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linux/drivers/ptp/ptp_chardev.c
Mahesh Bandewar c259acab83 ptp/ioctl: support MONOTONIC{,_RAW} timestamps for PTP_SYS_OFFSET_EXTENDED 
The ability to read the PHC (Physical Hardware Clock) alongside
multiple system clocks is currently dependent on the specific
hardware architecture. This limitation restricts the use of
PTP_SYS_OFFSET_PRECISE to certain hardware configurations.

The generic soultion which would work across all architectures
is to read the PHC along with the latency to perform PHC-read as
offered by PTP_SYS_OFFSET_EXTENDED which provides pre and post
timestamps.  However, these timestamps are currently limited
to the CLOCK_REALTIME timebase. Since CLOCK_REALTIME is affected
by NTP (or similar time synchronization services), it can
experience significant jumps forward or backward. This hinders
the precise latency measurements that PTP_SYS_OFFSET_EXTENDED
is designed to provide.

This problem could be addressed by supporting MONOTONIC_RAW
timestamps within PTP_SYS_OFFSET_EXTENDED. Unlike CLOCK_REALTIME
or CLOCK_MONOTONIC, the MONOTONIC_RAW timebase is unaffected
by NTP adjustments.

This enhancement can be implemented by utilizing one of the three
reserved words within the PTP_SYS_OFFSET_EXTENDED struct to pass
the clock-id for timestamps.  The current behavior aligns with
clock-id for CLOCK_REALTIME timebase (value of 0), ensuring
backward compatibility of the UAPI.

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-09-08 18:40:33 +01:00

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// 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;
}
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