drivers/ptp/ptp_chardev.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PTP 1588 clock support - character device implementation.
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 */
#include <linux/module.h>
#include <linux/posix-clock.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/timekeeping.h>
#include <linux/debugfs.h>

#include <linux/nospec.h>

#include "ptp_private.h"

static int ptp_disable_pinfunc(struct ptp_clock_info *ops,
			       enum ptp_pin_function func, unsigned int chan)
{
	struct ptp_clock_request rq;
	int err = 0;

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

	switch (func) {
	case PTP_PF_NONE:
		break;
	case PTP_PF_EXTTS:
		rq.type = PTP_CLK_REQ_EXTTS;
		rq.extts.index = chan;
		err = ops->enable(ops, &rq, 0);
		break;
	case PTP_PF_PEROUT:
		rq.type = PTP_CLK_REQ_PEROUT;
		rq.perout.index = chan;
		err = ops->enable(ops, &rq, 0);
		break;
	case PTP_PF_PHYSYNC:
		break;
	default:
		return -EINVAL;
	}

	return err;
}

int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
		    enum ptp_pin_function func, unsigned int chan)
{
	struct ptp_clock_info *info = ptp->info;
	struct ptp_pin_desc *pin1 = NULL, *pin2 = &info->pin_config[pin];
	unsigned int i;

	/* Check to see if any other pin previously had this function. */
	for (i = 0; i < info->n_pins; i++) {
		if (info->pin_config[i].func == func &&
		    info->pin_config[i].chan == chan) {
			pin1 = &info->pin_config[i];
			break;
		}
	}
	if (pin1 && i == pin)
		return 0;

	/* Check the desired function and channel. */
	switch (func) {
	case PTP_PF_NONE:
		break;
	case PTP_PF_EXTTS:
		if (chan >= info->n_ext_ts)
			return -EINVAL;
		break;
	case PTP_PF_PEROUT:
		if (chan >= info->n_per_out)
			return -EINVAL;
		break;
	case PTP_PF_PHYSYNC:
		if (chan != 0)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	if (info->verify(info, pin, func, chan)) {
		pr_err("driver cannot use function %u and channel %u on pin %u\n",
		       func, chan, pin);
		return -EOPNOTSUPP;
	}

	/* Disable whatever function was previously assigned. */
	if (pin1) {
		ptp_disable_pinfunc(info, func, chan);
		pin1->func = PTP_PF_NONE;
		pin1->chan = 0;
	}
	ptp_disable_pinfunc(info, pin2->func, pin2->chan);
	pin2->func = func;
	pin2->chan = chan;

	return 0;
}

int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
{
	struct ptp_clock *ptp =
		container_of(pccontext->clk, struct ptp_clock, clock);
	struct timestamp_event_queue *queue;
	char debugfsname[32];
	unsigned long flags;

	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
	if (!queue)
		return -EINVAL;
	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
	if (!queue->mask) {
		kfree(queue);
		return -EINVAL;
	}
	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
	spin_lock_init(&queue->lock);
	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
	list_add_tail(&queue->qlist, &ptp->tsevqs);
	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
	pccontext->private_clkdata = queue;

	/* Debugfs contents */
	sprintf(debugfsname, "0x%p", queue);
	queue->debugfs_instance =
		debugfs_create_dir(debugfsname, ptp->debugfs_root);
	queue->dfs_bitmap.array = (u32 *)queue->mask;
	queue->dfs_bitmap.n_elements =
		DIV_ROUND_UP(PTP_MAX_CHANNELS, BITS_PER_BYTE * sizeof(u32));
	debugfs_create_u32_array("mask", 0444, queue->debugfs_instance,
				 &queue->dfs_bitmap);

	return 0;
}

int ptp_release(struct posix_clock_context *pccontext)
{
	struct timestamp_event_queue *queue = pccontext->private_clkdata;
	unsigned long flags;
	struct ptp_clock *ptp =
		container_of(pccontext->clk, struct ptp_clock, clock);

