Paul Menzel <pmenzel@xxxxxxxxxxxxx> writes:
> Dear Vinicius,
>
>
> Am 05.06.21 um 02:23 schrieb Vinicius Costa Gomes:
>> i225 has support for PCIe PTM, which allows us to implement support
>> for the PTP_SYS_OFFSET_PRECISE ioctl(), implemented in the driver via
>> the getcrosststamp() function.
>
> Maybe:
>
> i225 supports PCIe Precision Time Measurement (PTM), allowing us to
> support the PTP_SYS_OFFSET_PRECISE ioctl() in the driver via the
> getcrosststamp() function.
Sure. Sounds good. Will change the commit message.
>
>> The easiest way to expose the PTM registers would be to configure the PTM
>> dialogs to run periodically, but the PTP_SYS_OFFSET_PRECISE ioctl()
>> semantics are more aligned to using a kind of "one-shot" way of retrieving
>> the PTM timestamps. But this causes a bit more code to be written: the
>
> Maybe: But this results in more code:
Will change.
>
>> trigger registers for the PTM dialogs are not cleared automatically.
>>
>> i225 can be configured to send "fake" packets with the PTM
>> information, adding support for handling these types of packets is
>> left for the future.
>>
>> PTM improves the accuracy of time synchronization, for example, using
>> phc2sys. Before:
>>
>> phc2sys[341.511]: CLOCK_REALTIME phc offset 289 s2 freq +961 delay 2963
>> phc2sys[342.511]: CLOCK_REALTIME phc offset -984 s2 freq -225 delay 3517
>> phc2sys[343.511]: CLOCK_REALTIME phc offset 427 s2 freq +891 delay 2312
>> phc2sys[344.511]: CLOCK_REALTIME phc offset 104 s2 freq +696 delay 2575
>> phc2sys[345.511]: CLOCK_REALTIME phc offset 149 s2 freq +772 delay 2388
>> phc2sys[346.511]: CLOCK_REALTIME phc offset 33 s2 freq +701 delay 2359
>> phc2sys[347.511]: CLOCK_REALTIME phc offset -216 s2 freq +462 delay 2706
>> phc2sys[348.512]: CLOCK_REALTIME phc offset 140 s2 freq +753 delay 2300
>> phc2sys[349.512]: CLOCK_REALTIME phc offset -14 s2 freq +641 delay 2385
>> phc2sys[350.512]: CLOCK_REALTIME phc offset 1048 s2 freq +1699 delay 4303
>> phc2sys[351.512]: CLOCK_REALTIME phc offset -1296 s2 freq -331 delay 2846
>> phc2sys[352.512]: CLOCK_REALTIME phc offset -912 s2 freq -336 delay 4006
>> phc2sys[353.512]: CLOCK_REALTIME phc offset 880 s2 freq +1183 delay 2338
>> phc2sys[354.512]: CLOCK_REALTIME phc offset 358 s2 freq +925 delay 2348
>> phc2sys[355.512]: CLOCK_REALTIME phc offset -211 s2 freq +463 delay 2941
>> phc2sys[356.512]: CLOCK_REALTIME phc offset 234 s2 freq +845 delay 2519
>> phc2sys[357.512]: CLOCK_REALTIME phc offset 45 s2 freq +726 delay 2357
>> phc2sys[358.512]: CLOCK_REALTIME phc offset -262 s2 freq +433 delay 2821
>> phc2sys[359.512]: CLOCK_REALTIME phc offset -424 s2 freq +192 delay 3579
>> phc2sys[360.513]: CLOCK_REALTIME phc offset 134 s2 freq +623 delay 3269
>> phc2sys[361.513]: CLOCK_REALTIME phc offset -213 s2 freq +316 delay 3999
>> phc2sys[362.513]: CLOCK_REALTIME phc offset 1023 s2 freq +1488 delay 2614
>> phc2sys[363.513]: CLOCK_REALTIME phc offset 57 s2 freq +829 delay 2332
>> phc2sys[364.513]: CLOCK_REALTIME phc offset -126 s2 freq +663 delay 2315
