Commit 3f2bba7d authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'ptp-more-accurate-PHC-system-clock-synchronization' 



Miroslav Lichvar says:

====================
More accurate PHC<->system clock synchronization

RFC->v1:
- added new patches
- separated PHC timestamp from ptp_system_timestamp
- fixed memory leak in PTP_SYS_OFFSET_EXTENDED
- changed PTP_SYS_OFFSET_EXTENDED to work with array of arrays
- fixed PTP_SYS_OFFSET_EXTENDED to break correctly from loop
- fixed timecounter updates in drivers
- split gettimex in igb driver
- fixed ptp_read_* functions to be available without
  CONFIG_PTP_1588_CLOCK

This series enables a more accurate synchronization between PTP hardware
clocks and the system clock.

The first two patches are minor cleanup/bug fixes.

The third patch adds an extended version of the PTP_SYS_OFFSET ioctl,
which returns three timestamps for each measurement. The idea is to
shorten the interval between the system timestamps to contain just the
reading of the lowest register of the PHC in order to reduce the error
in the measured offset and get a smaller upper bound on the maximum
error.

The fourth patch deprecates the original gettime function.

The remaining patches update the gettime function in order to support
the new ioctl in the e1000e, igb, ixgbe, and tg3 drivers.

Tests with few different NICs in different machines show that:
- with an I219 (e1000e) the measured delay was reduced from 2500 to 1300
  ns and the error in the measured offset, when compared to the cross
  timestamping supported by the driver, was reduced by a factor of 5
- with an I210 (igb) the delay was reduced from 5100 to 1700 ns
- with an I350 (igb) the delay was reduced from 2300 to 750 ns
- with an X550 (ixgbe) the delay was reduced from 1950 to 650 ns
- with a BCM5720 (tg3) the delay was reduced from 2400 to 1200 ns
====================

Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 70e79832 6fe42e22

drivers/net/ethernet/broadcom/tg3.c

+13 −6
Original line number Diff line number Diff line
@@ -6135,10 +6135,16 @@ static int tg3_setup_phy(struct tg3 *tp, bool force_reset) 
}



/* tp->lock must be held */

static u64 tg3_refclk_read(struct tg3 *tp)

static u64 tg3_refclk_read(struct tg3 *tp, struct ptp_system_timestamp *sts)

{

	u64 stamp = tr32(TG3_EAV_REF_CLCK_LSB);

	return stamp | (u64)tr32(TG3_EAV_REF_CLCK_MSB) << 32;

	u64 stamp;



	ptp_read_system_prets(sts);

	stamp = tr32(TG3_EAV_REF_CLCK_LSB);

	ptp_read_system_postts(sts);

	stamp |= (u64)tr32(TG3_EAV_REF_CLCK_MSB) << 32;



	return stamp;

}



/* tp->lock must be held */
@@ -6229,13 +6235,14 @@ static int tg3_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta) 
	return 0;

}



static int tg3_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)

static int tg3_ptp_gettimex(struct ptp_clock_info *ptp, struct timespec64 *ts,

			    struct ptp_system_timestamp *sts)

{

	u64 ns;

	struct tg3 *tp = container_of(ptp, struct tg3, ptp_info);



	tg3_full_lock(tp, 0);

	ns = tg3_refclk_read(tp);

	ns = tg3_refclk_read(tp, sts);

	ns += tp->ptp_adjust;

	tg3_full_unlock(tp);
@@ -6330,7 +6337,7 @@ static const struct ptp_clock_info tg3_ptp_caps = { 
	.pps		= 0,

	.adjfreq	= tg3_ptp_adjfreq,

	.adjtime	= tg3_ptp_adjtime,

	.gettime64	= tg3_ptp_gettime,

	.gettimex64	= tg3_ptp_gettimex,

	.settime64	= tg3_ptp_settime,

	.enable		= tg3_ptp_enable,

};

drivers/net/ethernet/intel/e1000e/e1000.h

+3 −0
Original line number Diff line number Diff line
@@ -505,6 +505,9 @@ extern const struct e1000_info e1000_es2_info; 
void e1000e_ptp_init(struct e1000_adapter *adapter);

void e1000e_ptp_remove(struct e1000_adapter *adapter);



u64 e1000e_read_systim(struct e1000_adapter *adapter,

		       struct ptp_system_timestamp *sts);



static inline s32 e1000_phy_hw_reset(struct e1000_hw *hw)

