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sfc: support second + quarter ns time format for receive datapath
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The time_format that we stash in the PTP data structure is never
 referenced, so we can remove it.  Instead, store the information needed
 to interpret sync event timestamps.
Also rolls in a couple of other related minor PTP fixes.

Based on patches by Bert Kenward <[email protected]> and Laurence
 Evans <[email protected]>.

Signed-off-by: Edward Cree <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@ecree-solarflare @davem330
ecree-solarflare authored and davem330 committed Jan 25, 2018
1 parent 04796f4 commit 1280c0f
Showing 1 changed file with 106 additions and 33 deletions.
139 changes: 106 additions & 33 deletions drivers/net/ethernet/sfc/ptp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -233,9 +233,17 @@ struct efx_ptp_timeset {
* @config: Current timestamp configuration
* @enabled: PTP operation enabled
* @mode: Mode in which PTP operating (PTP version)
* @time_format: Time format supported by this NIC
* @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.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.ptp_tx: Required driver correction of PTP packet transmit
Expand Down Expand Up @@ -292,10 +300,15 @@ struct efx_ptp_data {
struct hwtstamp_config config;
bool enabled;
unsigned int mode;
unsigned int time_format;
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;
struct {
s32 ptp_tx;
Expand Down Expand Up @@ -500,6 +513,32 @@ static ktime_t efx_ptp_s27_to_ktime_correction(u32 nic_major, u32 nic_minor,
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_ptp_channel(struct efx_nic *efx)
{
return efx->ptp_data ? efx->ptp_data->channel : NULL;
Expand All @@ -519,7 +558,8 @@ static u32 last_sync_timestamp_major(struct efx_nic *efx)
* 48 bits long and provides meta-information in the top 2 bits.
*/
static ktime_t
efx_ptp_mac_s27_to_ktime_correction(struct efx_nic *efx,
efx_ptp_mac_nic_to_ktime_correction(struct efx_nic *efx,
struct efx_ptp_data *ptp,
u32 nic_major, u32 nic_minor,
s32 correction)
{
Expand All @@ -531,8 +571,8 @@ efx_ptp_mac_s27_to_ktime_correction(struct efx_nic *efx,
nic_major &= 0xffff;
nic_major |= (last_sync_timestamp_major(efx) & 0xffff0000);

kt = efx_ptp_s27_to_ktime_correction(nic_major, nic_minor,
correction);
kt = ptp->nic_to_kernel_time(nic_major, nic_minor,
correction);
}
return kt;
}
Expand All @@ -544,7 +584,7 @@ ktime_t efx_ptp_nic_to_kernel_time(struct efx_tx_queue *tx_queue)
ktime_t kt;

if (efx_ptp_use_mac_tx_timestamps(efx))
kt = efx_ptp_mac_s27_to_ktime_correction(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);
Expand Down Expand Up @@ -587,23 +627,49 @@ static int efx_ptp_get_attributes(struct efx_nic *efx)
return rc;
}

if (fmt == MC_CMD_PTP_OUT_GET_ATTRIBUTES_SECONDS_27FRACTION) {
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;
} else if (fmt == MC_CMD_PTP_OUT_GET_ATTRIBUTES_SECONDS_NANOSECONDS) {
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;
} else {
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 = 4000000000;
ptp->nic_time.sync_event_minor_shift = 24;
break;
default:
return -ERANGE;
}

/* MC_CMD_PTP_OP_GET_ATTRIBUTES is an extended version of an older
* operation MC_CMD_PTP_OP_GET_TIME_FORMAT that also returns a value
* to use for the minimum acceptable corrected synchronization window.
/* 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_LEN)
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);
Expand Down Expand Up @@ -1855,25 +1921,27 @@ void efx_ptp_event(struct efx_nic *efx, efx_qword_t *ev)

void efx_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_26_19) << 19;
(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);
}

/* make some assumptions about the time representation rather than abstract it,
* since we currently only support one type of inline timestamping and only on
* EF10.
*/
#define MINOR_TICKS_PER_SECOND 0x8000000
/* Fuzz factor for sync events to be out of order with RX events */
#define FUZZ (MINOR_TICKS_PER_SECOND / 10)
#define EXPECTED_SYNC_EVENTS_PER_SECOND 4

static inline u32 efx_rx_buf_timestamp_minor(struct efx_nic *efx, const u8 *eh)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
Expand All @@ -1891,28 +1959,33 @@ void __efx_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) &
(MINOR_TICKS_PER_SECOND - 1);
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 + diff > MINOR_TICKS_PER_SECOND ?
carry = (channel->sync_timestamp_minor >= ptp->nic_time.minor_max - diff) ?
1 : 0;

if (diff <= MINOR_TICKS_PER_SECOND / EXPECTED_SYNC_EVENTS_PER_SECOND +
FUZZ) {
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 >= MINOR_TICKS_PER_SECOND - FUZZ) {
} 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.
Expand All @@ -1933,10 +2006,10 @@ void __efx_rx_skb_attach_timestamp(struct efx_channel *channel,

/* attach the timestamps to the skb */
timestamps = skb_hwtstamps(skb);
timestamps->hwtstamp = efx_ptp_s27_to_ktime_correction(
pkt_timestamp_major,
pkt_timestamp_minor,
efx->ptp_data->ts_corrections.general_rx);
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)
Expand Down

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