>> phc2sys[365.513]: CLOCK_REALTIME phc offset -85 s2 freq +666 delay 2449
>> phc2sys[366.513]: CLOCK_REALTIME phc offset -193 s2 freq +533 delay 2336
>> phc2sys[367.513]: CLOCK_REALTIME phc offset -645 s2 freq +23 delay 3870
>> phc2sys[368.513]: CLOCK_REALTIME phc offset 483 s2 freq +957 delay 2342
>> phc2sys[369.513]: CLOCK_REALTIME phc offset -166 s2 freq +453 delay 3025
>> phc2sys[370.513]: CLOCK_REALTIME phc offset 327 s2 freq +896 delay 2250
>>
>> After:
>>
>> phc2sys[617.838]: CLOCK_REALTIME phc offset -25 s2 freq +309 delay 0
>> phc2sys[618.838]: CLOCK_REALTIME phc offset -43 s2 freq +284 delay 0
>> phc2sys[619.838]: CLOCK_REALTIME phc offset -12 s2 freq +302 delay 0
>> phc2sys[620.838]: CLOCK_REALTIME phc offset -2 s2 freq +308 delay 0
>> phc2sys[621.838]: CLOCK_REALTIME phc offset 30 s2 freq +340 delay 0
>> phc2sys[622.838]: CLOCK_REALTIME phc offset 14 s2 freq +333 delay 0
>> phc2sys[623.839]: CLOCK_REALTIME phc offset -3 s2 freq +320 delay 0
>> phc2sys[624.839]: CLOCK_REALTIME phc offset 9 s2 freq +331 delay 0
>> phc2sys[625.839]: CLOCK_REALTIME phc offset -1 s2 freq +324 delay 0
>> phc2sys[626.839]: CLOCK_REALTIME phc offset -6 s2 freq +318 delay 0
>> phc2sys[627.839]: CLOCK_REALTIME phc offset -10 s2 freq +313 delay 0
>> phc2sys[628.839]: CLOCK_REALTIME phc offset 7 s2 freq +327 delay 0
>> phc2sys[629.839]: CLOCK_REALTIME phc offset 8 s2 freq +330 delay 0
>> phc2sys[630.840]: CLOCK_REALTIME phc offset -24 s2 freq +300 delay 0
>> phc2sys[631.840]: CLOCK_REALTIME phc offset -49 s2 freq +268 delay 0
>> phc2sys[632.840]: CLOCK_REALTIME phc offset 6 s2 freq +308 delay 0
>> phc2sys[633.840]: CLOCK_REALTIME phc offset 25 s2 freq +329 delay 0
>> phc2sys[634.840]: CLOCK_REALTIME phc offset 5 s2 freq +316 delay 0
>> phc2sys[635.840]: CLOCK_REALTIME phc offset 10 s2 freq +323 delay 0
>> phc2sys[636.840]: CLOCK_REALTIME phc offset -13 s2 freq +303 delay 0
>> phc2sys[637.841]: CLOCK_REALTIME phc offset 4 s2 freq +316 delay 0
>> phc2sys[638.841]: CLOCK_REALTIME phc offset 16 s2 freq +329 delay 0
>> phc2sys[639.841]: CLOCK_REALTIME phc offset 31 s2 freq +349 delay 0
>> phc2sys[640.841]: CLOCK_REALTIME phc offset -21 s2 freq +306 delay 0
>> phc2sys[641.841]: CLOCK_REALTIME phc offset -14 s2 freq +307 delay 0
>> phc2sys[642.841]: CLOCK_REALTIME phc offset -24 s2 freq +293 delay 0
>> phc2sys[643.841]: CLOCK_REALTIME phc offset -6 s2 freq +304 delay 0
>> phc2sys[644.842]: CLOCK_REALTIME phc offset 12 s2 freq +320 delay 0
>> phc2sys[645.842]: CLOCK_REALTIME phc offset 12 s2 freq +323 delay 0
>> phc2sys[646.842]: CLOCK_REALTIME phc offset -12 s2 freq +303 delay 0
>
> Please (additionally) summarize the findings by stating the
> min/max/avg?
Sure. Will do.
>
>> One possible explanation is that when PTM is not enabled, and there's a lot
>> of traffic in the PCIe fabric, some register reads will take more time than
>> the others (see the variation in the delay values "before").
>
> Can you please document the datasheet name and revision used to
> implement this?
Sure. Will document this for the next version.
