OSCL-LXR linux-6.0.1/​drivers/​net/​ethernet/​sfc/​siena/​ptp.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /****************************************************************************
  * Driver for Solarflare network controllers and boards
  * Copyright 2011-2013 Solarflare Communications Inc.
  */
 
 /* 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/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 "farch_regs.h"
 #include "tx.h"
 #include "nic.h" /* indirectly includes ptp.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 DEFAULT_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_EVENT_LIFETIME_MS       10
 
 /* Offsets into PTP packet for identification.  These offsets are from the
  * start of the IP header, not the MAC header.  Note that neither PTP V1 nor
  * PTP V2 permit the use of IPV4 options.
  */
 #define PTP_DPORT_OFFSET    22
 
 #define PTP_V1_VERSION_LENGTH   2
 #define PTP_V1_VERSION_OFFSET   28
 
 #define PTP_V1_UUID_LENGTH  6
 #define PTP_V1_UUID_OFFSET  50
 
 #define PTP_V1_SEQUENCE_LENGTH  2
 #define PTP_V1_SEQUENCE_OFFSET  58
 
 /* The minimum length of a PTP V1 packet for offsets, etc. to be valid:
  * includes IP header.
  */
 #define PTP_V1_MIN_LENGTH   64
 
 #define PTP_V2_VERSION_LENGTH   1
 #define PTP_V2_VERSION_OFFSET   29
 
 #define PTP_V2_UUID_LENGTH  8
 #define PTP_V2_UUID_OFFSET  48
 
 /* Although PTP V2 UUIDs are comprised a ClockIdentity (8) and PortNumber (2),
  * the MC only captures the last six bytes of the clock identity. These values
  * reflect those, not the ones used in the standard.  The standard permits
  * mapping of V1 UUIDs to V2 UUIDs with these same values.
  */
 #define PTP_V2_MC_UUID_LENGTH   6
 #define PTP_V2_MC_UUID_OFFSET   50
 
 #define PTP_V2_SEQUENCE_LENGTH  2
 #define PTP_V2_SEQUENCE_OFFSET  58
 
 /* The minimum length of a PTP V2 packet for offsets, etc. to be valid:
  * includes IP header.
  */
 #define PTP_V2_MIN_LENGTH   63
 
 #define PTP_MIN_LENGTH      63
 
 #define PTP_ADDRESS     0xe0000181  /* 224.0.1.129 */
 #define PTP_EVENT_PORT      319
 #define PTP_GENERAL_PORT    320
 
 /* Annoyingly the format of the version numbers are different between
  * versions 1 and 2 so it isn't possible to simply look for 1 or 2.
  */
 #define PTP_VERSION_V1      1
 
 #define PTP_VERSION_V2      2
 #define PTP_VERSION_V2_MASK 0x0f
 
 enum ptp_packet_state {
     PTP_PACKET_STATE_UNMATCHED = 0,
     PTP_PACKET_STATE_MATCHED,
     PTP_PACKET_STATE_TIMED_OUT,
     PTP_PACKET_STATE_MATCH_UNWANTED
 };
 
 /* NIC synchronised with single word of time only comprising
  * partial seconds and full nanoseconds: 10^9 ~ 2^30 so 2 bits for seconds.
  */
 #define MC_NANOSECOND_BITS  30
 #define MC_NANOSECOND_MASK  ((1 << MC_NANOSECOND_BITS) - 1)
 #define MC_SECOND_MASK      ((1 << (32 - MC_NANOSECOND_BITS)) - 1)
 
 /* Maximum parts-per-billion adjustment that is acceptable */
 #define MAX_PPB         1000000
 
 /* Precalculate scale word to avoid long long division at runtime */
 /* This is equivalent to 2^66 / 10^9. */
 #define PPB_SCALE_WORD  ((1LL << (57)) / 1953125LL)
 
 /* How much to shift down after scaling to convert to FP40 */
 #define PPB_SHIFT_FP40      26
 /* ... and FP44. */
 #define PPB_SHIFT_FP44      22
 
 #define PTP_SYNC_ATTEMPTS   4
 
 /**
  * struct efx_ptp_match - Matching structure, stored in sk_buff's cb area.
  * @words: UUID and (partial) sequence number
  * @expiry: Time after which the packet should be delivered irrespective of
  *            event arrival.
  * @state: The state of the packet - whether it is ready for processing or
  *         whether that is of no interest.
  */
 struct efx_ptp_match {
     u32 words[DIV_ROUND_UP(PTP_V1_UUID_LENGTH, 4)];
     unsigned long expiry;
     enum ptp_packet_state state;
 };
 
 /**
  * struct efx_ptp_event_rx - A PTP receive event (from MC)
  * @link: list of events
  * @seq0: First part of (PTP) UUID
  * @seq1: Second part of (PTP) UUID and sequence number
  * @hwtimestamp: Event timestamp
  * @expiry: Time which the packet arrived
  */
 struct efx_ptp_event_rx {
     struct list_head link;
     u32 seq0;
     u32 seq1;
     ktime_t hwtimestamp;
     unsigned long expiry;
 };
 
 /**
  * struct efx_ptp_timeset - Synchronisation between host and MC
  * @host_start: Host time immediately before hardware timestamp taken
  * @major: Hardware timestamp, major
  * @minor: Hardware timestamp, minor
  * @host_end: Host time immediately after hardware timestamp taken
  * @wait: Number of NIC clock ticks between hardware timestamp being read and
  *          host end time being seen
  * @window: Difference of host_end and host_start
  * @valid: Whether this timeset is valid
  */
 struct efx_ptp_timeset {
     u32 host_start;
     u32 major;
     u32 minor;
     u32 host_end;
     u32 wait;
     u32 window; /* Derived: end - start, allowing for wrap */
 };
 
 /**
  * struct efx_ptp_data - Precision Time Protocol (PTP) state
  * @efx: The NIC context
  * @channel: The PTP channel (Siena only)
  * @rx_ts_inline: Flag for whether RX timestamps are inline (else they are
  *  separate events)
  * @rxq: Receive SKB queue (awaiting timestamps)
  * @txq: Transmit SKB queue
  * @evt_list: List of MC receive events awaiting packets
  * @evt_free_list: List of free events
  * @evt_lock: Lock for manipulating evt_list and evt_free_list
  * @rx_evts: Instantiated events (on evt_list and evt_free_list)
  * @workwq: Work queue for processing pending PTP operations
  * @work: Work task
  * @reset_required: A serious error has occurred and the PTP task needs to be
  *                  reset (disable, enable).
  * @rxfilter_event: Receive filter when operating
  * @rxfilter_general: Receive filter when operating
  * @rxfilter_installed: Receive filter installed
  * @config: Current timestamp configuration
  * @enabled: PTP operation enabled
  * @mode: Mode in which PTP operating (PTP version)
  * @ns_to_nic_time: Function to convert from scalar nanoseconds to NIC time
  * @nic_to_kernel_time: Function to convert from NIC to kernel time
  * @nic_time: contains time details
  * @nic_time.minor_max: Wrap point for NIC minor times
  * @nic_time.sync_event_diff_min: Minimum acceptable difference between time
  * in packet prefix and last MCDI time sync event i.e. how much earlier than
  * the last sync event time a packet timestamp can be.
  * @nic_time.sync_event_diff_max: Maximum acceptable difference between time
  * in packet prefix and last MCDI time sync event i.e. how much later than
  * the last sync event time a packet timestamp can be.
  * @nic_time.sync_event_minor_shift: Shift required to make minor time from
  * field in MCDI time sync event.
  * @min_synchronisation_ns: Minimum acceptable corrected sync window
  * @capabilities: Capabilities flags from the NIC
  * @ts_corrections: contains corrections details
  * @ts_corrections.ptp_tx: Required driver correction of PTP packet transmit
  *                         timestamps
  * @ts_corrections.ptp_rx: Required driver correction of PTP packet receive
  *                         timestamps
  * @ts_corrections.pps_out: PPS output error (information only)
  * @ts_corrections.pps_in: Required driver correction of PPS input timestamps
  * @ts_corrections.general_tx: Required driver correction of general packet
  *                             transmit timestamps
  * @ts_corrections.general_rx: Required driver correction of general packet
  *                             receive timestamps
  * @evt_frags: Partly assembled PTP events
  * @evt_frag_idx: Current fragment number
  * @evt_code: Last event code
  * @start: Address at which MC indicates ready for synchronisation
  * @host_time_pps: Host time at last PPS
  * @adjfreq_ppb_shift: Shift required to convert scaled parts-per-billion
  * frequency adjustment into a fixed point fractional nanosecond format.
  * @current_adjfreq: Current ppb adjustment.
  * @phc_clock: Pointer to registered phc device (if primary function)
  * @phc_clock_info: Registration structure for phc device
  * @pps_work: pps work task for handling pps events
  * @pps_workwq: pps work queue
  * @nic_ts_enabled: Flag indicating if NIC generated TS events are handled
  * @txbuf: Buffer for use when transmitting (PTP) packets to MC (avoids
  *         allocations in main data path).
  * @good_syncs: Number of successful synchronisations.
  * @fast_syncs: Number of synchronisations requiring short delay
  * @bad_syncs: Number of failed synchronisations.
  * @sync_timeouts: Number of synchronisation timeouts
  * @no_time_syncs: Number of synchronisations with no good times.
  * @invalid_sync_windows: Number of sync windows with bad durations.
  * @undersize_sync_windows: Number of corrected sync windows that are too small
  * @oversize_sync_windows: Number of corrected sync windows that are too large
  * @rx_no_timestamp: Number of packets received without a timestamp.
  * @timeset: Last set of synchronisation statistics.
  * @xmit_skb: Transmit SKB function.
  */
 struct efx_ptp_data {
     struct efx_nic *efx;
     struct efx_channel *channel;
     bool rx_ts_inline;
     struct sk_buff_head rxq;
     struct sk_buff_head txq;
     struct list_head evt_list;
     struct list_head evt_free_list;
     spinlock_t evt_lock;
     struct efx_ptp_event_rx rx_evts[MAX_RECEIVE_EVENTS];
     struct workqueue_struct *workwq;
     struct work_struct work;
     bool reset_required;
     u32 rxfilter_event;
     u32 rxfilter_general;
     bool rxfilter_installed;
     struct hwtstamp_config config;
     bool enabled;
     unsigned int mode;
     void (*ns_to_nic_time)(s64 ns, u32 *nic_major, u32 *nic_minor);
     ktime_t (*nic_to_kernel_time)(u32 nic_major, u32 nic_minor,
                       s32 correction);
     struct {
         u32 minor_max;
         u32 sync_event_diff_min;
         u32 sync_event_diff_max;
         unsigned int sync_event_minor_shift;
     } nic_time;
     unsigned int min_synchronisation_ns;
     unsigned int capabilities;
     struct {
         s32 ptp_tx;
         s32 ptp_rx;
         s32 pps_out;
         s32 pps_in;
         s32 general_tx;
         s32 general_rx;
     } ts_corrections;
     efx_qword_t evt_frags[MAX_EVENT_FRAGS];
     int evt_frag_idx;
     int evt_code;
     struct efx_buffer start;
     struct pps_event_time host_time_pps;
     unsigned int adjfreq_ppb_shift;
     s64 current_adjfreq;
     struct ptp_clock *phc_clock;
     struct ptp_clock_info phc_clock_info;
     struct work_struct pps_work;
     struct workqueue_struct *pps_workwq;
     bool nic_ts_enabled;
     efx_dword_t txbuf[MCDI_TX_BUF_LEN(MC_CMD_PTP_IN_TRANSMIT_LENMAX)];
 
