/* Intel PRO/1000 Linux driver
 * Copyright(c) 1999 - 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.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Contact Information:
 * Linux NICS <linux.nics@intel.com>
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 */

/* 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"

/**
 * 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);

	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;
	s64 now;

	spin_lock_irqsave(&adapter->systim_lock, flags);
	now = timecounter_read(&adapter->tc);
	now += delta;
	timecounter_init(&adapter->tc, &adapter->cc, now);
	spin_unlock_irqrestore(&adapter->systim_lock, flags);

	return 0;
}

/**
 * e1000e_phc_gettime - Reads the current time from the hardware clock
 * @ptp: ptp clock structure
 * @ts: timespec structure to hold the current time value
 *
 * Read the timecounter and return the correct value in ns after converting
 * it into a struct timespec.
 **/
static int e1000e_phc_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
{
	struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
						     ptp_clock_info);
	unsigned long flags;
	u32 remainder;
	u64 ns;

	spin_lock_irqsave(&adapter->systim_lock, flags);
	ns = timecounter_read(&adapter->tc);
	spin_unlock_irqrestore(&adapter->systim_lock, flags);

	ts->tv_sec = div_u64_rem(ns, NSEC_PER_SEC, &remainder);
	ts->tv_nsec = remainder;

	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 timespec *ts)
{
	struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
						     ptp_clock_info);
	unsigned long flags;
	u64 ns;

	ns = timespec_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 timespec ts;

	adapter->ptp_clock_info.gettime(&adapter->ptp_clock_info, &ts);

	e_dbg("SYSTIM overflow check at %ld.%09lu\n", 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,
	.gettime	= e1000e_phc_gettime,
	.settime	= 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:
		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;
	}

	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 {
		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");
	}
}