/*******************************************************************************

  Intel PRO/1000 Linux driver
  Copyright(c) 1999 - 2013 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, write to the Free Software Foundation, Inc.,
  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

  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;
	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;

	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);

	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,
	.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");
	}
}