// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 1999 - 2018 Intel Corporation. */

/* PTP 1588 Hardware Clock (PHC)
 * Derived from PTP Hardware Clock driver for Intel 82576 and 82580 (igb)
 * Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
 */

#include "e1000.h"

#ifdef CONFIG_E1000E_HWTS
#include <linux/clocksource.h>
#include <linux/ktime.h>
#include <asm/tsc.h>
#endif

/**
 * e1000e_phc_adjfreq - adjust the frequency of the hardware clock
 * @ptp: ptp clock structure
 * @delta: Desired frequency change in parts per billion
 *
 * Adjust the frequency of the PHC cycle counter by the indicated delta from
 * the base frequency.
 **/
static int e1000e_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)
{
        struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
                                                     ptp_clock_info);
        struct e1000_hw *hw = &adapter->hw;
        bool neg_adj = false;
        unsigned long flags;
        u64 adjustment;
        u32 timinca, incvalue;
        s32 ret_val;

        if ((delta > ptp->max_adj) || (delta <= -1000000000))
                return -EINVAL;

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

        /* Get the System Time Register SYSTIM base frequency */
        ret_val = e1000e_get_base_timinca(adapter, &timinca);
        if (ret_val)
                return ret_val;

        spin_lock_irqsave(&adapter->systim_lock, flags);

        incvalue = timinca & E1000_TIMINCA_INCVALUE_MASK;

        adjustment = incvalue;
        adjustment *= delta;
        adjustment = div_u64(adjustment, 1000000000);

        incvalue = neg_adj ? (incvalue - adjustment) : (incvalue + adjustment);

        timinca &= ~E1000_TIMINCA_INCVALUE_MASK;
        timinca |= incvalue;

        ew32(TIMINCA, timinca);

        adapter->ptp_delta = delta;

        spin_unlock_irqrestore(&adapter->systim_lock, flags);

        return 0;
}

/**
 * e1000e_phc_adjtime - Shift the time of the hardware clock
 * @ptp: ptp clock structure
 * @delta: Desired change in nanoseconds
 *
 * Adjust the timer by resetting the timecounter structure.
 **/
static int e1000e_phc_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
                                                     ptp_clock_info);
        unsigned long flags;

        spin_lock_irqsave(&adapter->systim_lock, flags);
        timecounter_adjtime(&adapter->tc, delta);
        spin_unlock_irqrestore(&adapter->systim_lock, flags);

        return 0;
}

#ifdef CONFIG_E1000E_HWTS
#define MAX_HW_WAIT_COUNT (3)

/**
 * e1000e_phc_get_syncdevicetime - Callback given to timekeeping code reads system/device registers
 * @device: current device time
 * @system: system counter value read synchronously with device time
 * @ctx: context provided by timekeeping code
 *
 * Read device and system (ART) clock simultaneously and return the corrected
 * clock values in ns.
 **/
static int e1000e_phc_get_syncdevicetime(ktime_t *device,
                                         struct system_counterval_t *system,
                                         void *ctx)
{
        struct e1000_adapter *adapter = (struct e1000_adapter *)ctx;
        struct e1000_hw *hw = &adapter->hw;
        unsigned long flags;
        int i;
        u32 tsync_ctrl;
        u64 dev_cycles;
        u64 sys_cycles;

        tsync_ctrl = er32(TSYNCTXCTL);
        tsync_ctrl |= E1000_TSYNCTXCTL_START_SYNC |
                E1000_TSYNCTXCTL_MAX_ALLOWED_DLY_MASK;
        ew32(TSYNCTXCTL, tsync_ctrl);
        for (i = 0; i < MAX_HW_WAIT_COUNT; ++i) {
                udelay(1);
                tsync_ctrl = er32(TSYNCTXCTL);
                if (tsync_ctrl & E1000_TSYNCTXCTL_SYNC_COMP)
                        break;
        }

        if (i == MAX_HW_WAIT_COUNT)
                return -ETIMEDOUT;

