/*******************************************************************************
 *
 * Intel Ethernet Controller XL710 Family Linux Driver
 * Copyright(c) 2013 - 2014 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Contact Information:
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 ******************************************************************************/

#include "i40e.h"
#include <linux/ptp_classify.h>

/* The XL710 timesync is very much like Intel's 82599 design when it comes to
 * the fundamental clock design. However, the clock operations are much simpler
 * in the XL710 because the device supports a full 64 bits of nanoseconds.
 * Because the field is so wide, we can forgo the cycle counter and just
 * operate with the nanosecond field directly without fear of overflow.
 *
 * Much like the 82599, the update period is dependent upon the link speed:
 * At 40Gb link or no link, the period is 1.6ns.
 * At 10Gb link, the period is multiplied by 2. (3.2ns)
 * At 1Gb link, the period is multiplied by 20. (32ns)
 * 1588 functionality is not supported at 100Mbps.
 */
#define I40E_PTP_40GB_INCVAL 0x0199999999ULL
#define I40E_PTP_10GB_INCVAL 0x0333333333ULL
#define I40E_PTP_1GB_INCVAL  0x2000000000ULL

#define I40E_PRTTSYN_CTL1_TSYNTYPE_V1  BIT(I40E_PRTTSYN_CTL1_TSYNTYPE_SHIFT)
#define I40E_PRTTSYN_CTL1_TSYNTYPE_V2  (2 << \
                                        I40E_PRTTSYN_CTL1_TSYNTYPE_SHIFT)

/**
 * i40e_ptp_read - Read the PHC time from the device
 * @pf: Board private structure
 * @ts: timespec structure to hold the current time value
 *
 * This function reads the PRTTSYN_TIME registers and stores them in a
 * timespec. However, since the registers are 64 bits of nanoseconds, we must
 * convert the result to a timespec before we can return.
 **/
static void i40e_ptp_read(struct i40e_pf *pf, struct timespec64 *ts)
{
        struct i40e_hw *hw = &pf->hw;
        u32 hi, lo;
        u64 ns;

        /* The timer latches on the lowest register read. */
        lo = rd32(hw, I40E_PRTTSYN_TIME_L);
        hi = rd32(hw, I40E_PRTTSYN_TIME_H);

        ns = (((u64)hi) << 32) | lo;

        *ts = ns_to_timespec64(ns);
}

/**
 * i40e_ptp_write - Write the PHC time to the device
 * @pf: Board private structure
 * @ts: timespec structure that holds the new time value
 *
 * This function writes the PRTTSYN_TIME registers with the user value. Since
 * we receive a timespec from the stack, we must convert that timespec into
 * nanoseconds before programming the registers.
 **/
static void i40e_ptp_write(struct i40e_pf *pf, const struct timespec64 *ts)
{
        struct i40e_hw *hw = &pf->hw;
        u64 ns = timespec64_to_ns(ts);

        /* The timer will not update until the high register is written, so
         * write the low register first.
         */
        wr32(hw, I40E_PRTTSYN_TIME_L, ns & 0xFFFFFFFF);
        wr32(hw, I40E_PRTTSYN_TIME_H, ns >> 32);
}

/**
 * i40e_ptp_convert_to_hwtstamp - Convert device clock to system time
 * @hwtstamps: Timestamp structure to update
 * @timestamp: Timestamp from the hardware
 *
 * We need to convert the NIC clock value into a hwtstamp which can be used by
 * the upper level timestamping functions. Since the timestamp is simply a 64-
 * bit nanosecond value, we can call ns_to_ktime directly to handle this.
 **/
static void i40e_ptp_convert_to_hwtstamp(struct skb_shared_hwtstamps *hwtstamps,
                                         u64 timestamp)
{
        memset(hwtstamps, 0, sizeof(*hwtstamps));

        hwtstamps->hwtstamp = ns_to_ktime(timestamp);
}

/**
 * i40e_ptp_adjfreq - Adjust the PHC frequency
 * @ptp: The PTP clock structure
 * @ppb: Parts per billion adjustment from the base
 *
 * Adjust the frequency of the PHC by the indicated parts per billion from the
 * base frequency.
 **/
static int i40e_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
        struct i40e_pf *pf = container_of(ptp, struct i40e_pf, ptp_caps);
        struct i40e_hw *hw = &pf->hw;
        u64 adj, freq, diff;
        int neg_adj = 0;

