// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PTP 1588 clock support - character device implementation.
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 */
#include <linux/compat.h>
#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;
}

void ptp_disable_all_events(struct ptp_clock *ptp)
{
        struct ptp_clock_info *info = ptp->info;
        unsigned int i;

        mutex_lock(&ptp->pincfg_mux);
        /* Disable any pins that may raise EXTTS events */
        for (i = 0; i < info->n_pins; i++)
                if (info->pin_config[i].func == PTP_PF_EXTTS)
                        ptp_disable_pinfunc(info, info->pin_config[i].func,
                                            info->pin_config[i].chan);

        /* Disable the PPS event if the driver has PPS support */
        if (info->pps) {
                struct ptp_clock_request req = { .type = PTP_CLK_REQ_PPS };
                info->enable(info, &req, 0);
        }
        mutex_unlock(&ptp->pincfg_mux);
}

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 whichever pin was previously assigned to this function and
         * channel.
         */
        if (pin1) {
                ptp_disable_pinfunc(info, func, chan);
                pin1->func = PTP_PF_NONE;
                pin1->chan = 0;
        }

        /* Disable whatever function was previously assigned to the requested
         * pin.
         */
        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];

        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);
        scoped_guard(spinlock_irq, &ptp->tsevqs_lock)
                list_add_tail(&queue->qlist, &ptp->tsevqs);
        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;
        struct ptp_clock *ptp =
                container_of(pccontext->clk, struct ptp_clock, clock);

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

static long ptp_clock_getcaps(struct ptp_clock *ptp, void __user *arg)
{
        struct ptp_clock_caps caps = {
                .max_adj                = ptp->info->max_adj,
                .n_alarm                = ptp->info->n_alarm,
                .n_ext_ts               = ptp->info->n_ext_ts,
                .n_per_out              = ptp->info->n_per_out,
                .pps                    = ptp->info->pps,
                .n_pins                 = ptp->info->n_pins,
                .cross_timestamping     = ptp->info->getcrosststamp != NULL,
                .adjust_phase           = ptp->info->adjphase != NULL &&
                                          ptp->info->getmaxphase != NULL,
        };

        if (caps.adjust_phase)
                caps.max_phase_adj = ptp->info->getmaxphase(ptp->info);

        return copy_to_user(arg, &caps, sizeof(caps)) ? -EFAULT : 0;
}

static long ptp_extts_request(struct ptp_clock *ptp, unsigned int cmd, void __user *arg)
{
        struct ptp_clock_request req = { .type = PTP_CLK_REQ_EXTTS };
        struct ptp_clock_info *ops = ptp->info;
        unsigned int supported_extts_flags;

        if (copy_from_user(&req.extts, arg, sizeof(req.extts)))
                return -EFAULT;

        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])
                        return -EINVAL;

                /* Ensure one of the rising/falling edge bits is set. */
                if ((req.extts.flags & PTP_ENABLE_FEATURE) &&
                    (req.extts.flags & PTP_EXTTS_EDGES) == 0)
                        return -EINVAL;
        } else {
                req.extts.flags &= PTP_EXTTS_V1_VALID_FLAGS;
                memset(req.extts.rsv, 0, sizeof(req.extts.rsv));
        }

        if (req.extts.index >= ops->n_ext_ts)
                return -EINVAL;

        supported_extts_flags = ptp->info->supported_extts_flags;
        /* The PTP_ENABLE_FEATURE flag is always supported. */
        supported_extts_flags |= PTP_ENABLE_FEATURE;
        /* If the driver does not support strictly checking flags, the
         * PTP_RISING_EDGE and PTP_FALLING_EDGE flags are merely hints
         * which are not enforced.
         */
        if (!(supported_extts_flags & PTP_STRICT_FLAGS))
                supported_extts_flags |= PTP_EXTTS_EDGES;
        /* Reject unsupported flags */
        if (req.extts.flags & ~supported_extts_flags)
                return -EOPNOTSUPP;

        scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux)
                return ops->enable(ops, &req, req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0);
}

static long ptp_perout_request(struct ptp_clock *ptp, unsigned int cmd, void __user *arg)
{
        struct ptp_clock_request req = { .type = PTP_CLK_REQ_PEROUT };
        struct ptp_perout_request *perout = &req.perout;
        struct ptp_clock_info *ops = ptp->info;

        if (copy_from_user(perout, arg, sizeof(*perout)))
                return -EFAULT;

        if (cmd == PTP_PEROUT_REQUEST2) {
                if (perout->flags & ~PTP_PEROUT_VALID_FLAGS)
                        return -EINVAL;

                /*
                 * 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) &&
                    !mem_is_zero(perout->rsv, sizeof(perout->rsv)))
                        return -EINVAL;

                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))
                                return -ERANGE;
                }