     unsigned int good_syncs;
     unsigned int fast_syncs;
     unsigned int bad_syncs;
     unsigned int sync_timeouts;
     unsigned int no_time_syncs;
     unsigned int invalid_sync_windows;
     unsigned int undersize_sync_windows;
     unsigned int oversize_sync_windows;
     unsigned int rx_no_timestamp;
     struct efx_ptp_timeset
     timeset[MC_CMD_PTP_OUT_SYNCHRONIZE_TIMESET_MAXNUM];
     void (*xmit_skb)(struct efx_nic *efx, struct sk_buff *skb);
 };
 
 static int efx_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta);
 static int efx_phc_adjtime(struct ptp_clock_info *ptp, s64 delta);
 static int efx_phc_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts);
 static int efx_phc_settime(struct ptp_clock_info *ptp,
                const struct timespec64 *e_ts);
 static int efx_phc_enable(struct ptp_clock_info *ptp,
               struct ptp_clock_request *request, int on);
 
 bool efx_siena_ptp_use_mac_tx_timestamps(struct efx_nic *efx)
 {
     return efx_has_cap(efx, TX_MAC_TIMESTAMPING);
 }
 
 /* PTP 'extra' channel is still a traffic channel, but we only create TX queues
  * if PTP uses MAC TX timestamps, not if PTP uses the MC directly to transmit.
  */
 static bool efx_ptp_want_txqs(struct efx_channel *channel)
 {
     return efx_siena_ptp_use_mac_tx_timestamps(channel->efx);
 }
 
 #define PTP_SW_STAT(ext_name, field_name)               \
     { #ext_name, 0, offsetof(struct efx_ptp_data, field_name) }
 #define PTP_MC_STAT(ext_name, mcdi_name)                \
     { #ext_name, 32, MC_CMD_PTP_OUT_STATUS_STATS_ ## mcdi_name ## _OFST }
 static const struct efx_hw_stat_desc efx_ptp_stat_desc[] = {
     PTP_SW_STAT(ptp_good_syncs, good_syncs),
     PTP_SW_STAT(ptp_fast_syncs, fast_syncs),
     PTP_SW_STAT(ptp_bad_syncs, bad_syncs),
     PTP_SW_STAT(ptp_sync_timeouts, sync_timeouts),
     PTP_SW_STAT(ptp_no_time_syncs, no_time_syncs),
     PTP_SW_STAT(ptp_invalid_sync_windows, invalid_sync_windows),
     PTP_SW_STAT(ptp_undersize_sync_windows, undersize_sync_windows),
     PTP_SW_STAT(ptp_oversize_sync_windows, oversize_sync_windows),
     PTP_SW_STAT(ptp_rx_no_timestamp, rx_no_timestamp),
     PTP_MC_STAT(ptp_tx_timestamp_packets, TX),
     PTP_MC_STAT(ptp_rx_timestamp_packets, RX),
     PTP_MC_STAT(ptp_timestamp_packets, TS),
     PTP_MC_STAT(ptp_filter_matches, FM),
     PTP_MC_STAT(ptp_non_filter_matches, NFM),
 };
 #define PTP_STAT_COUNT ARRAY_SIZE(efx_ptp_stat_desc)
 static const unsigned long efx_ptp_stat_mask[] = {
     [0 ... BITS_TO_LONGS(PTP_STAT_COUNT) - 1] = ~0UL,
 };
 
 size_t efx_siena_ptp_describe_stats(struct efx_nic *efx, u8 *strings)
 {
     if (!efx->ptp_data)
         return 0;
 
     return efx_siena_describe_stats(efx_ptp_stat_desc, PTP_STAT_COUNT,
                     efx_ptp_stat_mask, strings);
 }
 
 size_t efx_siena_ptp_update_stats(struct efx_nic *efx, u64 *stats)
 {
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_STATUS_LEN);
     MCDI_DECLARE_BUF(outbuf, MC_CMD_PTP_OUT_STATUS_LEN);
     size_t i;
     int rc;
 
     if (!efx->ptp_data)
         return 0;
 
     /* Copy software statistics */
     for (i = 0; i < PTP_STAT_COUNT; i++) {
         if (efx_ptp_stat_desc[i].dma_width)
             continue;
         stats[i] = *(unsigned int *)((char *)efx->ptp_data +
                          efx_ptp_stat_desc[i].offset);
     }
 
     /* Fetch MC statistics.  We *must* fill in all statistics or
      * risk leaking kernel memory to userland, so if the MCDI
      * request fails we pretend we got zeroes.
      */
     MCDI_SET_DWORD(inbuf, PTP_IN_OP, MC_CMD_PTP_OP_STATUS);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
     rc = efx_siena_mcdi_rpc(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                 outbuf, sizeof(outbuf), NULL);
     if (rc)
         memset(outbuf, 0, sizeof(outbuf));
     efx_siena_update_stats(efx_ptp_stat_desc, PTP_STAT_COUNT,
                    efx_ptp_stat_mask,
                    stats, _MCDI_PTR(outbuf, 0), false);
 
     return PTP_STAT_COUNT;
 }
 
 /* For Siena platforms NIC time is s and ns */
 static void efx_ptp_ns_to_s_ns(s64 ns, u32 *nic_major, u32 *nic_minor)
 {
     struct timespec64 ts = ns_to_timespec64(ns);
     *nic_major = (u32)ts.tv_sec;
     *nic_minor = ts.tv_nsec;
 }
 
 static ktime_t efx_ptp_s_ns_to_ktime_correction(u32 nic_major, u32 nic_minor,
                         s32 correction)
 {
     ktime_t kt = ktime_set(nic_major, nic_minor);
     if (correction >= 0)
         kt = ktime_add_ns(kt, (u64)correction);
     else
         kt = ktime_sub_ns(kt, (u64)-correction);
     return kt;
 }
 
 /* To convert from s27 format to ns we multiply then divide by a power of 2.
  * For the conversion from ns to s27, the operation is also converted to a
  * multiply and shift.
  */
 #define S27_TO_NS_SHIFT (27)
 #define NS_TO_S27_MULT  (((1ULL << 63) + NSEC_PER_SEC / 2) / NSEC_PER_SEC)
 #define NS_TO_S27_SHIFT (63 - S27_TO_NS_SHIFT)
 #define S27_MINOR_MAX   (1 << S27_TO_NS_SHIFT)
 
 /* For Huntington platforms NIC time is in seconds and fractions of a second
  * where the minor register only uses 27 bits in units of 2^-27s.
  */
 static void efx_ptp_ns_to_s27(s64 ns, u32 *nic_major, u32 *nic_minor)
 {
     struct timespec64 ts = ns_to_timespec64(ns);
     u32 maj = (u32)ts.tv_sec;
     u32 min = (u32)(((u64)ts.tv_nsec * NS_TO_S27_MULT +
              (1ULL << (NS_TO_S27_SHIFT - 1))) >> NS_TO_S27_SHIFT);
 
     /* The conversion can result in the minor value exceeding the maximum.
      * In this case, round up to the next second.
      */
     if (min >= S27_MINOR_MAX) {
         min -= S27_MINOR_MAX;
         maj++;
     }
 
     *nic_major = maj;
     *nic_minor = min;
 }
 
 static inline ktime_t efx_ptp_s27_to_ktime(u32 nic_major, u32 nic_minor)
 {
     u32 ns = (u32)(((u64)nic_minor * NSEC_PER_SEC +
             (1ULL << (S27_TO_NS_SHIFT - 1))) >> S27_TO_NS_SHIFT);
     return ktime_set(nic_major, ns);
 }
 
 static ktime_t efx_ptp_s27_to_ktime_correction(u32 nic_major, u32 nic_minor,
                            s32 correction)
 {
     /* Apply the correction and deal with carry */
     nic_minor += correction;
     if ((s32)nic_minor < 0) {
         nic_minor += S27_MINOR_MAX;
         nic_major--;
     } else if (nic_minor >= S27_MINOR_MAX) {
         nic_minor -= S27_MINOR_MAX;
         nic_major++;
     }
 
     return efx_ptp_s27_to_ktime(nic_major, nic_minor);
 }
 
 /* For Medford2 platforms the time is in seconds and quarter nanoseconds. */
 static void efx_ptp_ns_to_s_qns(s64 ns, u32 *nic_major, u32 *nic_minor)
 {
     struct timespec64 ts = ns_to_timespec64(ns);
 
     *nic_major = (u32)ts.tv_sec;
     *nic_minor = ts.tv_nsec * 4;
 }
 
 static ktime_t efx_ptp_s_qns_to_ktime_correction(u32 nic_major, u32 nic_minor,
                          s32 correction)
 {
     ktime_t kt;
 
     nic_minor = DIV_ROUND_CLOSEST(nic_minor, 4);
     correction = DIV_ROUND_CLOSEST(correction, 4);
 
     kt = ktime_set(nic_major, nic_minor);
 
     if (correction >= 0)
         kt = ktime_add_ns(kt, (u64)correction);
     else
         kt = ktime_sub_ns(kt, (u64)-correction);
     return kt;
 }
 
 struct efx_channel *efx_siena_ptp_channel(struct efx_nic *efx)
 {
     return efx->ptp_data ? efx->ptp_data->channel : NULL;
 }
 
 static u32 last_sync_timestamp_major(struct efx_nic *efx)
 {
     struct efx_channel *channel = efx_siena_ptp_channel(efx);
     u32 major = 0;
 
     if (channel)
         major = channel->sync_timestamp_major;
     return major;
 }
 
