/****************************************************************************
* Driver for Solarflare Solarstorm network controllers and boards
* Copyright 2011 Solarflare Communications Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation, incorporated herein by reference.
*/
/* Theory of operation:
*
* PTP support is assisted by firmware running on the MC, which provides
* the hardware timestamping capabilities. Both transmitted and received
* PTP event packets are queued onto internal queues for subsequent processing;
* this is because the MC operations are relatively long and would block
* block NAPI/interrupt operation.
*
* Receive event processing:
* The event contains the packet's UUID and sequence number, together
* with the hardware timestamp. The PTP receive packet queue is searched
* for this UUID/sequence number and, if found, put on a pending queue.
* Packets not matching are delivered without timestamps (MCDI events will
* always arrive after the actual packet).
* It is important for the operation of the PTP protocol that the ordering
* of packets between the event and general port is maintained.
*
* Work queue processing:
* If work waiting, synchronise host/hardware time
*
* Transmit: send packet through MC, which returns the transmission time
* that is converted to an appropriate timestamp.
*
* Receive: the packet's reception time is converted to an appropriate
* timestamp.
*/
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/time.h>
#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/net_tstamp.h>
#include <linux/pps_kernel.h>
#include <linux/ptp_clock_kernel.h>
#include "net_driver.h"
#include "efx.h"
#include "mcdi.h"
#include "mcdi_pcol.h"
#include "io.h"
#include "regs.h"
#include "nic.h"
/* Maximum number of events expected to make up a PTP event */
#define MAX_EVENT_FRAGS 3
/* Maximum delay, ms, to begin synchronisation */
#define MAX_SYNCHRONISE_WAIT_MS 2
/* How long, at most, to spend synchronising */
#define SYNCHRONISE_PERIOD_NS 250000
/* How often to update the shared memory time */
#define SYNCHRONISATION_GRANULARITY_NS 200
/* Minimum permitted length of a (corrected) synchronisation time */
#define MIN_SYNCHRONISATION_NS 120
/* Maximum permitted length of a (corrected) synchronisation time */
#define MAX_SYNCHRONISATION_NS 1000
/* How many (MC) receive events that can be queued */
#define MAX_RECEIVE_EVENTS 8
/* Length of (modified) moving average. */
#define AVERAGE_LENGTH 16
/* How long an unmatched event or packet can be held */
#define PKT