{

	return hw->phy.ops.reset(hw);

drivers/net/ethernet/intel/e1000e/netdev.c

+32 −10
Original line number Diff line number Diff line
@@ -4319,13 +4319,16 @@ void e1000e_reinit_locked(struct e1000_adapter *adapter) 
/**

 * e1000e_sanitize_systim - sanitize raw cycle counter reads

 * @hw: pointer to the HW structure

 * @systim: time value read, sanitized and returned

 * @systim: PHC time value read, sanitized and returned

 * @sts: structure to hold system time before and after reading SYSTIML,

 * may be NULL

 *

 * Errata for 82574/82583 possible bad bits read from SYSTIMH/L:

 * check to see that the time is incrementing at a reasonable

 * rate and is a multiple of incvalue.

 **/

static u64 e1000e_sanitize_systim(struct e1000_hw *hw, u64 systim)

static u64 e1000e_sanitize_systim(struct e1000_hw *hw, u64 systim,

				  struct ptp_system_timestamp *sts)

{

	u64 time_delta, rem, temp;

	u64 systim_next;
@@ -4335,7 +4338,9 @@ static u64 e1000e_sanitize_systim(struct e1000_hw *hw, u64 systim) 
	incvalue = er32(TIMINCA) & E1000_TIMINCA_INCVALUE_MASK;

	for (i = 0; i < E1000_MAX_82574_SYSTIM_REREADS; i++) {

		/* latch SYSTIMH on read of SYSTIML */

		ptp_read_system_prets(sts);

		systim_next = (u64)er32(SYSTIML);

		ptp_read_system_postts(sts);

		systim_next |= (u64)er32(SYSTIMH) << 32;



		time_delta = systim_next - systim;
@@ -4353,15 +4358,16 @@ static u64 e1000e_sanitize_systim(struct e1000_hw *hw, u64 systim) 
}



/**

 * e1000e_cyclecounter_read - read raw cycle counter (used by time counter)

 * @cc: cyclecounter structure

 * e1000e_read_systim - read SYSTIM register

 * @adapter: board private structure

 * @sts: structure which will contain system time before and after reading

 * SYSTIML, may be NULL

 **/

static u64 e1000e_cyclecounter_read(const struct cyclecounter *cc)

u64 e1000e_read_systim(struct e1000_adapter *adapter,

		       struct ptp_system_timestamp *sts)

{

	struct e1000_adapter *adapter = container_of(cc, struct e1000_adapter,

						     cc);

	struct e1000_hw *hw = &adapter->hw;

	u32 systimel, systimeh;

	u32 systimel, systimel_2, systimeh;

	u64 systim;

	/* SYSTIMH latching upon SYSTIML read does not work well.

	 * This means that if SYSTIML overflows after we read it but before
@@ -4369,11 +4375,15 @@ static u64 e1000e_cyclecounter_read(const struct cyclecounter *cc) 
	 * will experience a huge non linear increment in the systime value

	 * to fix that we test for overflow and if true, we re-read systime.

	 */

	ptp_read_system_prets(sts);

	systimel = er32(SYSTIML);

	ptp_read_system_postts(sts);

	systimeh = er32(SYSTIMH);

	/* Is systimel is so large that overflow is possible? */

	if (systimel >= (u32)0xffffffff - E1000_TIMINCA_INCVALUE_MASK) {

		u32 systimel_2 = er32(SYSTIML);

		ptp_read_system_prets(sts);

		systimel_2 = er32(SYSTIML);

		ptp_read_system_postts(sts);

		if (systimel > systimel_2) {

			/* There was an overflow, read again SYSTIMH, and use

			 * systimel_2
@@ -4386,11 +4396,23 @@ static u64 e1000e_cyclecounter_read(const struct cyclecounter *cc) 
	systim |= (u64)systimeh << 32;



	if (adapter->flags2 & FLAG2_CHECK_SYSTIM_OVERFLOW)

		systim = e1000e_sanitize_systim(hw, systim);

		systim = e1000e_sanitize_systim(hw, systim, sts);



	return systim;

}



/**

 * e1000e_cyclecounter_read - read raw cycle counter (used by time counter)

