ptp_sysfs.c

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/*
 * PTP 1588 clock support - sysfs interface.
 *
 * 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/capability.h>

#include "ptp_private.h"

static ssize_t clock_name_show(struct device *dev,
                   struct device_attribute *attr, char *page)
{
    struct ptp_clock *ptp = dev_get_drvdata(dev);
    return snprintf(page, PAGE_SIZE-1, "%s\n", ptp->info->name);
}

#define PTP_SHOW_INT(name)                      \
static ssize_t name##_show(struct device *dev,              \
               struct device_attribute *attr, char *page)   \
{                                   \
    struct ptp_clock *ptp = dev_get_drvdata(dev);           \
    return snprintf(page, PAGE_SIZE-1, "%d\n", ptp->info->name);    \
}

PTP_SHOW_INT(max_adj);
PTP_SHOW_INT(n_alarm);
PTP_SHOW_INT(n_ext_ts);
PTP_SHOW_INT(n_per_out);
PTP_SHOW_INT(pps);

#define PTP_RO_ATTR(_var, _name) {              \
    .attr   = { .name = __stringify(_name), .mode = 0444 }, \
    .show   = _var##_show,                  \
}

struct device_attribute ptp_dev_attrs[] = {
    PTP_RO_ATTR(clock_name, clock_name),
    PTP_RO_ATTR(max_adj,    max_adjustment),
    PTP_RO_ATTR(n_alarm,    n_alarms),
    PTP_RO_ATTR(n_ext_ts,   n_external_timestamps),
    PTP_RO_ATTR(n_per_out,  n_periodic_outputs),
    PTP_RO_ATTR(pps,    pps_available),
    __ATTR_NULL,
};

static ssize_t extts_enable_store(struct device *dev,
                  struct device_attribute *attr,
                  const char *buf, size_t count)
{
    struct ptp_clock *ptp = dev_get_drvdata(dev);
    struct ptp_clock_info *ops = ptp->info;
    struct ptp_clock_request req = { .type = PTP_CLK_REQ_EXTTS };
    int cnt, enable;
    int err = -EINVAL;

    cnt = sscanf(buf, "%u %d", &req.extts.index, &enable);
    if (cnt != 2)
        goto out;
    if (req.extts.index >= ops->n_ext_ts)
        goto out;

    err = ops->enable(ops, &req, enable ? 1 : 0);
    if (err)
        goto out;

    return count;
out:
    return err;
}

static ssize_t extts_fifo_show(struct device *dev,
                   struct device_attribute *attr, char *page)
{
    struct ptp_clock *ptp = dev_get_drvdata(dev);
    struct timestamp_event_queue *queue = &ptp->tsevq;
    struct ptp_extts_event event;
    unsigned long flags;
    size_t qcnt;
    int cnt = 0;

    memset(&event, 0, sizeof(event));

    if (mutex_lock_interruptible(&ptp->tsevq_mux))
        return -ERESTARTSYS;

    spin_lock_irqsave(&queue->lock, flags);
    qcnt = queue_cnt(queue);
    if (qcnt) {
        event = queue->buf[queue->head];
        queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
    }
    spin_unlock_irqrestore(&queue->lock, flags);

    if (!qcnt)
        goto out;

    cnt = snprintf(page, PAGE_SIZE, "%u %lld %u\n",
               event.index, event.t.sec, event.t.nsec);
out:
    mutex_unlock(&ptp->tsevq_mux);
    return cnt;
}

static ssize_t period_store(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t count)
{
    struct ptp_clock *ptp = dev_get_drvdata(dev);
    struct ptp_clock_info *ops = ptp->info;
    struct ptp_clock_request req = { .type = PTP_CLK_REQ_PEROUT };
    int cnt, enable, err = -EINVAL;

    cnt = sscanf(buf, "%u %lld %u %lld %u", &req.perout.index,
             &req.perout.start.sec, &req.perout.start.nsec,
             &req.perout.period.sec, &req.perout.period.nsec);
    if (cnt != 5)
        goto out;
    if (req.perout.index >= ops->n_per_out)
        goto out;

    enable = req.perout.period.sec || req.perout.period.nsec;
    err = ops->enable(ops, &req, enable);
    if (err)
        goto out;

    return count;
out:
    return err;
}

static ssize_t pps_enable_store(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t count)
{
    struct ptp_clock *ptp = dev_get_drvdata(dev);
    struct ptp_clock_info *ops = ptp->info;
    struct ptp_clock_request req = { .type = PTP_CLK_REQ_PPS };
    int cnt, enable;
    int err = -EINVAL;

    if (!capable(CAP_SYS_TIME))
        return -EPERM;

    cnt = sscanf(buf, "%d", &enable);
    if (cnt != 1)
        goto out;

    err = ops->enable(ops, &req, enable ? 1 : 0);
    if (err)
        goto out;

    return count;
out:
    return err;
}

static DEVICE_ATTR(extts_enable, 0220, NULL, extts_enable_store);
static DEVICE_ATTR(fifo,         0444, extts_fifo_show, NULL);
static DEVICE_ATTR(period,       0220, NULL, period_store);
static DEVICE_ATTR(pps_enable,   0220, NULL, pps_enable_store);

int ptp_cleanup_sysfs(struct ptp_clock *ptp)
{
    struct device *dev = ptp->dev;
    struct ptp_clock_info *info = ptp->info;

    if (info->n_ext_ts) {
        device_remove_file(dev, &dev_attr_extts_enable);
        device_remove_file(dev, &dev_attr_fifo);
    }
    if (info->n_per_out)
        device_remove_file(dev, &dev_attr_period);

    if (info->pps)
        device_remove_file(dev, &dev_attr_pps_enable);

    return 0;
}

int ptp_populate_sysfs(struct ptp_clock *ptp)
{
    struct device *dev = ptp->dev;
    struct ptp_clock_info *info = ptp->info;
    int err;

    if (info->n_ext_ts) {
        err = device_create_file(dev, &dev_attr_extts_enable);
        if (err)
            goto out1;
        err = device_create_file(dev, &dev_attr_fifo);
        if (err)
            goto out2;
    }
    if (info->n_per_out) {
        err = device_create_file(dev, &dev_attr_period);
        if (err)
            goto out3;
    }
    if (info->pps) {
        err = device_create_file(dev, &dev_attr_pps_enable);
        if (err)
            goto out4;
    }
    return 0;
out4:
    if (info->n_per_out)
        device_remove_file(dev, &dev_attr_period);
out3:
    if (info->n_ext_ts)
        device_remove_file(dev, &dev_attr_fifo);
out2:
    if (info->n_ext_ts)
        device_remove_file(dev, &dev_attr_extts_enable);
out1:
    return err;
}