 /* The 8000 series and later can provide the time from the MAC, which is only
  * 48 bits long and provides meta-information in the top 2 bits.
  */
 static ktime_t
 efx_ptp_mac_nic_to_ktime_correction(struct efx_nic *efx,
                     struct efx_ptp_data *ptp,
                     u32 nic_major, u32 nic_minor,
                     s32 correction)
 {
     u32 sync_timestamp;
     ktime_t kt = { 0 };
     s16 delta;
 
     if (!(nic_major & 0x80000000)) {
         WARN_ON_ONCE(nic_major >> 16);
 
         /* Medford provides 48 bits of timestamp, so we must get the top
          * 16 bits from the timesync event state.
          *
          * We only have the lower 16 bits of the time now, but we do
          * have a full resolution timestamp at some point in past. As
          * long as the difference between the (real) now and the sync
          * is less than 2^15, then we can reconstruct the difference
          * between those two numbers using only the lower 16 bits of
          * each.
          *
          * Put another way
          *
          * a - b = ((a mod k) - b) mod k
          *
          * when -k/2 < (a-b) < k/2. In our case k is 2^16. We know
          * (a mod k) and b, so can calculate the delta, a - b.
          *
          */
         sync_timestamp = last_sync_timestamp_major(efx);
 
         /* Because delta is s16 this does an implicit mask down to
          * 16 bits which is what we need, assuming
          * MEDFORD_TX_SECS_EVENT_BITS is 16. delta is signed so that
          * we can deal with the (unlikely) case of sync timestamps
          * arriving from the future.
          */
         delta = nic_major - sync_timestamp;
 
         /* Recover the fully specified time now, by applying the offset
          * to the (fully specified) sync time.
          */
         nic_major = sync_timestamp + delta;
 
         kt = ptp->nic_to_kernel_time(nic_major, nic_minor,
                          correction);
     }
     return kt;
 }
 
 ktime_t efx_siena_ptp_nic_to_kernel_time(struct efx_tx_queue *tx_queue)
 {
     struct efx_nic *efx = tx_queue->efx;
     struct efx_ptp_data *ptp = efx->ptp_data;
     ktime_t kt;
 
     if (efx_siena_ptp_use_mac_tx_timestamps(efx))
         kt = efx_ptp_mac_nic_to_ktime_correction(efx, ptp,
                 tx_queue->completed_timestamp_major,
                 tx_queue->completed_timestamp_minor,
                 ptp->ts_corrections.general_tx);
     else
         kt = ptp->nic_to_kernel_time(
                 tx_queue->completed_timestamp_major,
                 tx_queue->completed_timestamp_minor,
                 ptp->ts_corrections.general_tx);
     return kt;
 }
 
 /* Get PTP attributes and set up time conversions */
 static int efx_ptp_get_attributes(struct efx_nic *efx)
 {
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_GET_ATTRIBUTES_LEN);
     MCDI_DECLARE_BUF(outbuf, MC_CMD_PTP_OUT_GET_ATTRIBUTES_LEN);
     struct efx_ptp_data *ptp = efx->ptp_data;
     int rc;
     u32 fmt;
     size_t out_len;
 
     /* Get the PTP attributes. If the NIC doesn't support the operation we
      * use the default format for compatibility with older NICs i.e.
      * seconds and nanoseconds.
      */
     MCDI_SET_DWORD(inbuf, PTP_IN_OP, MC_CMD_PTP_OP_GET_ATTRIBUTES);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
     rc = efx_siena_mcdi_rpc_quiet(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                       outbuf, sizeof(outbuf), &out_len);
     if (rc == 0) {
         fmt = MCDI_DWORD(outbuf, PTP_OUT_GET_ATTRIBUTES_TIME_FORMAT);
     } else if (rc == -EINVAL) {
         fmt = MC_CMD_PTP_OUT_GET_ATTRIBUTES_SECONDS_NANOSECONDS;
     } else if (rc == -EPERM) {
         pci_info(efx->pci_dev, "no PTP support\n");
         return rc;
     } else {
         efx_siena_mcdi_display_error(efx, MC_CMD_PTP, sizeof(inbuf),
                          outbuf, sizeof(outbuf), rc);
         return rc;
     }
 
     switch (fmt) {
     case MC_CMD_PTP_OUT_GET_ATTRIBUTES_SECONDS_27FRACTION:
         ptp->ns_to_nic_time = efx_ptp_ns_to_s27;
         ptp->nic_to_kernel_time = efx_ptp_s27_to_ktime_correction;
         ptp->nic_time.minor_max = 1 << 27;
         ptp->nic_time.sync_event_minor_shift = 19;
         break;
     case MC_CMD_PTP_OUT_GET_ATTRIBUTES_SECONDS_NANOSECONDS:
         ptp->ns_to_nic_time = efx_ptp_ns_to_s_ns;
         ptp->nic_to_kernel_time = efx_ptp_s_ns_to_ktime_correction;
         ptp->nic_time.minor_max = 1000000000;
         ptp->nic_time.sync_event_minor_shift = 22;
         break;
     case MC_CMD_PTP_OUT_GET_ATTRIBUTES_SECONDS_QTR_NANOSECONDS:
         ptp->ns_to_nic_time = efx_ptp_ns_to_s_qns;
         ptp->nic_to_kernel_time = efx_ptp_s_qns_to_ktime_correction;
         ptp->nic_time.minor_max = 4000000000UL;
         ptp->nic_time.sync_event_minor_shift = 24;
         break;
     default:
         return -ERANGE;
     }
 
     /* Precalculate acceptable difference between the minor time in the
      * packet prefix and the last MCDI time sync event. We expect the
      * packet prefix timestamp to be after of sync event by up to one
      * sync event interval (0.25s) but we allow it to exceed this by a
      * fuzz factor of (0.1s)
      */
     ptp->nic_time.sync_event_diff_min = ptp->nic_time.minor_max
         - (ptp->nic_time.minor_max / 10);
     ptp->nic_time.sync_event_diff_max = (ptp->nic_time.minor_max / 4)
         + (ptp->nic_time.minor_max / 10);
 
     /* MC_CMD_PTP_OP_GET_ATTRIBUTES has been extended twice from an older
      * operation MC_CMD_PTP_OP_GET_TIME_FORMAT. The function now may return
      * a value to use for the minimum acceptable corrected synchronization
      * window and may return further capabilities.
      * If we have the extra information store it. For older firmware that
      * does not implement the extended command use the default value.
      */
     if (rc == 0 &&
         out_len >= MC_CMD_PTP_OUT_GET_ATTRIBUTES_CAPABILITIES_OFST)
         ptp->min_synchronisation_ns =
             MCDI_DWORD(outbuf,
                    PTP_OUT_GET_ATTRIBUTES_SYNC_WINDOW_MIN);
     else
         ptp->min_synchronisation_ns = DEFAULT_MIN_SYNCHRONISATION_NS;
 
     if (rc == 0 &&
         out_len >= MC_CMD_PTP_OUT_GET_ATTRIBUTES_LEN)
         ptp->capabilities = MCDI_DWORD(outbuf,
                     PTP_OUT_GET_ATTRIBUTES_CAPABILITIES);
     else
         ptp->capabilities = 0;
 
     /* Set up the shift for conversion between frequency
      * adjustments in parts-per-billion and the fixed-point
      * fractional ns format that the adapter uses.
      */
     if (ptp->capabilities & (1 << MC_CMD_PTP_OUT_GET_ATTRIBUTES_FP44_FREQ_ADJ_LBN))
         ptp->adjfreq_ppb_shift = PPB_SHIFT_FP44;
     else
         ptp->adjfreq_ppb_shift = PPB_SHIFT_FP40;
 
     return 0;
 }
 
 /* Get PTP timestamp corrections */
 static int efx_ptp_get_timestamp_corrections(struct efx_nic *efx)
 {
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_GET_TIMESTAMP_CORRECTIONS_LEN);
     MCDI_DECLARE_BUF(outbuf, MC_CMD_PTP_OUT_GET_TIMESTAMP_CORRECTIONS_V2_LEN);
     int rc;
     size_t out_len;
 
     /* Get the timestamp corrections from the NIC. If this operation is
      * not supported (older NICs) then no correction is required.
      */
     MCDI_SET_DWORD(inbuf, PTP_IN_OP,
                MC_CMD_PTP_OP_GET_TIMESTAMP_CORRECTIONS);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
 
     rc = efx_siena_mcdi_rpc_quiet(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                       outbuf, sizeof(outbuf), &out_len);
     if (rc == 0) {
         efx->ptp_data->ts_corrections.ptp_tx = MCDI_DWORD(outbuf,
             PTP_OUT_GET_TIMESTAMP_CORRECTIONS_TRANSMIT);
         efx->ptp_data->ts_corrections.ptp_rx = MCDI_DWORD(outbuf,
             PTP_OUT_GET_TIMESTAMP_CORRECTIONS_RECEIVE);
         efx->ptp_data->ts_corrections.pps_out = MCDI_DWORD(outbuf,
             PTP_OUT_GET_TIMESTAMP_CORRECTIONS_PPS_OUT);
         efx->ptp_data->ts_corrections.pps_in = MCDI_DWORD(outbuf,
             PTP_OUT_GET_TIMESTAMP_CORRECTIONS_PPS_IN);
 
         if (out_len >= MC_CMD_PTP_OUT_GET_TIMESTAMP_CORRECTIONS_V2_LEN) {
             efx->ptp_data->ts_corrections.general_tx = MCDI_DWORD(
                 outbuf,
                 PTP_OUT_GET_TIMESTAMP_CORRECTIONS_V2_GENERAL_TX);
             efx->ptp_data->ts_corrections.general_rx = MCDI_DWORD(
                 outbuf,
                 PTP_OUT_GET_TIMESTAMP_CORRECTIONS_V2_GENERAL_RX);
         } else {
             efx->ptp_data->ts_corrections.general_tx =
                 efx->ptp_data->ts_corrections.ptp_tx;
             efx->ptp_data->ts_corrections.general_rx =
                 efx->ptp_data->ts_corrections.ptp_rx;
         }
     } else if (rc == -EINVAL) {
         efx->ptp_data->ts_corrections.ptp_tx = 0;
         efx->ptp_data->ts_corrections.ptp_rx = 0;
         efx->ptp_data->ts_corrections.pps_out = 0;
         efx->ptp_data->ts_corrections.pps_in = 0;
         efx->ptp_data->ts_corrections.general_tx = 0;
         efx->ptp_data->ts_corrections.general_rx = 0;
     } else {
         efx_siena_mcdi_display_error(efx, MC_CMD_PTP, sizeof(inbuf),
                          outbuf, sizeof(outbuf), rc);
         return rc;
     }
 
     return 0;
 }
 
 /* Enable MCDI PTP support. */
 static int efx_ptp_enable(struct efx_nic *efx)
 {
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_ENABLE_LEN);
     MCDI_DECLARE_BUF_ERR(outbuf);
     int rc;
 
