfig ppp0 > ppp0...... ");
status = system("ifconfig ppp0>/ppp0");
if(status == 127||status == -1||status != 0)
{
printf("Exec ifconfig ppp0 error! ");
GPRSPoweroff();
return -1;
}
}
printf("Open file ppp0...... ");
if ((ppp0 = fopen("/ppp0","r")) <= 0)
{
printf("Open ppp0 info file fail! ");
GPRSPoweroff();
return -1;
}
/*格式：
# ifconfig ppp0
ppp0 Link encap:Point-to-Point Protocol
inet addr:211.74.48.254 P-t-P:211.74.48.1 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1492 Metric:1
RX packets:5 errors:0 dropped:0 overruns:0 frame:0
TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
*/
if (fread(buf,sizeof(char),sizeof(buf),ppp0)>0)
{
printf("Get ppp0 IP...... ");
ch = strchr(buf,' ');
ch = strchr(ch,':');
nlch = strchr(ch,'P');
memcpy(IP,++ch,(nlch-ch)-2);
}
最後更新：2017-04-03 14:54:03