X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=drivers%2Fpps%2Fkapi.c;fp=drivers%2Fpps%2Fkapi.c;h=35a0b192d768939b4f1ecfb5f9687cc2f72e3be0;hp=0000000000000000000000000000000000000000;hb=eae9d2ba0cfc27a2ad9765f23efb98fb80d80234;hpb=8820f27ad9a5ad2a62cdcdf425d7921c31831800;ds=sidebyside diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c new file mode 100644 index 000000000000..35a0b192d768 --- /dev/null +++ b/drivers/pps/kapi.c @@ -0,0 +1,329 @@ +/* + * kernel API + * + * + * Copyright (C) 2005-2009 Rodolfo Giometti + * + * 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. + */ + + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Global variables + */ + +DEFINE_SPINLOCK(pps_idr_lock); +DEFINE_IDR(pps_idr); + +/* + * 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; +} + +/* + * Exported functions + */ + +/* pps_get_source - find a PPS source + * @source: the PPS source ID. + * + * This function is used to find an already registered PPS source into the + * system. + * + * The function returns NULL if found nothing, otherwise it returns a pointer + * to the PPS source data struct (the refcounter is incremented by 1). + */ + +struct pps_device *pps_get_source(int source) +{ + struct pps_device *pps; + unsigned long flags; + + spin_lock_irqsave(&pps_idr_lock, flags); + + pps = idr_find(&pps_idr, source); + if (pps != NULL) + atomic_inc(&pps->usage); + + spin_unlock_irqrestore(&pps_idr_lock, flags); + + return pps; +} + +/* pps_put_source - free the PPS source data + * @pps: a pointer to the PPS source. + * + * This function is used to free a PPS data struct if its refcount is 0. + */ + +void pps_put_source(struct pps_device *pps) +{ + unsigned long flags; + + spin_lock_irqsave(&pps_idr_lock, flags); + BUG_ON(atomic_read(&pps->usage) == 0); + + if (!atomic_dec_and_test(&pps->usage)) { + pps = NULL; + goto exit; + } + + /* No more reference to the PPS source. We can safely remove the + * PPS data struct. + */ + idr_remove(&pps_idr, pps->id); + +exit: + spin_unlock_irqrestore(&pps_idr_lock, flags); + kfree(pps); +} + +/* 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 source ID. + */ + +int pps_register_source(struct pps_source_info *info, int default_params) +{ + struct pps_device *pps; + int id; + int err; + + /* Sanity checks */ + if ((info->mode & default_params) != default_params) { + printk(KERN_ERR "pps: %s: unsupported default parameters\n", + info->name); + err = -EINVAL; + goto pps_register_source_exit; + } + if ((info->mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) != 0 && + info->echo == NULL) { + printk(KERN_ERR "pps: %s: echo function is not defined\n", + info->name); + err = -EINVAL; + goto pps_register_source_exit; + } + if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { + printk(KERN_ERR "pps: %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_get_new() + * in order to avoid reces into pps_event(). + */ + pps->params.api_version = PPS_API_VERS; + pps->params.mode = default_params; + pps->info = *info; + + init_waitqueue_head(&pps->queue); + spin_lock_init(&pps->lock); + atomic_set(&pps->usage, 1); + + /* Get new ID for the new PPS source */ + if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) { + err = -ENOMEM; + goto kfree_pps; + } + + spin_lock_irq(&pps_idr_lock); + + /* Now really allocate the PPS source. + * After idr_get_new() calling the new source will be freely available + * into the kernel. + */ + err = idr_get_new(&pps_idr, pps, &id); + if (err < 0) { + spin_unlock_irq(&pps_idr_lock); + goto kfree_pps; + } + + id = id & MAX_ID_MASK; + if (id >= PPS_MAX_SOURCES) { + spin_unlock_irq(&pps_idr_lock); + + printk(KERN_ERR "pps: %s: too many PPS sources in the system\n", + info->name); + err = -EBUSY; + goto free_idr; + } + pps->id = id; + + spin_unlock_irq(&pps_idr_lock); + + /* Create the char device */ + err = pps_register_cdev(pps); + if (err < 0) { + printk(KERN_ERR "pps: %s: unable to create char device\n", + info->name); + goto free_idr; + } + + pr_info("new PPS source %s at ID %d\n", info->name, id); + + return id; + +free_idr: + spin_lock_irq(&pps_idr_lock); + idr_remove(&pps_idr, id); + spin_unlock_irq(&pps_idr_lock); + +kfree_pps: + kfree(pps); + +pps_register_source_exit: + printk(KERN_ERR "pps: %s: unable to register source\n", info->name); + + return err; +} +EXPORT_SYMBOL(pps_register_source); + +/* pps_unregister_source - remove a PPS source from the system + * @source: the PPS source ID + * + * This function is used to remove a previously registered PPS source from + * the system. + */ + +void pps_unregister_source(int source) +{ + struct pps_device *pps; + + spin_lock_irq(&pps_idr_lock); + pps = idr_find(&pps_idr, source); + + if (!pps) { + BUG(); + spin_unlock_irq(&pps_idr_lock); + return; + } + spin_unlock_irq(&pps_idr_lock); + + pps_unregister_cdev(pps); + pps_put_source(pps); +} +EXPORT_SYMBOL(pps_unregister_source); + +/* pps_event - register a PPS event into the system + * @source: the PPS source ID + * @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 source it will be called + * as: + * pps->info.echo(source, event, data); + */ + +void pps_event(int source, struct pps_ktime *ts, int event, void *data) +{ + struct pps_device *pps; + unsigned long flags; + + if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) { + printk(KERN_ERR "pps: unknown event (%x) for source %d\n", + event, source); + return; + } + + pps = pps_get_source(source); + if (!pps) + return; + + pr_debug("PPS event on source %d at %llu.%06u\n", + pps->id, (unsigned long long) ts->sec, ts->nsec); + + spin_lock_irqsave(&pps->lock, flags); + + /* Must call the echo function? */ + if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) + pps->info.echo(source, event, data); + + /* Check the event */ + pps->current_mode = pps->params.mode; + if (event & PPS_CAPTUREASSERT) { + /* We have to add an offset? */ + if (pps->params.mode & PPS_OFFSETASSERT) + pps_add_offset(ts, &pps->params.assert_off_tu); + + /* Save the time stamp */ + pps->assert_tu = *ts; + pps->assert_sequence++; + pr_debug("capture assert seq #%u for source %d\n", + pps->assert_sequence, source); + } + if (event & PPS_CAPTURECLEAR) { + /* We have to add an offset? */ + if (pps->params.mode & PPS_OFFSETCLEAR) + pps_add_offset(ts, &pps->params.clear_off_tu); + + /* Save the time stamp */ + pps->clear_tu = *ts; + pps->clear_sequence++; + pr_debug("capture clear seq #%u for source %d\n", + pps->clear_sequence, source); + } + + pps->go = ~0; + wake_up_interruptible(&pps->queue); + + kill_fasync(&pps->async_queue, SIGIO, POLL_IN); + + spin_unlock_irqrestore(&pps->lock, flags); + + /* Now we can release the PPS source for (possible) deregistration */ + pps_put_source(pps); +} +EXPORT_SYMBOL(pps_event);