// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
 */
#include <linux/spi/spi.h>
#include "sja1105.h"

/* The adjfine API clamps ppb between [-32,768,000, 32,768,000], and
 * therefore scaled_ppm between [-2,147,483,648, 2,147,483,647].
 * Set the maximum supported ppb to a round value smaller than the maximum.
 *
 * Percentually speaking, this is a +/- 0.032x adjustment of the
 * free-running counter (0.968x to 1.032x).
 */
#define SJA1105_MAX_ADJ_PPB             32000000
#define SJA1105_SIZE_PTP_CMD            4

/* PTPSYNCTS has no interrupt or update mechanism, because the intended
 * hardware use case is for the timestamp to be collected synchronously,
 * immediately after the CAS_MASTER SJA1105 switch has performed a CASSYNC
 * one-shot toggle (no return to level) on the PTP_CLK pin. When used as a
 * generic extts source, the PTPSYNCTS register needs polling and a comparison
 * with the old value. The polling interval is configured as the Nyquist rate
 * of a signal with 50% duty cycle and 1Hz frequency, which is sadly all that
 * this hardware can do (but may be enough for some setups). Anything of higher
 * frequency than 1 Hz will be lost, since there is no timestamp FIFO.
 */
#define SJA1105_EXTTS_INTERVAL          (HZ / 6)

/*            This range is actually +/- SJA1105_MAX_ADJ_PPB
 *            divided by 1000 (ppb -> ppm) and with a 16-bit
 *            "fractional" part (actually fixed point).
 *                                    |
 *                                    v
 * Convert scaled_ppm from the +/- ((10^6) << 16) range
 * into the +/- (1 << 31) range.
 *
 * This forgoes a "ppb" numeric representation (up to NSEC_PER_SEC)
 * and defines the scaling factor between scaled_ppm and the actual
 * frequency adjustments of the PHC.
 *
 *   ptpclkrate = scaled_ppm * 2^31 / (10^6 * 2^16)
 *   simplifies to
 *   ptpclkrate = scaled_ppm * 2^9 / 5^6
 */
#define SJA1105_CC_MULT_NUM             (1 << 9)
#define SJA1105_CC_MULT_DEM             15625
#define SJA1105_CC_MULT                 0x80000000

enum sja1105_ptp_clk_mode {
        PTP_ADD_MODE = 1,
        PTP_SET_MODE = 0,
};

#define extts_to_data(t) \
                container_of((t), struct sja1105_ptp_data, extts_timer)
#define ptp_caps_to_data(d) \
                container_of((d), struct sja1105_ptp_data, caps)
#define ptp_data_to_sja1105(d) \
                container_of((d), struct sja1105_private, ptp_data)

int sja1105_hwtstamp_set(struct dsa_switch *ds, int port,
                         struct kernel_hwtstamp_config *config,
                         struct netlink_ext_ack *extack)
{
        struct sja1105_private *priv = ds->priv;
        unsigned long hwts_tx_en, hwts_rx_en;

        hwts_tx_en = priv->hwts_tx_en;
        hwts_rx_en = priv->hwts_rx_en;

        switch (config->tx_type) {
        case HWTSTAMP_TX_OFF:
                hwts_tx_en &= ~BIT(port);
                break;
        case HWTSTAMP_TX_ON:
                hwts_tx_en |= BIT(port);
                break;
        default:
                return -ERANGE;
        }

        switch (config->rx_filter) {
        case HWTSTAMP_FILTER_NONE:
                hwts_rx_en &= ~BIT(port);
                break;
        case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
                hwts_rx_en |= BIT(port);
                break;
        default:
                return -ERANGE;
        }

        priv->hwts_tx_en = hwts_tx_en;
        priv->hwts_rx_en = hwts_rx_en;

        return 0;
}

int sja1105_hwtstamp_get(struct dsa_switch *ds, int port,
                         struct kernel_hwtstamp_config *config)
{
        struct sja1105_private *priv = ds->priv;

        config->flags = 0;
        if (priv->hwts_tx_en & BIT(port))
                config->tx_type = HWTSTAMP_TX_ON;
        else
                config->tx_type = HWTSTAMP_TX_OFF;
        if (priv->hwts_rx_en & BIT(port))
                config->rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
        else
                config->rx_filter = HWTSTAMP_FILTER_NONE;

        return 0;
}

int sja1105_get_ts_info(struct dsa_switch *ds, int port,
                        struct kernel_ethtool_ts_info *info)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;