     MCDI_SET_DWORD(inbuf, PTP_IN_OP, MC_CMD_PTP_OP_ENABLE);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
     MCDI_SET_DWORD(inbuf, PTP_IN_ENABLE_QUEUE,
                efx->ptp_data->channel ?
                efx->ptp_data->channel->channel : 0);
     MCDI_SET_DWORD(inbuf, PTP_IN_ENABLE_MODE, efx->ptp_data->mode);
 
     rc = efx_siena_mcdi_rpc_quiet(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                       outbuf, sizeof(outbuf), NULL);
     rc = (rc == -EALREADY) ? 0 : rc;
     if (rc)
         efx_siena_mcdi_display_error(efx, MC_CMD_PTP,
                          MC_CMD_PTP_IN_ENABLE_LEN,
                          outbuf, sizeof(outbuf), rc);
     return rc;
 }
 
 /* Disable MCDI PTP support.
  *
  * Note that this function should never rely on the presence of ptp_data -
  * may be called before that exists.
  */
 static int efx_ptp_disable(struct efx_nic *efx)
 {
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_DISABLE_LEN);
     MCDI_DECLARE_BUF_ERR(outbuf);
     int rc;
 
     MCDI_SET_DWORD(inbuf, PTP_IN_OP, MC_CMD_PTP_OP_DISABLE);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
     rc = efx_siena_mcdi_rpc_quiet(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                       outbuf, sizeof(outbuf), NULL);
     rc = (rc == -EALREADY) ? 0 : rc;
     /* If we get ENOSYS, the NIC doesn't support PTP, and thus this function
      * should only have been called during probe.
      */
     if (rc == -ENOSYS || rc == -EPERM)
         pci_info(efx->pci_dev, "no PTP support\n");
     else if (rc)
         efx_siena_mcdi_display_error(efx, MC_CMD_PTP,
                          MC_CMD_PTP_IN_DISABLE_LEN,
                          outbuf, sizeof(outbuf), rc);
     return rc;
 }
 
 static void efx_ptp_deliver_rx_queue(struct sk_buff_head *q)
 {
     struct sk_buff *skb;
 
     while ((skb = skb_dequeue(q))) {
         local_bh_disable();
         netif_receive_skb(skb);
         local_bh_enable();
     }
 }
 
 static void efx_ptp_handle_no_channel(struct efx_nic *efx)
 {
     netif_err(efx, drv, efx->net_dev,
           "ERROR: PTP requires MSI-X and 1 additional interrupt"
           "vector. PTP disabled\n");
 }
 
 /* Repeatedly send the host time to the MC which will capture the hardware
  * time.
  */
 static void efx_ptp_send_times(struct efx_nic *efx,
                    struct pps_event_time *last_time)
 {
     struct pps_event_time now;
     struct timespec64 limit;
     struct efx_ptp_data *ptp = efx->ptp_data;
     int *mc_running = ptp->start.addr;
 
     pps_get_ts(&now);
     limit = now.ts_real;
     timespec64_add_ns(&limit, SYNCHRONISE_PERIOD_NS);
 
     /* Write host time for specified period or until MC is done */
     while ((timespec64_compare(&now.ts_real, &limit) < 0) &&
            READ_ONCE(*mc_running)) {
         struct timespec64 update_time;
         unsigned int host_time;
 
         /* Don't update continuously to avoid saturating the PCIe bus */
         update_time = now.ts_real;
         timespec64_add_ns(&update_time, SYNCHRONISATION_GRANULARITY_NS);
         do {
             pps_get_ts(&now);
         } while ((timespec64_compare(&now.ts_real, &update_time) < 0) &&
              READ_ONCE(*mc_running));
 
         /* Synchronise NIC with single word of time only */
         host_time = (now.ts_real.tv_sec << MC_NANOSECOND_BITS |
                  now.ts_real.tv_nsec);
         /* Update host time in NIC memory */
         efx->type->ptp_write_host_time(efx, host_time);
     }
     *last_time = now;
 }
 
 /* Read a timeset from the MC's results and partial process. */
 static void efx_ptp_read_timeset(MCDI_DECLARE_STRUCT_PTR(data),
                  struct efx_ptp_timeset *timeset)
 {
     unsigned start_ns, end_ns;
 
     timeset->host_start = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_HOSTSTART);
     timeset->major = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_MAJOR);
     timeset->minor = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_MINOR);
     timeset->host_end = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_HOSTEND),
     timeset->wait = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_WAITNS);
 
     /* Ignore seconds */
     start_ns = timeset->host_start & MC_NANOSECOND_MASK;
     end_ns = timeset->host_end & MC_NANOSECOND_MASK;
     /* Allow for rollover */
     if (end_ns < start_ns)
         end_ns += NSEC_PER_SEC;
     /* Determine duration of operation */
     timeset->window = end_ns - start_ns;
 }
 
 /* Process times received from MC.
  *
  * Extract times from returned results, and establish the minimum value
  * seen.  The minimum value represents the "best" possible time and events
  * too much greater than this are rejected - the machine is, perhaps, too
  * busy. A number of readings are taken so that, hopefully, at least one good
  * synchronisation will be seen in the results.
  */
 static int
 efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
               size_t response_length,
               const struct pps_event_time *last_time)
 {
     unsigned number_readings =
         MCDI_VAR_ARRAY_LEN(response_length,
                    PTP_OUT_SYNCHRONIZE_TIMESET);
     unsigned i;
     unsigned ngood = 0;
     unsigned last_good = 0;
     struct efx_ptp_data *ptp = efx->ptp_data;
     u32 last_sec;
     u32 start_sec;
     struct timespec64 delta;
     ktime_t mc_time;
 
     if (number_readings == 0)
         return -EAGAIN;
 
     /* Read the set of results and find the last good host-MC
      * synchronization result. The MC times when it finishes reading the
      * host time so the corrected window time should be fairly constant
      * for a given platform. Increment stats for any results that appear
      * to be erroneous.
      */
     for (i = 0; i < number_readings; i++) {
         s32 window, corrected;
         struct timespec64 wait;
 
         efx_ptp_read_timeset(
             MCDI_ARRAY_STRUCT_PTR(synch_buf,
                           PTP_OUT_SYNCHRONIZE_TIMESET, i),
             &ptp->timeset[i]);
 
         wait = ktime_to_timespec64(
             ptp->nic_to_kernel_time(0, ptp->timeset[i].wait, 0));
         window = ptp->timeset[i].window;
         corrected = window - wait.tv_nsec;
 
         /* We expect the uncorrected synchronization window to be at
          * least as large as the interval between host start and end
          * times. If it is smaller than this then this is mostly likely
          * to be a consequence of the host's time being adjusted.
          * Check that the corrected sync window is in a reasonable
          * range. If it is out of range it is likely to be because an
          * interrupt or other delay occurred between reading the system
          * time and writing it to MC memory.
          */
         if (window < SYNCHRONISATION_GRANULARITY_NS) {
             ++ptp->invalid_sync_windows;
         } else if (corrected >= MAX_SYNCHRONISATION_NS) {
             ++ptp->oversize_sync_windows;
         } else if (corrected < ptp->min_synchronisation_ns) {
             ++ptp->undersize_sync_windows;
         } else {
             ngood++;
             last_good = i;
         }
     }
 
     if (ngood == 0) {
         netif_warn(efx, drv, efx->net_dev,
                "PTP no suitable synchronisations\n");
         return -EAGAIN;
     }
 
     /* Calculate delay from last good sync (host time) to last_time.
      * It is possible that the seconds rolled over between taking
      * the start reading and the last value written by the host.  The
      * timescales are such that a gap of more than one second is never
      * expected.  delta is *not* normalised.
      */
     start_sec = ptp->timeset[last_good].host_start >> MC_NANOSECOND_BITS;
     last_sec = last_time->ts_real.tv_sec & MC_SECOND_MASK;
     if (start_sec != last_sec &&
         ((start_sec + 1) & MC_SECOND_MASK) != last_sec) {
         netif_warn(efx, hw, efx->net_dev,
                "PTP bad synchronisation seconds\n");
         return -EAGAIN;
     }
     delta.tv_sec = (last_sec - start_sec) & 1;
     delta.tv_nsec =
         last_time->ts_real.tv_nsec -
         (ptp->timeset[last_good].host_start & MC_NANOSECOND_MASK);
 
     /* Convert the NIC time at last good sync into kernel time.
      * No correction is required - this time is the output of a
      * firmware process.
      */
     mc_time = ptp->nic_to_kernel_time(ptp->timeset[last_good].major,
                       ptp->timeset[last_good].minor, 0);
 
     /* Calculate delay from NIC top of second to last_time */
     delta.tv_nsec += ktime_to_timespec64(mc_time).tv_nsec;
 
     /* Set PPS timestamp to match NIC top of second */
     ptp->host_time_pps = *last_time;
     pps_sub_ts(&ptp->host_time_pps, delta);
 
     return 0;
 }
 
 /* Synchronize times between the host and the MC */
 static int efx_ptp_synchronize(struct efx_nic *efx, unsigned int num_readings)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     MCDI_DECLARE_BUF(synch_buf, MC_CMD_PTP_OUT_SYNCHRONIZE_LENMAX);
     size_t response_length;
     int rc;
     unsigned long timeout;
     struct pps_event_time last_time = {};
     unsigned int loops = 0;
     int *start = ptp->start.addr;
 
     MCDI_SET_DWORD(synch_buf, PTP_IN_OP, MC_CMD_PTP_OP_SYNCHRONIZE);
     MCDI_SET_DWORD(synch_buf, PTP_IN_PERIPH_ID, 0);
     MCDI_SET_DWORD(synch_buf, PTP_IN_SYNCHRONIZE_NUMTIMESETS,
                num_readings);
     MCDI_SET_QWORD(synch_buf, PTP_IN_SYNCHRONIZE_START_ADDR,
                ptp->start.dma_addr);
 
     /* Clear flag that signals MC ready */
     WRITE_ONCE(*start, 0);
     rc = efx_siena_mcdi_rpc_start(efx, MC_CMD_PTP, synch_buf,
                       MC_CMD_PTP_IN_SYNCHRONIZE_LEN);
     EFX_WARN_ON_ONCE_PARANOID(rc);
 
     /* Wait for start from MCDI (or timeout) */
     timeout = jiffies + msecs_to_jiffies(MAX_SYNCHRONISE_WAIT_MS);
     while (!READ_ONCE(*start) && (time_before(jiffies, timeout))) {
         udelay(20); /* Usually start MCDI execution quickly */
         loops++;
     }
 
     if (loops <= 1)
         ++ptp->fast_syncs;
     if (!time_before(jiffies, timeout))
         ++ptp->sync_timeouts;
 
     if (READ_ONCE(*start))
         efx_ptp_send_times(efx, &last_time);
 
