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linux/drivers/ptp/ptp_chardev.c
Vladimir Oltean f65b71aa25 ptp: add ability to configure duty cycle for periodic output 
There are external event timestampers (PHCs with support for
PTP_EXTTS_REQUEST) that timestamp both event edges.

When those edges are very close (such as in the case of a short pulse),
there is a chance that the collected timestamp might be of the rising,
or of the falling edge, we never know.

There are also PHCs capable of generating periodic output with a
configurable duty cycle. This is good news, because we can space the
rising and falling edge out enough in time, that the risks to overrun
the 1-entry timestamp FIFO of the extts PHC are lower (example: the
perout PHC can be configured for a period of 1 second, and an "on" time
of 0.5 seconds, resulting in a duty cycle of 50%).

A flag is introduced for signaling that an on time is present in the
perout request structure, for preserving compatibility. Logically
speaking, the duty cycle cannot exceed 100% and the PTP core checks for
this.

PHC drivers that don't support this flag emit a periodic output of an
unspecified duty cycle, same as before.

The duty cycle is encoded as an "on" time, similar to the "start" and
"period" times, and reuses the reserved space while preserving overall
binary layout.

Pahole reported before:

struct ptp_perout_request {
        struct ptp_clock_time start;                     /*     0    16 */
        struct ptp_clock_time period;                    /*    16    16 */
        unsigned int               index;                /*    32     4 */
        unsigned int               flags;                /*    36     4 */
        unsigned int               rsv[4];               /*    40    16 */

        /* size: 56, cachelines: 1, members: 5 */
        /* last cacheline: 56 bytes */
};

And now:

struct ptp_perout_request {
        struct ptp_clock_time start;                     /*     0    16 */
        struct ptp_clock_time period;                    /*    16    16 */
        unsigned int               index;                /*    32     4 */
        unsigned int               flags;                /*    36     4 */
        union {
                struct ptp_clock_time on;                /*    40    16 */
                unsigned int       rsv[4];               /*    40    16 */
        };                                               /*    40    16 */

        /* size: 56, cachelines: 1, members: 5 */
        /* last cacheline: 56 bytes */
};

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-19 19:22:56 -07:00

493 lines
12 KiB
C
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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/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 on pin %u\n", func, chan);
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 *pc, fmode_t fmode)
{
return 0;
}
long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
{
struct ptp_clock *ptp = container_of(pc, 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 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;
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;
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;
}
}
} 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->rsv[2]) {
err = -EINVAL;
break;
}
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;
default:
err = -ENOTTY;
break;
}
out:
kfree(extoff);
kfree(sysoff);
return err;
}
__poll_t ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
poll_wait(fp, &ptp->tsev_wq, wait);
return queue_cnt(&ptp->tsevq) ? EPOLLIN : 0;
}
#define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))
ssize_t ptp_read(struct posix_clock *pc,
uint rdflags, char __user *buf, size_t cnt)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct timestamp_event_queue *queue = &ptp->tsevq;
struct ptp_extts_event *event;
unsigned long flags;
size_t qcnt, i;
int result;
if (cnt % sizeof(struct ptp_extts_event) != 0)
return -EINVAL;
if (cnt > EXTTS_BUFSIZE)
cnt = EXTTS_BUFSIZE;
cnt = cnt / sizeof(struct ptp_extts_event);
if (mutex_lock_interruptible(&ptp->tsevq_mux))
return -ERESTARTSYS;
if (wait_event_interruptible(ptp->tsev_wq,
ptp->defunct || queue_cnt(queue))) {
mutex_unlock(&ptp->tsevq_mux);
return -ERESTARTSYS;
}
if (ptp->defunct) {
mutex_unlock(&ptp->tsevq_mux);
return -ENODEV;
}
event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
if (!event) {
mutex_unlock(&ptp->tsevq_mux);
return -ENOMEM;
}
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];
queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
}
spin_unlock_irqrestore(&queue->lock, flags);
cnt = cnt * sizeof(struct ptp_extts_event);
mutex_unlock(&ptp->tsevq_mux);
result = cnt;
if (copy_to_user(buf, event, cnt))
result = -EFAULT;
kfree(event);
return result;
}
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