>
>> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
>> ---
>> drivers/net/ethernet/intel/igc/igc.h | 1 +
>> drivers/net/ethernet/intel/igc/igc_defines.h | 31 ++++
>> drivers/net/ethernet/intel/igc/igc_ptp.c | 182 +++++++++++++++++++
>> drivers/net/ethernet/intel/igc/igc_regs.h | 23 +++
>> 4 files changed, 237 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
>> index 5901ed9fb545..36ef4ba10e2c 100644
>> --- a/drivers/net/ethernet/intel/igc/igc.h
>> +++ b/drivers/net/ethernet/intel/igc/igc.h
>> @@ -225,6 +225,7 @@ struct igc_adapter {
>> struct timecounter tc;
>> struct timespec64 prev_ptp_time; /* Pre-reset PTP clock */
>> ktime_t ptp_reset_start; /* Reset time in clock mono */
>> + struct system_time_snapshot snapshot;
>>
>> char fw_version[32];
>>
>> diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
>> index 71fe5b5ad2ed..0432ba26192e 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_defines.h
>> +++ b/drivers/net/ethernet/intel/igc/igc_defines.h
>> @@ -481,6 +481,37 @@
>> #define IGC_RXCSUM_CRCOFL 0x00000800 /* CRC32 offload enable */
>> #define IGC_RXCSUM_PCSD 0x00002000 /* packet checksum disabled */
>>
>> +/* PCIe PTM Control */
>> +#define IGC_PTM_CTRL_START_NOW BIT(29) /* Start PTM Now */
>> +#define IGC_PTM_CTRL_EN BIT(30) /* Enable PTM */
>> +#define IGC_PTM_CTRL_TRIG BIT(31) /* PTM Cycle trigger */
>> +#define IGC_PTM_CTRL_SHRT_CYC(usec) (((usec) & 0x2f) << 2)
>> +#define IGC_PTM_CTRL_PTM_TO(usec) (((usec) & 0xff) << 8)
>> +
>> +#define IGC_PTM_SHORT_CYC_DEFAULT 10 /* Default Short/interrupted cycle interval */
>> +#define IGC_PTM_CYC_TIME_DEFAULT 5 /* Default PTM cycle time */
>> +#define IGC_PTM_TIMEOUT_DEFAULT 255 /* Default timeout for PTM errors */
>> +
>> +/* PCIe Digital Delay */
>> +#define IGC_PCIE_DIG_DELAY_DEFAULT 0x01440000
>> +
>> +/* PCIe PHY Delay */
>> +#define IGC_PCIE_PHY_DELAY_DEFAULT 0x40900000
>> +
>> +#define IGC_TIMADJ_ADJUST_METH 0x40000000
>> +
>> +/* PCIe PTM Status */
>> +#define IGC_PTM_STAT_VALID BIT(0) /* PTM Status */
>> +#define IGC_PTM_STAT_RET_ERR BIT(1) /* Root port timeout */
>> +#define IGC_PTM_STAT_BAD_PTM_RES BIT(2) /* PTM Response msg instead of PTM Response Data */
>> +#define IGC_PTM_STAT_T4M1_OVFL BIT(3) /* T4 minus T1 overflow */
>> +#define IGC_PTM_STAT_ADJUST_1ST BIT(4) /* 1588 timer adjusted during 1st PTM cycle */
>> +#define IGC_PTM_STAT_ADJUST_CYC BIT(5) /* 1588 timer adjusted during non-1st PTM cycle */
>> +
>> +/* PCIe PTM Cycle Control */
>> +#define IGC_PTM_CYCLE_CTRL_CYC_TIME(msec) ((msec) & 0x3ff) /* PTM Cycle Time (msec) */
>> +#define IGC_PTM_CYCLE_CTRL_AUTO_CYC_EN BIT(31) /* PTM Cycle Control */
>> +
>> /* GPY211 - I225 defines */
>> #define GPY_MMD_MASK 0xFFFF0000
>> #define GPY_MMD_SHIFT 16
>> diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c
>> index 69617d2c1be2..1683b2f7cc8c 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_ptp.c
>> +++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
>> @@ -9,6 +9,8 @@
>> #include <linux/ptp_classify.h>
>> #include <linux/clocksource.h>
>> #include <linux/ktime.h>
>> +#include <linux/delay.h>
>> +#include <linux/iopoll.h>
>>
>> #define INCVALUE_MASK 0x7fffffff
>> #define ISGN 0x80000000
>> @@ -16,6 +18,9 @@
>> #define IGC_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9)
>> #define IGC_PTP_TX_TIMEOUT (HZ * 15)
>>
>> +#define IGC_PTM_STAT_SLEEP 2
>> +#define IGC_PTM_STAT_TIMEOUT 100
>> +
>> /* SYSTIM read access for I225 */
>> void igc_ptp_read(struct igc_adapter *adapter, struct timespec64 *ts)
>> {
>> @@ -752,6 +757,150 @@ int igc_ptp_get_ts_config(struct net_device *netdev, struct ifreq *ifr)
>> -EFAULT : 0;
>> }
>>
>> +/* Support for cross timestamping via PCIe PTM is only supported if
>> + * two conditions are met:
>
> Maybe: The two conditions below must be met for cross timestamping via
> PCIe PTM
>
Will use your suggestion.