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

        smp_mb(); /* Force any pending update before accessing. */
        adj = ACCESS_ONCE(pf->ptp_base_adj);

        freq = adj;
        freq *= ppb;
        diff = div_u64(freq, 1000000000ULL);

        if (neg_adj)
                adj -= diff;
        else
                adj += diff;

        wr32(hw, I40E_PRTTSYN_INC_L, adj & 0xFFFFFFFF);
        wr32(hw, I40E_PRTTSYN_INC_H, adj >> 32);

        return 0;
}

/**
 * i40e_ptp_adjtime - Adjust the PHC time
 * @ptp: The PTP clock structure
 * @delta: Offset in nanoseconds to adjust the PHC time by
 *
 * Adjust the frequency of the PHC by the indicated parts per billion from the
 * base frequency.
 **/
static int i40e_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        struct i40e_pf *pf = container_of(ptp, struct i40e_pf, ptp_caps);
        struct timespec64 now, then;

        then = ns_to_timespec64(delta);
        mutex_lock(&pf->tmreg_lock);

        i40e_ptp_read(pf, &now);
        now = timespec64_add(now, then);
        i40e_ptp_write(pf, (const struct timespec64 *)&now);

        mutex_unlock(&pf->tmreg_lock);

        return 0;
}

/**
 * i40e_ptp_gettime - Get the time of the PHC
 * @ptp: The PTP clock structure
 * @ts: timespec structure to hold the current time value
 *
 * Read the device clock and return the correct value on ns, after converting it
 * into a timespec struct.
 **/
static int i40e_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
        struct i40e_pf *pf = container_of(ptp, struct i40e_pf, ptp_caps);

        mutex_lock(&pf->tmreg_lock);
        i40e_ptp_read(pf, ts);
        mutex_unlock(&pf->tmreg_lock);

        return 0;
}

/**
 * i40e_ptp_settime - Set the time of the PHC
 * @ptp: The PTP clock structure
 * @ts: timespec structure that holds the new time value
 *
 * Set the device clock to the user input value. The conversion from timespec
 * to ns happens in the write function.
 **/
static int i40e_ptp_settime(struct ptp_clock_info *ptp,
                            const struct timespec64 *ts)
{
        struct i40e_pf *pf = container_of(ptp, struct i40e_pf, ptp_caps);

        mutex_lock(&pf->tmreg_lock);
        i40e_ptp_write(pf, ts);
        mutex_unlock(&pf->tmreg_lock);

        return 0;
}

/**
 * i40e_ptp_feature_enable - Enable/disable ancillary features of the PHC subsystem
 * @ptp: The PTP clock structure
 * @rq: The requested feature to change
 * @on: Enable/disable flag
 *
 * The XL710 does not support any of the ancillary features of the PHC
 * subsystem, so this function may just return.
 **/
static int i40e_ptp_feature_enable(struct ptp_clock_info *ptp,
                                   struct ptp_clock_request *rq, int on)
{
        return -EOPNOTSUPP;
}

/**
 * i40e_ptp_update_latch_events - Read I40E_PRTTSYN_STAT_1 and latch events
 * @pf: the PF data structure
 *
 * This function reads I40E_PRTTSYN_STAT_1 and updates the corresponding timers
 * for noticed latch events. This allows the driver to keep track of the first
 * time a latch event was noticed which will be used to help clear out Rx
 * timestamps for packets that got dropped or lost.
 *
 * This function will return the current value of I40E_PRTTSYN_STAT_1 and is
 * expected to be called only while under the ptp_rx_lock.
 **/
static u32 i40e_ptp_get_rx_events(struct i40e_pf *pf)
{
        struct i40e_hw *hw = &pf->hw;
        u32 prttsyn_stat, new_latch_events;
        int  i;

        prttsyn_stat = rd32(hw, I40E_PRTTSYN_STAT_1);
        new_latch_events = prttsyn_stat & ~pf->latch_event_flags;

