164 строки
4.0 KiB
C
164 строки
4.0 KiB
C
/*
|
|
* pps-ldisc.c -- PPS line discipline
|
|
*
|
|
*
|
|
* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/serial_core.h>
|
|
#include <linux/tty.h>
|
|
#include <linux/pps_kernel.h>
|
|
#include <linux/bug.h>
|
|
|
|
#define PPS_TTY_MAGIC 0x0001
|
|
|
|
static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status)
|
|
{
|
|
struct pps_device *pps;
|
|
struct pps_event_time ts;
|
|
|
|
pps_get_ts(&ts);
|
|
|
|
pps = pps_lookup_dev(tty);
|
|
/*
|
|
* This should never fail, but the ldisc locking is very
|
|
* convoluted, so don't crash just in case.
|
|
*/
|
|
if (WARN_ON_ONCE(pps == NULL))
|
|
return;
|
|
|
|
/* Now do the PPS event report */
|
|
pps_event(pps, &ts, status ? PPS_CAPTUREASSERT :
|
|
PPS_CAPTURECLEAR, NULL);
|
|
|
|
dev_dbg(pps->dev, "PPS %s at %lu\n",
|
|
status ? "assert" : "clear", jiffies);
|
|
}
|
|
|
|
static int (*alias_n_tty_open)(struct tty_struct *tty);
|
|
|
|
static int pps_tty_open(struct tty_struct *tty)
|
|
{
|
|
struct pps_source_info info;
|
|
struct tty_driver *drv = tty->driver;
|
|
int index = tty->index + drv->name_base;
|
|
struct pps_device *pps;
|
|
int ret;
|
|
|
|
info.owner = THIS_MODULE;
|
|
info.dev = NULL;
|
|
snprintf(info.name, PPS_MAX_NAME_LEN, "%s%d", drv->driver_name, index);
|
|
snprintf(info.path, PPS_MAX_NAME_LEN, "/dev/%s%d", drv->name, index);
|
|
info.mode = PPS_CAPTUREBOTH | \
|
|
PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
|
|
PPS_CANWAIT | PPS_TSFMT_TSPEC;
|
|
|
|
pps = pps_register_source(&info, PPS_CAPTUREBOTH | \
|
|
PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
|
|
if (pps == NULL) {
|
|
pr_err("cannot register PPS source \"%s\"\n", info.path);
|
|
return -ENOMEM;
|
|
}
|
|
pps->lookup_cookie = tty;
|
|
|
|
/* Now open the base class N_TTY ldisc */
|
|
ret = alias_n_tty_open(tty);
|
|
if (ret < 0) {
|
|
pr_err("cannot open tty ldisc \"%s\"\n", info.path);
|
|
goto err_unregister;
|
|
}
|
|
|
|
dev_info(pps->dev, "source \"%s\" added\n", info.path);
|
|
|
|
return 0;
|
|
|
|
err_unregister:
|
|
pps_unregister_source(pps);
|
|
return ret;
|
|
}
|
|
|
|
static void (*alias_n_tty_close)(struct tty_struct *tty);
|
|
|
|
static void pps_tty_close(struct tty_struct *tty)
|
|
{
|
|
struct pps_device *pps = pps_lookup_dev(tty);
|
|
|
|
alias_n_tty_close(tty);
|
|
|
|
if (WARN_ON(!pps))
|
|
return;
|
|
|
|
dev_info(pps->dev, "removed\n");
|
|
pps_unregister_source(pps);
|
|
}
|
|
|
|
static struct tty_ldisc_ops pps_ldisc_ops;
|
|
|
|
/*
|
|
* Module stuff
|
|
*/
|
|
|
|
static int __init pps_tty_init(void)
|
|
{
|
|
int err;
|
|
|
|
/* Inherit the N_TTY's ops */
|
|
n_tty_inherit_ops(&pps_ldisc_ops);
|
|
|
|
/* Save N_TTY's open()/close() methods */
|
|
alias_n_tty_open = pps_ldisc_ops.open;
|
|
alias_n_tty_close = pps_ldisc_ops.close;
|
|
|
|
/* Init PPS_TTY data */
|
|
pps_ldisc_ops.owner = THIS_MODULE;
|
|
pps_ldisc_ops.magic = PPS_TTY_MAGIC;
|
|
pps_ldisc_ops.name = "pps_tty";
|
|
pps_ldisc_ops.dcd_change = pps_tty_dcd_change;
|
|
pps_ldisc_ops.open = pps_tty_open;
|
|
pps_ldisc_ops.close = pps_tty_close;
|
|
|
|
err = tty_register_ldisc(N_PPS, &pps_ldisc_ops);
|
|
if (err)
|
|
pr_err("can't register PPS line discipline\n");
|
|
else
|
|
pr_info("PPS line discipline registered\n");
|
|
|
|
return err;
|
|
}
|
|
|
|
static void __exit pps_tty_cleanup(void)
|
|
{
|
|
int err;
|
|
|
|
err = tty_unregister_ldisc(N_PPS);
|
|
if (err)
|
|
pr_err("can't unregister PPS line discipline\n");
|
|
else
|
|
pr_info("PPS line discipline removed\n");
|
|
}
|
|
|
|
module_init(pps_tty_init);
|
|
module_exit(pps_tty_cleanup);
|
|
|
|
MODULE_ALIAS_LDISC(N_PPS);
|
|
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
|
|
MODULE_DESCRIPTION("PPS TTY device driver");
|
|
MODULE_LICENSE("GPL");
|