// SPDX-License-Identifier: GPL-2.0-only
/*******************************************************************************
  PTP 1588 clock using the STMMAC.

  Copyright (C) 2013  Vayavya Labs Pvt Ltd


  Author: Rayagond Kokatanur <rayagond@vayavyalabs.com>
*******************************************************************************/
#include "stmmac.h"
#include "stmmac_ptp.h"

#define PTP_SAFE_TIME_OFFSET_NS 500000

/**
 * stmmac_adjust_freq
 *
 * @ptp: pointer to ptp_clock_info structure
 * @scaled_ppm: desired period change in scaled parts per million
 *
 * Description: this function will adjust the frequency of hardware clock.
 *
 * Scaled parts per million is ppm with a 16-bit binary fractional field.
 */
static int stmmac_adjust_freq(struct ptp_clock_info *ptp, long scaled_ppm)
{
        struct stmmac_priv *priv =
            container_of(ptp, struct stmmac_priv, ptp_clock_ops);
        unsigned long flags;
        u32 addend;

        addend = adjust_by_scaled_ppm(priv->default_addend, scaled_ppm);

        write_lock_irqsave(&priv->ptp_lock, flags);
        stmmac_config_addend(priv, priv->ptpaddr, addend);
        write_unlock_irqrestore(&priv->ptp_lock, flags);

        return 0;
}

/**
 * stmmac_adjust_time
 *
 * @ptp: pointer to ptp_clock_info structure
 * @delta: desired change in nanoseconds
 *
 * Description: this function will shift/adjust the hardware clock time.
 */
static int stmmac_adjust_time(struct ptp_clock_info *ptp, s64 delta)
{
        struct stmmac_priv *priv =
            container_of(ptp, struct stmmac_priv, ptp_clock_ops);
        unsigned long flags;
        u32 sec, nsec;
        u32 quotient, reminder;
        int neg_adj = 0;
        bool xmac, est_rst = false;
        int ret;

        xmac = dwmac_is_xmac(priv->plat->core_type);

        if (delta < 0) {
                neg_adj = 1;
                delta = -delta;
        }

        quotient = div_u64_rem(delta, 1000000000ULL, &reminder);
        sec = quotient;
        nsec = reminder;

        /* If EST is enabled, disabled it before adjust ptp time. */
        if (priv->est && priv->est->enable) {
                est_rst = true;
                mutex_lock(&priv->est_lock);
                priv->est->enable = false;
                stmmac_est_configure(priv, priv, priv->est,
                                     priv->plat->clk_ptp_rate);
                mutex_unlock(&priv->est_lock);
        }

        write_lock_irqsave(&priv->ptp_lock, flags);
        stmmac_adjust_systime(priv, priv->ptpaddr, sec, nsec, neg_adj, xmac);
        write_unlock_irqrestore(&priv->ptp_lock, flags);

        /* Calculate new basetime and re-configured EST after PTP time adjust. */
        if (est_rst) {
                struct timespec64 current_time, time;
                ktime_t current_time_ns, basetime;
                u64 cycle_time;

                mutex_lock(&priv->est_lock);
                priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops, &current_time);
                current_time_ns = timespec64_to_ktime(current_time);
                time.tv_nsec = priv->est->btr_reserve[0];
                time.tv_sec = priv->est->btr_reserve[1];
                basetime = timespec64_to_ktime(time);
                cycle_time = (u64)priv->est->ctr[1] * NSEC_PER_SEC +
                             priv->est->ctr[0];
                time = stmmac_calc_tas_basetime(basetime,
                                                current_time_ns,
                                                cycle_time);

                priv->est->btr[0] = (u32)time.tv_nsec;
                priv->est->btr[1] = (u32)time.tv_sec;
                priv->est->enable = true;
                ret = stmmac_est_configure(priv, priv, priv->est,
                                           priv->plat->clk_ptp_rate);
                mutex_unlock(&priv->est_lock);
                if (ret)
                        netdev_err(priv->dev, "failed to configure EST\n");
        }

        return 0;
}

/**
 * stmmac_get_time
 *
 * @ptp: pointer to ptp_clock_info structure
 * @ts: pointer to hold time/result
 *
 * Description: this function will read the current time from the
 * hardware clock and store it in @ts.
 */
static int stmmac_get_time(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
        struct stmmac_priv *priv =
            container_of(ptp, struct stmmac_priv, ptp_clock_ops);
        unsigned long flags;
        u64 ns = 0;

        read_lock_irqsave(&priv->ptp_lock, flags);
        stmmac_get_systime(priv, priv->ptpaddr, &ns);
        read_unlock_irqrestore(&priv->ptp_lock, flags);