        dev_cycles = er32(SYSSTMPH);
        dev_cycles <<= 32;
        dev_cycles |= er32(SYSSTMPL);
        spin_lock_irqsave(&adapter->systim_lock, flags);
        *device = ns_to_ktime(timecounter_cyc2time(&adapter->tc, dev_cycles));
        spin_unlock_irqrestore(&adapter->systim_lock, flags);

        sys_cycles = er32(PLTSTMPH);
        sys_cycles <<= 32;
        sys_cycles |= er32(PLTSTMPL);
        *system = convert_art_to_tsc(sys_cycles);

        return 0;
}

/**
 * e1000e_phc_getsynctime - Reads the current system/device cross timestamp
 * @ptp: ptp clock structure
 * @cts: structure containing timestamp
 *
 * Read device and system (ART) clock simultaneously and return the scaled
 * clock values in ns.
 **/
static int e1000e_phc_getcrosststamp(struct ptp_clock_info *ptp,
                                     struct system_device_crosststamp *xtstamp)
{
        struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
                                                     ptp_clock_info);

        return get_device_system_crosststamp(e1000e_phc_get_syncdevicetime,
                                                adapter, NULL, xtstamp);
}
#endif/*CONFIG_E1000E_HWTS*/

/**
 * e1000e_phc_gettimex - Reads the current time from the hardware clock and
 *                       system clock
 * @ptp: ptp clock structure
 * @ts: timespec structure to hold the current PHC time
 * @sts: structure to hold the current system time
 *
 * Read the timecounter and return the correct value in ns after converting
 * it into a struct timespec.
 **/
static int e1000e_phc_gettimex(struct ptp_clock_info *ptp,
                               struct timespec64 *ts,
                               struct ptp_system_timestamp *sts)
{
        struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
                                                     ptp_clock_info);
        unsigned long flags;
        u64 cycles, ns;

        spin_lock_irqsave(&adapter->systim_lock, flags);

        /* NOTE: Non-monotonic SYSTIM readings may be returned */
        cycles = e1000e_read_systim(adapter, sts);
        ns = timecounter_cyc2time(&adapter->tc, cycles);

        spin_unlock_irqrestore(&adapter->systim_lock, flags);

        *ts = ns_to_timespec64(ns);

        return 0;
}

/**
 * e1000e_phc_settime - Set the current time on the hardware clock
 * @ptp: ptp clock structure
 * @ts: timespec containing the new time for the cycle counter
 *
 * Reset the timecounter to use a new base value instead of the kernel
 * wall timer value.
 **/
static int e1000e_phc_settime(struct ptp_clock_info *ptp,
                              const struct timespec64 *ts)
{
        struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
                                                     ptp_clock_info);
        unsigned long flags;
        u64 ns;

        ns = timespec64_to_ns(ts);

        /* reset the timecounter */
        spin_lock_irqsave(&adapter->systim_lock, flags);
        timecounter_init(&adapter->tc, &adapter->cc, ns);
        spin_unlock_irqrestore(&adapter->systim_lock, flags);

        return 0;
}

/**
 * e1000e_phc_enable - enable or disable an ancillary feature
 * @ptp: ptp clock structure
 * @request: Desired resource to enable or disable
 * @on: Caller passes one to enable or zero to disable
 *
 * Enable (or disable) ancillary features of the PHC subsystem.
 * Currently, no ancillary features are supported.
 **/
static int e1000e_phc_enable(struct ptp_clock_info __always_unused *ptp,
                             struct ptp_clock_request __always_unused *request,
                             int __always_unused on)
{
        return -EOPNOTSUPP;
}

static void e1000e_systim_overflow_work(struct work_struct *work)
{
        struct e1000_adapter *adapter = container_of(work, struct e1000_adapter,
                                                     systim_overflow_work.work);
        struct e1000_hw *hw = &adapter->hw;
        struct timespec64 ts;
        u64 ns;

