// SPDX-License-Identifier: GPL-2.0
/* Copyright (c)  2019 Intel Corporation */

#include "igc.h"

#include <linux/module.h>
#include <linux/device.h>
#include <linux/pci.h>
#include <linux/ptp_classify.h>
#include <linux/clocksource.h>
#include <linux/ktime.h>

#define INCVALUE_MASK           0x7fffffff
#define ISGN                    0x80000000

#define IGC_SYSTIM_OVERFLOW_PERIOD      (HZ * 60 * 9)
#define IGC_PTP_TX_TIMEOUT              (HZ * 15)

/* SYSTIM read access for I225 */
void igc_ptp_read(struct igc_adapter *adapter, struct timespec64 *ts)
{
        struct igc_hw *hw = &adapter->hw;
        u32 sec, nsec;

        /* The timestamp is latched when SYSTIML is read. */
        nsec = rd32(IGC_SYSTIML);
        sec = rd32(IGC_SYSTIMH);

        ts->tv_sec = sec;
        ts->tv_nsec = nsec;
}

static void igc_ptp_write_i225(struct igc_adapter *adapter,
                               const struct timespec64 *ts)
{
        struct igc_hw *hw = &adapter->hw;

        wr32(IGC_SYSTIML, ts->tv_nsec);
        wr32(IGC_SYSTIMH, ts->tv_sec);
}

static int igc_ptp_adjfine_i225(struct ptp_clock_info *ptp, long scaled_ppm)
{
        struct igc_adapter *igc = container_of(ptp, struct igc_adapter,
                                               ptp_caps);
        struct igc_hw *hw = &igc->hw;
        int neg_adj = 0;
        u64 rate;
        u32 inca;

        if (scaled_ppm < 0) {
                neg_adj = 1;
                scaled_ppm = -scaled_ppm;
        }
        rate = scaled_ppm;
        rate <<= 14;
        rate = div_u64(rate, 78125);

        inca = rate & INCVALUE_MASK;
        if (neg_adj)
                inca |= ISGN;

        wr32(IGC_TIMINCA, inca);

        return 0;
}

static int igc_ptp_adjtime_i225(struct ptp_clock_info *ptp, s64 delta)
{
        struct igc_adapter *igc = container_of(ptp, struct igc_adapter,
                                               ptp_caps);
        struct timespec64 now, then = ns_to_timespec64(delta);
        unsigned long flags;

        spin_lock_irqsave(&igc->tmreg_lock, flags);

        igc_ptp_read(igc, &now);
        now = timespec64_add(now, then);
        igc_ptp_write_i225(igc, (const struct timespec64 *)&now);

        spin_unlock_irqrestore(&igc->tmreg_lock, flags);

        return 0;
}

static int igc_ptp_gettimex64_i225(struct ptp_clock_info *ptp,
                                   struct timespec64 *ts,
                                   struct ptp_system_timestamp *sts)
{
        struct igc_adapter *igc = container_of(ptp, struct igc_adapter,
                                               ptp_caps);
        struct igc_hw *hw = &igc->hw;
        unsigned long flags;

        spin_lock_irqsave(&igc->tmreg_lock, flags);

        ptp_read_system_prets(sts);
        ts->tv_nsec = rd32(IGC_SYSTIML);
        ts->tv_sec = rd32(IGC_SYSTIMH);
        ptp_read_system_postts(sts);

        spin_unlock_irqrestore(&igc->tmreg_lock, flags);

        return 0;
}

static int igc_ptp_settime_i225(struct ptp_clock_info *ptp,
                                const struct timespec64 *ts)
{
        struct igc_adapter *igc = container_of(ptp, struct igc_adapter,
                                               ptp_caps);
        unsigned long flags;

        spin_lock_irqsave(&igc->tmreg_lock, flags);

        igc_ptp_write_i225(igc, ts);

        spin_unlock_irqrestore(&igc->tmreg_lock, flags);

        return 0;
}

static int igc_ptp_feature_enable_i225(struct ptp_clock_info *ptp,
                                       struct ptp_clock_request *rq, int on)
{
        return -EOPNOTSUPP;
}