     /* Collect results */
     rc = efx_siena_mcdi_rpc_finish(efx, MC_CMD_PTP,
                        MC_CMD_PTP_IN_SYNCHRONIZE_LEN,
                        synch_buf, sizeof(synch_buf),
                        &response_length);
     if (rc == 0) {
         rc = efx_ptp_process_times(efx, synch_buf, response_length,
                        &last_time);
         if (rc == 0)
             ++ptp->good_syncs;
         else
             ++ptp->no_time_syncs;
     }
 
     /* Increment the bad syncs counter if the synchronize fails, whatever
      * the reason.
      */
     if (rc != 0)
         ++ptp->bad_syncs;
 
     return rc;
 }
 
 /* Transmit a PTP packet via the dedicated hardware timestamped queue. */
 static void efx_ptp_xmit_skb_queue(struct efx_nic *efx, struct sk_buff *skb)
 {
     struct efx_ptp_data *ptp_data = efx->ptp_data;
     u8 type = efx_tx_csum_type_skb(skb);
     struct efx_tx_queue *tx_queue;
 
     tx_queue = efx_channel_get_tx_queue(ptp_data->channel, type);
     if (tx_queue && tx_queue->timestamping) {
         efx_enqueue_skb(tx_queue, skb);
     } else {
         WARN_ONCE(1, "PTP channel has no timestamped tx queue\n");
         dev_kfree_skb_any(skb);
     }
 }
 
 /* Transmit a PTP packet, via the MCDI interface, to the wire. */
 static void efx_ptp_xmit_skb_mc(struct efx_nic *efx, struct sk_buff *skb)
 {
     struct efx_ptp_data *ptp_data = efx->ptp_data;
     struct skb_shared_hwtstamps timestamps;
     int rc = -EIO;
     MCDI_DECLARE_BUF(txtime, MC_CMD_PTP_OUT_TRANSMIT_LEN);
     size_t len;
 
     MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_OP, MC_CMD_PTP_OP_TRANSMIT);
     MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_PERIPH_ID, 0);
     MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_TRANSMIT_LENGTH, skb->len);
     if (skb_shinfo(skb)->nr_frags != 0) {
         rc = skb_linearize(skb);
         if (rc != 0)
             goto fail;
     }
 
     if (skb->ip_summed == CHECKSUM_PARTIAL) {
         rc = skb_checksum_help(skb);
         if (rc != 0)
             goto fail;
     }
     skb_copy_from_linear_data(skb,
                   MCDI_PTR(ptp_data->txbuf,
                        PTP_IN_TRANSMIT_PACKET),
                   skb->len);
     rc = efx_siena_mcdi_rpc(efx, MC_CMD_PTP, ptp_data->txbuf,
                 MC_CMD_PTP_IN_TRANSMIT_LEN(skb->len), txtime,
                 sizeof(txtime), &len);
     if (rc != 0)
         goto fail;
 
     memset(&timestamps, 0, sizeof(timestamps));
     timestamps.hwtstamp = ptp_data->nic_to_kernel_time(
         MCDI_DWORD(txtime, PTP_OUT_TRANSMIT_MAJOR),
         MCDI_DWORD(txtime, PTP_OUT_TRANSMIT_MINOR),
         ptp_data->ts_corrections.ptp_tx);
 
     skb_tstamp_tx(skb, &timestamps);
 
     rc = 0;
 
 fail:
     dev_kfree_skb_any(skb);
 
     return;
 }
 
 static void efx_ptp_drop_time_expired_events(struct efx_nic *efx)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     struct list_head *cursor;
     struct list_head *next;
 
     if (ptp->rx_ts_inline)
         return;
 
     /* Drop time-expired events */
     spin_lock_bh(&ptp->evt_lock);
     list_for_each_safe(cursor, next, &ptp->evt_list) {
         struct efx_ptp_event_rx *evt;
 
         evt = list_entry(cursor, struct efx_ptp_event_rx,
                  link);
         if (time_after(jiffies, evt->expiry)) {
             list_move(&evt->link, &ptp->evt_free_list);
             netif_warn(efx, hw, efx->net_dev,
                    "PTP rx event dropped\n");
         }
     }
     spin_unlock_bh(&ptp->evt_lock);
 }
 
 static enum ptp_packet_state efx_ptp_match_rx(struct efx_nic *efx,
                           struct sk_buff *skb)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     bool evts_waiting;
     struct list_head *cursor;
     struct list_head *next;
     struct efx_ptp_match *match;
     enum ptp_packet_state rc = PTP_PACKET_STATE_UNMATCHED;
 
     WARN_ON_ONCE(ptp->rx_ts_inline);
 
     spin_lock_bh(&ptp->evt_lock);
     evts_waiting = !list_empty(&ptp->evt_list);
     spin_unlock_bh(&ptp->evt_lock);
 
     if (!evts_waiting)
         return PTP_PACKET_STATE_UNMATCHED;
 
     match = (struct efx_ptp_match *)skb->cb;
     /* Look for a matching timestamp in the event queue */
     spin_lock_bh(&ptp->evt_lock);
     list_for_each_safe(cursor, next, &ptp->evt_list) {
         struct efx_ptp_event_rx *evt;
 
         evt = list_entry(cursor, struct efx_ptp_event_rx, link);
         if ((evt->seq0 == match->words[0]) &&
             (evt->seq1 == match->words[1])) {
             struct skb_shared_hwtstamps *timestamps;
 
             /* Match - add in hardware timestamp */
             timestamps = skb_hwtstamps(skb);
             timestamps->hwtstamp = evt->hwtimestamp;
 
             match->state = PTP_PACKET_STATE_MATCHED;
             rc = PTP_PACKET_STATE_MATCHED;
             list_move(&evt->link, &ptp->evt_free_list);
             break;
         }
     }
     spin_unlock_bh(&ptp->evt_lock);
 
     return rc;
 }
 
 /* Process any queued receive events and corresponding packets
  *
  * q is returned with all the packets that are ready for delivery.
  */
 static void efx_ptp_process_events(struct efx_nic *efx, struct sk_buff_head *q)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     struct sk_buff *skb;
 
     while ((skb = skb_dequeue(&ptp->rxq))) {
         struct efx_ptp_match *match;
 
         match = (struct efx_ptp_match *)skb->cb;
         if (match->state == PTP_PACKET_STATE_MATCH_UNWANTED) {
             __skb_queue_tail(q, skb);
         } else if (efx_ptp_match_rx(efx, skb) ==
                PTP_PACKET_STATE_MATCHED) {
             __skb_queue_tail(q, skb);
         } else if (time_after(jiffies, match->expiry)) {
             match->state = PTP_PACKET_STATE_TIMED_OUT;
             ++ptp->rx_no_timestamp;
             __skb_queue_tail(q, skb);
         } else {
             /* Replace unprocessed entry and stop */
             skb_queue_head(&ptp->rxq, skb);
             break;
         }
     }
 }
 
 /* Complete processing of a received packet */
 static inline void efx_ptp_process_rx(struct efx_nic *efx, struct sk_buff *skb)
 {
     local_bh_disable();
     netif_receive_skb(skb);
     local_bh_enable();
 }
 
 static void efx_ptp_remove_multicast_filters(struct efx_nic *efx)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
 
     if (ptp->rxfilter_installed) {
         efx_filter_remove_id_safe(efx, EFX_FILTER_PRI_REQUIRED,
                       ptp->rxfilter_general);
         efx_filter_remove_id_safe(efx, EFX_FILTER_PRI_REQUIRED,
                       ptp->rxfilter_event);
         ptp->rxfilter_installed = false;
     }
 }
 
 static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     struct efx_filter_spec rxfilter;
     int rc;
 
     if (!ptp->channel || ptp->rxfilter_installed)
         return 0;
 
     /* Must filter on both event and general ports to ensure
      * that there is no packet re-ordering.
      */
     efx_filter_init_rx(&rxfilter, EFX_FILTER_PRI_REQUIRED, 0,
                efx_rx_queue_index(
                    efx_channel_get_rx_queue(ptp->channel)));
     rc = efx_filter_set_ipv4_local(&rxfilter, IPPROTO_UDP,
                        htonl(PTP_ADDRESS),
                        htons(PTP_EVENT_PORT));
     if (rc != 0)
         return rc;
 
     rc = efx_filter_insert_filter(efx, &rxfilter, true);
     if (rc < 0)
         return rc;
     ptp->rxfilter_event = rc;
 
     efx_filter_init_rx(&rxfilter, EFX_FILTER_PRI_REQUIRED, 0,
                efx_rx_queue_index(
                    efx_channel_get_rx_queue(ptp->channel)));
     rc = efx_filter_set_ipv4_local(&rxfilter, IPPROTO_UDP,
                        htonl(PTP_ADDRESS),
                        htons(PTP_GENERAL_PORT));
     if (rc != 0)
         goto fail;
 
     rc = efx_filter_insert_filter(efx, &rxfilter, true);
     if (rc < 0)
         goto fail;
     ptp->rxfilter_general = rc;
 
     ptp->rxfilter_installed = true;
     return 0;
 
 fail:
     efx_filter_remove_id_safe(efx, EFX_FILTER_PRI_REQUIRED,
                   ptp->rxfilter_event);
     return rc;
 }
 
 static int efx_ptp_start(struct efx_nic *efx)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     int rc;
 
     ptp->reset_required = false;
 
     rc = efx_ptp_insert_multicast_filters(efx);
     if (rc)
         return rc;
 
     rc = efx_ptp_enable(efx);
     if (rc != 0)
         goto fail;
 
     ptp->evt_frag_idx = 0;
     ptp->current_adjfreq = 0;
 
     return 0;
 
 fail:
     efx_ptp_remove_multicast_filters(efx);
     return rc;
 }
 
 static int efx_ptp_stop(struct efx_nic *efx)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     struct list_head *cursor;
     struct list_head *next;
     int rc;
 
     if (ptp == NULL)
         return 0;
 
     rc = efx_ptp_disable(efx);
 
     efx_ptp_remove_multicast_filters(efx);
 
     /* Make sure RX packets are really delivered */
     efx_ptp_deliver_rx_queue(&efx->ptp_data->rxq);
     skb_queue_purge(&efx->ptp_data->txq);
 