        /* Update the jiffies time for any newly latched timestamp. This
         * ensures that we store the time that we first discovered a timestamp
         * was latched by the hardware. The service task will later determine
         * if we should free the latch and drop that timestamp should too much
         * time pass. This flow ensures that we only update jiffies for new
         * events latched since the last time we checked, and not all events
         * currently latched, so that the service task accounting remains
         * accurate.
         */
        for (i = 0; i < 4; i++) {
                if (new_latch_events & BIT(i))
                        pf->latch_events[i] = jiffies;
        }

        /* Finally, we store the current status of the Rx timestamp latches */
        pf->latch_event_flags = prttsyn_stat;

        return prttsyn_stat;
}

/**
 * i40e_ptp_rx_hang - Detect error case when Rx timestamp registers are hung
 * @vsi: The VSI with the rings relevant to 1588
 *
 * This watchdog task is scheduled to detect error case where hardware has
 * dropped an Rx packet that was timestamped when the ring is full. The
 * particular error is rare but leaves the device in a state unable to timestamp
 * any future packets.
 **/
void i40e_ptp_rx_hang(struct i40e_vsi *vsi)
{
        struct i40e_pf *pf = vsi->back;
        struct i40e_hw *hw = &pf->hw;
        unsigned int i, cleared = 0;

        /* Since we cannot turn off the Rx timestamp logic if the device is
         * configured for Tx timestamping, we check if Rx timestamping is
         * configured. We don't want to spuriously warn about Rx timestamp
         * hangs if we don't care about the timestamps.
         */
        if (!(pf->flags & I40E_FLAG_PTP) || !pf->ptp_rx)
                return;

        spin_lock_bh(&pf->ptp_rx_lock);

        /* Update current latch times for Rx events */
        i40e_ptp_get_rx_events(pf);

        /* Check all the currently latched Rx events and see whether they have
         * been latched for over a second. It is assumed that any timestamp
         * should have been cleared within this time, or else it was captured
         * for a dropped frame that the driver never received. Thus, we will
         * clear any timestamp that has been latched for over 1 second.
         */
        for (i = 0; i < 4; i++) {
                if ((pf->latch_event_flags & BIT(i)) &&
                    time_is_before_jiffies(pf->latch_events[i] + HZ)) {
                        rd32(hw, I40E_PRTTSYN_RXTIME_H(i));
                        pf->latch_event_flags &= ~BIT(i);
                        cleared++;
                }
        }

        spin_unlock_bh(&pf->ptp_rx_lock);

        /* Log a warning if more than 2 timestamps got dropped in the same
         * check. We don't want to warn about all drops because it can occur
         * in normal scenarios such as PTP frames on multicast addresses we
         * aren't listening to. However, administrator should know if this is
         * the reason packets aren't receiving timestamps.
         */
        if (cleared > 2)
                dev_dbg(&pf->pdev->dev,
                        "Dropped %d missed RXTIME timestamp events\n",
                        cleared);

        /* Finally, update the rx_hwtstamp_cleared counter */
        pf->rx_hwtstamp_cleared += cleared;
}

/**
 * i40e_ptp_tx_hwtstamp - Utility function which returns the Tx timestamp
 * @pf: Board private structure
 *
 * Read the value of the Tx timestamp from the registers, convert it into a
 * value consumable by the stack, and store that result into the shhwtstamps
 * struct before returning it up the stack.
 **/
void i40e_ptp_tx_hwtstamp(struct i40e_pf *pf)
{
        struct skb_shared_hwtstamps shhwtstamps;
        struct i40e_hw *hw = &pf->hw;
        u32 hi, lo;
        u64 ns;

        if (!(pf->flags & I40E_FLAG_PTP) || !pf->ptp_tx)
                return;