/**
 * igc_ptp_systim_to_hwtstamp - convert system time value to HW timestamp
 * @adapter: board private structure
 * @hwtstamps: timestamp structure to update
 * @systim: unsigned 64bit system time value
 *
 * We need to convert the system time value stored in the RX/TXSTMP registers
 * into a hwtstamp which can be used by the upper level timestamping functions.
 **/
static void igc_ptp_systim_to_hwtstamp(struct igc_adapter *adapter,
                                       struct skb_shared_hwtstamps *hwtstamps,
                                       u64 systim)
{
        switch (adapter->hw.mac.type) {
        case igc_i225:
                memset(hwtstamps, 0, sizeof(*hwtstamps));
                /* Upper 32 bits contain s, lower 32 bits contain ns. */
                hwtstamps->hwtstamp = ktime_set(systim >> 32,
                                                systim & 0xFFFFFFFF);
                break;
        default:
                break;
        }
}

/**
 * igc_ptp_rx_pktstamp - Retrieve timestamp from Rx packet buffer
 * @q_vector: Pointer to interrupt specific structure
 * @va: Pointer to address containing Rx buffer
 * @skb: Buffer containing timestamp and packet
 *
 * This function retrieves the timestamp saved in the beginning of packet
 * buffer. While two timestamps are available, one in timer0 reference and the
 * other in timer1 reference, this function considers only the timestamp in
 * timer0 reference.
 */
void igc_ptp_rx_pktstamp(struct igc_q_vector *q_vector, __le32 *va,
                         struct sk_buff *skb)
{
        struct igc_adapter *adapter = q_vector->adapter;
        u64 regval;
        int adjust;

        /* Timestamps are saved in little endian at the beginning of the packet
         * buffer following the layout:
         *
         * DWORD: | 0              | 1              | 2              | 3              |
         * Field: | Timer1 SYSTIML | Timer1 SYSTIMH | Timer0 SYSTIML | Timer0 SYSTIMH |
         *
         * SYSTIML holds the nanoseconds part while SYSTIMH holds the seconds
         * part of the timestamp.
         */
        regval = le32_to_cpu(va[2]);
        regval |= (u64)le32_to_cpu(va[3]) << 32;
        igc_ptp_systim_to_hwtstamp(adapter, skb_hwtstamps(skb), regval);

        /* Adjust timestamp for the RX latency based on link speed */
        switch (adapter->link_speed) {
        case SPEED_10:
                adjust = IGC_I225_RX_LATENCY_10;
                break;
        case SPEED_100:
                adjust = IGC_I225_RX_LATENCY_100;
                break;
        case SPEED_1000:
                adjust = IGC_I225_RX_LATENCY_1000;
                break;
        case SPEED_2500:
                adjust = IGC_I225_RX_LATENCY_2500;
                break;
        default:
                adjust = 0;
                netdev_warn_once(adapter->netdev, "Imprecise timestamp\n");
                break;
        }
        skb_hwtstamps(skb)->hwtstamp =
                ktime_sub_ns(skb_hwtstamps(skb)->hwtstamp, adjust);
}

static void igc_ptp_disable_rx_timestamp(struct igc_adapter *adapter)
{
        struct igc_hw *hw = &adapter->hw;
        u32 val;
        int i;

        wr32(IGC_TSYNCRXCTL, 0);

        for (i = 0; i < adapter->num_rx_queues; i++) {
                val = rd32(IGC_SRRCTL(i));
                val &= ~IGC_SRRCTL_TIMESTAMP;
                wr32(IGC_SRRCTL(i), val);
        }

        val = rd32(IGC_RXPBS);
        val &= ~IGC_RXPBS_CFG_TS_EN;
        wr32(IGC_RXPBS, val);
}

static void igc_ptp_enable_rx_timestamp(struct igc_adapter *adapter)
{
        struct igc_hw *hw = &adapter->hw;
        u32 val;
        int i;

        val = rd32(IGC_RXPBS);
        val |= IGC_RXPBS_CFG_TS_EN;
        wr32(IGC_RXPBS, val);

        for (i = 0; i < adapter->num_rx_queues; i++) {
                val = rd32(IGC_SRRCTL(i));
                /* FIXME: For now, only support retrieving RX timestamps from
                 * timer 0.
                 */
                val |= IGC_SRRCTL_TIMER1SEL(0) | IGC_SRRCTL_TIMER0SEL(0) |
                       IGC_SRRCTL_TIMESTAMP;
                wr32(IGC_SRRCTL(i), val);
        }