        /* Called during cleanup */
        if (!ptp_data->clock)
                return -ENODEV;

        info->so_timestamping = SOF_TIMESTAMPING_TX_HARDWARE |
                                SOF_TIMESTAMPING_RX_HARDWARE |
                                SOF_TIMESTAMPING_RAW_HARDWARE;
        info->tx_types = (1 << HWTSTAMP_TX_OFF) |
                         (1 << HWTSTAMP_TX_ON);
        info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |
                           (1 << HWTSTAMP_FILTER_PTP_V2_L2_EVENT);
        info->phc_index = ptp_clock_index(ptp_data->clock);
        return 0;
}

void sja1105et_ptp_cmd_packing(u8 *buf, struct sja1105_ptp_cmd *cmd,
                               enum packing_op op)
{
        const int size = SJA1105_SIZE_PTP_CMD;
        /* No need to keep this as part of the structure */
        u64 valid = 1;

        sja1105_packing(buf, &valid,           31, 31, size, op);
        sja1105_packing(buf, &cmd->ptpstrtsch, 30, 30, size, op);
        sja1105_packing(buf, &cmd->ptpstopsch, 29, 29, size, op);
        sja1105_packing(buf, &cmd->startptpcp, 28, 28, size, op);
        sja1105_packing(buf, &cmd->stopptpcp,  27, 27, size, op);
        sja1105_packing(buf, &cmd->resptp,      2,  2, size, op);
        sja1105_packing(buf, &cmd->corrclk4ts,  1,  1, size, op);
        sja1105_packing(buf, &cmd->ptpclkadd,   0,  0, size, op);
}

void sja1105pqrs_ptp_cmd_packing(u8 *buf, struct sja1105_ptp_cmd *cmd,
                                 enum packing_op op)
{
        const int size = SJA1105_SIZE_PTP_CMD;
        /* No need to keep this as part of the structure */
        u64 valid = 1;

        sja1105_packing(buf, &valid,           31, 31, size, op);
        sja1105_packing(buf, &cmd->ptpstrtsch, 30, 30, size, op);
        sja1105_packing(buf, &cmd->ptpstopsch, 29, 29, size, op);
        sja1105_packing(buf, &cmd->startptpcp, 28, 28, size, op);
        sja1105_packing(buf, &cmd->stopptpcp,  27, 27, size, op);
        sja1105_packing(buf, &cmd->resptp,      3,  3, size, op);
        sja1105_packing(buf, &cmd->corrclk4ts,  2,  2, size, op);
        sja1105_packing(buf, &cmd->ptpclkadd,   0,  0, size, op);
}

int sja1105_ptp_commit(struct dsa_switch *ds, struct sja1105_ptp_cmd *cmd,
                       sja1105_spi_rw_mode_t rw)
{
        const struct sja1105_private *priv = ds->priv;
        const struct sja1105_regs *regs = priv->info->regs;
        u8 buf[SJA1105_SIZE_PTP_CMD] = {0};
        int rc;

        if (rw == SPI_WRITE)
                priv->info->ptp_cmd_packing(buf, cmd, PACK);

        rc = sja1105_xfer_buf(priv, rw, regs->ptp_control, buf,
                              SJA1105_SIZE_PTP_CMD);

        if (rw == SPI_READ)
                priv->info->ptp_cmd_packing(buf, cmd, UNPACK);

        return rc;
}

/* The switch returns partial timestamps (24 bits for SJA1105 E/T, which wrap
 * around in 0.135 seconds, and 32 bits for P/Q/R/S, wrapping around in 34.35
 * seconds).
 *
 * This receives the RX or TX MAC timestamps, provided by hardware as
 * the lower bits of the cycle counter, sampled at the time the timestamp was
 * collected.
 *
 * To reconstruct into a full 64-bit-wide timestamp, the cycle counter is
 * read and the high-order bits are filled in.
 *
 * Must be called within one wraparound period of the partial timestamp since
 * it was generated by the MAC.
 */
static u64 sja1105_tstamp_reconstruct(struct dsa_switch *ds, u64 now,
                                      u64 ts_partial)
{
        struct sja1105_private *priv = ds->priv;
        u64 partial_tstamp_mask = CYCLECOUNTER_MASK(priv->info->ptp_ts_bits);
        u64 ts_reconstructed;

        ts_reconstructed = (now & ~partial_tstamp_mask) | ts_partial;

