/* * kernel API * * * Copyright (C) 2005-2009 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/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/time.h> #include <linux/timex.h> #include <linux/spinlock.h> #include <linux/fs.h> #include <linux/pps_kernel.h> #include <linux/slab.h> #include "kc.h" /* * Local functions */ static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) { ts->nsec += offset->nsec; while (ts->nsec >= NSEC_PER_SEC) { ts->nsec -= NSEC_PER_SEC; ts->sec++; } while (ts->nsec < 0) { ts->nsec += NSEC_PER_SEC; ts->sec--; } ts->sec += offset->sec; } static void pps_echo_client_default(struct pps_device *pps, int event, void *data) { dev_info(pps->dev, "echo %s %s\n", event & PPS_CAPTUREASSERT ? "assert" : "", event & PPS_CAPTURECLEAR ? "clear" : ""); } /* * Exported functions */ /* pps_register_source - add a PPS source in the system * @info: the PPS info struct * @default_params: the default PPS parameters of the new source * * This function is used to add a new PPS source in the system. The new * source is described by info's fields and it will have, as default PPS * parameters, the ones specified into default_params. * * The function returns, in case of success, the PPS device. Otherwise NULL. */ struct pps_device *pps_register_source(struct pps_source_info *info, int default_params) { struct pps_device *pps; int err; /* Sanity checks */ if ((info->mode & default_params) != default_params) { pr_err("%s: unsupported default parameters\n", info->name); err = -EINVAL; goto pps_register_source_exit; } if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { pr_err("%s: unspecified time format\n", info->name); err = -EINVAL; goto pps_register_source_exit; } /* Allocate memory for the new PPS source struct */ pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); if (pps == NULL) { err = -ENOMEM; goto pps_register_source_exit; } /* These initializations must be done before calling idr_alloc() * in order to avoid reces into pps_event(). */ pps->params.api_version = PPS_API_VERS; pps->params.mode = default_params; pps->info = *info; /* check for default echo function */ if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) && pps->info.echo == NULL) pps->info.echo = pps_echo_client_default; init_waitqueue_head(&pps->queue); spin_lock_init(&pps->lock); /* Create the char device */ err = pps_register_cdev(pps); if (err < 0) { pr_err("%s: unable to create char device\n", info->name); goto kfree_pps; } dev_info(pps->dev, "new PPS source %s\n", info->name); return pps; kfree_pps: kfree(pps); pps_register_source_exit: pr_err("%s: unable to register source\n", info->name); return NULL; } EXPORT_SYMBOL(pps_register_source); /* pps_unregister_source - remove a PPS source from the system * @pps: the PPS source * * This function is used to remove a previously registered PPS source from * the system. */ void pps_unregister_source(struct pps_device *pps) { pps_kc_remove(pps); pps_unregister_cdev(pps); /* don't have to kfree(pps) here because it will be done on * device destruction */ } EXPORT_SYMBOL(pps_unregister_source); /* pps_event - register a PPS event into the system * @pps: the PPS device * @ts: the event timestamp * @event: the event type * @data: userdef pointer * * This function is used by each PPS client in order to register a new * PPS event into the system (it's usually called inside an IRQ handler). * * If an echo function is associated with the PPS device it will be called * as: * pps->info.echo(pps, event, data); */ void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, void *data) { unsigned long flags; int captured = 0; struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; /* check event type */ BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); dev_dbg(pps->dev, "PPS event at %ld.%09ld\n", ts->ts_real.tv_sec, ts->ts_real.tv_nsec); timespec_to_pps_ktime(&ts_real, ts->ts_real); spin_lock_irqsave(&pps->lock, flags); /* Must call the echo function? */ if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) pps->info.echo(pps, event, data); /* Check the event */ pps->current_mode = pps->params.mode; if (event & pps->params.mode & PPS_CAPTUREASSERT) { /* We have to add an offset? */ if (pps->params.mode & PPS_OFFSETASSERT) pps_add_offset(&ts_real, &pps->params.assert_off_tu); /* Save the time stamp */ pps->assert_tu = ts_real; pps->assert_sequence++; dev_dbg(pps->dev, "capture assert seq #%u\n", pps->assert_sequence); captured = ~0; } if (event & pps->params.mode & PPS_CAPTURECLEAR) { /* We have to add an offset? */ if (pps->params.mode & PPS_OFFSETCLEAR) pps_add_offset(&ts_real, &pps->params.clear_off_tu); /* Save the time stamp */ pps->clear_tu = ts_real; pps->clear_sequence++; dev_dbg(pps->dev, "capture clear seq #%u\n", pps->clear_sequence); captured = ~0; } pps_kc_event(pps, ts, event); /* Wake up if captured something */ if (captured) { pps->last_ev++; wake_up_interruptible_all(&pps->queue); kill_fasync(&pps->async_queue, SIGIO, POLL_IN); } spin_unlock_irqrestore(&pps->lock, flags); } EXPORT_SYMBOL(pps_event);