        val = IGC_TSYNCRXCTL_ENABLED | IGC_TSYNCRXCTL_TYPE_ALL |
              IGC_TSYNCRXCTL_RXSYNSIG;
        wr32(IGC_TSYNCRXCTL, val);
}

static void igc_ptp_disable_tx_timestamp(struct igc_adapter *adapter)
{
        struct igc_hw *hw = &adapter->hw;

        wr32(IGC_TSYNCTXCTL, 0);
}

static void igc_ptp_enable_tx_timestamp(struct igc_adapter *adapter)
{
        struct igc_hw *hw = &adapter->hw;

        wr32(IGC_TSYNCTXCTL, IGC_TSYNCTXCTL_ENABLED | IGC_TSYNCTXCTL_TXSYNSIG);

        /* Read TXSTMP registers to discard any timestamp previously stored. */
        rd32(IGC_TXSTMPL);
        rd32(IGC_TXSTMPH);
}

/**
 * igc_ptp_set_timestamp_mode - setup hardware for timestamping
 * @adapter: networking device structure
 * @config: hwtstamp configuration
 *
 * Return: 0 in case of success, negative errno code otherwise.
 */
static int igc_ptp_set_timestamp_mode(struct igc_adapter *adapter,
                                      struct hwtstamp_config *config)
{
        /* reserved for future extensions */
        if (config->flags)
                return -EINVAL;

        switch (config->tx_type) {
        case HWTSTAMP_TX_OFF:
                igc_ptp_disable_tx_timestamp(adapter);
                break;
        case HWTSTAMP_TX_ON:
                igc_ptp_enable_tx_timestamp(adapter);
                break;
        default:
                return -ERANGE;
        }

        switch (config->rx_filter) {
        case HWTSTAMP_FILTER_NONE:
                igc_ptp_disable_rx_timestamp(adapter);
                break;
        case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
        case HWTSTAMP_FILTER_NTP_ALL:
        case HWTSTAMP_FILTER_ALL:
                igc_ptp_enable_rx_timestamp(adapter);
                config->rx_filter = HWTSTAMP_FILTER_ALL;
                break;
        default:
                return -ERANGE;
        }

        return 0;
}

static void igc_ptp_tx_timeout(struct igc_adapter *adapter)
{
        struct igc_hw *hw = &adapter->hw;

        dev_kfree_skb_any(adapter->ptp_tx_skb);
        adapter->ptp_tx_skb = NULL;
        adapter->tx_hwtstamp_timeouts++;
        clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);
        /* Clear the tx valid bit in TSYNCTXCTL register to enable interrupt. */
        rd32(IGC_TXSTMPH);
        netdev_warn(adapter->netdev, "Tx timestamp timeout\n");
}

void igc_ptp_tx_hang(struct igc_adapter *adapter)
{
        bool timeout = time_is_before_jiffies(adapter->ptp_tx_start +
                                              IGC_PTP_TX_TIMEOUT);

        if (!test_bit(__IGC_PTP_TX_IN_PROGRESS, &adapter->state))
                return;

        /* If we haven't received a timestamp within the timeout, it is
         * reasonable to assume that it will never occur, so we can unlock the
         * timestamp bit when this occurs.
         */
        if (timeout) {
                cancel_work_sync(&adapter->ptp_tx_work);
                igc_ptp_tx_timeout(adapter);
        }
}

/**
 * igc_ptp_tx_hwtstamp - utility function which checks for TX time stamp
 * @adapter: Board private structure
 *
 * If we were asked to do hardware stamping and such a time stamp is
 * available, then it must have been for this skb here because we only
 * allow only one such packet into the queue.
 */
static void igc_ptp_tx_hwtstamp(struct igc_adapter *adapter)
{
        struct sk_buff *skb = adapter->ptp_tx_skb;
        struct skb_shared_hwtstamps shhwtstamps;
        struct igc_hw *hw = &adapter->hw;
        int adjust = 0;
        u64 regval;

        if (WARN_ON_ONCE(!skb))
                return;