        /* Check lower bits of current cycle counter against the timestamp.
         * If the current cycle counter is lower than the partial timestamp,
         * then wraparound surely occurred and must be accounted for.
         */
        if ((now & partial_tstamp_mask) <= ts_partial)
                ts_reconstructed -= (partial_tstamp_mask + 1);

        return ts_reconstructed;
}

/* Reads the SPI interface for an egress timestamp generated by the switch
 * for frames sent using management routes.
 *
 * SJA1105 E/T layout of the 4-byte SPI payload:
 *
 * 31    23    15    7     0
 * |     |     |     |     |
 * +-----+-----+-----+     ^
 *          ^              |
 *          |              |
 *  24-bit timestamp   Update bit
 *
 *
 * SJA1105 P/Q/R/S layout of the 8-byte SPI payload:
 *
 * 31    23    15    7     0     63    55    47    39    32
 * |     |     |     |     |     |     |     |     |     |
 *                         ^     +-----+-----+-----+-----+
 *                         |                 ^
 *                         |                 |
 *                    Update bit    32-bit timestamp
 *
 * Notice that the update bit is in the same place.
 * To have common code for E/T and P/Q/R/S for reading the timestamp,
 * we need to juggle with the offset and the bit indices.
 */
static int sja1105_ptpegr_ts_poll(struct dsa_switch *ds, int port, u64 *ts)
{
        struct sja1105_private *priv = ds->priv;
        const struct sja1105_regs *regs = priv->info->regs;
        int tstamp_bit_start, tstamp_bit_end;
        int timeout = 10;
        u8 packed_buf[8];
        u64 update;
        int rc;

        do {
                rc = sja1105_xfer_buf(priv, SPI_READ, regs->ptpegr_ts[port],
                                      packed_buf, priv->info->ptpegr_ts_bytes);
                if (rc < 0)
                        return rc;

                sja1105_unpack(packed_buf, &update, 0, 0,
                               priv->info->ptpegr_ts_bytes);
                if (update)
                        break;

                usleep_range(10, 50);
        } while (--timeout);

        if (!timeout)
                return -ETIMEDOUT;

        /* Point the end bit to the second 32-bit word on P/Q/R/S,
         * no-op on E/T.
         */
        tstamp_bit_end = (priv->info->ptpegr_ts_bytes - 4) * 8;
        /* Shift the 24-bit timestamp on E/T to be collected from 31:8.
         * No-op on P/Q/R/S.
         */
        tstamp_bit_end += 32 - priv->info->ptp_ts_bits;
        tstamp_bit_start = tstamp_bit_end + priv->info->ptp_ts_bits - 1;

        *ts = 0;

        sja1105_unpack(packed_buf, ts, tstamp_bit_start, tstamp_bit_end,
                       priv->info->ptpegr_ts_bytes);

        return 0;
}

/* Caller must hold ptp_data->lock */
static int sja1105_ptpclkval_read(struct sja1105_private *priv, u64 *ticks,
                                  struct ptp_system_timestamp *ptp_sts)
{
        const struct sja1105_regs *regs = priv->info->regs;

        return sja1105_xfer_u64(priv, SPI_READ, regs->ptpclkval, ticks,
                                ptp_sts);
}