	debugfs_remove(queue->debugfs_instance);
	pccontext->private_clkdata = NULL;
	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
	list_del(&queue->qlist);
	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
	bitmap_free(queue->mask);
	kfree(queue);
	return 0;
}

long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
	       unsigned long arg)
{
	struct ptp_clock *ptp =
		container_of(pccontext->clk, struct ptp_clock, clock);
	struct ptp_sys_offset_extended *extoff = NULL;
	struct ptp_sys_offset_precise precise_offset;
	struct system_device_crosststamp xtstamp;
	struct ptp_clock_info *ops = ptp->info;
	struct ptp_sys_offset *sysoff = NULL;
	struct timestamp_event_queue *tsevq;
	struct ptp_system_timestamp sts;
	struct ptp_clock_request req;
	struct ptp_clock_caps caps;
	struct ptp_clock_time *pct;
	unsigned int i, pin_index;
	struct ptp_pin_desc pd;
	struct timespec64 ts;
	int enable, err = 0;

	tsevq = pccontext->private_clkdata;

	switch (cmd) {

	case PTP_CLOCK_GETCAPS:
	case PTP_CLOCK_GETCAPS2:
		memset(&caps, 0, sizeof(caps));

		caps.max_adj = ptp->info->max_adj;
		caps.n_alarm = ptp->info->n_alarm;
		caps.n_ext_ts = ptp->info->n_ext_ts;
		caps.n_per_out = ptp->info->n_per_out;
		caps.pps = ptp->info->pps;
		caps.n_pins = ptp->info->n_pins;
		caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
		caps.adjust_phase = ptp->info->adjphase != NULL &&
				    ptp->info->getmaxphase != NULL;
		if (caps.adjust_phase)
			caps.max_phase_adj = ptp->info->getmaxphase(ptp->info);
		if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
			err = -EFAULT;
		break;

	case PTP_EXTTS_REQUEST:
	case PTP_EXTTS_REQUEST2:
		memset(&req, 0, sizeof(req));

		if (copy_from_user(&req.extts, (void __user *)arg,
				   sizeof(req.extts))) {
			err = -EFAULT;
			break;
		}
		if (cmd == PTP_EXTTS_REQUEST2) {
			/* Tell the drivers to check the flags carefully. */
			req.extts.flags |= PTP_STRICT_FLAGS;
			/* Make sure no reserved bit is set. */
			if ((req.extts.flags & ~PTP_EXTTS_VALID_FLAGS) ||
			    req.extts.rsv[0] || req.extts.rsv[1]) {
				err = -EINVAL;
				break;
			}
			/* Ensure one of the rising/falling edge bits is set. */
			if ((req.extts.flags & PTP_ENABLE_FEATURE) &&
			    (req.extts.flags & PTP_EXTTS_EDGES) == 0) {
				err = -EINVAL;
				break;
			}
		} else if (cmd == PTP_EXTTS_REQUEST) {
			req.extts.flags &= PTP_EXTTS_V1_VALID_FLAGS;
			req.extts.rsv[0] = 0;
			req.extts.rsv[1] = 0;
		}
		if (req.extts.index >= ops->n_ext_ts) {
			err = -EINVAL;
			break;
		}
		req.type = PTP_CLK_REQ_EXTTS;
		enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
		if (mutex_lock_interruptible(&ptp->pincfg_mux))
			return -ERESTARTSYS;
		err = ops->enable(ops, &req, enable);
		mutex_unlock(&ptp->pincfg_mux);
		break;

	case PTP_PEROUT_REQUEST:
	case PTP_PEROUT_REQUEST2:
		memset(&req, 0, sizeof(req));

		if (copy_from_user(&req.perout, (void __user *)arg,
				   sizeof(req.perout))) {
			err = -EFAULT;
			break;
		}
		if (cmd == PTP_PEROUT_REQUEST2) {
			struct ptp_perout_request *perout = &req.perout;

