74ba9207e1
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 441 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
150 lines
3.3 KiB
C
150 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* pps-ldisc.c -- PPS line discipline
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*
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* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/serial_core.h>
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#include <linux/tty.h>
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#include <linux/pps_kernel.h>
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#include <linux/bug.h>
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#define PPS_TTY_MAGIC 0x0001
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static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status)
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{
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struct pps_device *pps;
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struct pps_event_time ts;
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pps_get_ts(&ts);
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pps = pps_lookup_dev(tty);
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/*
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* This should never fail, but the ldisc locking is very
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* convoluted, so don't crash just in case.
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*/
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if (WARN_ON_ONCE(pps == NULL))
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return;
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/* Now do the PPS event report */
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pps_event(pps, &ts, status ? PPS_CAPTUREASSERT :
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PPS_CAPTURECLEAR, NULL);
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dev_dbg(pps->dev, "PPS %s at %lu\n",
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status ? "assert" : "clear", jiffies);
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}
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static int (*alias_n_tty_open)(struct tty_struct *tty);
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static int pps_tty_open(struct tty_struct *tty)
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{
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struct pps_source_info info;
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struct tty_driver *drv = tty->driver;
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int index = tty->index + drv->name_base;
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struct pps_device *pps;
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int ret;
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info.owner = THIS_MODULE;
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info.dev = NULL;
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snprintf(info.name, PPS_MAX_NAME_LEN, "%s%d", drv->driver_name, index);
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snprintf(info.path, PPS_MAX_NAME_LEN, "/dev/%s%d", drv->name, index);
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info.mode = PPS_CAPTUREBOTH | \
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PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
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PPS_CANWAIT | PPS_TSFMT_TSPEC;
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pps = pps_register_source(&info, PPS_CAPTUREBOTH | \
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PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
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if (IS_ERR(pps)) {
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pr_err("cannot register PPS source \"%s\"\n", info.path);
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return PTR_ERR(pps);
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}
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pps->lookup_cookie = tty;
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/* Now open the base class N_TTY ldisc */
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ret = alias_n_tty_open(tty);
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if (ret < 0) {
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pr_err("cannot open tty ldisc \"%s\"\n", info.path);
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goto err_unregister;
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}
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dev_info(pps->dev, "source \"%s\" added\n", info.path);
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return 0;
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err_unregister:
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pps_unregister_source(pps);
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return ret;
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}
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static void (*alias_n_tty_close)(struct tty_struct *tty);
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static void pps_tty_close(struct tty_struct *tty)
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{
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struct pps_device *pps = pps_lookup_dev(tty);
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alias_n_tty_close(tty);
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if (WARN_ON(!pps))
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return;
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dev_info(pps->dev, "removed\n");
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pps_unregister_source(pps);
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}
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static struct tty_ldisc_ops pps_ldisc_ops;
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/*
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* Module stuff
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*/
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static int __init pps_tty_init(void)
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{
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int err;
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/* Inherit the N_TTY's ops */
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n_tty_inherit_ops(&pps_ldisc_ops);
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/* Save N_TTY's open()/close() methods */
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alias_n_tty_open = pps_ldisc_ops.open;
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alias_n_tty_close = pps_ldisc_ops.close;
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/* Init PPS_TTY data */
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pps_ldisc_ops.owner = THIS_MODULE;
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pps_ldisc_ops.magic = PPS_TTY_MAGIC;
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pps_ldisc_ops.name = "pps_tty";
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pps_ldisc_ops.dcd_change = pps_tty_dcd_change;
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pps_ldisc_ops.open = pps_tty_open;
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pps_ldisc_ops.close = pps_tty_close;
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err = tty_register_ldisc(N_PPS, &pps_ldisc_ops);
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if (err)
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pr_err("can't register PPS line discipline\n");
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else
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pr_info("PPS line discipline registered\n");
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return err;
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}
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static void __exit pps_tty_cleanup(void)
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{
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int err;
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err = tty_unregister_ldisc(N_PPS);
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if (err)
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pr_err("can't unregister PPS line discipline\n");
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else
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pr_info("PPS line discipline removed\n");
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}
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module_init(pps_tty_init);
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module_exit(pps_tty_cleanup);
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MODULE_ALIAS_LDISC(N_PPS);
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MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
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MODULE_DESCRIPTION("PPS TTY device driver");
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MODULE_LICENSE("GPL");
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