        regval = rd32(IGC_TXSTMPL);
        regval |= (u64)rd32(IGC_TXSTMPH) << 32;
        igc_ptp_systim_to_hwtstamp(adapter, &shhwtstamps, regval);

        switch (adapter->link_speed) {
        case SPEED_10:
                adjust = IGC_I225_TX_LATENCY_10;
                break;
        case SPEED_100:
                adjust = IGC_I225_TX_LATENCY_100;
                break;
        case SPEED_1000:
                adjust = IGC_I225_TX_LATENCY_1000;
                break;
        case SPEED_2500:
                adjust = IGC_I225_TX_LATENCY_2500;
                break;
        }

        shhwtstamps.hwtstamp =
                ktime_add_ns(shhwtstamps.hwtstamp, adjust);

        /* Clear the lock early before calling skb_tstamp_tx so that
         * applications are not woken up before the lock bit is clear. We use
         * a copy of the skb pointer to ensure other threads can't change it
         * while we're notifying the stack.
         */
        adapter->ptp_tx_skb = NULL;
        clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);

        /* Notify the stack and free the skb after we've unlocked */
        skb_tstamp_tx(skb, &shhwtstamps);
        dev_kfree_skb_any(skb);
}

/**
 * igc_ptp_tx_work
 * @work: pointer to work struct
 *
 * This work function polls the TSYNCTXCTL valid bit to determine when a
 * timestamp has been taken for the current stored skb.
 */
static void igc_ptp_tx_work(struct work_struct *work)
{
        struct igc_adapter *adapter = container_of(work, struct igc_adapter,
                                                   ptp_tx_work);
        struct igc_hw *hw = &adapter->hw;
        u32 tsynctxctl;

        if (!test_bit(__IGC_PTP_TX_IN_PROGRESS, &adapter->state))
                return;

        tsynctxctl = rd32(IGC_TSYNCTXCTL);
        if (WARN_ON_ONCE(!(tsynctxctl & IGC_TSYNCTXCTL_TXTT_0)))
                return;

        igc_ptp_tx_hwtstamp(adapter);
}

/**
 * igc_ptp_set_ts_config - set hardware time stamping config
 * @netdev: network interface device structure
 * @ifr: interface request data
 *
 **/
int igc_ptp_set_ts_config(struct net_device *netdev, struct ifreq *ifr)
{
        struct igc_adapter *adapter = netdev_priv(netdev);
        struct hwtstamp_config config;
        int err;

        if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
                return -EFAULT;

        err = igc_ptp_set_timestamp_mode(adapter, &config);
        if (err)
                return err;

        /* save these settings for future reference */
        memcpy(&adapter->tstamp_config, &config,
               sizeof(adapter->tstamp_config));

        return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
                -EFAULT : 0;
}

/**
 * igc_ptp_get_ts_config - get hardware time stamping config
 * @netdev: network interface device structure
 * @ifr: interface request data
 *
 * Get the hwtstamp_config settings to return to the user. Rather than attempt
 * to deconstruct the settings from the registers, just return a shadow copy
 * of the last known settings.
 **/
int igc_ptp_get_ts_config(struct net_device *netdev, struct ifreq *ifr)
{
        struct igc_adapter *adapter = netdev_priv(netdev);
        struct hwtstamp_config *config = &adapter->tstamp_config;

        return copy_to_user(ifr->ifr_data, config, sizeof(*config)) ?
                -EFAULT : 0;
}

/**
 * igc_ptp_init - Initialize PTP functionality
 * @adapter: Board private structure
 *
 * This function is called at device probe to initialize the PTP
 * functionality.
 */
void igc_ptp_init(struct igc_adapter *adapter)
{
        struct net_device *netdev = adapter->netdev;
        struct igc_hw *hw = &adapter->hw;

        switch (hw->mac.type) {
        case igc_i225:
                snprintf(adapter->ptp_caps.name, 16, "%pm", netdev->dev_addr);
                adapter->ptp_caps.owner = THIS_MODULE;
                adapter->ptp_caps.max_adj = 62499999;
                adapter->ptp_caps.adjfine = igc_ptp_adjfine_i225;
                adapter->ptp_caps.adjtime = igc_ptp_adjtime_i225;
                adapter->ptp_caps.gettimex64 = igc_ptp_gettimex64_i225;
                adapter->ptp_caps.settime64 = igc_ptp_settime_i225;
                adapter->ptp_caps.enable = igc_ptp_feature_enable_i225;
                break;
        default:
                adapter->ptp_clock = NULL;
                return;
        }

