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Documentation: tty: n_gsm, use power of ReST

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Reformat the whole document, so that automatic numbering and TOC is
properly generated.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220411110143.10019-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2022-04-11 13:01:43 +02:00 committed by Greg Kroah-Hartman
parent e937eb43b8
commit 7fb4028fbb
1 changed files with 74 additions and 70 deletions
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144
Documentation/driver-api/tty/n_gsm.rst
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@ -2,6 +2,8 @@
GSM 0710 tty multiplexor HOWTO GSM 0710 tty multiplexor HOWTO
============================== ==============================
.. contents:: :local:
This line discipline implements the GSM 07.10 multiplexing protocol This line discipline implements the GSM 07.10 multiplexing protocol
detailed in the following 3GPP document: detailed in the following 3GPP document:
@ -11,79 +13,81 @@ This document give some hints on how to use this driver with GPRS and 3G
modems connected to a physical serial port. modems connected to a physical serial port.
How to use it How to use it
------------- =============
1. config initiator
^^^^^^^^^^^^^^^^^^^^^
1.1 initialize the modem in 0710 mux mode (usually AT+CMUX= command) through Config Initiator
its serial port. Depending on the modem used, you can pass more or less ----------------
parameters to this command.
1.2 switch the serial line to using the n_gsm line discipline by using #. Initialize the modem in 0710 mux mode (usually ``AT+CMUX=`` command) through
TIOCSETD ioctl. its serial port. Depending on the modem used, you can pass more or less
parameters to this command.
1.3 configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl. #. Switch the serial line to using the n_gsm line discipline by using
``TIOCSETD`` ioctl.
1.4 obtain base gsmtty number for the used serial port. #. Configure the mux using ``GSMIOC_GETCONF``/``GSMIOC_SETCONF`` ioctl.
Major parts of the initialization program : #. Obtain base gsmtty number for the used serial port.
(a good starting point is util-linux-ng/sys-utils/ldattach.c)::
#include <stdio.h> Major parts of the initialization program
#include <stdint.h> (a good starting point is util-linux-ng/sys-utils/ldattach.c)::
#include <linux/gsmmux.h>
#include <linux/tty.h>
#define DEFAULT_SPEED B115200
#define SERIAL_PORT /dev/ttyS0
int ldisc = N_GSM0710; #include <stdio.h>
struct gsm_config c; #include <stdint.h>
struct termios configuration; #include <linux/gsmmux.h>
uint32_t first; #include <linux/tty.h>
/* open the serial port connected to the modem */ #define DEFAULT_SPEED B115200
fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY); #define SERIAL_PORT /dev/ttyS0
/* configure the serial port : speed, flow control ... */ int ldisc = N_GSM0710;
struct gsm_config c;
struct termios configuration;
uint32_t first;
/* send the AT commands to switch the modem to CMUX mode /* open the serial port connected to the modem */
and check that it's successful (should return OK) */ fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY);
write(fd, "AT+CMUX=0\r", 10);
/* experience showed that some modems need some time before /* configure the serial port : speed, flow control ... */
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 */ /* send the AT commands to switch the modem to CMUX mode
ioctl(fd, TIOCSETD, &ldisc); and check that it's successful (should return OK) */
write(fd, "AT+CMUX=0\r", 10);
/* get n_gsm configuration */ /* experience showed that some modems need some time before
ioctl(fd, GSMIOC_GETCONF, &c); being able to answer to the first MUX packet so a delay
/* we are initiator and need encoding 0 (basic) */ may be needed here in some case */
c.initiator = 1; sleep(3);
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);
/* get first gsmtty device node */
ioctl(fd, GSMIOC_GETFIRST, &first);
printf("first muxed line: /dev/gsmtty%i\n", first);
/* and wait for ever to keep the line discipline enabled */ /* use n_gsm line discipline */
daemon(0,0); ioctl(fd, TIOCSETD, &ldisc);
pause();
1.5 use these devices as plain serial ports. /* 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);
/* get first gsmtty device node */
ioctl(fd, GSMIOC_GETFIRST, &first);
printf("first muxed line: /dev/gsmtty%i\n", first);
for example, it's possible: /* and wait for ever to keep the line discipline enabled */
daemon(0,0);
pause();
- and to use gnokii to send / receive SMS on ttygsm1 #. Use these devices as plain serial ports.
- to use ppp to establish a datalink on ttygsm2
1.6 first close all virtual ports before closing the physical port. For example, it's possible:
- to use *gnokii* to send / receive SMS on ``ttygsm1``
- to use *ppp* to establish a datalink on ``ttygsm2``
#. First close all virtual ports before closing the physical port.
Note that after closing the physical port the modem is still in multiplexing Note that after closing the physical port the modem is still in multiplexing
mode. This may prevent a successful re-opening of the port later. To avoid mode. This may prevent a successful re-opening of the port later. To avoid
@ -91,27 +95,27 @@ Major parts of the initialization program :
a disconnect command frame manually before initializing the multiplexing mode a disconnect command frame manually before initializing the multiplexing mode
for the second time. The byte sequence for the disconnect command frame is:: for the second time. The byte sequence for the disconnect command frame is::
0xf9, 0x03, 0xef, 0x03, 0xc3, 0x16, 0xf9. 0xf9, 0x03, 0xef, 0x03, 0xc3, 0x16, 0xf9
2. config requester Config Requester
^^^^^^^^^^^^^^^^^^^^^ ----------------
2.1 receive string "AT+CMUX= command" through its serial port,initialize #. Receive ``AT+CMUX=`` command through its serial port, initialize mux mode
mux mode config config.
2.2 switch the serial line to using the n_gsm line discipline by using #. Switch the serial line to using the *n_gsm* line discipline by using
TIOCSETD ioctl. ``TIOCSETD`` ioctl.
2.3 configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl. #. Configure the mux using ``GSMIOC_GETCONF``/``GSMIOC_SETCONF`` ioctl.
2.4 obtain base gsmtty number for the used serial port:: #. Obtain base gsmtty number for the used serial port::
#include <stdio.h> #include <stdio.h>
#include <stdint.h> #include <stdint.h>
#include <linux/gsmmux.h> #include <linux/gsmmux.h>
#include <linux/tty.h> #include <linux/tty.h>
#define DEFAULT_SPEED B115200 #define DEFAULT_SPEED B115200
#define SERIAL_PORT /dev/ttyS0 #define SERIAL_PORT /dev/ttyS0
int ldisc = N_GSM0710; int ldisc = N_GSM0710;
struct gsm_config c; struct gsm_config c;