/*
* PTP 1588 clock support
*
* Copyright (C) 2010 OMICRON electronics GmbH
*
* 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 <linux/bitops.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/posix-clock.h>
#include <linux/pps_kernel.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include "ptp_private.h"
#define PTP_MAX_ALARMS 4
#define PTP_MAX_CLOCKS 8
#define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
#define PTP_PPS_EVENT PPS_CAPTUREASSERT
#define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
/* private globals */
static dev_t ptp_devt;
static struct class *ptp_class;
static DECLARE_BITMAP(ptp_clocks_map, PTP_MAX_CLOCKS);
static DEFINE_MUTEX(ptp_clocks_mutex); /* protects 'ptp_clocks_map' */
/* time stamp event queue operations */
static inline int queue_free(struct timestamp_event_queue *q)
{
return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
}
static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
struct ptp_clock_event *src)
{
struct ptp_extts_event *dst;
unsigned long flags;
s64 seconds;
u32 remainder;
seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
spin_lock_irqsave(&queue->lock, flags);
dst = &queue->buf[queue->tail];
dst->index = src->index;
dst->t.sec = seconds;
dst->t.nsec = remainder;
if (!queue_free(queue))
queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
spin_unlock_irqrestore(&queue->lock, flags);
}
static s32 scaled_ppm_to_ppb(long ppm)
{
/*
* The 'freq' field in the 'struct timex' is in parts per
* million, but with a 16 bit binary fractional field.
*
* We want to calculate
*
* ppb = scaled_ppm * 1000 / 2^16
*
* which simplifies to
*
* ppb = scaled_ppm * 125 / 2^13
*/
s64 ppb = 1 + ppm;
ppb *= 125;
ppb >>= 13;
return (s32) ppb;
}
/* posix clock implementation */
static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp)
{
return 1; /* always round timer functions to one nanosecond */
}
static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
return ptp->info->settime(ptp->info, tp);
}
static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
return ptp->info->gettime(ptp->info, tp);
}
static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct ptp_clock_info *ops;
int err = -EOPNOTSUPP;
ops = ptp->info;
if (tx->modes & ADJ_SETOFFSET) {
struct timespec ts;
ktime_t kt;
s64 delta;
ts.tv_sec = tx->time.tv_sec;
ts.tv_nsec = tx->time.tv_usec;
if (!(tx->modes & ADJ_NANO))
ts.tv_nsec *= 1000;
if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
kt = timespec_to_ktime(ts);
delta = ktime_to_ns(kt);
err = ops->adjtime(ops, delta);
} else if (tx->modes & ADJ_FREQUENCY) {
err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq));
}
return err;
}
static struct posix_clock_operations ptp_clock_ops = {
.owner = THIS_MODULE,
.clock_adjtime = ptp_clock_adjtime,
.clock_gettime = ptp_clock_gettime,
.clock_getres = ptp_clock_getres,
.clock_settime = ptp_clock_settime,
.ioctl = ptp_ioctl,
.open = ptp_open,
.poll = ptp_poll,
.read = ptp_read,
};
static void delete_ptp_clock(struct posix_clock *pc)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
mutex_destroy(&ptp->tsevq_mux);
/* Remove the clock from the bit map. */
mutex_lock(&ptp_clocks_mutex);
clear_bit(ptp->index, ptp_clocks_map);
mutex_unlock(&ptp_clocks_mutex);
kfree(ptp);
}
/* public interface */
struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info)
{
struct ptp_clock *ptp;