        /* Update the timecounter */
        ns = timecounter_read(&adapter->tc);

        ts = ns_to_timespec64(ns);
        e_dbg("SYSTIM overflow check at %lld.%09lu\n",
              (long long) ts.tv_sec, ts.tv_nsec);

        schedule_delayed_work(&adapter->systim_overflow_work,
                              E1000_SYSTIM_OVERFLOW_PERIOD);
}

static const struct ptp_clock_info e1000e_ptp_clock_info = {
        .owner          = THIS_MODULE,
        .n_alarm        = 0,
        .n_ext_ts       = 0,
        .n_per_out      = 0,
        .n_pins         = 0,
        .pps            = 0,
        .adjfreq        = e1000e_phc_adjfreq,
        .adjtime        = e1000e_phc_adjtime,
        .gettimex64     = e1000e_phc_gettimex,
        .settime64      = e1000e_phc_settime,
        .enable         = e1000e_phc_enable,
};

/**
 * e1000e_ptp_init - initialize PTP for devices which support it
 * @adapter: board private structure
 *
 * This function performs the required steps for enabling PTP support.
 * If PTP support has already been loaded it simply calls the cyclecounter
 * init routine and exits.
 **/
void e1000e_ptp_init(struct e1000_adapter *adapter)
{
        struct e1000_hw *hw = &adapter->hw;

        adapter->ptp_clock = NULL;

        if (!(adapter->flags & FLAG_HAS_HW_TIMESTAMP))
                return;

        adapter->ptp_clock_info = e1000e_ptp_clock_info;

        snprintf(adapter->ptp_clock_info.name,
                 sizeof(adapter->ptp_clock_info.name), "%pm",
                 adapter->netdev->perm_addr);

        switch (hw->mac.type) {
        case e1000_pch2lan:
        case e1000_pch_lpt:
        case e1000_pch_spt:
        case e1000_pch_cnp:
                if ((hw->mac.type < e1000_pch_lpt) ||
                    (er32(TSYNCRXCTL) & E1000_TSYNCRXCTL_SYSCFI)) {
                        adapter->ptp_clock_info.max_adj = 24000000 - 1;
                        break;
                }
                /* fall-through */
        case e1000_82574:
        case e1000_82583:
                adapter->ptp_clock_info.max_adj = 600000000 - 1;
                break;
        default:
                break;
        }

#ifdef CONFIG_E1000E_HWTS
        /* CPU must have ART and GBe must be from Sunrise Point or greater */
        if (hw->mac.type >= e1000_pch_spt && boot_cpu_has(X86_FEATURE_ART))
                adapter->ptp_clock_info.getcrosststamp =
                        e1000e_phc_getcrosststamp;
#endif/*CONFIG_E1000E_HWTS*/

        INIT_DELAYED_WORK(&adapter->systim_overflow_work,
                          e1000e_systim_overflow_work);

        schedule_delayed_work(&adapter->systim_overflow_work,
                              E1000_SYSTIM_OVERFLOW_PERIOD);

        adapter->ptp_clock = ptp_clock_register(&adapter->ptp_clock_info,
                                                &adapter->pdev->dev);
        if (IS_ERR(adapter->ptp_clock)) {
                adapter->ptp_clock = NULL;
                e_err("ptp_clock_register failed\n");
        } else if (adapter->ptp_clock) {
                e_info("registered PHC clock\n");
        }
}

/**
 * e1000e_ptp_remove - disable PTP device and stop the overflow check
 * @adapter: board private structure
 *
 * Stop the PTP support, and cancel the delayed work.
 **/
void e1000e_ptp_remove(struct e1000_adapter *adapter)
{
        if (!(adapter->flags & FLAG_HAS_HW_TIMESTAMP))
                return;

        cancel_delayed_work_sync(&adapter->systim_overflow_work);

        if (adapter->ptp_clock) {
                ptp_clock_unregister(adapter->ptp_clock);
                adapter->ptp_clock = NULL;
                e_info("removed PHC\n");
        }
}