			if (perout->flags & ~PTP_PEROUT_VALID_FLAGS) {
				err = -EINVAL;
				break;
			}
			/*
			 * The "on" field has undefined meaning if
			 * PTP_PEROUT_DUTY_CYCLE isn't set, we must still treat
			 * it as reserved, which must be set to zero.
			 */
			if (!(perout->flags & PTP_PEROUT_DUTY_CYCLE) &&
			    (perout->rsv[0] || perout->rsv[1] ||
			     perout->rsv[2] || perout->rsv[3])) {
				err = -EINVAL;
				break;
			}
			if (perout->flags & PTP_PEROUT_DUTY_CYCLE) {
				/* The duty cycle must be subunitary. */
				if (perout->on.sec > perout->period.sec ||
				    (perout->on.sec == perout->period.sec &&
				     perout->on.nsec > perout->period.nsec)) {
					err = -ERANGE;
					break;
				}
			}
			if (perout->flags & PTP_PEROUT_PHASE) {
				/*
				 * The phase should be specified modulo the
				 * period, therefore anything equal or larger
				 * than 1 period is invalid.
				 */
				if (perout->phase.sec > perout->period.sec ||
				    (perout->phase.sec == perout->period.sec &&
				     perout->phase.nsec >= perout->period.nsec)) {
					err = -ERANGE;
					break;
				}
			}
		} else if (cmd == PTP_PEROUT_REQUEST) {
			req.perout.flags &= PTP_PEROUT_V1_VALID_FLAGS;
			req.perout.rsv[0] = 0;
			req.perout.rsv[1] = 0;
			req.perout.rsv[2] = 0;
			req.perout.rsv[3] = 0;
		}
		if (req.perout.index >= ops->n_per_out) {
			err = -EINVAL;
			break;
		}
		req.type = PTP_CLK_REQ_PEROUT;
		enable = req.perout.period.sec || req.perout.period.nsec;
		if (mutex_lock_interruptible(&ptp->pincfg_mux))
			return -ERESTARTSYS;
		err = ops->enable(ops, &req, enable);
		mutex_unlock(&ptp->pincfg_mux);
		break;

	case PTP_ENABLE_PPS:
	case PTP_ENABLE_PPS2:
		memset(&req, 0, sizeof(req));

		if (!capable(CAP_SYS_TIME))
			return -EPERM;
		req.type = PTP_CLK_REQ_PPS;
		enable = arg ? 1 : 0;
		if (mutex_lock_interruptible(&ptp->pincfg_mux))
			return -ERESTARTSYS;
		err = ops->enable(ops, &req, enable);
		mutex_unlock(&ptp->pincfg_mux);
		break;

	case PTP_SYS_OFFSET_PRECISE:
	case PTP_SYS_OFFSET_PRECISE2:
		if (!ptp->info->getcrosststamp) {
			err = -EOPNOTSUPP;
			break;
		}
		err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
		if (err)
			break;

		memset(&precise_offset, 0, sizeof(precise_offset));
		ts = ktime_to_timespec64(xtstamp.device);
		precise_offset.device.sec = ts.tv_sec;
		precise_offset.device.nsec = ts.tv_nsec;
		ts = ktime_to_timespec64(xtstamp.sys_realtime);
		precise_offset.sys_realtime.sec = ts.tv_sec;
		precise_offset.sys_realtime.nsec = ts.tv_nsec;
		ts = ktime_to_timespec64(xtstamp.sys_monoraw);
		precise_offset.sys_monoraw.sec = ts.tv_sec;
		precise_offset.sys_monoraw.nsec = ts.tv_nsec;
		if (copy_to_user((void __user *)arg, &precise_offset,
				 sizeof(precise_offset)))
			err = -EFAULT;
		break;