/* Caller must hold ptp_data->lock */
static int sja1105_ptpclkval_write(struct sja1105_private *priv, u64 ticks,
                                   struct ptp_system_timestamp *ptp_sts)
{
        const struct sja1105_regs *regs = priv->info->regs;

        return sja1105_xfer_u64(priv, SPI_WRITE, regs->ptpclkval, &ticks,
                                ptp_sts);
}

static void sja1105_extts_poll(struct sja1105_private *priv)
{
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
        const struct sja1105_regs *regs = priv->info->regs;
        struct ptp_clock_event event;
        u64 ptpsyncts = 0;
        int rc;

        rc = sja1105_xfer_u64(priv, SPI_READ, regs->ptpsyncts, &ptpsyncts,
                              NULL);
        if (rc < 0)
                dev_err_ratelimited(priv->ds->dev,
                                    "Failed to read PTPSYNCTS: %d\n", rc);

        if (ptpsyncts && ptp_data->ptpsyncts != ptpsyncts) {
                event.index = 0;
                event.type = PTP_CLOCK_EXTTS;
                event.timestamp = ns_to_ktime(sja1105_ticks_to_ns(ptpsyncts));
                ptp_clock_event(ptp_data->clock, &event);

                ptp_data->ptpsyncts = ptpsyncts;
        }
}

static long sja1105_rxtstamp_work(struct ptp_clock_info *ptp)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);
        struct dsa_switch *ds = priv->ds;
        struct sk_buff *skb;

        mutex_lock(&ptp_data->lock);

        while ((skb = skb_dequeue(&ptp_data->skb_rxtstamp_queue)) != NULL) {
                struct skb_shared_hwtstamps *shwt = skb_hwtstamps(skb);
                u64 ticks, ts;
                int rc;

                rc = sja1105_ptpclkval_read(priv, &ticks, NULL);
                if (rc < 0) {
                        dev_err(ds->dev, "Failed to read PTP clock: %d\n", rc);
                        kfree_skb(skb);
                        continue;
                }

                *shwt = (struct skb_shared_hwtstamps) {0};

                ts = SJA1105_SKB_CB(skb)->tstamp;
                ts = sja1105_tstamp_reconstruct(ds, ticks, ts);

                shwt->hwtstamp = ns_to_ktime(sja1105_ticks_to_ns(ts));
                netif_rx(skb);
        }

        if (ptp_data->extts_enabled)
                sja1105_extts_poll(priv);

        mutex_unlock(&ptp_data->lock);

        /* Don't restart */
        return -1;
}

bool sja1105_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;

        if (!(priv->hwts_rx_en & BIT(port)))
                return false;

        /* We need to read the full PTP clock to reconstruct the Rx
         * timestamp. For that we need a sleepable context.
         */
        skb_queue_tail(&ptp_data->skb_rxtstamp_queue, skb);
        ptp_schedule_worker(ptp_data->clock, 0);
        return true;
}

bool sja1110_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
{
        struct skb_shared_hwtstamps *shwt = skb_hwtstamps(skb);
        u64 ts = SJA1105_SKB_CB(skb)->tstamp;

        *shwt = (struct skb_shared_hwtstamps) {0};

        shwt->hwtstamp = ns_to_ktime(sja1105_ticks_to_ns(ts));

        /* Don't defer */
        return false;
}

/* Called from dsa_skb_defer_rx_timestamp */
bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
                           struct sk_buff *skb, unsigned int type)
{
        struct sja1105_private *priv = ds->priv;

        return priv->info->rxtstamp(ds, port, skb);
}

void sja1110_process_meta_tstamp(struct dsa_switch *ds, int port, u8 ts_id,
                                 enum sja1110_meta_tstamp dir, u64 tstamp)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
        struct sk_buff *skb, *skb_tmp, *skb_match = NULL;
        struct skb_shared_hwtstamps shwt = {0};

        /* We don't care about RX timestamps on the CPU port */
        if (dir == SJA1110_META_TSTAMP_RX)
                return;

        spin_lock(&ptp_data->skb_txtstamp_queue.lock);

        skb_queue_walk_safe(&ptp_data->skb_txtstamp_queue, skb, skb_tmp) {
                if (SJA1105_SKB_CB(skb)->ts_id != ts_id)
                        continue;