int err = 0, index, major = MAJOR(ptp_devt);
if (info->n_alarm > PTP_MAX_ALARMS)
return ERR_PTR(-EINVAL);
/* Find a free clock slot and reserve it. */
err = -EBUSY;
mutex_lock(&ptp_clocks_mutex);
index = find_first_zero_bit(ptp_clocks_map, PTP_MAX_CLOCKS);
if (index < PTP_MAX_CLOCKS)
set_bit(index, ptp_clocks_map);
else
goto no_slot;
/* Initialize a clock structure. */
err = -ENOMEM;
ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
if (ptp == NULL)
goto no_memory;
ptp->clock.ops = ptp_clock_ops;
ptp->clock.release = delete_ptp_clock;
ptp->info = info;
ptp->devid = MKDEV(major, index);
ptp->index = index;
spin_lock_init(&ptp->tsevq.lock);
mutex_init(&ptp->tsevq_mux);
init_waitqueue_head(&ptp->tsev_wq);
/* Create a new device in our class. */
ptp->dev = device_create(ptp_class, NULL, ptp->devid, ptp,
"ptp%d", ptp->index);
if (IS_ERR(ptp->dev))
goto no_device;
dev_set_drvdata(ptp->dev, ptp);
err = ptp_populate_sysfs(ptp);
if (err)
goto no_sysfs;
/* Register a new PPS source. */
if (info->pps) {
struct pps_source_info pps;
memset(&pps, 0, sizeof(pps));
snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
pps.mode = PTP_PPS_MODE;
pps.owner = info->owner;
ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
if (!ptp->pps_source) {
pr_err("failed to register pps source\n");
goto no_pps;
}
}
/* Create a posix clock. */
err = posix_clock_register(&ptp->clock, ptp->devid);
if (err) {
pr_err("failed to create posix clock\n");
goto no_clock;
}
mutex_unlock(&ptp_clocks_mutex);
return ptp;
no_clock:
if (ptp->pps_source)
pps_unregister_source(ptp->pps_source);
no_pps:
ptp_cleanup_sysfs(ptp);
no_sysfs:
device_destroy(ptp_class, ptp->devid);
no_device:
mutex_destroy(&ptp->tsevq_mux);
kfree(ptp);
no_memory:
clear_bit(index, ptp_clocks_map);
no_slot:
mutex_unlock(&ptp_clocks_mutex);
return ERR_PTR(err);
}
EXPORT_SYMBOL(ptp_clock_register);
int ptp_clock_unregister(struct ptp_clock *ptp)
{
ptp->defunct = 1;
wake_up_interruptible(&ptp->tsev_wq);
/* Release the clock's resources. */
if (ptp->pps_source)
pps_unregister_source(ptp->pps_source);
ptp_cleanup_sysfs(ptp);
device_destroy(ptp_class, ptp->devid);
posix_clock_unregister(&ptp->clock);
return 0;
}
EXPORT_SYMBOL(ptp_clock_unregister);
void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
{
struct pps_event_time evt;
switch (event->type) {
case PTP_CLOCK_ALARM:
break;
case PTP_CLOCK_EXTTS:
enqueue_external_timestamp(&ptp->tsevq, event);
wake_up_interruptible(&ptp->tsev_wq);
break;
case PTP_CLOCK_PPS:
pps_get_ts(&evt);
pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
break;
}
}
EXPORT_SYMBOL(ptp_clock_event);
/* module operations */
static void __exit ptp_exit(void)
{
class_destroy(ptp_class);
unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS);
}
static int __init ptp_init(void)
{
int err;
ptp_class = class_create(THIS_MODULE, "ptp");
if (IS_ERR(ptp_class)) {
pr_err("ptp: failed to allocate class\n");
return PTR_ERR(ptp_class);
}
err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp");
if (err < 0) {
pr_err("ptp: failed to allocate device region\n");
goto no_region;
}
ptp_class->dev_attrs = ptp_dev_attrs;
pr_info("PTP clock support registered\n");
return 0;
no_region:
class_destroy(ptp_class);
return err;
}
subsys_initcall(ptp_init);
module_exit(ptp_exit);
MODULE_AUTHOR("Richard Cochran <richard.cochran@omicron.at>");
MODULE_DESCRIPTION("PTP clocks support");
MODULE_LICENSE("GPL");