                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))
                                return -ERANGE;
                }
        } else {
                perout->flags &= PTP_PEROUT_V1_VALID_FLAGS;
                memset(perout->rsv, 0, sizeof(perout->rsv));
        }

        if (perout->index >= ops->n_per_out)
                return -EINVAL;
        if (perout->flags & ~ops->supported_perout_flags)
                return -EOPNOTSUPP;

        scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux)
                return ops->enable(ops, &req, perout->period.sec || perout->period.nsec);
}

static long ptp_enable_pps(struct ptp_clock *ptp, bool enable)
{
        struct ptp_clock_request req = { .type = PTP_CLK_REQ_PPS };
        struct ptp_clock_info *ops = ptp->info;

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

        scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux)
                return ops->enable(ops, &req, enable);
}

typedef int (*ptp_crosststamp_fn)(struct ptp_clock_info *,
                                  struct system_device_crosststamp *);

static long ptp_sys_offset_precise(struct ptp_clock *ptp, void __user *arg,
                                   ptp_crosststamp_fn crosststamp_fn)
{
        struct ptp_sys_offset_precise precise_offset;
        struct system_device_crosststamp xtstamp;
        struct timespec64 ts;
        int err;

        if (!crosststamp_fn)
                return -EOPNOTSUPP;

        err = crosststamp_fn(ptp->info, &xtstamp);
        if (err)
                return err;

        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;

        return copy_to_user(arg, &precise_offset, sizeof(precise_offset)) ? -EFAULT : 0;
}

typedef int (*ptp_gettimex_fn)(struct ptp_clock_info *,
                               struct timespec64 *,
                               struct ptp_system_timestamp *);

static long ptp_sys_offset_extended(struct ptp_clock *ptp, void __user *arg,
                                    ptp_gettimex_fn gettimex_fn)
{
        struct ptp_sys_offset_extended *extoff __free(kfree) = NULL;
        struct ptp_system_timestamp sts;

        if (!gettimex_fn)
                return -EOPNOTSUPP;

        extoff = memdup_user(arg, sizeof(*extoff));
        if (IS_ERR(extoff))
                return PTR_ERR(extoff);

        if (extoff->n_samples > PTP_MAX_SAMPLES || extoff->rsv[0] || extoff->rsv[1])
                return -EINVAL;

        switch (extoff->clockid) {
        case CLOCK_REALTIME:
        case CLOCK_MONOTONIC:
        case CLOCK_MONOTONIC_RAW:
                break;
        case CLOCK_AUX ... CLOCK_AUX_LAST:
                if (IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS))
                        break;
                fallthrough;
        default:
                return -EINVAL;
        }

        sts.clockid = extoff->clockid;
        for (unsigned int i = 0; i < extoff->n_samples; i++) {
                struct timespec64 ts;
                int err;

                err = gettimex_fn(ptp->info, &ts, &sts);
                if (err)
                        return err;

                /* Filter out disabled or unavailable clocks */
                if (sts.pre_ts.tv_sec < 0 || sts.post_ts.tv_sec < 0)
                        return -EINVAL;

                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;
        }

        return copy_to_user(arg, extoff, sizeof(*extoff)) ? -EFAULT : 0;
}

static long ptp_sys_offset(struct ptp_clock *ptp, void __user *arg)
{
        struct ptp_sys_offset *sysoff __free(kfree) = NULL;
        struct ptp_clock_time *pct;
        struct timespec64 ts;

        sysoff = memdup_user(arg, sizeof(*sysoff));
        if (IS_ERR(sysoff))
                return PTR_ERR(sysoff);

        if (sysoff->n_samples > PTP_MAX_SAMPLES)
                return -EINVAL;

        pct = &sysoff->ts[0];
        for (unsigned int i = 0; i < sysoff->n_samples; i++) {
                struct ptp_clock_info *ops = ptp->info;
                int err;

                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)
                        return err;
                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;

        return copy_to_user(arg, sysoff, sizeof(*sysoff)) ? -EFAULT : 0;
}

static long ptp_pin_getfunc(struct ptp_clock *ptp, unsigned int cmd, void __user *arg)
{
        struct ptp_clock_info *ops = ptp->info;
        struct ptp_pin_desc pd;

        if (copy_from_user(&pd, arg, sizeof(pd)))
                return -EFAULT;

        if (cmd == PTP_PIN_GETFUNC2 && !mem_is_zero(pd.rsv, sizeof(pd.rsv)))
                return -EINVAL;

        if (pd.index >= ops->n_pins)
                return -EINVAL;

        scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux)
                pd = ops->pin_config[array_index_nospec(pd.index, ops->n_pins)];

        return copy_to_user(arg, &pd, sizeof(pd)) ? -EFAULT : 0;
}

static long ptp_pin_setfunc(struct ptp_clock *ptp, unsigned int cmd, void __user *arg)
{
        struct ptp_clock_info *ops = ptp->info;
        struct ptp_pin_desc pd;
        unsigned int pin_index;

