mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-21 03:33:59 +08:00
25985edced
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
90 lines
3.1 KiB
Plaintext
90 lines
3.1 KiB
Plaintext
n_gsm.c GSM 0710 tty multiplexor HOWTO
|
|
===================================================
|
|
|
|
This line discipline implements the GSM 07.10 multiplexing protocol
|
|
detailed in the following 3GPP document :
|
|
http://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip
|
|
|
|
This document give some hints on how to use this driver with GPRS and 3G
|
|
modems connected to a physical serial port.
|
|
|
|
How to use it
|
|
-------------
|
|
1- initialize the modem in 0710 mux mode (usually AT+CMUX= command) through
|
|
its serial port. Depending on the modem used, you can pass more or less
|
|
parameters to this command,
|
|
2- switch the serial line to using the n_gsm line discipline by using
|
|
TIOCSETD ioctl,
|
|
3- configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl,
|
|
|
|
Major parts of the initialization program :
|
|
(a good starting point is util-linux-ng/sys-utils/ldattach.c)
|
|
#include <linux/gsmmux.h>
|
|
#define N_GSM0710 21 /* GSM 0710 Mux */
|
|
#define DEFAULT_SPEED B115200
|
|
#define SERIAL_PORT /dev/ttyS0
|
|
|
|
int ldisc = N_GSM0710;
|
|
struct gsm_config c;
|
|
struct termios configuration;
|
|
|
|
/* open the serial port connected to the modem */
|
|
fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY);
|
|
|
|
/* configure the serial port : speed, flow control ... */
|
|
|
|
/* send the AT commands to switch the modem to CMUX mode
|
|
and check that it's successful (should return OK) */
|
|
write(fd, "AT+CMUX=0\r", 10);
|
|
|
|
/* experience showed that some modems need some time before
|
|
being able to answer to the first MUX packet so a delay
|
|
may be needed here in some case */
|
|
sleep(3);
|
|
|
|
/* use n_gsm line discipline */
|
|
ioctl(fd, TIOCSETD, &ldisc);
|
|
|
|
/* get n_gsm configuration */
|
|
ioctl(fd, GSMIOC_GETCONF, &c);
|
|
/* we are initiator and need encoding 0 (basic) */
|
|
c.initiator = 1;
|
|
c.encapsulation = 0;
|
|
/* our modem defaults to a maximum size of 127 bytes */
|
|
c.mru = 127;
|
|
c.mtu = 127;
|
|
/* set the new configuration */
|
|
ioctl(fd, GSMIOC_SETCONF, &c);
|
|
|
|
/* and wait for ever to keep the line discipline enabled */
|
|
daemon(0,0);
|
|
pause();
|
|
|
|
4- create the devices corresponding to the "virtual" serial ports (take care,
|
|
each modem has its configuration and some DLC have dedicated functions,
|
|
for example GPS), starting with minor 1 (DLC0 is reserved for the management
|
|
of the mux)
|
|
|
|
MAJOR=`cat /proc/devices |grep gsmtty | awk '{print $1}`
|
|
for i in `seq 1 4`; do
|
|
mknod /dev/ttygsm$i c $MAJOR $i
|
|
done
|
|
|
|
5- use these devices as plain serial ports.
|
|
for example, it's possible :
|
|
- and to use gnokii to send / receive SMS on ttygsm1
|
|
- to use ppp to establish a datalink on ttygsm2
|
|
|
|
6- first close all virtual ports before closing the physical port.
|
|
|
|
Additional Documentation
|
|
------------------------
|
|
More practical details on the protocol and how it's supported by industrial
|
|
modems can be found in the following documents :
|
|
http://www.telit.com/module/infopool/download.php?id=616
|
|
http://www.u-blox.com/images/downloads/Product_Docs/LEON-G100-G200-MuxImplementation_ApplicationNote_%28GSM%20G1-CS-10002%29.pdf
|
|
http://www.sierrawireless.com/Support/Downloads/AirPrime/WMP_Series/~/media/Support_Downloads/AirPrime/Application_notes/CMUX_Feature_Application_Note-Rev004.ashx
|
|
http://wm.sim.com/sim/News/photo/2010721161442.pdf
|
|
|
|
11-03-08 - Eric Bénard - <eric@eukrea.com>
|