        *ts = ns_to_timespec64(ns);

        return 0;
}

/**
 * stmmac_set_time
 *
 * @ptp: pointer to ptp_clock_info structure
 * @ts: time value to set
 *
 * Description: this function will set the current time on the
 * hardware clock.
 */
static int stmmac_set_time(struct ptp_clock_info *ptp,
                           const struct timespec64 *ts)
{
        struct stmmac_priv *priv =
            container_of(ptp, struct stmmac_priv, ptp_clock_ops);
        unsigned long flags;

        write_lock_irqsave(&priv->ptp_lock, flags);
        stmmac_init_systime(priv, priv->ptpaddr, ts->tv_sec, ts->tv_nsec);
        write_unlock_irqrestore(&priv->ptp_lock, flags);

        return 0;
}

static int stmmac_enable(struct ptp_clock_info *ptp,
                         struct ptp_clock_request *rq, int on)
{
        struct stmmac_priv *priv =
            container_of(ptp, struct stmmac_priv, ptp_clock_ops);
        void __iomem *ptpaddr = priv->ptpaddr;
        struct stmmac_pps_cfg *cfg;
        int ret = -EOPNOTSUPP;
        unsigned long flags;
        u32 acr_value;

        switch (rq->type) {
        case PTP_CLK_REQ_PEROUT: {
                struct timespec64 curr_time;
                u64 target_ns = 0;
                u64 ns = 0;

                /* Reject requests with unsupported flags */
                if (rq->perout.flags)
                        return -EOPNOTSUPP;

                cfg = &priv->pps[rq->perout.index];

                cfg->start.tv_sec = rq->perout.start.sec;
                cfg->start.tv_nsec = rq->perout.start.nsec;

                /* A time set in the past won't trigger the start of the flexible PPS generation for
                 * the GMAC5. For some reason it does for the GMAC4 but setting a time in the past
                 * should be addressed anyway. Therefore, any value set it the past is considered as
                 * an offset compared to the current MAC system time.
                 * Be aware that an offset too low may not trigger flexible PPS generation
                 * if time spent in this configuration makes the targeted time already outdated.
                 * To address this, add a safe time offset.
                 */
                if (!cfg->start.tv_sec && cfg->start.tv_nsec < PTP_SAFE_TIME_OFFSET_NS)
                        cfg->start.tv_nsec += PTP_SAFE_TIME_OFFSET_NS;

                target_ns = cfg->start.tv_nsec + ((u64)cfg->start.tv_sec * NSEC_PER_SEC);

                stmmac_get_systime(priv, priv->ptpaddr, &ns);
                if (ns > TIME64_MAX - PTP_SAFE_TIME_OFFSET_NS)
                        return -EINVAL;

                curr_time = ns_to_timespec64(ns);
                if (target_ns < ns + PTP_SAFE_TIME_OFFSET_NS) {
                        cfg->start = timespec64_add_safe(cfg->start, curr_time);
                        if (cfg->start.tv_sec == TIME64_MAX)
                                return -EINVAL;
                }

                cfg->period.tv_sec = rq->perout.period.sec;
                cfg->period.tv_nsec = rq->perout.period.nsec;

                write_lock_irqsave(&priv->ptp_lock, flags);
                ret = stmmac_flex_pps_config(priv, priv->ioaddr,
                                             rq->perout.index, cfg, on,
                                             priv->sub_second_inc,
                                             priv->systime_flags);
                write_unlock_irqrestore(&priv->ptp_lock, flags);
                break;
        }
        case PTP_CLK_REQ_EXTTS: {
                u8 channel;

                mutex_lock(&priv->aux_ts_lock);
                acr_value = readl(ptpaddr + PTP_ACR);
                channel = ilog2(FIELD_GET(PTP_ACR_MASK, acr_value));
                acr_value &= ~PTP_ACR_MASK;

                if (on) {
                        if (FIELD_GET(PTP_ACR_MASK, acr_value)) {
                                netdev_err(priv->dev,
                                           "Cannot enable auxiliary snapshot %d as auxiliary snapshot %d is already enabled",
                                        rq->extts.index, channel);
                                mutex_unlock(&priv->aux_ts_lock);
                                return -EBUSY;
                        }

                        priv->plat->flags |= STMMAC_FLAG_EXT_SNAPSHOT_EN;

                        /* Enable External snapshot trigger */
                        acr_value |= PTP_ACR_ATSEN(rq->extts.index);
                        acr_value |= PTP_ACR_ATSFC;
                } else {
                        priv->plat->flags &= ~STMMAC_FLAG_EXT_SNAPSHOT_EN;
                }
                netdev_dbg(priv->dev, "Auxiliary Snapshot %d %s.\n",
                           rq->extts.index, on ? "enabled" : "disabled");
                writel(acr_value, ptpaddr + PTP_ACR);
                mutex_unlock(&priv->aux_ts_lock);
                /* wait for auxts fifo clear to finish */
                ret = readl_poll_timeout(ptpaddr + PTP_ACR, acr_value,
                                         !(acr_value & PTP_ACR_ATSFC),
                                         10, 10000);
                break;
        }