     /* Drop any pending receive events */
     spin_lock_bh(&efx->ptp_data->evt_lock);
     list_for_each_safe(cursor, next, &efx->ptp_data->evt_list) {
         list_move(cursor, &efx->ptp_data->evt_free_list);
     }
     spin_unlock_bh(&efx->ptp_data->evt_lock);
 
     return rc;
 }
 
 static int efx_ptp_restart(struct efx_nic *efx)
 {
     if (efx->ptp_data && efx->ptp_data->enabled)
         return efx_ptp_start(efx);
     return 0;
 }
 
 static void efx_ptp_pps_worker(struct work_struct *work)
 {
     struct efx_ptp_data *ptp =
         container_of(work, struct efx_ptp_data, pps_work);
     struct efx_nic *efx = ptp->efx;
     struct ptp_clock_event ptp_evt;
 
     if (efx_ptp_synchronize(efx, PTP_SYNC_ATTEMPTS))
         return;
 
     ptp_evt.type = PTP_CLOCK_PPSUSR;
     ptp_evt.pps_times = ptp->host_time_pps;
     ptp_clock_event(ptp->phc_clock, &ptp_evt);
 }
 
 static void efx_ptp_worker(struct work_struct *work)
 {
     struct efx_ptp_data *ptp_data =
         container_of(work, struct efx_ptp_data, work);
     struct efx_nic *efx = ptp_data->efx;
     struct sk_buff *skb;
     struct sk_buff_head tempq;
 
     if (ptp_data->reset_required) {
         efx_ptp_stop(efx);
         efx_ptp_start(efx);
         return;
     }
 
     efx_ptp_drop_time_expired_events(efx);
 
     __skb_queue_head_init(&tempq);
     efx_ptp_process_events(efx, &tempq);
 
     while ((skb = skb_dequeue(&ptp_data->txq)))
         ptp_data->xmit_skb(efx, skb);
 
     while ((skb = __skb_dequeue(&tempq)))
         efx_ptp_process_rx(efx, skb);
 }
 
 static const struct ptp_clock_info efx_phc_clock_info = {
     .owner      = THIS_MODULE,
     .name       = "sfc_siena",
     .max_adj    = MAX_PPB,
     .n_alarm    = 0,
     .n_ext_ts   = 0,
     .n_per_out  = 0,
     .n_pins     = 0,
     .pps        = 1,
     .adjfreq    = efx_phc_adjfreq,
     .adjtime    = efx_phc_adjtime,
     .gettime64  = efx_phc_gettime,
     .settime64  = efx_phc_settime,
     .enable     = efx_phc_enable,
 };
 
 /* Initialise PTP state. */
 static int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
 {
     struct efx_ptp_data *ptp;
     int rc = 0;
     unsigned int pos;
 
     ptp = kzalloc(sizeof(struct efx_ptp_data), GFP_KERNEL);
     efx->ptp_data = ptp;
     if (!efx->ptp_data)
         return -ENOMEM;
 
     ptp->efx = efx;
     ptp->channel = channel;
     ptp->rx_ts_inline = efx_nic_rev(efx) >= EFX_REV_HUNT_A0;
 
     rc = efx_siena_alloc_buffer(efx, &ptp->start, sizeof(int), GFP_KERNEL);
     if (rc != 0)
         goto fail1;
 
     skb_queue_head_init(&ptp->rxq);
     skb_queue_head_init(&ptp->txq);
     ptp->workwq = create_singlethread_workqueue("sfc_siena_ptp");
     if (!ptp->workwq) {
         rc = -ENOMEM;
         goto fail2;
     }
 
     if (efx_siena_ptp_use_mac_tx_timestamps(efx)) {
         ptp->xmit_skb = efx_ptp_xmit_skb_queue;
         /* Request sync events on this channel. */
         channel->sync_events_state = SYNC_EVENTS_QUIESCENT;
     } else {
         ptp->xmit_skb = efx_ptp_xmit_skb_mc;
     }
 
     INIT_WORK(&ptp->work, efx_ptp_worker);
     ptp->config.flags = 0;
     ptp->config.tx_type = HWTSTAMP_TX_OFF;
     ptp->config.rx_filter = HWTSTAMP_FILTER_NONE;
     INIT_LIST_HEAD(&ptp->evt_list);
     INIT_LIST_HEAD(&ptp->evt_free_list);
     spin_lock_init(&ptp->evt_lock);
     for (pos = 0; pos < MAX_RECEIVE_EVENTS; pos++)
         list_add(&ptp->rx_evts[pos].link, &ptp->evt_free_list);
 
     /* Get the NIC PTP attributes and set up time conversions */
     rc = efx_ptp_get_attributes(efx);
     if (rc < 0)
         goto fail3;
 
     /* Get the timestamp corrections */
     rc = efx_ptp_get_timestamp_corrections(efx);
     if (rc < 0)
         goto fail3;
 
     if (efx->mcdi->fn_flags &
         (1 << MC_CMD_DRV_ATTACH_EXT_OUT_FLAG_PRIMARY)) {
         ptp->phc_clock_info = efx_phc_clock_info;
         ptp->phc_clock = ptp_clock_register(&ptp->phc_clock_info,
                             &efx->pci_dev->dev);
         if (IS_ERR(ptp->phc_clock)) {
             rc = PTR_ERR(ptp->phc_clock);
             goto fail3;
         } else if (ptp->phc_clock) {
             INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
             ptp->pps_workwq =
                 create_singlethread_workqueue("sfc_siena_pps");
             if (!ptp->pps_workwq) {
                 rc = -ENOMEM;
                 goto fail4;
             }
         }
     }
     ptp->nic_ts_enabled = false;
 
     return 0;
 fail4:
     ptp_clock_unregister(efx->ptp_data->phc_clock);
 
 fail3:
     destroy_workqueue(efx->ptp_data->workwq);
 
 fail2:
     efx_siena_free_buffer(efx, &ptp->start);
 
 fail1:
     kfree(efx->ptp_data);
     efx->ptp_data = NULL;
 
     return rc;
 }
 
 /* Initialise PTP channel.
  *
  * Setting core_index to zero causes the queue to be initialised and doesn't
  * overlap with 'rxq0' because ptp.c doesn't use skb_record_rx_queue.
  */
 static int efx_ptp_probe_channel(struct efx_channel *channel)
 {
     struct efx_nic *efx = channel->efx;
     int rc;
 
     channel->irq_moderation_us = 0;
     channel->rx_queue.core_index = 0;
 
     rc = efx_ptp_probe(efx, channel);
     /* Failure to probe PTP is not fatal; this channel will just not be
      * used for anything.
      * In the case of EPERM, efx_ptp_probe will print its own message (in
      * efx_ptp_get_attributes()), so we don't need to.
      */
     if (rc && rc != -EPERM)
         netif_warn(efx, drv, efx->net_dev,
                "Failed to probe PTP, rc=%d\n", rc);
     return 0;
 }
 
 static void efx_ptp_remove(struct efx_nic *efx)
 {
     if (!efx->ptp_data)
         return;
 
     (void)efx_ptp_disable(efx);
 
     cancel_work_sync(&efx->ptp_data->work);
     if (efx->ptp_data->pps_workwq)
         cancel_work_sync(&efx->ptp_data->pps_work);
 
     skb_queue_purge(&efx->ptp_data->rxq);
     skb_queue_purge(&efx->ptp_data->txq);
 
     if (efx->ptp_data->phc_clock) {
         destroy_workqueue(efx->ptp_data->pps_workwq);
         ptp_clock_unregister(efx->ptp_data->phc_clock);
     }
 
     destroy_workqueue(efx->ptp_data->workwq);
 
     efx_siena_free_buffer(efx, &efx->ptp_data->start);
     kfree(efx->ptp_data);
     efx->ptp_data = NULL;
 }
 
 static void efx_ptp_remove_channel(struct efx_channel *channel)
 {
     efx_ptp_remove(channel->efx);
 }
 
 static void efx_ptp_get_channel_name(struct efx_channel *channel,
                      char *buf, size_t len)
 {
     snprintf(buf, len, "%s-ptp", channel->efx->name);
 }
 
 /* Determine whether this packet should be processed by the PTP module
  * or transmitted conventionally.
  */
 bool efx_siena_ptp_is_ptp_tx(struct efx_nic *efx, struct sk_buff *skb)
 {
     return efx->ptp_data &&
         efx->ptp_data->enabled &&
         skb->len >= PTP_MIN_LENGTH &&
         skb->len <= MC_CMD_PTP_IN_TRANSMIT_PACKET_MAXNUM &&
         likely(skb->protocol == htons(ETH_P_IP)) &&
         skb_transport_header_was_set(skb) &&
         skb_network_header_len(skb) >= sizeof(struct iphdr) &&
         ip_hdr(skb)->protocol == IPPROTO_UDP &&
         skb_headlen(skb) >=
         skb_transport_offset(skb) + sizeof(struct udphdr) &&
         udp_hdr(skb)->dest == htons(PTP_EVENT_PORT);
 }
 
 /* Receive a PTP packet.  Packets are queued until the arrival of
  * the receive timestamp from the MC - this will probably occur after the
  * packet arrival because of the processing in the MC.
  */
 static bool efx_ptp_rx(struct efx_channel *channel, struct sk_buff *skb)
 {
     struct efx_nic *efx = channel->efx;
     struct efx_ptp_data *ptp = efx->ptp_data;
     struct efx_ptp_match *match = (struct efx_ptp_match *)skb->cb;
     u8 *match_data_012, *match_data_345;
     unsigned int version;
     u8 *data;
 
     match->expiry = jiffies + msecs_to_jiffies(PKT_EVENT_LIFETIME_MS);
 
     /* Correct version? */
     if (ptp->mode == MC_CMD_PTP_MODE_V1) {
         if (!pskb_may_pull(skb, PTP_V1_MIN_LENGTH)) {
             return false;
         }
         data = skb->data;
         version = ntohs(*(__be16 *)&data[PTP_V1_VERSION_OFFSET]);
         if (version != PTP_VERSION_V1) {
             return false;
         }
 
         /* PTP V1 uses all six bytes of the UUID to match the packet
          * to the timestamp
          */
         match_data_012 = data + PTP_V1_UUID_OFFSET;
         match_data_345 = data + PTP_V1_UUID_OFFSET + 3;
     } else {
         if (!pskb_may_pull(skb, PTP_V2_MIN_LENGTH)) {
             return false;
         }
         data = skb->data;
         version = data[PTP_V2_VERSION_OFFSET];
         if ((version & PTP_VERSION_V2_MASK) != PTP_VERSION_V2) {
             return false;
         }
 
         /* The original V2 implementation uses bytes 2-7 of
          * the UUID to match the packet to the timestamp. This
          * discards two of the bytes of the MAC address used
          * to create the UUID (SF bug 33070).  The PTP V2
          * enhanced mode fixes this issue and uses bytes 0-2
          * and byte 5-7 of the UUID.
          */
         match_data_345 = data + PTP_V2_UUID_OFFSET + 5;
         if (ptp->mode == MC_CMD_PTP_MODE_V2) {
             match_data_012 = data + PTP_V2_UUID_OFFSET + 2;
         } else {
             match_data_012 = data + PTP_V2_UUID_OFFSET + 0;
             BUG_ON(ptp->mode != MC_CMD_PTP_MODE_V2_ENHANCED);
         }
     }
 