 * @cc: cyclecounter structure

 **/

static u64 e1000e_cyclecounter_read(const struct cyclecounter *cc)

{

	struct e1000_adapter *adapter = container_of(cc, struct e1000_adapter,

						     cc);



	return e1000e_read_systim(adapter, NULL);

}



/**

 * e1000_sw_init - Initialize general software structures (struct e1000_adapter)

 * @adapter: board private structure to initialize

drivers/net/ethernet/intel/e1000e/ptp.c

+10 −6
Original line number Diff line number Diff line
@@ -161,14 +161,18 @@ static int e1000e_phc_getcrosststamp(struct ptp_clock_info *ptp, 
#endif/*CONFIG_E1000E_HWTS*/



/**

 * e1000e_phc_gettime - Reads the current time from the hardware clock

 * e1000e_phc_gettimex - Reads the current time from the hardware clock and

 *                       system clock

 * @ptp: ptp clock structure

 * @ts: timespec structure to hold the current time value

 * @ts: timespec structure to hold the current PHC time

 * @sts: structure to hold the current system time

 *

 * Read the timecounter and return the correct value in ns after converting

 * it into a struct timespec.

 **/

static int e1000e_phc_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)

static int e1000e_phc_gettimex(struct ptp_clock_info *ptp,

			       struct timespec64 *ts,

			       struct ptp_system_timestamp *sts)

{

	struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,

						     ptp_clock_info);
@@ -177,8 +181,8 @@ static int e1000e_phc_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) 


	spin_lock_irqsave(&adapter->systim_lock, flags);



	/* Use timecounter_cyc2time() to allow non-monotonic SYSTIM readings */

	cycles = adapter->cc.read(&adapter->cc);

	/* NOTE: Non-monotonic SYSTIM readings may be returned */

	cycles = e1000e_read_systim(adapter, sts);

	ns = timecounter_cyc2time(&adapter->tc, cycles);



	spin_unlock_irqrestore(&adapter->systim_lock, flags);
@@ -258,7 +262,7 @@ static const struct ptp_clock_info e1000e_ptp_clock_info = { 
	.pps		= 0,

	.adjfreq	= e1000e_phc_adjfreq,

	.adjtime	= e1000e_phc_adjtime,

	.gettime64	= e1000e_phc_gettime,

	.gettimex64	= e1000e_phc_gettimex,

	.settime64	= e1000e_phc_settime,

	.enable		= e1000e_phc_enable,

};

drivers/net/ethernet/intel/igb/igb_ptp.c

+55 −10
Original line number Diff line number Diff line
@@ -275,17 +275,25 @@ static int igb_ptp_adjtime_i210(struct ptp_clock_info *ptp, s64 delta) 
	return 0;

}



static int igb_ptp_gettime_82576(struct ptp_clock_info *ptp,

				 struct timespec64 *ts)

static int igb_ptp_gettimex_82576(struct ptp_clock_info *ptp,

				  struct timespec64 *ts,

				  struct ptp_system_timestamp *sts)

{

	struct igb_adapter *igb = container_of(ptp, struct igb_adapter,

					       ptp_caps);

	struct e1000_hw *hw = &igb->hw;

	unsigned long flags;

	u32 lo, hi;

	u64 ns;



	spin_lock_irqsave(&igb->tmreg_lock, flags);



	ns = timecounter_read(&igb->tc);

	ptp_read_system_prets(sts);

	lo = rd32(E1000_SYSTIML);

	ptp_read_system_postts(sts);

	hi = rd32(E1000_SYSTIMH);



	ns = timecounter_cyc2time(&igb->tc, ((u64)hi << 32) | lo);



	spin_unlock_irqrestore(&igb->tmreg_lock, flags);
@@ -294,16 +302,50 @@ static int igb_ptp_gettime_82576(struct ptp_clock_info *ptp, 
	return 0;

}



static int igb_ptp_gettime_i210(struct ptp_clock_info *ptp,

				struct timespec64 *ts)

static int igb_ptp_gettimex_82580(struct ptp_clock_info *ptp,

				  struct timespec64 *ts,

				  struct ptp_system_timestamp *sts)

