^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * pps-ldisc.c -- PPS line discipline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/serial_core.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/tty.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/pps_kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/bug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #define PPS_TTY_MAGIC 0x0001
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) struct pps_device *pps;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) struct pps_event_time ts;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) pps_get_ts(&ts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) pps = pps_lookup_dev(tty);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * This should never fail, but the ldisc locking is very
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * convoluted, so don't crash just in case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) if (WARN_ON_ONCE(pps == NULL))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) /* Now do the PPS event report */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) pps_event(pps, &ts, status ? PPS_CAPTUREASSERT :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) PPS_CAPTURECLEAR, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) dev_dbg(pps->dev, "PPS %s at %lu\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) status ? "assert" : "clear", jiffies);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) static int (*alias_n_tty_open)(struct tty_struct *tty);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) static int pps_tty_open(struct tty_struct *tty)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) struct pps_source_info info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) struct tty_driver *drv = tty->driver;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) int index = tty->index + drv->name_base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) struct pps_device *pps;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) info.owner = THIS_MODULE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) info.dev = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) snprintf(info.name, PPS_MAX_NAME_LEN, "%s%d", drv->driver_name, index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) snprintf(info.path, PPS_MAX_NAME_LEN, "/dev/%s%d", drv->name, index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) info.mode = PPS_CAPTUREBOTH | \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) PPS_CANWAIT | PPS_TSFMT_TSPEC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) pps = pps_register_source(&info, PPS_CAPTUREBOTH | \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) if (IS_ERR(pps)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) pr_err("cannot register PPS source \"%s\"\n", info.path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) return PTR_ERR(pps);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) pps->lookup_cookie = tty;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) /* Now open the base class N_TTY ldisc */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) ret = alias_n_tty_open(tty);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) if (ret < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) pr_err("cannot open tty ldisc \"%s\"\n", info.path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) goto err_unregister;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) dev_info(pps->dev, "source \"%s\" added\n", info.path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) err_unregister:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) pps_unregister_source(pps);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) static void (*alias_n_tty_close)(struct tty_struct *tty);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) static void pps_tty_close(struct tty_struct *tty)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) struct pps_device *pps = pps_lookup_dev(tty);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) alias_n_tty_close(tty);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) if (WARN_ON(!pps))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) dev_info(pps->dev, "removed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) pps_unregister_source(pps);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) static struct tty_ldisc_ops pps_ldisc_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) * Module stuff
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) static int __init pps_tty_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) /* Inherit the N_TTY's ops */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) n_tty_inherit_ops(&pps_ldisc_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) /* Save N_TTY's open()/close() methods */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) alias_n_tty_open = pps_ldisc_ops.open;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) alias_n_tty_close = pps_ldisc_ops.close;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) /* Init PPS_TTY data */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) pps_ldisc_ops.owner = THIS_MODULE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) pps_ldisc_ops.magic = PPS_TTY_MAGIC;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) pps_ldisc_ops.name = "pps_tty";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) pps_ldisc_ops.dcd_change = pps_tty_dcd_change;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) pps_ldisc_ops.open = pps_tty_open;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) pps_ldisc_ops.close = pps_tty_close;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) err = tty_register_ldisc(N_PPS, &pps_ldisc_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) pr_err("can't register PPS line discipline\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) pr_info("PPS line discipline registered\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) static void __exit pps_tty_cleanup(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) err = tty_unregister_ldisc(N_PPS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) pr_err("can't unregister PPS line discipline\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) pr_info("PPS line discipline removed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) module_init(pps_tty_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) module_exit(pps_tty_cleanup);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) MODULE_ALIAS_LDISC(N_PPS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) MODULE_DESCRIPTION("PPS TTY device driver");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) MODULE_LICENSE("GPL");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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