        /* don't attempt to timestamp if we don't have an skb */
        if (!pf->ptp_tx_skb)
                return;

        lo = rd32(hw, I40E_PRTTSYN_TXTIME_L);
        hi = rd32(hw, I40E_PRTTSYN_TXTIME_H);

        ns = (((u64)hi) << 32) | lo;

        i40e_ptp_convert_to_hwtstamp(&shhwtstamps, ns);
        skb_tstamp_tx(pf->ptp_tx_skb, &shhwtstamps);
        dev_kfree_skb_any(pf->ptp_tx_skb);
        pf->ptp_tx_skb = NULL;
        clear_bit_unlock(__I40E_PTP_TX_IN_PROGRESS, &pf->state);
}

/**
 * i40e_ptp_rx_hwtstamp - Utility function which checks for an Rx timestamp
 * @pf: Board private structure
 * @skb: Particular skb to send timestamp with
 * @index: Index into the receive timestamp registers for the timestamp
 *
 * The XL710 receives a notification in the receive descriptor with an offset
 * into the set of RXTIME registers where the timestamp is for that skb. This
 * function goes and fetches the receive timestamp from that offset, if a valid
 * one exists. The RXTIME registers are in ns, so we must convert the result
 * first.
 **/
void i40e_ptp_rx_hwtstamp(struct i40e_pf *pf, struct sk_buff *skb, u8 index)
{
        u32 prttsyn_stat, hi, lo;
        struct i40e_hw *hw;
        u64 ns;

        /* Since we cannot turn off the Rx timestamp logic if the device is
         * doing Tx timestamping, check if Rx timestamping is configured.
         */
        if (!(pf->flags & I40E_FLAG_PTP) || !pf->ptp_rx)
                return;

        hw = &pf->hw;

        spin_lock_bh(&pf->ptp_rx_lock);

        /* Get current Rx events and update latch times */
        prttsyn_stat = i40e_ptp_get_rx_events(pf);

        /* TODO: Should we warn about missing Rx timestamp event? */
        if (!(prttsyn_stat & BIT(index))) {
                spin_unlock_bh(&pf->ptp_rx_lock);
                return;
        }

        /* Clear the latched event since we're about to read its register */
        pf->latch_event_flags &= ~BIT(index);

        lo = rd32(hw, I40E_PRTTSYN_RXTIME_L(index));
        hi = rd32(hw, I40E_PRTTSYN_RXTIME_H(index));

        spin_unlock_bh(&pf->ptp_rx_lock);

        ns = (((u64)hi) << 32) | lo;

        i40e_ptp_convert_to_hwtstamp(skb_hwtstamps(skb), ns);
}

/**
 * i40e_ptp_set_increment - Utility function to update clock increment rate
 * @pf: Board private structure
 *
 * During a link change, the DMA frequency that drives the 1588 logic will
 * change. In order to keep the PRTTSYN_TIME registers in units of nanoseconds,
 * we must update the increment value per clock tick.
 **/
void i40e_ptp_set_increment(struct i40e_pf *pf)
{
        struct i40e_link_status *hw_link_info;
        struct i40e_hw *hw = &pf->hw;
        u64 incval;

        hw_link_info = &hw->phy.link_info;

        i40e_aq_get_link_info(&pf->hw, true, NULL, NULL);

        switch (hw_link_info->link_speed) {
        case I40E_LINK_SPEED_10GB:
                incval = I40E_PTP_10GB_INCVAL;
                break;
        case I40E_LINK_SPEED_1GB:
                incval = I40E_PTP_1GB_INCVAL;
                break;
        case I40E_LINK_SPEED_100MB:
        {
                static int warn_once;

                if (!warn_once) {
                        dev_warn(&pf->pdev->dev,
                                 "1588 functionality is not supported at 100 Mbps. Stopping the PHC.\n");
                        warn_once++;
                }
                incval = 0;
                break;
        }
        case I40E_LINK_SPEED_40GB:
        default:
                incval = I40E_PTP_40GB_INCVAL;
                break;
        }

        /* Write the new increment value into the increment register. The
         * hardware will not update the clock until both registers have been
         * written.
         */
        wr32(hw, I40E_PRTTSYN_INC_L, incval & 0xFFFFFFFF);
        wr32(hw, I40E_PRTTSYN_INC_H, incval >> 32);