{

	struct igb_adapter *igb = container_of(ptp, struct igb_adapter,

					       ptp_caps);

	struct e1000_hw *hw = &igb->hw;

	unsigned long flags;

	u32 lo, hi;

	u64 ns;



	spin_lock_irqsave(&igb->tmreg_lock, flags);



	igb_ptp_read_i210(igb, ts);

	ptp_read_system_prets(sts);

	rd32(E1000_SYSTIMR);

	ptp_read_system_postts(sts);

	lo = rd32(E1000_SYSTIML);

	hi = rd32(E1000_SYSTIMH);



	ns = timecounter_cyc2time(&igb->tc, ((u64)hi << 32) | lo);



	spin_unlock_irqrestore(&igb->tmreg_lock, flags);



	*ts = ns_to_timespec64(ns);



	return 0;

}



static int igb_ptp_gettimex_i210(struct ptp_clock_info *ptp,

				 struct timespec64 *ts,

				 struct ptp_system_timestamp *sts)

{

	struct igb_adapter *igb = container_of(ptp, struct igb_adapter,

					       ptp_caps);

	struct e1000_hw *hw = &igb->hw;

	unsigned long flags;



	spin_lock_irqsave(&igb->tmreg_lock, flags);



	ptp_read_system_prets(sts);

	rd32(E1000_SYSTIMR);

	ptp_read_system_postts(sts);

	ts->tv_nsec = rd32(E1000_SYSTIML);

	ts->tv_sec = rd32(E1000_SYSTIMH);



	spin_unlock_irqrestore(&igb->tmreg_lock, flags);
@@ -656,9 +698,12 @@ static void igb_ptp_overflow_check(struct work_struct *work) 
	struct igb_adapter *igb =

		container_of(work, struct igb_adapter, ptp_overflow_work.work);

	struct timespec64 ts;

	u64 ns;



	igb->ptp_caps.gettime64(&igb->ptp_caps, &ts);

	/* Update the timecounter */

	ns = timecounter_read(&igb->tc);



	ts = ns_to_timespec64(ns);

	pr_debug("igb overflow check at %lld.%09lu\n",

		 (long long) ts.tv_sec, ts.tv_nsec);
@@ -1124,7 +1169,7 @@ void igb_ptp_init(struct igb_adapter *adapter) 
		adapter->ptp_caps.pps = 0;

		adapter->ptp_caps.adjfreq = igb_ptp_adjfreq_82576;

		adapter->ptp_caps.adjtime = igb_ptp_adjtime_82576;

		adapter->ptp_caps.gettime64 = igb_ptp_gettime_82576;

		adapter->ptp_caps.gettimex64 = igb_ptp_gettimex_82576;

		adapter->ptp_caps.settime64 = igb_ptp_settime_82576;

		adapter->ptp_caps.enable = igb_ptp_feature_enable;

		adapter->cc.read = igb_ptp_read_82576;
@@ -1143,7 +1188,7 @@ void igb_ptp_init(struct igb_adapter *adapter) 
		adapter->ptp_caps.pps = 0;

		adapter->ptp_caps.adjfine = igb_ptp_adjfine_82580;

		adapter->ptp_caps.adjtime = igb_ptp_adjtime_82576;

		adapter->ptp_caps.gettime64 = igb_ptp_gettime_82576;

		adapter->ptp_caps.gettimex64 = igb_ptp_gettimex_82580;

		adapter->ptp_caps.settime64 = igb_ptp_settime_82576;

		adapter->ptp_caps.enable = igb_ptp_feature_enable;

		adapter->cc.read = igb_ptp_read_82580;
@@ -1171,7 +1216,7 @@ void igb_ptp_init(struct igb_adapter *adapter) 
		adapter->ptp_caps.pin_config = adapter->sdp_config;

		adapter->ptp_caps.adjfine = igb_ptp_adjfine_82580;

		adapter->ptp_caps.adjtime = igb_ptp_adjtime_i210;

		adapter->ptp_caps.gettime64 = igb_ptp_gettime_i210;

		adapter->ptp_caps.gettimex64 = igb_ptp_gettimex_i210;

		adapter->ptp_caps.settime64 = igb_ptp_settime_i210;

		adapter->ptp_caps.enable = igb_ptp_feature_enable_i210;

		adapter->ptp_caps.verify = igb_ptp_verify_pin;

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