>> + *
>> + * 1. We have an way to convert the timestamps in the PTM messages
>
> s/an way/a way/
Will fix.
>
>> + * to something related to the system clocks (right now, only
>> + * X86 systems with support for the Always Running Timer allow that);
>> + *
>> + * 2. We have PTM enabled in the path from the device to the PCIe root port.
>> + */
>> +static bool igc_is_crosststamp_supported(struct igc_adapter *adapter)
>> +{
>> +#if IS_ENABLED(CONFIG_X86_TSC)
>> + return pcie_ptm_enabled(adapter->pdev);
>> +#endif
>> + return false;
>
> I’d also add the preprocessor else branch as below (despite the compiler
> opitimzing it away) for readability. Also, I’d do the check in C and not
> the preprocessor.
>
> return IS_ENABLED(CONFIG_X86_TSC) ? pcie_ptm_enabled(adapter->pdev)
> : false;
>
I was using the preprocessor because, before, there was a check for
CONFIG_PCIE_PTM, now that that check doesn't exist anymore. I can do it
in C. Will change. Thanks.
>> +}
>> +
>> +static struct system_counterval_t igc_device_tstamp_to_system(u64 tstamp)
>> +{
>> +#if IS_ENABLED(CONFIG_X86_TSC)
>> + return convert_art_ns_to_tsc(tstamp);
>> +#else
>> + return (struct system_counterval_t) { };
>> +#endif
>> +}
>> +
>> +static void igc_ptm_log_error(struct igc_adapter *adapter, u32 ptm_stat)
>> +{
>> + struct net_device *netdev = adapter->netdev;
>> +
>> + switch (ptm_stat) {
>> + case IGC_PTM_STAT_RET_ERR:
>> + netdev_err(netdev, "PTM Error: Root port timeout\n");
>> + break;
>> + case IGC_PTM_STAT_BAD_PTM_RES:
>> + netdev_err(netdev, "PTM Error: Bad response, PTM Response Data expected\n");
>> + break;
>> + case IGC_PTM_STAT_T4M1_OVFL:
>> + netdev_err(netdev, "PTM Error: T4 minus T1 overflow\n");
>> + break;
>> + case IGC_PTM_STAT_ADJUST_1ST:
>> + netdev_err(netdev, "PTM Error: 1588 timer adjusted during first PTM cycle\n");
>> + break;
>> + case IGC_PTM_STAT_ADJUST_CYC:
>> + netdev_err(netdev, "PTM Error: 1588 timer adjusted during non-first PTM cycle\n");
>> + break;
>> + default:
>> + netdev_err(netdev, "PTM Error: Unknown error (%#x)\n", ptm_stat);
>> + break;
>> + }
>> +}
>> +
>> +static int igc_phc_get_syncdevicetime(ktime_t *device,
>> + struct system_counterval_t *system,
>> + void *ctx)
>> +{
>> + struct igc_adapter *adapter = ctx;
>> + struct igc_hw *hw = &adapter->hw;
>> + u32 stat, t2_curr_h, t2_curr_l, ctrl;
>> + u32 t4mt1_prev, t3mt2_prev, delay;
>> + ktime_t t1, t2_curr;
>> + int err;
>> +
>> + /* Get a snapshot of system clocks to use as historic value. */
>> + ktime_get_snapshot(&adapter->snapshot);
>> +
>> + do {
>> + /* Doing this in a loop because in the event of a
>> + * badly timed (ha!) system clock adjustment, we may
>> + * get PTM Errors from the PCI root, but these errors
>
> PTM errors
Will fix. Thanks.
>
>> + * are transitory. Repeating the process returns valid
>> + * data eventually.
>> + */
>> +
>> + /* To "manually" start the PTM cycle we need to clear and
>> + * then set again the TRIG bit.
>> + */
>> + ctrl = rd32(IGC_PTM_CTRL);
>> + ctrl &= ~IGC_PTM_CTRL_TRIG;
>> + wr32(IGC_PTM_CTRL, ctrl);
>> + ctrl |= IGC_PTM_CTRL_TRIG;
>> + wr32(IGC_PTM_CTRL, ctrl);
>> +
>> + /* The cycle only starts "for real" when software notifies
>> + * that it has read the registers, this is done by setting
>> + * VALID bit.