                __skb_unlink(skb, &ptp_data->skb_txtstamp_queue);
                skb_match = skb;

                break;
        }

        spin_unlock(&ptp_data->skb_txtstamp_queue.lock);

        if (WARN_ON(!skb_match))
                return;

        shwt.hwtstamp = ns_to_ktime(sja1105_ticks_to_ns(tstamp));
        skb_complete_tx_timestamp(skb_match, &shwt);
}

/* In addition to cloning the skb which is done by the common
 * sja1105_port_txtstamp, we need to generate a timestamp ID and save the
 * packet to the TX timestamping queue.
 */
void sja1110_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
{
        struct sk_buff *clone = SJA1105_SKB_CB(skb)->clone;
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
        u8 ts_id;

        skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;

        spin_lock(&priv->ts_id_lock);

        ts_id = priv->ts_id;
        /* Deal automatically with 8-bit wraparound */
        priv->ts_id++;

        SJA1105_SKB_CB(clone)->ts_id = ts_id;

        spin_unlock(&priv->ts_id_lock);

        skb_queue_tail(&ptp_data->skb_txtstamp_queue, clone);
}

/* Called from dsa_skb_tx_timestamp. This callback is just to clone
 * the skb and have it available in SJA1105_SKB_CB in the .port_deferred_xmit
 * callback, where we will timestamp it synchronously.
 */
void sja1105_port_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb)
{
        struct sja1105_private *priv = ds->priv;
        struct sk_buff *clone;

        if (!(priv->hwts_tx_en & BIT(port)))
                return;

        clone = skb_clone_sk(skb);
        if (!clone)
                return;

        SJA1105_SKB_CB(skb)->clone = clone;

        if (priv->info->txtstamp)
                priv->info->txtstamp(ds, port, skb);
}

static int sja1105_ptp_reset(struct dsa_switch *ds)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
        struct sja1105_ptp_cmd cmd = ptp_data->cmd;
        int rc;

        mutex_lock(&ptp_data->lock);

        cmd.resptp = 1;

        dev_dbg(ds->dev, "Resetting PTP clock\n");
        rc = sja1105_ptp_commit(ds, &cmd, SPI_WRITE);

        sja1105_tas_clockstep(priv->ds);

        mutex_unlock(&ptp_data->lock);

        return rc;
}

/* Caller must hold ptp_data->lock */
int __sja1105_ptp_gettimex(struct dsa_switch *ds, u64 *ns,
                           struct ptp_system_timestamp *ptp_sts)
{
        struct sja1105_private *priv = ds->priv;
        u64 ticks;
        int rc;

        rc = sja1105_ptpclkval_read(priv, &ticks, ptp_sts);
        if (rc < 0) {
                dev_err(ds->dev, "Failed to read PTP clock: %d\n", rc);
                return rc;
        }

        *ns = sja1105_ticks_to_ns(ticks);

        return 0;
}

static int sja1105_ptp_gettimex(struct ptp_clock_info *ptp,
                                struct timespec64 *ts,
                                struct ptp_system_timestamp *ptp_sts)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);
        u64 now = 0;
        int rc;

        mutex_lock(&ptp_data->lock);

        rc = __sja1105_ptp_gettimex(priv->ds, &now, ptp_sts);
        *ts = ns_to_timespec64(now);

        mutex_unlock(&ptp_data->lock);

        return rc;
}

/* Caller must hold ptp_data->lock */
static int sja1105_ptp_mode_set(struct sja1105_private *priv,
                                enum sja1105_ptp_clk_mode mode)
{
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;

        if (ptp_data->cmd.ptpclkadd == mode)
                return 0;

        ptp_data->cmd.ptpclkadd = mode;

        return sja1105_ptp_commit(priv->ds, &ptp_data->cmd, SPI_WRITE);
}

/* Write to PTPCLKVAL while PTPCLKADD is 0 */
int __sja1105_ptp_settime(struct dsa_switch *ds, u64 ns,
                          struct ptp_system_timestamp *ptp_sts)
{
        struct sja1105_private *priv = ds->priv;
        u64 ticks = ns_to_sja1105_ticks(ns);
        int rc;

        rc = sja1105_ptp_mode_set(priv, PTP_SET_MODE);
        if (rc < 0) {
                dev_err(priv->ds->dev, "Failed to put PTPCLK in set mode\n");
                return rc;
        }