	case PTP_SYS_OFFSET_EXTENDED:
	case PTP_SYS_OFFSET_EXTENDED2:
		if (!ptp->info->gettimex64) {
			err = -EOPNOTSUPP;
			break;
		}
		extoff = memdup_user((void __user *)arg, sizeof(*extoff));
		if (IS_ERR(extoff)) {
			err = PTR_ERR(extoff);
			extoff = NULL;
			break;
		}
		if (extoff->n_samples > PTP_MAX_SAMPLES ||
		    extoff->rsv[0] || extoff->rsv[1] ||
		    (extoff->clockid != CLOCK_REALTIME &&
		     extoff->clockid != CLOCK_MONOTONIC &&
		     extoff->clockid != CLOCK_MONOTONIC_RAW)) {
			err = -EINVAL;
			break;
		}
		sts.clockid = extoff->clockid;
		for (i = 0; i < extoff->n_samples; i++) {
			err = ptp->info->gettimex64(ptp->info, &ts, &sts);
			if (err)
				goto out;
			extoff->ts[i][0].sec = sts.pre_ts.tv_sec;
			extoff->ts[i][0].nsec = sts.pre_ts.tv_nsec;
			extoff->ts[i][1].sec = ts.tv_sec;
			extoff->ts[i][1].nsec = ts.tv_nsec;
			extoff->ts[i][2].sec = sts.post_ts.tv_sec;
			extoff->ts[i][2].nsec = sts.post_ts.tv_nsec;
		}
		if (copy_to_user((void __user *)arg, extoff, sizeof(*extoff)))
			err = -EFAULT;
		break;

	case PTP_SYS_OFFSET:
	case PTP_SYS_OFFSET2:
		sysoff = memdup_user((void __user *)arg, sizeof(*sysoff));
		if (IS_ERR(sysoff)) {
			err = PTR_ERR(sysoff);
			sysoff = NULL;
			break;
		}
		if (sysoff->n_samples > PTP_MAX_SAMPLES) {
			err = -EINVAL;
			break;
		}
		pct = &sysoff->ts[0];
		for (i = 0; i < sysoff->n_samples; i++) {
			ktime_get_real_ts64(&ts);
			pct->sec = ts.tv_sec;
			pct->nsec = ts.tv_nsec;
			pct++;
			if (ops->gettimex64)
				err = ops->gettimex64(ops, &ts, NULL);
			else
				err = ops->gettime64(ops, &ts);
			if (err)
				goto out;
			pct->sec = ts.tv_sec;
			pct->nsec = ts.tv_nsec;
			pct++;
		}
		ktime_get_real_ts64(&ts);
		pct->sec = ts.tv_sec;
		pct->nsec = ts.tv_nsec;
		if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))
			err = -EFAULT;
		break;

	case PTP_PIN_GETFUNC:
	case PTP_PIN_GETFUNC2:
		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
			err = -EFAULT;
			break;
		}
		if ((pd.rsv[0] || pd.rsv[1] || pd.rsv[2]
				|| pd.rsv[3] || pd.rsv[4])
			&& cmd == PTP_PIN_GETFUNC2) {
			err = -EINVAL;
			break;
		} else if (cmd == PTP_PIN_GETFUNC) {
			pd.rsv[0] = 0;
			pd.rsv[1] = 0;
			pd.rsv[2] = 0;
			pd.rsv[3] = 0;
			pd.rsv[4] = 0;
		}
		pin_index = pd.index;
		if (pin_index >= ops->n_pins) {
			err = -EINVAL;
			break;
		}
		pin_index = array_index_nospec(pin_index, ops->n_pins);
		if (mutex_lock_interruptible(&ptp->pincfg_mux))
			return -ERESTARTSYS;
		pd = ops->pin_config[pin_index];
		mutex_unlock(&ptp->pincfg_mux);
		if (!err && copy_to_user((void __user *)arg, &pd, sizeof(pd)))
			err = -EFAULT;
		break;