        if (copy_from_user(&pd, arg, sizeof(pd)))
                return -EFAULT;

        if (cmd == PTP_PIN_SETFUNC2 && !mem_is_zero(pd.rsv, sizeof(pd.rsv)))
                return -EINVAL;

        if (pd.index >= ops->n_pins)
                return -EINVAL;

        pin_index = array_index_nospec(pd.index, ops->n_pins);
        scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &ptp->pincfg_mux)
                return ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
}

static long ptp_mask_clear_all(struct timestamp_event_queue *tsevq)
{
        bitmap_clear(tsevq->mask, 0, PTP_MAX_CHANNELS);
        return 0;
}

static long ptp_mask_en_single(struct timestamp_event_queue *tsevq, void __user *arg)
{
        unsigned int channel;

        if (copy_from_user(&channel, arg, sizeof(channel)))
                return -EFAULT;
        if (channel >= PTP_MAX_CHANNELS)
                return -EFAULT;
        set_bit(channel, tsevq->mask);
        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);
        void __user *argptr;

        if (in_compat_syscall() && cmd != PTP_ENABLE_PPS && cmd != PTP_ENABLE_PPS2)
                arg = (unsigned long)compat_ptr(arg);
        argptr = (void __force __user *)arg;

        switch (cmd) {
        case PTP_CLOCK_GETCAPS:
        case PTP_CLOCK_GETCAPS2:
                return ptp_clock_getcaps(ptp, argptr);

        case PTP_EXTTS_REQUEST:
        case PTP_EXTTS_REQUEST2:
                if ((pccontext->fp->f_mode & FMODE_WRITE) == 0)
                        return -EACCES;
                return ptp_extts_request(ptp, cmd, argptr);

        case PTP_PEROUT_REQUEST:
        case PTP_PEROUT_REQUEST2:
                if ((pccontext->fp->f_mode & FMODE_WRITE) == 0)
                        return -EACCES;
                return ptp_perout_request(ptp, cmd, argptr);

        case PTP_ENABLE_PPS:
        case PTP_ENABLE_PPS2:
                if ((pccontext->fp->f_mode & FMODE_WRITE) == 0)
                        return -EACCES;
                return ptp_enable_pps(ptp, !!arg);

        case PTP_SYS_OFFSET_PRECISE:
        case PTP_SYS_OFFSET_PRECISE2:
                return ptp_sys_offset_precise(ptp, argptr,
                                              ptp->info->getcrosststamp);

        case PTP_SYS_OFFSET_EXTENDED:
        case PTP_SYS_OFFSET_EXTENDED2:
                return ptp_sys_offset_extended(ptp, argptr,
                                               ptp->info->gettimex64);

        case PTP_SYS_OFFSET:
        case PTP_SYS_OFFSET2:
                return ptp_sys_offset(ptp, argptr);

        case PTP_PIN_GETFUNC:
        case PTP_PIN_GETFUNC2:
                return ptp_pin_getfunc(ptp, cmd, argptr);

        case PTP_PIN_SETFUNC:
        case PTP_PIN_SETFUNC2:
                if ((pccontext->fp->f_mode & FMODE_WRITE) == 0)
                        return -EACCES;
                return ptp_pin_setfunc(ptp, cmd, argptr);

        case PTP_MASK_CLEAR_ALL:
                return ptp_mask_clear_all(pccontext->private_clkdata);

        case PTP_MASK_EN_SINGLE:
                return ptp_mask_en_single(pccontext->private_clkdata, argptr);

        case PTP_SYS_OFFSET_PRECISE_CYCLES:
                if (!ptp->has_cycles)
                        return -EOPNOTSUPP;
                return ptp_sys_offset_precise(ptp, argptr,
                                              ptp->info->getcrosscycles);

        case PTP_SYS_OFFSET_EXTENDED_CYCLES:
                if (!ptp->has_cycles)
                        return -EOPNOTSUPP;
                return ptp_sys_offset_extended(ptp, argptr,
                                               ptp->info->getcyclesx64);
        default:
                return -ENOTTY;
        }
}

__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;
        ssize_t result;

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

        if (cnt % sizeof(*event) != 0)
                return -EINVAL;

        if (cnt > EXTTS_BUFSIZE)
                cnt = EXTTS_BUFSIZE;

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

        if (ptp->defunct)
                return -ENODEV;

        event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
        if (!event)
                return -ENOMEM;

        scoped_guard(spinlock_irq, &queue->lock) {
                size_t qcnt = min((size_t)queue_cnt(queue), cnt / sizeof(*event));

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

        result = cnt;
        if (copy_to_user(buf, event, cnt))
                result = -EFAULT;

        kfree(event);
        return result;
}