        /* Update the base adjustement value. */
        ACCESS_ONCE(pf->ptp_base_adj) = incval;
        smp_mb(); /* Force the above update. */
}

/**
 * i40e_ptp_get_ts_config - ioctl interface to read the HW timestamping
 * @pf: Board private structure
 * @ifreq: ioctl data
 *
 * Obtain the current hardware timestamping settigs as requested. To do this,
 * keep a shadow copy of the timestamp settings rather than attempting to
 * deconstruct it from the registers.
 **/
int i40e_ptp_get_ts_config(struct i40e_pf *pf, struct ifreq *ifr)
{
        struct hwtstamp_config *config = &pf->tstamp_config;

        if (!(pf->flags & I40E_FLAG_PTP))
                return -EOPNOTSUPP;

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

/**
 * i40e_ptp_set_timestamp_mode - setup hardware for requested timestamp mode
 * @pf: Board private structure
 * @config: hwtstamp settings requested or saved
 *
 * Control hardware registers to enter the specific mode requested by the
 * user. Also used during reset path to ensure that timestamp settings are
 * maintained.
 *
 * Note: modifies config in place, and may update the requested mode to be
 * more broad if the specific filter is not directly supported.
 **/
static int i40e_ptp_set_timestamp_mode(struct i40e_pf *pf,
                                       struct hwtstamp_config *config)
{
        struct i40e_hw *hw = &pf->hw;
        u32 tsyntype, regval;

        /* Reserved for future extensions. */
        if (config->flags)
                return -EINVAL;

        switch (config->tx_type) {
        case HWTSTAMP_TX_OFF:
                pf->ptp_tx = false;
                break;
        case HWTSTAMP_TX_ON:
                pf->ptp_tx = true;
                break;
        default:
                return -ERANGE;
        }

        switch (config->rx_filter) {
        case HWTSTAMP_FILTER_NONE:
                pf->ptp_rx = false;
                /* We set the type to V1, but do not enable UDP packet
                 * recognition. In this way, we should be as close to
                 * disabling PTP Rx timestamps as possible since V1 packets
                 * are always UDP, since L2 packets are a V2 feature.
                 */
                tsyntype = I40E_PRTTSYN_CTL1_TSYNTYPE_V1;
                break;
        case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
                if (!(pf->flags & I40E_FLAG_PTP_L4_CAPABLE))
                        return -ERANGE;
                pf->ptp_rx = true;
                tsyntype = I40E_PRTTSYN_CTL1_V1MESSTYPE0_MASK |
                           I40E_PRTTSYN_CTL1_TSYNTYPE_V1 |
                           I40E_PRTTSYN_CTL1_UDP_ENA_MASK;
                config->rx_filter = HWTSTAMP_FILTER_PTP_V1_L4_EVENT;
                break;
        case HWTSTAMP_FILTER_PTP_V2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
                if (!(pf->flags & I40E_FLAG_PTP_L4_CAPABLE))
                        return -ERANGE;
                /* fall through */
        case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
                pf->ptp_rx = true;
                tsyntype = I40E_PRTTSYN_CTL1_V2MESSTYPE0_MASK |
                           I40E_PRTTSYN_CTL1_TSYNTYPE_V2;
                if (pf->flags & I40E_FLAG_PTP_L4_CAPABLE) {
                        tsyntype |= I40E_PRTTSYN_CTL1_UDP_ENA_MASK;
                        config->rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
                } else {
                        config->rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
                }
                break;
        case HWTSTAMP_FILTER_ALL:
        default:
                return -ERANGE;
        }

        /* Clear out all 1588-related registers to clear and unlatch them. */
        spin_lock_bh(&pf->ptp_rx_lock);
        rd32(hw, I40E_PRTTSYN_STAT_0);
        rd32(hw, I40E_PRTTSYN_TXTIME_H);
        rd32(hw, I40E_PRTTSYN_RXTIME_H(0));
        rd32(hw, I40E_PRTTSYN_RXTIME_H(1));
        rd32(hw, I40E_PRTTSYN_RXTIME_H(2));
        rd32(hw, I40E_PRTTSYN_RXTIME_H(3));
        pf->latch_event_flags = 0;
        spin_unlock_bh(&pf->ptp_rx_lock);