     /* Does this packet require timestamping? */
     if (ntohs(*(__be16 *)&data[PTP_DPORT_OFFSET]) == PTP_EVENT_PORT) {
         match->state = PTP_PACKET_STATE_UNMATCHED;
 
         /* We expect the sequence number to be in the same position in
          * the packet for PTP V1 and V2
          */
         BUILD_BUG_ON(PTP_V1_SEQUENCE_OFFSET != PTP_V2_SEQUENCE_OFFSET);
         BUILD_BUG_ON(PTP_V1_SEQUENCE_LENGTH != PTP_V2_SEQUENCE_LENGTH);
 
         /* Extract UUID/Sequence information */
         match->words[0] = (match_data_012[0]         |
                    (match_data_012[1] << 8)  |
                    (match_data_012[2] << 16) |
                    (match_data_345[0] << 24));
         match->words[1] = (match_data_345[1]         |
                    (match_data_345[2] << 8)  |
                    (data[PTP_V1_SEQUENCE_OFFSET +
                      PTP_V1_SEQUENCE_LENGTH - 1] <<
                     16));
     } else {
         match->state = PTP_PACKET_STATE_MATCH_UNWANTED;
     }
 
     skb_queue_tail(&ptp->rxq, skb);
     queue_work(ptp->workwq, &ptp->work);
 
     return true;
 }
 
 /* Transmit a PTP packet.  This has to be transmitted by the MC
  * itself, through an MCDI call.  MCDI calls aren't permitted
  * in the transmit path so defer the actual transmission to a suitable worker.
  */
 int efx_siena_ptp_tx(struct efx_nic *efx, struct sk_buff *skb)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
 
     skb_queue_tail(&ptp->txq, skb);
 
     if ((udp_hdr(skb)->dest == htons(PTP_EVENT_PORT)) &&
         (skb->len <= MC_CMD_PTP_IN_TRANSMIT_PACKET_MAXNUM))
         efx_xmit_hwtstamp_pending(skb);
     queue_work(ptp->workwq, &ptp->work);
 
     return NETDEV_TX_OK;
 }
 
 int efx_siena_ptp_get_mode(struct efx_nic *efx)
 {
     return efx->ptp_data->mode;
 }
 
 int efx_siena_ptp_change_mode(struct efx_nic *efx, bool enable_wanted,
                   unsigned int new_mode)
 {
     if ((enable_wanted != efx->ptp_data->enabled) ||
         (enable_wanted && (efx->ptp_data->mode != new_mode))) {
         int rc = 0;
 
         if (enable_wanted) {
             /* Change of mode requires disable */
             if (efx->ptp_data->enabled &&
                 (efx->ptp_data->mode != new_mode)) {
                 efx->ptp_data->enabled = false;
                 rc = efx_ptp_stop(efx);
                 if (rc != 0)
                     return rc;
             }
 
             /* Set new operating mode and establish
              * baseline synchronisation, which must
              * succeed.
              */
             efx->ptp_data->mode = new_mode;
             if (netif_running(efx->net_dev))
                 rc = efx_ptp_start(efx);
             if (rc == 0) {
                 rc = efx_ptp_synchronize(efx,
                              PTP_SYNC_ATTEMPTS * 2);
                 if (rc != 0)
                     efx_ptp_stop(efx);
             }
         } else {
             rc = efx_ptp_stop(efx);
         }
 
         if (rc != 0)
             return rc;
 
         efx->ptp_data->enabled = enable_wanted;
     }
 
     return 0;
 }
 
 static int efx_ptp_ts_init(struct efx_nic *efx, struct hwtstamp_config *init)
 {
     int rc;
 
     if ((init->tx_type != HWTSTAMP_TX_OFF) &&
         (init->tx_type != HWTSTAMP_TX_ON))
         return -ERANGE;
 
     rc = efx->type->ptp_set_ts_config(efx, init);
     if (rc)
         return rc;
 
     efx->ptp_data->config = *init;
     return 0;
 }
 
 void efx_siena_ptp_get_ts_info(struct efx_nic *efx,
                    struct ethtool_ts_info *ts_info)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     struct efx_nic *primary = efx->primary;
 
     ASSERT_RTNL();
 
     if (!ptp)
         return;
 
     ts_info->so_timestamping |= (SOF_TIMESTAMPING_TX_HARDWARE |
                      SOF_TIMESTAMPING_RX_HARDWARE |
                      SOF_TIMESTAMPING_RAW_HARDWARE);
     if (primary && primary->ptp_data && primary->ptp_data->phc_clock)
         ts_info->phc_index =
             ptp_clock_index(primary->ptp_data->phc_clock);
     ts_info->tx_types = 1 << HWTSTAMP_TX_OFF | 1 << HWTSTAMP_TX_ON;
     ts_info->rx_filters = ptp->efx->type->hwtstamp_filters;
 }
 
 int efx_siena_ptp_set_ts_config(struct efx_nic *efx, struct ifreq *ifr)
 {
     struct hwtstamp_config config;
     int rc;
 
     /* Not a PTP enabled port */
     if (!efx->ptp_data)
         return -EOPNOTSUPP;
 
     if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
         return -EFAULT;
 
     rc = efx_ptp_ts_init(efx, &config);
     if (rc != 0)
         return rc;
 
     return copy_to_user(ifr->ifr_data, &config, sizeof(config))
         ? -EFAULT : 0;
 }
 
 int efx_siena_ptp_get_ts_config(struct efx_nic *efx, struct ifreq *ifr)
 {
     if (!efx->ptp_data)
         return -EOPNOTSUPP;
 
     return copy_to_user(ifr->ifr_data, &efx->ptp_data->config,
                 sizeof(efx->ptp_data->config)) ? -EFAULT : 0;
 }
 
 static void ptp_event_failure(struct efx_nic *efx, int expected_frag_len)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
 
     netif_err(efx, hw, efx->net_dev,
         "PTP unexpected event length: got %d expected %d\n",
         ptp->evt_frag_idx, expected_frag_len);
     ptp->reset_required = true;
     queue_work(ptp->workwq, &ptp->work);
 }
 
 /* Process a completed receive event.  Put it on the event queue and
  * start worker thread.  This is required because event and their
  * correspoding packets may come in either order.
  */
 static void ptp_event_rx(struct efx_nic *efx, struct efx_ptp_data *ptp)
 {
     struct efx_ptp_event_rx *evt = NULL;
 
     if (WARN_ON_ONCE(ptp->rx_ts_inline))
         return;
 
     if (ptp->evt_frag_idx != 3) {
         ptp_event_failure(efx, 3);
         return;
     }
 
     spin_lock_bh(&ptp->evt_lock);
     if (!list_empty(&ptp->evt_free_list)) {
         evt = list_first_entry(&ptp->evt_free_list,
                        struct efx_ptp_event_rx, link);
         list_del(&evt->link);
 
         evt->seq0 = EFX_QWORD_FIELD(ptp->evt_frags[2], MCDI_EVENT_DATA);
         evt->seq1 = (EFX_QWORD_FIELD(ptp->evt_frags[2],
                          MCDI_EVENT_SRC)        |
                  (EFX_QWORD_FIELD(ptp->evt_frags[1],
                           MCDI_EVENT_SRC) << 8) |
                  (EFX_QWORD_FIELD(ptp->evt_frags[0],
                           MCDI_EVENT_SRC) << 16));
         evt->hwtimestamp = efx->ptp_data->nic_to_kernel_time(
             EFX_QWORD_FIELD(ptp->evt_frags[0], MCDI_EVENT_DATA),
             EFX_QWORD_FIELD(ptp->evt_frags[1], MCDI_EVENT_DATA),
             ptp->ts_corrections.ptp_rx);
         evt->expiry = jiffies + msecs_to_jiffies(PKT_EVENT_LIFETIME_MS);
         list_add_tail(&evt->link, &ptp->evt_list);
 
         queue_work(ptp->workwq, &ptp->work);
     } else if (net_ratelimit()) {
         /* Log a rate-limited warning message. */
         netif_err(efx, rx_err, efx->net_dev, "PTP event queue overflow\n");
     }
     spin_unlock_bh(&ptp->evt_lock);
 }
 
 static void ptp_event_fault(struct efx_nic *efx, struct efx_ptp_data *ptp)
 {
     int code = EFX_QWORD_FIELD(ptp->evt_frags[0], MCDI_EVENT_DATA);
     if (ptp->evt_frag_idx != 1) {
         ptp_event_failure(efx, 1);
         return;
     }
 
     netif_err(efx, hw, efx->net_dev, "PTP error %d\n", code);
 }
 
 static void ptp_event_pps(struct efx_nic *efx, struct efx_ptp_data *ptp)
 {
     if (ptp->nic_ts_enabled)
         queue_work(ptp->pps_workwq, &ptp->pps_work);
 }
 
 void efx_siena_ptp_event(struct efx_nic *efx, efx_qword_t *ev)
 {
     struct efx_ptp_data *ptp = efx->ptp_data;
     int code = EFX_QWORD_FIELD(*ev, MCDI_EVENT_CODE);
 
     if (!ptp) {
         if (!efx->ptp_warned) {
             netif_warn(efx, drv, efx->net_dev,
                    "Received PTP event but PTP not set up\n");
             efx->ptp_warned = true;
         }
         return;
     }
 
     if (!ptp->enabled)
         return;
 
     if (ptp->evt_frag_idx == 0) {
         ptp->evt_code = code;
     } else if (ptp->evt_code != code) {
         netif_err(efx, hw, efx->net_dev,
               "PTP out of sequence event %d\n", code);
         ptp->evt_frag_idx = 0;
     }
 
     ptp->evt_frags[ptp->evt_frag_idx++] = *ev;
     if (!MCDI_EVENT_FIELD(*ev, CONT)) {
         /* Process resulting event */
         switch (code) {
         case MCDI_EVENT_CODE_PTP_RX:
             ptp_event_rx(efx, ptp);
             break;
         case MCDI_EVENT_CODE_PTP_FAULT:
             ptp_event_fault(efx, ptp);
             break;
         case MCDI_EVENT_CODE_PTP_PPS:
             ptp_event_pps(efx, ptp);
             break;
         default:
             netif_err(efx, hw, efx->net_dev,
                   "PTP unknown event %d\n", code);
             break;
         }
         ptp->evt_frag_idx = 0;
     } else if (MAX_EVENT_FRAGS == ptp->evt_frag_idx) {
         netif_err(efx, hw, efx->net_dev,
               "PTP too many event fragments\n");
         ptp->evt_frag_idx = 0;
     }
 }
 
 void efx_siena_time_sync_event(struct efx_channel *channel, efx_qword_t *ev)
 {
     struct efx_nic *efx = channel->efx;
     struct efx_ptp_data *ptp = efx->ptp_data;
 