        default:
                break;
        }

        return ret;
}

/**
 * stmmac_get_syncdevicetime
 * @device: current device time
 * @system: system counter value read synchronously with device time
 * @ctx: context provided by timekeeping code
 * Description: Read device and system clock simultaneously and return the
 * corrected clock values in ns.
 **/
static int stmmac_get_syncdevicetime(ktime_t *device,
                                     struct system_counterval_t *system,
                                     void *ctx)
{
        struct stmmac_priv *priv = (struct stmmac_priv *)ctx;

        return priv->plat->crosststamp(device, system, ctx);
}

static int stmmac_getcrosststamp(struct ptp_clock_info *ptp,
                                 struct system_device_crosststamp *xtstamp)
{
        struct stmmac_priv *priv =
                container_of(ptp, struct stmmac_priv, ptp_clock_ops);

        return get_device_system_crosststamp(stmmac_get_syncdevicetime,
                                             priv, NULL, xtstamp);
}

/* structure describing a PTP hardware clock */
const struct ptp_clock_info stmmac_ptp_clock_ops = {
        .owner = THIS_MODULE,
        .name = "stmmac ptp",
        .max_adj = 62500000,
        .n_alarm = 0,
        .n_ext_ts = 0, /* will be overwritten in stmmac_ptp_register */
        .n_per_out = 0, /* will be overwritten in stmmac_ptp_register */
        .n_pins = 0,
        .pps = 0,
        .adjfine = stmmac_adjust_freq,
        .adjtime = stmmac_adjust_time,
        .gettime64 = stmmac_get_time,
        .settime64 = stmmac_set_time,
        .enable = stmmac_enable,
};

/* structure describing a PTP hardware clock */
const struct ptp_clock_info dwmac1000_ptp_clock_ops = {
        .owner = THIS_MODULE,
        .name = "stmmac ptp",
        .max_adj = 62500000,
        .n_alarm = 0,
        .n_ext_ts = 1,
        .n_per_out = 0,
        .n_pins = 0,
        .pps = 0,
        .adjfine = stmmac_adjust_freq,
        .adjtime = stmmac_adjust_time,
        .gettime64 = stmmac_get_time,
        .settime64 = stmmac_set_time,
        .enable = dwmac1000_ptp_enable,
};

/**
 * stmmac_ptp_register
 * @priv: driver private structure
 * Description: this function will register the ptp clock driver
 * to kernel. It also does some house keeping work.
 */
void stmmac_ptp_register(struct stmmac_priv *priv)
{
        int i;

        for (i = 0; i < priv->dma_cap.pps_out_num; i++) {
                if (i >= STMMAC_PPS_MAX)
                        break;
                priv->pps[i].available = true;
        }

        /* Calculate the clock domain crossing (CDC) error if necessary */
        priv->plat->cdc_error_adj = 0;
        if (priv->plat->core_type == DWMAC_CORE_GMAC4)
                priv->plat->cdc_error_adj = (2 * NSEC_PER_SEC) / priv->plat->clk_ptp_rate;

        /* Update the ptp clock parameters based on feature discovery, when
         * available
         */
        if (priv->dma_cap.pps_out_num)
                priv->ptp_clock_ops.n_per_out = priv->dma_cap.pps_out_num;

        if (priv->dma_cap.aux_snapshot_n)
                priv->ptp_clock_ops.n_ext_ts = priv->dma_cap.aux_snapshot_n;

        if (priv->plat->ptp_max_adj)
                priv->ptp_clock_ops.max_adj = priv->plat->ptp_max_adj;

        if (priv->plat->crosststamp)
                priv->ptp_clock_ops.getcrosststamp = stmmac_getcrosststamp;

        rwlock_init(&priv->ptp_lock);
        mutex_init(&priv->aux_ts_lock);

        priv->ptp_clock = ptp_clock_register(&priv->ptp_clock_ops,
                                             priv->device);
        if (IS_ERR(priv->ptp_clock)) {
                netdev_err(priv->dev, "ptp_clock_register failed\n");
                priv->ptp_clock = NULL;
        }

        if (priv->ptp_clock)
                netdev_info(priv->dev, "registered PTP clock\n");
        else
                mutex_destroy(&priv->aux_ts_lock);
}

/**
 * stmmac_ptp_unregister
 * @priv: driver private structure
 * Description: this function will remove/unregister the ptp clock driver
 * from the kernel.
 */
void stmmac_ptp_unregister(struct stmmac_priv *priv)
{
        if (priv->ptp_clock) {
                ptp_clock_unregister(priv->ptp_clock);
                priv->ptp_clock = NULL;
                pr_debug("Removed PTP HW clock successfully on %s\n",
                         priv->dev->name);

                mutex_destroy(&priv->aux_ts_lock);
        }
}