        /* Enable/disable the Tx timestamp interrupt based on user input. */
        regval = rd32(hw, I40E_PRTTSYN_CTL0);
        if (pf->ptp_tx)
                regval |= I40E_PRTTSYN_CTL0_TXTIME_INT_ENA_MASK;
        else
                regval &= ~I40E_PRTTSYN_CTL0_TXTIME_INT_ENA_MASK;
        wr32(hw, I40E_PRTTSYN_CTL0, regval);

        regval = rd32(hw, I40E_PFINT_ICR0_ENA);
        if (pf->ptp_tx)
                regval |= I40E_PFINT_ICR0_ENA_TIMESYNC_MASK;
        else
                regval &= ~I40E_PFINT_ICR0_ENA_TIMESYNC_MASK;
        wr32(hw, I40E_PFINT_ICR0_ENA, regval);

        /* Although there is no simple on/off switch for Rx, we "disable" Rx
         * timestamps by setting to V1 only mode and clear the UDP
         * recognition. This ought to disable all PTP Rx timestamps as V1
         * packets are always over UDP. Note that software is configured to
         * ignore Rx timestamps via the pf->ptp_rx flag.
         */
        regval = rd32(hw, I40E_PRTTSYN_CTL1);
        /* clear everything but the enable bit */
        regval &= I40E_PRTTSYN_CTL1_TSYNENA_MASK;
        /* now enable bits for desired Rx timestamps */
        regval |= tsyntype;
        wr32(hw, I40E_PRTTSYN_CTL1, regval);

        return 0;
}

/**
 * i40e_ptp_set_ts_config - ioctl interface to control the HW timestamping
 * @pf: Board private structure
 * @ifreq: ioctl data
 *
 * Respond to the user filter requests and make the appropriate hardware
 * changes here. The XL710 cannot support splitting of the Tx/Rx timestamping
 * logic, so keep track in software of whether to indicate these timestamps
 * or not.
 *
 * It is permissible to "upgrade" the user request to a broader filter, as long
 * as the user receives the timestamps they care about and the user is notified
 * the filter has been broadened.
 **/
int i40e_ptp_set_ts_config(struct i40e_pf *pf, struct ifreq *ifr)
{
        struct hwtstamp_config config;
        int err;

        if (!(pf->flags & I40E_FLAG_PTP))
                return -EOPNOTSUPP;

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

        err = i40e_ptp_set_timestamp_mode(pf, &config);
        if (err)
                return err;

        /* save these settings for future reference */
        pf->tstamp_config = config;

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

/**
 * i40e_ptp_create_clock - Create PTP clock device for userspace
 * @pf: Board private structure
 *
 * This function creates a new PTP clock device. It only creates one if we
 * don't already have one, so it is safe to call. Will return error if it
 * can't create one, but success if we already have a device. Should be used
 * by i40e_ptp_init to create clock initially, and prevent global resets from
 * creating new clock devices.
 **/
static long i40e_ptp_create_clock(struct i40e_pf *pf)
{
        /* no need to create a clock device if we already have one */
        if (!IS_ERR_OR_NULL(pf->ptp_clock))
                return 0;

        strncpy(pf->ptp_caps.name, i40e_driver_name, sizeof(pf->ptp_caps.name));
        pf->ptp_caps.owner = THIS_MODULE;
        pf->ptp_caps.max_adj = 999999999;
        pf->ptp_caps.n_ext_ts = 0;
        pf->ptp_caps.pps = 0;
        pf->ptp_caps.adjfreq = i40e_ptp_adjfreq;
        pf->ptp_caps.adjtime = i40e_ptp_adjtime;
        pf->ptp_caps.gettime64 = i40e_ptp_gettime;
        pf->ptp_caps.settime64 = i40e_ptp_settime;
        pf->ptp_caps.enable = i40e_ptp_feature_enable;

        /* Attempt to register the clock before enabling the hardware. */
        pf->ptp_clock = ptp_clock_register(&pf->ptp_caps, &pf->pdev->dev);
        if (IS_ERR(pf->ptp_clock))
                return PTR_ERR(pf->ptp_clock);