        spin_lock_init(&adapter->tmreg_lock);
        INIT_WORK(&adapter->ptp_tx_work, igc_ptp_tx_work);

        adapter->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
        adapter->tstamp_config.tx_type = HWTSTAMP_TX_OFF;

        adapter->prev_ptp_time = ktime_to_timespec64(ktime_get_real());
        adapter->ptp_reset_start = ktime_get();

        adapter->ptp_clock = ptp_clock_register(&adapter->ptp_caps,
                                                &adapter->pdev->dev);
        if (IS_ERR(adapter->ptp_clock)) {
                adapter->ptp_clock = NULL;
                netdev_err(netdev, "ptp_clock_register failed\n");
        } else if (adapter->ptp_clock) {
                netdev_info(netdev, "PHC added\n");
                adapter->ptp_flags |= IGC_PTP_ENABLED;
        }
}

static void igc_ptp_time_save(struct igc_adapter *adapter)
{
        igc_ptp_read(adapter, &adapter->prev_ptp_time);
        adapter->ptp_reset_start = ktime_get();
}

static void igc_ptp_time_restore(struct igc_adapter *adapter)
{
        struct timespec64 ts = adapter->prev_ptp_time;
        ktime_t delta;

        delta = ktime_sub(ktime_get(), adapter->ptp_reset_start);

        timespec64_add_ns(&ts, ktime_to_ns(delta));

        igc_ptp_write_i225(adapter, &ts);
}

/**
 * igc_ptp_suspend - Disable PTP work items and prepare for suspend
 * @adapter: Board private structure
 *
 * This function stops the overflow check work and PTP Tx timestamp work, and
 * will prepare the device for OS suspend.
 */
void igc_ptp_suspend(struct igc_adapter *adapter)
{
        if (!(adapter->ptp_flags & IGC_PTP_ENABLED))
                return;

        cancel_work_sync(&adapter->ptp_tx_work);
        dev_kfree_skb_any(adapter->ptp_tx_skb);
        adapter->ptp_tx_skb = NULL;
        clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);

        igc_ptp_time_save(adapter);
}

/**
 * igc_ptp_stop - Disable PTP device and stop the overflow check.
 * @adapter: Board private structure.
 *
 * This function stops the PTP support and cancels the delayed work.
 **/
void igc_ptp_stop(struct igc_adapter *adapter)
{
        igc_ptp_suspend(adapter);

        if (adapter->ptp_clock) {
                ptp_clock_unregister(adapter->ptp_clock);
                netdev_info(adapter->netdev, "PHC removed\n");
                adapter->ptp_flags &= ~IGC_PTP_ENABLED;
        }
}

/**
 * igc_ptp_reset - Re-enable the adapter for PTP following a reset.
 * @adapter: Board private structure.
 *
 * This function handles the reset work required to re-enable the PTP device.
 **/
void igc_ptp_reset(struct igc_adapter *adapter)
{
        struct igc_hw *hw = &adapter->hw;
        unsigned long flags;

        /* reset the tstamp_config */
        igc_ptp_set_timestamp_mode(adapter, &adapter->tstamp_config);

        spin_lock_irqsave(&adapter->tmreg_lock, flags);

        switch (adapter->hw.mac.type) {
        case igc_i225:
                wr32(IGC_TSAUXC, 0x0);
                wr32(IGC_TSSDP, 0x0);
                wr32(IGC_TSIM, IGC_TSICR_INTERRUPTS);
                wr32(IGC_IMS, IGC_IMS_TS);
                break;
        default:
                /* No work to do. */
                goto out;
        }

        /* Re-initialize the timer. */
        if (hw->mac.type == igc_i225) {
                igc_ptp_time_restore(adapter);
        } else {
                timecounter_init(&adapter->tc, &adapter->cc,
                                 ktime_to_ns(ktime_get_real()));
        }
out:
        spin_unlock_irqrestore(&adapter->tmreg_lock, flags);

        wrfl();
}