        rc = sja1105_ptpclkval_write(priv, ticks, ptp_sts);

        sja1105_tas_clockstep(priv->ds);

        return rc;
}

static int sja1105_ptp_settime(struct ptp_clock_info *ptp,
                               const struct timespec64 *ts)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);
        u64 ns = timespec64_to_ns(ts);
        int rc;

        mutex_lock(&ptp_data->lock);

        rc = __sja1105_ptp_settime(priv->ds, ns, NULL);

        mutex_unlock(&ptp_data->lock);

        return rc;
}

static int sja1105_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);
        const struct sja1105_regs *regs = priv->info->regs;
        u32 clkrate32;
        s64 clkrate;
        int rc;

        clkrate = (s64)scaled_ppm * SJA1105_CC_MULT_NUM;
        clkrate = div_s64(clkrate, SJA1105_CC_MULT_DEM);

        /* Take a +/- value and re-center it around 2^31. */
        clkrate = SJA1105_CC_MULT + clkrate;
        WARN_ON(abs(clkrate) >= GENMASK_ULL(31, 0));
        clkrate32 = clkrate;

        mutex_lock(&ptp_data->lock);

        rc = sja1105_xfer_u32(priv, SPI_WRITE, regs->ptpclkrate, &clkrate32,
                              NULL);

        sja1105_tas_adjfreq(priv->ds);

        mutex_unlock(&ptp_data->lock);

        return rc;
}

/* Write to PTPCLKVAL while PTPCLKADD is 1 */
int __sja1105_ptp_adjtime(struct dsa_switch *ds, s64 delta)
{
        struct sja1105_private *priv = ds->priv;
        s64 ticks = ns_to_sja1105_ticks(delta);
        int rc;

        rc = sja1105_ptp_mode_set(priv, PTP_ADD_MODE);
        if (rc < 0) {
                dev_err(priv->ds->dev, "Failed to put PTPCLK in add mode\n");
                return rc;
        }

        rc = sja1105_ptpclkval_write(priv, ticks, NULL);

        sja1105_tas_clockstep(priv->ds);

        return rc;
}

static int sja1105_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);
        int rc;

        mutex_lock(&ptp_data->lock);

        rc = __sja1105_ptp_adjtime(priv->ds, delta);

        mutex_unlock(&ptp_data->lock);

        return rc;
}

static void sja1105_ptp_extts_setup_timer(struct sja1105_ptp_data *ptp_data)
{
        unsigned long expires = ((jiffies / SJA1105_EXTTS_INTERVAL) + 1) *
                                SJA1105_EXTTS_INTERVAL;

        mod_timer(&ptp_data->extts_timer, expires);
}

static void sja1105_ptp_extts_timer(struct timer_list *t)
{
        struct sja1105_ptp_data *ptp_data = extts_to_data(t);

        ptp_schedule_worker(ptp_data->clock, 0);

        sja1105_ptp_extts_setup_timer(ptp_data);
}

static int sja1105_change_ptp_clk_pin_func(struct sja1105_private *priv,
                                           enum ptp_pin_function func)
{
        struct sja1105_avb_params_entry *avb;
        enum ptp_pin_function old_func;

        avb = priv->static_config.tables[BLK_IDX_AVB_PARAMS].entries;

        if (priv->info->device_id == SJA1105E_DEVICE_ID ||
            priv->info->device_id == SJA1105T_DEVICE_ID ||
            avb->cas_master)
                old_func = PTP_PF_PEROUT;
        else
                old_func = PTP_PF_EXTTS;

        if (func == old_func)
                return 0;

        avb->cas_master = (func == PTP_PF_PEROUT);

        return sja1105_dynamic_config_write(priv, BLK_IDX_AVB_PARAMS, 0, avb,
                                            true);
}

/* The PTP_CLK pin may be configured to toggle with a 50% duty cycle and a
 * frequency f:
 *
 *           NSEC_PER_SEC
 * f = ----------------------
 *     (PTPPINDUR * 8 ns) * 2
 */
static int sja1105_per_out_enable(struct sja1105_private *priv,
                                  struct ptp_perout_request *perout,
                                  bool on)
{
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
        const struct sja1105_regs *regs = priv->info->regs;
        struct sja1105_ptp_cmd cmd = ptp_data->cmd;
        int rc;