        /* clear the hwtstamp settings here during clock create, instead of
         * during regular init, so that we can maintain settings across a
         * reset or suspend.
         */
        pf->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
        pf->tstamp_config.tx_type = HWTSTAMP_TX_OFF;

        return 0;
}

/**
 * i40e_ptp_init - Initialize the 1588 support after device probe or reset
 * @pf: Board private structure
 *
 * This function sets device up for 1588 support. The first time it is run, it
 * will create a PHC clock device. It does not create a clock device if one
 * already exists. It also reconfigures the device after a reset.
 **/
void i40e_ptp_init(struct i40e_pf *pf)
{
        struct net_device *netdev = pf->vsi[pf->lan_vsi]->netdev;
        struct i40e_hw *hw = &pf->hw;
        u32 pf_id;
        long err;

        /* Only one PF is assigned to control 1588 logic per port. Do not
         * enable any support for PFs not assigned via PRTTSYN_CTL0.PF_ID
         */
        pf_id = (rd32(hw, I40E_PRTTSYN_CTL0) & I40E_PRTTSYN_CTL0_PF_ID_MASK) >>
                I40E_PRTTSYN_CTL0_PF_ID_SHIFT;
        if (hw->pf_id != pf_id) {
                pf->flags &= ~I40E_FLAG_PTP;
                dev_info(&pf->pdev->dev, "%s: PTP not supported on %s\n",
                         __func__,
                         netdev->name);
                return;
        }

        mutex_init(&pf->tmreg_lock);
        spin_lock_init(&pf->ptp_rx_lock);

        /* ensure we have a clock device */
        err = i40e_ptp_create_clock(pf);
        if (err) {
                pf->ptp_clock = NULL;
                dev_err(&pf->pdev->dev, "%s: ptp_clock_register failed\n",
                        __func__);
        } else if (pf->ptp_clock) {
                struct timespec64 ts;
                u32 regval;

                if (pf->hw.debug_mask & I40E_DEBUG_LAN)
                        dev_info(&pf->pdev->dev, "PHC enabled\n");
                pf->flags |= I40E_FLAG_PTP;

                /* Ensure the clocks are running. */
                regval = rd32(hw, I40E_PRTTSYN_CTL0);
                regval |= I40E_PRTTSYN_CTL0_TSYNENA_MASK;
                wr32(hw, I40E_PRTTSYN_CTL0, regval);
                regval = rd32(hw, I40E_PRTTSYN_CTL1);
                regval |= I40E_PRTTSYN_CTL1_TSYNENA_MASK;
                wr32(hw, I40E_PRTTSYN_CTL1, regval);

                /* Set the increment value per clock tick. */
                i40e_ptp_set_increment(pf);

                /* reset timestamping mode */
                i40e_ptp_set_timestamp_mode(pf, &pf->tstamp_config);

                /* Set the clock value. */
                ts = ktime_to_timespec64(ktime_get_real());
                i40e_ptp_settime(&pf->ptp_caps, &ts);
        }
}

/**
 * i40e_ptp_stop - Disable the driver/hardware support and unregister the PHC
 * @pf: Board private structure
 *
 * This function handles the cleanup work required from the initialization by
 * clearing out the important information and unregistering the PHC.
 **/
void i40e_ptp_stop(struct i40e_pf *pf)
{
        pf->flags &= ~I40E_FLAG_PTP;
        pf->ptp_tx = false;
        pf->ptp_rx = false;

        if (pf->ptp_tx_skb) {
                dev_kfree_skb_any(pf->ptp_tx_skb);
                pf->ptp_tx_skb = NULL;
                clear_bit_unlock(__I40E_PTP_TX_IN_PROGRESS, &pf->state);
        }

        if (pf->ptp_clock) {
                ptp_clock_unregister(pf->ptp_clock);
                pf->ptp_clock = NULL;
                dev_info(&pf->pdev->dev, "%s: removed PHC on %s\n", __func__,
                         pf->vsi[pf->lan_vsi]->netdev->name);
        }
}