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sfc: Add support for SFC9100 timestamp format
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The clock minor tick on the SFC9100 family is 2^-27 s, not 1 ns.
There are also various pipeline delays which we need to correct for
when interpreting timestamps.

We query the firmware for the clock format and corrections at run-time.

[bwh: Combined and rebased several changes]
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
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Laurence Evans authored and Ben Hutchings committed Dec 12, 2013
1 parent dfd8d58 commit a6f7346
Showing 1 changed file with 231 additions and 25 deletions.
256 changes: 231 additions & 25 deletions drivers/net/ethernet/sfc/ptp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@
#define SYNCHRONISATION_GRANULARITY_NS 200

/* Minimum permitted length of a (corrected) synchronisation time */
#define MIN_SYNCHRONISATION_NS 120
#define DEFAULT_MIN_SYNCHRONISATION_NS 120

/* Maximum permitted length of a (corrected) synchronisation time */
#define MAX_SYNCHRONISATION_NS 1000
Expand Down Expand Up @@ -195,20 +195,20 @@ struct efx_ptp_event_rx {
/**
* struct efx_ptp_timeset - Synchronisation between host and MC
* @host_start: Host time immediately before hardware timestamp taken
* @seconds: Hardware timestamp, seconds
* @nanoseconds: Hardware timestamp, nanoseconds
* @major: Hardware timestamp, major
* @minor: Hardware timestamp, minor
* @host_end: Host time immediately after hardware timestamp taken
* @waitns: Number of nanoseconds between hardware timestamp being read and
* @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 seconds;
u32 nanoseconds;
u32 major;
u32 minor;
u32 host_end;
u32 waitns;
u32 wait;
u32 window; /* Derived: end - start, allowing for wrap */
};

Expand All @@ -232,6 +232,14 @@ 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
* @min_synchronisation_ns: Minimum acceptable corrected sync window
* @ts_corrections.tx: Required driver correction of transmit timestamps
* @ts_corrections.rx: Required driver correction of receive timestamps
* @ts_corrections.pps_out: PPS output error (information only)
* @ts_corrections.pps_in: Required driver correction of PPS input timestamps
* @evt_frags: Partly assembled PTP events
* @evt_frag_idx: Current fragment number
* @evt_code: Last event code
Expand Down Expand Up @@ -266,6 +274,17 @@ 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);
unsigned int min_synchronisation_ns;
struct {
s32 tx;
s32 rx;
s32 pps_out;
s32 pps_in;
} ts_corrections;
efx_qword_t evt_frags[MAX_EVENT_FRAGS];
int evt_frag_idx;
int evt_code;
Expand All @@ -290,6 +309,167 @@ static int efx_phc_settime(struct ptp_clock_info *ptp,
static int efx_phc_enable(struct ptp_clock_info *ptp,
struct ptp_clock_request *request, int on);

/* 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 timespec ts = ns_to_timespec(ns);
*nic_major = ts.tv_sec;
*nic_minor = ts.tv_nsec;
}

static ktime_t efx_ptp_s_ns_to_ktime(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 timespec ts = ns_to_timespec(ns);
u32 maj = 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 ktime_t efx_ptp_s27_to_ktime(u32 nic_major, u32 nic_minor,
s32 correction)
{
u32 ns;

/* 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++;
}

ns = (u32)(((u64)nic_minor * NSEC_PER_SEC +
(1ULL << (S27_TO_NS_SHIFT - 1))) >> S27_TO_NS_SHIFT);

return ktime_set(nic_major, ns);
}

/* 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_mcdi_rpc(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
return rc;

if (fmt == 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;
} else if (fmt == 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;
} else {
return -ERANGE;
}

ptp->time_format = fmt;

/* 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.
* 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)
ptp->min_synchronisation_ns =
MCDI_DWORD(outbuf,
PTP_OUT_GET_ATTRIBUTES_SYNC_WINDOW_MIN);
else
ptp->min_synchronisation_ns = DEFAULT_MIN_SYNCHRONISATION_NS;

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_LEN);
int rc;

/* 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_mcdi_rpc(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
outbuf, sizeof(outbuf), NULL);
if (rc == 0) {
efx->ptp_data->ts_corrections.tx = MCDI_DWORD(outbuf,
PTP_OUT_GET_TIMESTAMP_CORRECTIONS_TRANSMIT);
efx->ptp_data->ts_corrections.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);
} else if (rc == -EINVAL) {
efx->ptp_data->ts_corrections.tx = 0;
efx->ptp_data->ts_corrections.rx = 0;
efx->ptp_data->ts_corrections.pps_out = 0;
efx->ptp_data->ts_corrections.pps_in = 0;
} else {
return rc;
}

return 0;
}

/* Enable MCDI PTP support. */
static int efx_ptp_enable(struct efx_nic *efx)
{
Expand Down Expand Up @@ -402,11 +582,10 @@ static void efx_ptp_read_timeset(MCDI_DECLARE_STRUCT_PTR(data),
unsigned start_ns, end_ns;

timeset->host_start = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_HOSTSTART);
timeset->seconds = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_SECONDS);
timeset->nanoseconds = MCDI_DWORD(data,
PTP_OUT_SYNCHRONIZE_NANOSECONDS);
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->waitns = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_WAITNS);
timeset->wait = MCDI_DWORD(data, PTP_OUT_SYNCHRONIZE_WAITNS);