        /* We only support one channel */
        if (perout->index != 0)
                return -EOPNOTSUPP;

        mutex_lock(&ptp_data->lock);

        rc = sja1105_change_ptp_clk_pin_func(priv, PTP_PF_PEROUT);
        if (rc)
                goto out;

        if (on) {
                struct timespec64 pin_duration_ts = {
                        .tv_sec = perout->period.sec,
                        .tv_nsec = perout->period.nsec,
                };
                struct timespec64 pin_start_ts = {
                        .tv_sec = perout->start.sec,
                        .tv_nsec = perout->start.nsec,
                };
                u64 pin_duration = timespec64_to_ns(&pin_duration_ts);
                u64 pin_start = timespec64_to_ns(&pin_start_ts);
                u32 pin_duration32;
                u64 now;

                /* ptppindur: 32 bit register which holds the interval between
                 * 2 edges on PTP_CLK. So check for truncation which happens
                 * at periods larger than around 68.7 seconds.
                 */
                pin_duration = ns_to_sja1105_ticks(pin_duration / 2);
                if (pin_duration > U32_MAX) {
                        rc = -ERANGE;
                        goto out;
                }
                pin_duration32 = pin_duration;

                /* ptppins: 64 bit register which needs to hold a PTP time
                 * larger than the current time, otherwise the startptpcp
                 * command won't do anything. So advance the current time
                 * by a number of periods in a way that won't alter the
                 * phase offset.
                 */
                rc = __sja1105_ptp_gettimex(priv->ds, &now, NULL);
                if (rc < 0)
                        goto out;

                pin_start = future_base_time(pin_start, pin_duration,
                                             now + 1ull * NSEC_PER_SEC);
                pin_start = ns_to_sja1105_ticks(pin_start);

                rc = sja1105_xfer_u64(priv, SPI_WRITE, regs->ptppinst,
                                      &pin_start, NULL);
                if (rc < 0)
                        goto out;

                rc = sja1105_xfer_u32(priv, SPI_WRITE, regs->ptppindur,
                                      &pin_duration32, NULL);
                if (rc < 0)
                        goto out;
        }

        if (on)
                cmd.startptpcp = true;
        else
                cmd.stopptpcp = true;

        rc = sja1105_ptp_commit(priv->ds, &cmd, SPI_WRITE);

out:
        mutex_unlock(&ptp_data->lock);

        return rc;
}

static int sja1105_extts_enable(struct sja1105_private *priv,
                                struct ptp_extts_request *extts,
                                bool on)
{
        int rc;

        /* We only support one channel */
        if (extts->index != 0)
                return -EOPNOTSUPP;

        /* We can only enable time stamping on both edges, sadly. */
        if ((extts->flags & PTP_STRICT_FLAGS) &&
            (extts->flags & PTP_ENABLE_FEATURE) &&
            (extts->flags & PTP_EXTTS_EDGES) != PTP_EXTTS_EDGES)
                return -EOPNOTSUPP;

        rc = sja1105_change_ptp_clk_pin_func(priv, PTP_PF_EXTTS);
        if (rc)
                return rc;

        priv->ptp_data.extts_enabled = on;

        if (on)
                sja1105_ptp_extts_setup_timer(&priv->ptp_data);
        else
                timer_delete_sync(&priv->ptp_data.extts_timer);

        return 0;
}

static int sja1105_ptp_enable(struct ptp_clock_info *ptp,
                              struct ptp_clock_request *req, int on)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);
        int rc = -EOPNOTSUPP;

        if (req->type == PTP_CLK_REQ_PEROUT)
                rc = sja1105_per_out_enable(priv, &req->perout, on);
        else if (req->type == PTP_CLK_REQ_EXTTS)
                rc = sja1105_extts_enable(priv, &req->extts, on);

        return rc;
}

static int sja1105_ptp_verify_pin(struct ptp_clock_info *ptp, unsigned int pin,
                                  enum ptp_pin_function func, unsigned int chan)
{
        struct sja1105_ptp_data *ptp_data = ptp_caps_to_data(ptp);
        struct sja1105_private *priv = ptp_data_to_sja1105(ptp_data);