>> + */
>> + wr32(IGC_PTM_STAT, IGC_PTM_STAT_VALID);
>> +
>> + err = readx_poll_timeout(rd32, IGC_PTM_STAT, stat,
>> + stat, IGC_PTM_STAT_SLEEP,
>> + IGC_PTM_STAT_TIMEOUT);
>> + if (err < 0)
>> + return err;
>
> Should this be logged?
Good catch. Will fix.
>
>> +
>> + if ((stat & IGC_PTM_STAT_VALID) == IGC_PTM_STAT_VALID)
>> + break;
>> +
>> + if (stat & ~IGC_PTM_STAT_VALID) {
>> + /* An error occurred, log it. */
>> + igc_ptm_log_error(adapter, stat);
>> + /* The STAT register is write-1-to-clear (W1C),
>> + * so write the previous error status to clear it.
>> + */
>> + wr32(IGC_PTM_STAT, stat);
>> + continue;
>> + }
>> + } while (true);
>
> I personally prefer to write at least one condition in the loop
> condition.
I can do that. Will fix.
>
>> +
>> + t1 = ktime_set(rd32(IGC_PTM_T1_TIM0_H),
>> + rd32(IGC_PTM_T1_TIM0_L));
>
> Why not put it into one line?
No reason. Will fix.
>
>> +
>> + t2_curr_l = rd32(IGC_PTM_CURR_T2_L);
>> + t2_curr_h = rd32(IGC_PTM_CURR_T2_H);
>> +
>> + /* FIXME: When the register that tells the endianness of the
>> + * PTM registers are implemented, check them here and add the
>> + * appropriate conversion.
>> + */
>> + t2_curr_h = swab32(t2_curr_h);
>> +
>> + t2_curr = ((s64)t2_curr_h << 32 | t2_curr_l);
>> +
>> + t4mt1_prev = rd32(IGC_PTM_PREV_T4M1);
>> + t3mt2_prev = rd32(IGC_PTM_PREV_T3M2);
>> +
>> + delay = (t4mt1_prev - t3mt2_prev) / 2;
>> +
>> + *device = t1 + delay;
>> + *system = igc_device_tstamp_to_system(t2_curr);
>> +
>> + return 0;
>> +}
>> +
>> +static int igc_ptp_getcrosststamp(struct ptp_clock_info *ptp,
>> + struct system_device_crosststamp *cts)
>> +{
>> + struct igc_adapter *adapter = container_of(ptp, struct igc_adapter,
>> + ptp_caps);
>> +
>> + return get_device_system_crosststamp(igc_phc_get_syncdevicetime,
>> + adapter, &adapter->snapshot, cts);
>> +}
>> +
>> /**
>> * igc_ptp_init - Initialize PTP functionality
>> * @adapter: Board private structure
>> @@ -788,6 +937,11 @@ void igc_ptp_init(struct igc_adapter *adapter)
>> adapter->ptp_caps.n_per_out = IGC_N_PEROUT;
>> adapter->ptp_caps.n_pins = IGC_N_SDP;
>> adapter->ptp_caps.verify = igc_ptp_verify_pin;
>> +
>> + if (!igc_is_crosststamp_supported(adapter))
>> + break;
>> +
>> + adapter->ptp_caps.getcrosststamp = igc_ptp_getcrosststamp;
>> break;
>> default:
>> adapter->ptp_clock = NULL;
>> @@ -878,7 +1032,9 @@ void igc_ptp_stop(struct igc_adapter *adapter)
>> void igc_ptp_reset(struct igc_adapter *adapter)
>> {
>> struct igc_hw *hw = &adapter->hw;
>> + u32 cycle_ctrl, ctrl;
>> unsigned long flags;
>> + u32 timadj;
>>
>> /* reset the tstamp_config */
>> igc_ptp_set_timestamp_mode(adapter, &adapter->tstamp_config);
>> @@ -887,12 +1043,38 @@ void igc_ptp_reset(struct igc_adapter *adapter)
>>
>> switch (adapter->hw.mac.type) {
>> case igc_i225:
>> + timadj = rd32(IGC_TIMADJ);
>> + timadj |= IGC_TIMADJ_ADJUST_METH;
>> + wr32(IGC_TIMADJ, timadj);
>> +
>> wr32(IGC_TSAUXC, 0x0);
