diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-16 15:11:04 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-16 15:11:04 -0700 |
commit | e6bee325e49f17c65c1fd66e9e8b348c85788341 (patch) | |
tree | bcc9e5d8e82efa9009edd481a837cc3626360091 /Documentation | |
parent | a5e6b135bdff649e4330f98e2e80dbb1984f7e77 (diff) | |
parent | 6ae705b23be8da52d3163be9d81e9b767876aaf9 (diff) |
Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (76 commits)
pch_uart: reference clock on CM-iTC
pch_phub: add new device ML7213
n_gsm: fix UIH control byte : P bit should be 0
n_gsm: add a documentation
serial: msm_serial_hs: Add MSM high speed UART driver
tty_audit: fix tty_audit_add_data live lock on audit disabled
tty: move cd1865.h to drivers/staging/tty/
Staging: tty: fix build with epca.c driver
pcmcia: synclink_cs: fix prototype for mgslpc_ioctl()
Staging: generic_serial: fix double locking bug
nozomi: don't use flush_scheduled_work()
tty/serial: Relax the device_type restriction from of_serial
MAINTAINERS: Update HVC file patterns
tty: phase out of ioctl file pointer for tty3270 as well
tty: forgot to remove ipwireless from drivers/char/pcmcia/Makefile
pch_uart: Fix DMA channel miss-setting issue.
pch_uart: fix exclusive access issue
pch_uart: fix auto flow control miss-setting issue
pch_uart: fix uart clock setting issue
pch_uart : Use dev_xxx not pr_xxx
...
Fix up trivial conflicts in drivers/misc/pch_phub.c (same patch applied
twice, then changes to the same area in one branch)
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/serial/n_gsm.txt | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/Documentation/serial/n_gsm.txt b/Documentation/serial/n_gsm.txt new file mode 100644 index 000000000000..397f41a1f153 --- /dev/null +++ b/Documentation/serial/n_gsm.txt @@ -0,0 +1,89 @@ +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 succesful (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 BĂ©nard - <eric@eukrea.com> |