     /* When extracting the sync timestamp minor value, we should discard
      * the least significant two bits. These are not required in order
      * to reconstruct full-range timestamps and they are optionally used
      * to report status depending on the options supplied when subscribing
      * for sync events.
      */
     channel->sync_timestamp_major = MCDI_EVENT_FIELD(*ev, PTP_TIME_MAJOR);
     channel->sync_timestamp_minor =
         (MCDI_EVENT_FIELD(*ev, PTP_TIME_MINOR_MS_8BITS) & 0xFC)
             << ptp->nic_time.sync_event_minor_shift;
 
     /* if sync events have been disabled then we want to silently ignore
      * this event, so throw away result.
      */
     (void) cmpxchg(&channel->sync_events_state, SYNC_EVENTS_REQUESTED,
                SYNC_EVENTS_VALID);
 }
 
 static inline u32 efx_rx_buf_timestamp_minor(struct efx_nic *efx, const u8 *eh)
 {
 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
     return __le32_to_cpup((const __le32 *)(eh + efx->rx_packet_ts_offset));
 #else
     const u8 *data = eh + efx->rx_packet_ts_offset;
     return (u32)data[0]       |
            (u32)data[1] << 8  |
            (u32)data[2] << 16 |
            (u32)data[3] << 24;
 #endif
 }
 
 void __efx_siena_rx_skb_attach_timestamp(struct efx_channel *channel,
                      struct sk_buff *skb)
 {
     struct efx_nic *efx = channel->efx;
     struct efx_ptp_data *ptp = efx->ptp_data;
     u32 pkt_timestamp_major, pkt_timestamp_minor;
     u32 diff, carry;
     struct skb_shared_hwtstamps *timestamps;
 
     if (channel->sync_events_state != SYNC_EVENTS_VALID)
         return;
 
     pkt_timestamp_minor = efx_rx_buf_timestamp_minor(efx, skb_mac_header(skb));
 
     /* get the difference between the packet and sync timestamps,
      * modulo one second
      */
     diff = pkt_timestamp_minor - channel->sync_timestamp_minor;
     if (pkt_timestamp_minor < channel->sync_timestamp_minor)
         diff += ptp->nic_time.minor_max;
 
     /* do we roll over a second boundary and need to carry the one? */
     carry = (channel->sync_timestamp_minor >= ptp->nic_time.minor_max - diff) ?
         1 : 0;
 
     if (diff <= ptp->nic_time.sync_event_diff_max) {
         /* packet is ahead of the sync event by a quarter of a second or
          * less (allowing for fuzz)
          */
         pkt_timestamp_major = channel->sync_timestamp_major + carry;
     } else if (diff >= ptp->nic_time.sync_event_diff_min) {
         /* packet is behind the sync event but within the fuzz factor.
          * This means the RX packet and sync event crossed as they were
          * placed on the event queue, which can sometimes happen.
          */
         pkt_timestamp_major = channel->sync_timestamp_major - 1 + carry;
     } else {
         /* it's outside tolerance in both directions. this might be
          * indicative of us missing sync events for some reason, so
          * we'll call it an error rather than risk giving a bogus
          * timestamp.
          */
         netif_vdbg(efx, drv, efx->net_dev,
               "packet timestamp %x too far from sync event %x:%x\n",
               pkt_timestamp_minor, channel->sync_timestamp_major,
               channel->sync_timestamp_minor);
         return;
     }
 
     /* attach the timestamps to the skb */
     timestamps = skb_hwtstamps(skb);
     timestamps->hwtstamp =
         ptp->nic_to_kernel_time(pkt_timestamp_major,
                     pkt_timestamp_minor,
                     ptp->ts_corrections.general_rx);
 }
 
 static int efx_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)
 {
     struct efx_ptp_data *ptp_data = container_of(ptp,
                              struct efx_ptp_data,
                              phc_clock_info);
     struct efx_nic *efx = ptp_data->efx;
     MCDI_DECLARE_BUF(inadj, MC_CMD_PTP_IN_ADJUST_LEN);
     s64 adjustment_ns;
     int rc;
 
     if (delta > MAX_PPB)
         delta = MAX_PPB;
     else if (delta < -MAX_PPB)
         delta = -MAX_PPB;
 
     /* Convert ppb to fixed point ns taking care to round correctly. */
     adjustment_ns = ((s64)delta * PPB_SCALE_WORD +
              (1 << (ptp_data->adjfreq_ppb_shift - 1))) >>
             ptp_data->adjfreq_ppb_shift;
 
     MCDI_SET_DWORD(inadj, PTP_IN_OP, MC_CMD_PTP_OP_ADJUST);
     MCDI_SET_DWORD(inadj, PTP_IN_PERIPH_ID, 0);
     MCDI_SET_QWORD(inadj, PTP_IN_ADJUST_FREQ, adjustment_ns);
     MCDI_SET_DWORD(inadj, PTP_IN_ADJUST_SECONDS, 0);
     MCDI_SET_DWORD(inadj, PTP_IN_ADJUST_NANOSECONDS, 0);
     rc = efx_siena_mcdi_rpc(efx, MC_CMD_PTP, inadj, sizeof(inadj),
                 NULL, 0, NULL);
     if (rc != 0)
         return rc;
 
     ptp_data->current_adjfreq = adjustment_ns;
     return 0;
 }
 
 static int efx_phc_adjtime(struct ptp_clock_info *ptp, s64 delta)
 {
     u32 nic_major, nic_minor;
     struct efx_ptp_data *ptp_data = container_of(ptp,
                              struct efx_ptp_data,
                              phc_clock_info);
     struct efx_nic *efx = ptp_data->efx;
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_ADJUST_LEN);
 
     efx->ptp_data->ns_to_nic_time(delta, &nic_major, &nic_minor);
 
     MCDI_SET_DWORD(inbuf, PTP_IN_OP, MC_CMD_PTP_OP_ADJUST);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
     MCDI_SET_QWORD(inbuf, PTP_IN_ADJUST_FREQ, ptp_data->current_adjfreq);
     MCDI_SET_DWORD(inbuf, PTP_IN_ADJUST_MAJOR, nic_major);
     MCDI_SET_DWORD(inbuf, PTP_IN_ADJUST_MINOR, nic_minor);
     return efx_siena_mcdi_rpc(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                   NULL, 0, NULL);
 }
 
 static int efx_phc_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 {
     struct efx_ptp_data *ptp_data = container_of(ptp,
                              struct efx_ptp_data,
                              phc_clock_info);
     struct efx_nic *efx = ptp_data->efx;
     MCDI_DECLARE_BUF(inbuf, MC_CMD_PTP_IN_READ_NIC_TIME_LEN);
     MCDI_DECLARE_BUF(outbuf, MC_CMD_PTP_OUT_READ_NIC_TIME_LEN);
     int rc;
     ktime_t kt;
 
     MCDI_SET_DWORD(inbuf, PTP_IN_OP, MC_CMD_PTP_OP_READ_NIC_TIME);
     MCDI_SET_DWORD(inbuf, PTP_IN_PERIPH_ID, 0);
 
     rc = efx_siena_mcdi_rpc(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
                 outbuf, sizeof(outbuf), NULL);
     if (rc != 0)
         return rc;
 
     kt = ptp_data->nic_to_kernel_time(
         MCDI_DWORD(outbuf, PTP_OUT_READ_NIC_TIME_MAJOR),
         MCDI_DWORD(outbuf, PTP_OUT_READ_NIC_TIME_MINOR), 0);
     *ts = ktime_to_timespec64(kt);
     return 0;
 }
 
 static int efx_phc_settime(struct ptp_clock_info *ptp,
                const struct timespec64 *e_ts)
 {
     /* Get the current NIC time, efx_phc_gettime.
      * Subtract from the desired time to get the offset
      * call efx_phc_adjtime with the offset
      */
     int rc;
     struct timespec64 time_now;
     struct timespec64 delta;
 
     rc = efx_phc_gettime(ptp, &time_now);
     if (rc != 0)
         return rc;
 
     delta = timespec64_sub(*e_ts, time_now);
 
     rc = efx_phc_adjtime(ptp, timespec64_to_ns(&delta));
     if (rc != 0)
         return rc;
 
     return 0;
 }
 
 static int efx_phc_enable(struct ptp_clock_info *ptp,
               struct ptp_clock_request *request,
               int enable)
 {
     struct efx_ptp_data *ptp_data = container_of(ptp,
                              struct efx_ptp_data,
                              phc_clock_info);
     if (request->type != PTP_CLK_REQ_PPS)
         return -EOPNOTSUPP;
 
     ptp_data->nic_ts_enabled = !!enable;
     return 0;
 }
 
 static const struct efx_channel_type efx_ptp_channel_type = {
     .handle_no_channel  = efx_ptp_handle_no_channel,
     .pre_probe      = efx_ptp_probe_channel,
     .post_remove        = efx_ptp_remove_channel,
     .get_name       = efx_ptp_get_channel_name,
     /* no copy operation; there is no need to reallocate this channel */
     .receive_skb        = efx_ptp_rx,
     .want_txqs      = efx_ptp_want_txqs,
     .keep_eventq        = false,
 };
 
 void efx_siena_ptp_defer_probe_with_channel(struct efx_nic *efx)
 {
     /* Check whether PTP is implemented on this NIC.  The DISABLE
      * operation will succeed if and only if it is implemented.
      */
     if (efx_ptp_disable(efx) == 0)
         efx->extra_channel_type[EFX_EXTRA_CHANNEL_PTP] =
             &efx_ptp_channel_type;
 }
 
 void efx_siena_ptp_start_datapath(struct efx_nic *efx)
 {
     if (efx_ptp_restart(efx))
         netif_err(efx, drv, efx->net_dev, "Failed to restart PTP.\n");
     /* re-enable timestamping if it was previously enabled */
     if (efx->type->ptp_set_ts_sync_events)
         efx->type->ptp_set_ts_sync_events(efx, true, true);
 }
 
 void efx_siena_ptp_stop_datapath(struct efx_nic *efx)
 {
     /* temporarily disable timestamping */
     if (efx->type->ptp_set_ts_sync_events)
         efx->type->ptp_set_ts_sync_events(efx, false, true);
     efx_ptp_stop(efx);
 }

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