>> wr32(IGC_TSSDP, 0x0);
>> wr32(IGC_TSIM,
>> IGC_TSICR_INTERRUPTS |
>> (adapter->pps_sys_wrap_on ? IGC_TSICR_SYS_WRAP : 0));
>> wr32(IGC_IMS, IGC_IMS_TS);
>> +
>> + if (!igc_is_crosststamp_supported(adapter))
>> + break;
>> +
>> + wr32(IGC_PCIE_DIG_DELAY, IGC_PCIE_DIG_DELAY_DEFAULT);
>> + wr32(IGC_PCIE_PHY_DELAY, IGC_PCIE_PHY_DELAY_DEFAULT);
>> +
>> + cycle_ctrl = IGC_PTM_CYCLE_CTRL_CYC_TIME(IGC_PTM_CYC_TIME_DEFAULT);
>> +
>> + wr32(IGC_PTM_CYCLE_CTRL, cycle_ctrl);
>> +
>> + ctrl = IGC_PTM_CTRL_EN |
>> + IGC_PTM_CTRL_START_NOW |
>> + IGC_PTM_CTRL_SHRT_CYC(IGC_PTM_SHORT_CYC_DEFAULT) |
>> + IGC_PTM_CTRL_PTM_TO(IGC_PTM_TIMEOUT_DEFAULT) |
>> + IGC_PTM_CTRL_TRIG;
>> +
>> + wr32(IGC_PTM_CTRL, ctrl);
>> +
>> + /* Force the first cycle to run. */
>> + wr32(IGC_PTM_STAT, IGC_PTM_STAT_VALID);
>> +
>> break;
>> default:
>> /* No work to do. */
>> diff --git a/drivers/net/ethernet/intel/igc/igc_regs.h b/drivers/net/ethernet/intel/igc/igc_regs.h
>> index 0f82990567d9..4499a6f7c577 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_regs.h
>> +++ b/drivers/net/ethernet/intel/igc/igc_regs.h
>> @@ -229,6 +229,29 @@
>> #define IGC_TXSTMPL 0x0B618 /* Tx timestamp value Low - RO */
>> #define IGC_TXSTMPH 0x0B61C /* Tx timestamp value High - RO */
>>
>> +#define IGC_TIMADJ 0x0B60C /* Time Adjustment Offset Register */
>> +
>> +/* PCIe Registers */
>> +#define IGC_PTM_CTRL 0x12540 /* PTM Control */
>> +#define IGC_PTM_STAT 0x12544 /* PTM Status */
>> +#define IGC_PTM_CYCLE_CTRL 0x1254C /* PTM Cycle Control */
>> +
>> +/* PTM Time registers */
>> +#define IGC_PTM_T1_TIM0_L 0x12558 /* T1 on Timer 0 Low */
>> +#define IGC_PTM_T1_TIM0_H 0x1255C /* T1 on Timer 0 High */
>> +
>> +#define IGC_PTM_CURR_T2_L 0x1258C /* Current T2 Low */
>> +#define IGC_PTM_CURR_T2_H 0x12590 /* Current T2 High */
>> +#define IGC_PTM_PREV_T2_L 0x12584 /* Previous T2 Low */
>> +#define IGC_PTM_PREV_T2_H 0x12588 /* Previous T2 High */
>> +#define IGC_PTM_PREV_T4M1 0x12578 /* T4 Minus T1 on previous PTM Cycle */
>> +#define IGC_PTM_CURR_T4M1 0x1257C /* T4 Minus T1 on this PTM Cycle */
>> +#define IGC_PTM_PREV_T3M2 0x12580 /* T3 Minus T2 on previous PTM Cycle */
>> +#define IGC_PTM_TDELAY 0x12594 /* PTM PCIe Link Delay */
>> +
>> +#define IGC_PCIE_DIG_DELAY 0x12550 /* PCIe Digital Delay */
>> +#define IGC_PCIE_PHY_DELAY 0x12554 /* PCIe PHY Delay */
>> +
>> /* Management registers */
>> #define IGC_MANC 0x05820 /* Management Control - RW */
>>
>
> How can the user find out, that PTP grecroosstamp() is used?
If by user you mean the system administrator or similar, they could look
at the output of phc2sys, they would see that the "delay" (meaning the
delay between the device and system timestamps) is going to be zero.
If you mean applications in general, they could check the return value
of the PTP_SYS_OFFSET_PRECISE(2) ioctl(), it's going to return not
supported if getcrosststamp() is not used.
>
>
> Kind regards,
>
> Paul
Cheers,
--
Vinicius