        if (chan != 0 || pin != 0)
                return -1;

        switch (func) {
        case PTP_PF_NONE:
        case PTP_PF_PEROUT:
                break;
        case PTP_PF_EXTTS:
                if (priv->info->device_id == SJA1105E_DEVICE_ID ||
                    priv->info->device_id == SJA1105T_DEVICE_ID)
                        return -1;
                break;
        default:
                return -1;
        }
        return 0;
}

static struct ptp_pin_desc sja1105_ptp_pin = {
        .name = "ptp_clk",
        .index = 0,
        .func = PTP_PF_NONE,
};

int sja1105_ptp_clock_register(struct dsa_switch *ds)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;

        ptp_data->caps = (struct ptp_clock_info) {
                .owner          = THIS_MODULE,
                .name           = "SJA1105 PHC",
                .adjfine        = sja1105_ptp_adjfine,
                .adjtime        = sja1105_ptp_adjtime,
                .gettimex64     = sja1105_ptp_gettimex,
                .settime64      = sja1105_ptp_settime,
                .enable         = sja1105_ptp_enable,
                .verify         = sja1105_ptp_verify_pin,
                .do_aux_work    = sja1105_rxtstamp_work,
                .max_adj        = SJA1105_MAX_ADJ_PPB,
                .pin_config     = &sja1105_ptp_pin,
                .n_pins         = 1,
                .n_ext_ts       = 1,
                .n_per_out      = 1,
                .supported_extts_flags = PTP_RISING_EDGE |
                                         PTP_FALLING_EDGE |
                                         PTP_STRICT_FLAGS,
        };

        /* Only used on SJA1105 */
        skb_queue_head_init(&ptp_data->skb_rxtstamp_queue);
        /* Only used on SJA1110 */
        skb_queue_head_init(&ptp_data->skb_txtstamp_queue);

        ptp_data->clock = ptp_clock_register(&ptp_data->caps, ds->dev);
        if (IS_ERR_OR_NULL(ptp_data->clock))
                return PTR_ERR(ptp_data->clock);

        ptp_data->cmd.corrclk4ts = true;
        ptp_data->cmd.ptpclkadd = PTP_SET_MODE;

        timer_setup(&ptp_data->extts_timer, sja1105_ptp_extts_timer, 0);

        return sja1105_ptp_reset(ds);
}

void sja1105_ptp_clock_unregister(struct dsa_switch *ds)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;

        if (IS_ERR_OR_NULL(ptp_data->clock))
                return;

        timer_delete_sync(&ptp_data->extts_timer);
        ptp_cancel_worker_sync(ptp_data->clock);
        skb_queue_purge(&ptp_data->skb_txtstamp_queue);
        skb_queue_purge(&ptp_data->skb_rxtstamp_queue);
        ptp_clock_unregister(ptp_data->clock);
        ptp_data->clock = NULL;
}

void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int port,
                              struct sk_buff *skb)
{
        struct sja1105_private *priv = ds->priv;
        struct sja1105_ptp_data *ptp_data = &priv->ptp_data;
        struct skb_shared_hwtstamps shwt = {0};
        u64 ticks, ts;
        int rc;

        skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;

        mutex_lock(&ptp_data->lock);

        rc = sja1105_ptpegr_ts_poll(ds, port, &ts);
        if (rc < 0) {
                dev_err(ds->dev, "timed out polling for tstamp\n");
                kfree_skb(skb);
                goto out;
        }

        rc = sja1105_ptpclkval_read(priv, &ticks, NULL);
        if (rc < 0) {
                dev_err(ds->dev, "Failed to read PTP clock: %d\n", rc);
                kfree_skb(skb);
                goto out;
        }

        ts = sja1105_tstamp_reconstruct(ds, ticks, ts);

        shwt.hwtstamp = ns_to_ktime(sja1105_ticks_to_ns(ts));
        skb_complete_tx_timestamp(skb, &shwt);

out:
        mutex_unlock(&ptp_data->lock);
}