	case PTP_PIN_SETFUNC:
	case PTP_PIN_SETFUNC2:
		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
			err = -EFAULT;
			break;
		}
		if ((pd.rsv[0] || pd.rsv[1] || pd.rsv[2]
				|| pd.rsv[3] || pd.rsv[4])
			&& cmd == PTP_PIN_SETFUNC2) {
			err = -EINVAL;
			break;
		} else if (cmd == PTP_PIN_SETFUNC) {
			pd.rsv[0] = 0;
			pd.rsv[1] = 0;
			pd.rsv[2] = 0;
			pd.rsv[3] = 0;
			pd.rsv[4] = 0;
		}
		pin_index = pd.index;
		if (pin_index >= ops->n_pins) {
			err = -EINVAL;
			break;
		}
		pin_index = array_index_nospec(pin_index, ops->n_pins);
		if (mutex_lock_interruptible(&ptp->pincfg_mux))
			return -ERESTARTSYS;
		err = ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
		mutex_unlock(&ptp->pincfg_mux);
		break;

	case PTP_MASK_CLEAR_ALL:
		bitmap_clear(tsevq->mask, 0, PTP_MAX_CHANNELS);
		break;

	case PTP_MASK_EN_SINGLE:
		if (copy_from_user(&i, (void __user *)arg, sizeof(i))) {
			err = -EFAULT;
			break;
		}
		if (i >= PTP_MAX_CHANNELS) {
			err = -EFAULT;
			break;
		}
		set_bit(i, tsevq->mask);
		break;

	default:
		err = -ENOTTY;
		break;
	}

out:
	kfree(extoff);
	kfree(sysoff);
	return err;
}

__poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
		  poll_table *wait)
{
	struct ptp_clock *ptp =
		container_of(pccontext->clk, struct ptp_clock, clock);
	struct timestamp_event_queue *queue;

	queue = pccontext->private_clkdata;
	if (!queue)
		return EPOLLERR;

	poll_wait(fp, &ptp->tsev_wq, wait);

	return queue_cnt(queue) ? EPOLLIN : 0;
}

#define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))

ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags,
		 char __user *buf, size_t cnt)
{
	struct ptp_clock *ptp =
		container_of(pccontext->clk, struct ptp_clock, clock);
	struct timestamp_event_queue *queue;
	struct ptp_extts_event *event;
	unsigned long flags;
	size_t qcnt, i;
	int result;

	queue = pccontext->private_clkdata;
	if (!queue) {
		result = -EINVAL;
		goto exit;
	}

	if (cnt % sizeof(struct ptp_extts_event) != 0) {
		result = -EINVAL;
		goto exit;
	}

	if (cnt > EXTTS_BUFSIZE)
		cnt = EXTTS_BUFSIZE;

	cnt = cnt / sizeof(struct ptp_extts_event);

	if (wait_event_interruptible(ptp->tsev_wq,
				     ptp->defunct || queue_cnt(queue))) {
		return -ERESTARTSYS;
	}

	if (ptp->defunct) {
		result = -ENODEV;
		goto exit;
	}

	event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
	if (!event) {
		result = -ENOMEM;
		goto exit;
	}

	spin_lock_irqsave(&queue->lock, flags);

	qcnt = queue_cnt(queue);

	if (cnt > qcnt)
		cnt = qcnt;

	for (i = 0; i < cnt; i++) {
		event[i] = queue->buf[queue->head];
		/* Paired with READ_ONCE() in queue_cnt() */
		WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
	}

	spin_unlock_irqrestore(&queue->lock, flags);

	cnt = cnt * sizeof(struct ptp_extts_event);

	result = cnt;
	if (copy_to_user(buf, event, cnt)) {
		result = -EFAULT;
		goto free_event;
	}

free_event:
	kfree(event);
exit:
	return result;
}