![Richard Cochran](/assets/img/avatar_default.png)
This patch adds an infrastructure for hardware clocks that implement IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a registration method to particular hardware clock drivers. Each clock is presented as a standard POSIX clock. The ancillary clock features are exposed in two different ways, via the sysfs and by a character device. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: John Stultz <john.stultz@linaro.org>
160 lines
3.9 KiB
C
160 lines
3.9 KiB
C
/*
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* PTP 1588 clock support - character device implementation.
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*
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* Copyright (C) 2010 OMICRON electronics GmbH
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/module.h>
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#include <linux/posix-clock.h>
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#include <linux/poll.h>
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#include <linux/sched.h>
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#include "ptp_private.h"
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int ptp_open(struct posix_clock *pc, fmode_t fmode)
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{
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return 0;
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}
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long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
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{
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struct ptp_clock_caps caps;
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struct ptp_clock_request req;
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struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
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struct ptp_clock_info *ops = ptp->info;
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int enable, err = 0;
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switch (cmd) {
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case PTP_CLOCK_GETCAPS:
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memset(&caps, 0, sizeof(caps));
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caps.max_adj = ptp->info->max_adj;
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caps.n_alarm = ptp->info->n_alarm;
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caps.n_ext_ts = ptp->info->n_ext_ts;
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caps.n_per_out = ptp->info->n_per_out;
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caps.pps = ptp->info->pps;
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err = copy_to_user((void __user *)arg, &caps, sizeof(caps));
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break;
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case PTP_EXTTS_REQUEST:
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if (copy_from_user(&req.extts, (void __user *)arg,
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sizeof(req.extts))) {
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err = -EFAULT;
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break;
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}
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if (req.extts.index >= ops->n_ext_ts) {
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err = -EINVAL;
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break;
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}
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req.type = PTP_CLK_REQ_EXTTS;
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enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
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err = ops->enable(ops, &req, enable);
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break;
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case PTP_PEROUT_REQUEST:
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if (copy_from_user(&req.perout, (void __user *)arg,
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sizeof(req.perout))) {
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err = -EFAULT;
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break;
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}
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if (req.perout.index >= ops->n_per_out) {
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err = -EINVAL;
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break;
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}
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req.type = PTP_CLK_REQ_PEROUT;
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enable = req.perout.period.sec || req.perout.period.nsec;
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err = ops->enable(ops, &req, enable);
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break;
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case PTP_ENABLE_PPS:
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if (!capable(CAP_SYS_TIME))
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return -EPERM;
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req.type = PTP_CLK_REQ_PPS;
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enable = arg ? 1 : 0;
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err = ops->enable(ops, &req, enable);
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break;
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default:
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err = -ENOTTY;
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break;
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}
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return err;
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}
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unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
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{
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struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
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poll_wait(fp, &ptp->tsev_wq, wait);
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return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
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}
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ssize_t ptp_read(struct posix_clock *pc,
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uint rdflags, char __user *buf, size_t cnt)
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{
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struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
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struct timestamp_event_queue *queue = &ptp->tsevq;
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struct ptp_extts_event event[PTP_BUF_TIMESTAMPS];
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unsigned long flags;
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size_t qcnt, i;
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if (cnt % sizeof(struct ptp_extts_event) != 0)
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return -EINVAL;
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if (cnt > sizeof(event))
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cnt = sizeof(event);
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cnt = cnt / sizeof(struct ptp_extts_event);
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if (mutex_lock_interruptible(&ptp->tsevq_mux))
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return -ERESTARTSYS;
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if (wait_event_interruptible(ptp->tsev_wq,
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ptp->defunct || queue_cnt(queue))) {
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mutex_unlock(&ptp->tsevq_mux);
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return -ERESTARTSYS;
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}
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if (ptp->defunct)
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return -ENODEV;
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spin_lock_irqsave(&queue->lock, flags);
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qcnt = queue_cnt(queue);
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if (cnt > qcnt)
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cnt = qcnt;
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for (i = 0; i < cnt; i++) {
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event[i] = queue->buf[queue->head];
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queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
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}
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spin_unlock_irqrestore(&queue->lock, flags);
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cnt = cnt * sizeof(struct ptp_extts_event);
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mutex_unlock(&ptp->tsevq_mux);
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if (copy_to_user(buf, event, cnt)) {
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mutex_unlock(&ptp->tsevq_mux);
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return -EFAULT;
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}
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return cnt;
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}
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