/* Ignore seconds */
start_ns = timeset->host_start & MC_NANOSECOND_MASK;
Expand Down Expand Up @@ -441,6 +620,7 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
u32 last_sec;
u32 start_sec;
struct timespec delta;
ktime_t mc_time;

if (number_readings == 0)
return -EAGAIN;
Expand All @@ -452,14 +632,17 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
*/
for (i = 0; i < number_readings; i++) {
s32 window, corrected;
struct timespec wait;

efx_ptp_read_timeset(
MCDI_ARRAY_STRUCT_PTR(synch_buf,
PTP_OUT_SYNCHRONIZE_TIMESET, i),
&ptp->timeset[i]);

wait = ktime_to_timespec(
ptp->nic_to_kernel_time(0, ptp->timeset[i].wait, 0));
window = ptp->timeset[i].window;
corrected = window - ptp->timeset[i].waitns;
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
Expand All @@ -472,7 +655,7 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
*/
if (window >= SYNCHRONISATION_GRANULARITY_NS &&
corrected < MAX_SYNCHRONISATION_NS &&
corrected >= MIN_SYNCHRONISATION_NS) {
corrected >= ptp->min_synchronisation_ns) {
ngood++;
last_good = i;
}
Expand All @@ -484,9 +667,15 @@ efx_ptp_process_times(struct efx_nic *efx, MCDI_DECLARE_STRUCT_PTR(synch_buf),
return -EAGAIN;
}

/* Convert the NIC time 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 actual PPS to last_time */
delta.tv_nsec =
ptp->timeset[last_good].nanoseconds +
delta = ktime_to_timespec(mc_time);
delta.tv_nsec +=
last_time->ts_real.tv_nsec -
(ptp->timeset[last_good].host_start & MC_NANOSECOND_MASK);

Expand Down Expand Up @@ -596,9 +785,10 @@ static int efx_ptp_xmit_skb(struct efx_nic *efx, struct sk_buff *skb)
goto fail;

memset(&timestamps, 0, sizeof(timestamps));
timestamps.hwtstamp = ktime_set(
MCDI_DWORD(txtime, PTP_OUT_TRANSMIT_SECONDS),
MCDI_DWORD(txtime, PTP_OUT_TRANSMIT_NANOSECONDS));
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.tx);

skb_tstamp_tx(skb, &timestamps);

Expand Down Expand Up @@ -954,6 +1144,16 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
list_add(&ptp->rx_evts[pos].link, &ptp->evt_free_list);
ptp->evt_overflow = false;

/* 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;

ptp->phc_clock_info = efx_phc_clock_info;
ptp->phc_clock = ptp_clock_register(&ptp->phc_clock_info,
&efx->pci_dev->dev);
Expand Down Expand Up @@ -1358,9 +1558,10 @@ static void ptp_event_rx(struct efx_nic *efx, struct efx_ptp_data *ptp)
MCDI_EVENT_SRC) << 8) |
(EFX_QWORD_FIELD(ptp->evt_frags[0],
MCDI_EVENT_SRC) << 16));
evt->hwtimestamp = ktime_set(
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));
EFX_QWORD_FIELD(ptp->evt_frags[1], MCDI_EVENT_DATA),
ptp->ts_corrections.rx);
evt->expiry = jiffies + msecs_to_jiffies(PKT_EVENT_LIFETIME_MS);
list_add_tail(&evt->link, &ptp->evt_list);

Expand Down Expand Up @@ -1470,18 +1671,20 @@ static int efx_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)

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;
struct timespec delta_ts = ns_to_timespec(delta);
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_SECONDS, (u32)delta_ts.tv_sec);
MCDI_SET_DWORD(inbuf, PTP_IN_ADJUST_NANOSECONDS, (u32)delta_ts.tv_nsec);
MCDI_SET_DWORD(inbuf, PTP_IN_ADJUST_MAJOR, nic_major);
MCDI_SET_DWORD(inbuf, PTP_IN_ADJUST_MINOR, nic_minor);
return efx_mcdi_rpc(efx, MC_CMD_PTP, inbuf, sizeof(inbuf),
NULL, 0, NULL);
}
Expand All @@ -1495,6 +1698,7 @@ static int efx_phc_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
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);
Expand All @@ -1504,8 +1708,10 @@ static int efx_phc_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
if (rc != 0)
return rc;

ts->tv_sec = MCDI_DWORD(outbuf, PTP_OUT_READ_NIC_TIME_SECONDS);
ts->tv_nsec = MCDI_DWORD(outbuf, PTP_OUT_READ_NIC_TIME_NANOSECONDS);
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_timespec(kt);
return 0;
}

Expand Down

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