[PATCH net v3 0/3] net: dsa: mv88e6xxx: fix MV88E6393X PHC frequency on internal clock

[PATCH net v3 0/3] net: dsa: mv88e6xxx: fix MV88E6393X PHC frequency on internal clock

[Shenghao Yang]

The MV88E6393X family of switches can additionally run their cycle
counters using a 250MHz internal clock instead of the usual 125MHz
external clock [1].

The driver currently assumes all designs utilize that external clock,
but MikroTik's RB5009 uses the internal source - causing the PHC to be
seen running at 2x real time in userspace, making synchronization
with ptp4l impossible.

This series adds support for reading off the cycle counter frequency
known to the hardware in the TAI_CLOCK_PERIOD register and picking an
appropriate set of scaling coefficients instead of using a fixed set
for each switch family.

Patch 1 groups those cycle counter coefficients into a new structure to
make it easier to pass them around.

Patch 2 modifies PTP initialization to probe TAI_CLOCK_PERIOD and
use an appropriate set of coefficients.

Patch 3 adds support for 4000ps cycle counter periods.

Changes since v2 [2]:

- Patch 1: "net: dsa: mv88e6xxx: group cycle counter coefficients"
  - Moved declaration of mv88e6xxx_cc_coeffs to avoid moving that in
    Patch 2.

- Patch 2: "net: dsa: mv88e6xxx: read cycle counter period from hardware"
  - Removed move of mv88e6xxx_cc_coeffs declaration.

- Patch 3: "net: dsa: mv88e6xxx: support 4000ps cycle counter periods"
  - No change.

Thanks,

Shenghao

[1] https://lore.kernel.org/netdev/d6622575-bf1b-445a-b08f-2739e3642aae@lunn.ch/
[2] https://lore.kernel.org/netdev/20241006145951.719162-1-me@shenghaoyang.info/

Shenghao Yang (3):
  net: dsa: mv88e6xxx: group cycle counter coefficients
  net: dsa: mv88e6xxx: read cycle counter period from hardware
  net: dsa: mv88e6xxx: support 4000ps cycle counter period

 drivers/net/dsa/mv88e6xxx/chip.h |   6 +-
 drivers/net/dsa/mv88e6xxx/ptp.c  | 108 +++++++++++++++++++++----------
 2 files changed, 77 insertions(+), 37 deletions(-)

-- 
2.47.0

[PATCH net v3 1/3] net: dsa: mv88e6xxx: group cycle counter coefficients

[Shenghao Yang]

Instead of having them as individual fields in ptp_ops, wrap the
coefficients in a separate struct so they can be referenced together.

Fixes: de776d0d316f ("net: dsa: mv88e6xxx: add support for mv88e6393x family")
Signed-off-by: Shenghao Yang <me@shenghaoyang.info>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/mv88e6xxx/chip.h |  6 ++--
 drivers/net/dsa/mv88e6xxx/ptp.c  | 59 ++++++++++++++++----------------
 2 files changed, 32 insertions(+), 33 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index c34caf9815c5..1d003a9deafa 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -206,6 +206,7 @@ struct mv88e6xxx_gpio_ops;
 struct mv88e6xxx_avb_ops;
 struct mv88e6xxx_ptp_ops;
 struct mv88e6xxx_pcs_ops;
+struct mv88e6xxx_cc_coeffs;
 
 struct mv88e6xxx_irq {
 	u16 masked;
@@ -731,10 +732,7 @@ struct mv88e6xxx_ptp_ops {
 	int arr1_sts_reg;
 	int dep_sts_reg;
 	u32 rx_filters;
-	u32 cc_shift;
-	u32 cc_mult;
-	u32 cc_mult_num;
-	u32 cc_mult_dem;
+	const struct mv88e6xxx_cc_coeffs *cc_coeffs;
 };
 
 struct mv88e6xxx_pcs_ops {
diff --git a/drivers/net/dsa/mv88e6xxx/ptp.c b/drivers/net/dsa/mv88e6xxx/ptp.c
index 56391e09b325..641af44e00af 100644
--- a/drivers/net/dsa/mv88e6xxx/ptp.c
+++ b/drivers/net/dsa/mv88e6xxx/ptp.c
@@ -18,6 +18,13 @@
 
 #define MV88E6XXX_MAX_ADJ_PPB	1000000
 
+struct mv88e6xxx_cc_coeffs {
+	u32 cc_shift;
+	u32 cc_mult;
+	u32 cc_mult_num;
+	u32 cc_mult_dem;
+};
+
 /* Family MV88E6250:
  * Raw timestamps are in units of 10-ns clock periods.
  *
@@ -25,10 +32,13 @@
  * simplifies to
  * clkadj = scaled_ppm * 2^7 / 5^5
  */
-#define MV88E6250_CC_SHIFT	28
-#define MV88E6250_CC_MULT	(10 << MV88E6250_CC_SHIFT)
-#define MV88E6250_CC_MULT_NUM	(1 << 7)
-#define MV88E6250_CC_MULT_DEM	3125ULL
+#define MV88E6250_CC_SHIFT 28
+static const struct mv88e6xxx_cc_coeffs mv88e6250_cc_coeffs = {
+	.cc_shift = MV88E6250_CC_SHIFT,
+	.cc_mult = 10 << MV88E6250_CC_SHIFT,
+	.cc_mult_num = 1 << 7,
+	.cc_mult_dem = 3125ULL,
+};
 
 /* Other families:
  * Raw timestamps are in units of 8-ns clock periods.
@@ -37,10 +47,13 @@
  * simplifies to
  * clkadj = scaled_ppm * 2^9 / 5^6
  */
-#define MV88E6XXX_CC_SHIFT	28
-#define MV88E6XXX_CC_MULT	(8 << MV88E6XXX_CC_SHIFT)
-#define MV88E6XXX_CC_MULT_NUM	(1 << 9)
-#define MV88E6XXX_CC_MULT_DEM	15625ULL
+#define MV88E6XXX_CC_SHIFT 28
+static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_coeffs = {
+	.cc_shift = MV88E6XXX_CC_SHIFT,
+	.cc_mult = 8 << MV88E6XXX_CC_SHIFT,
+	.cc_mult_num = 1 << 9,
+	.cc_mult_dem = 15625ULL
+};
 
 #define TAI_EVENT_WORK_INTERVAL msecs_to_jiffies(100)
 
@@ -214,10 +227,10 @@ static int mv88e6xxx_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 		scaled_ppm = -scaled_ppm;
 	}
 
-	mult = ptp_ops->cc_mult;
-	adj = ptp_ops->cc_mult_num;
+	mult = ptp_ops->cc_coeffs->cc_mult;
+	adj = ptp_ops->cc_coeffs->cc_mult_num;
 	adj *= scaled_ppm;
-	diff = div_u64(adj, ptp_ops->cc_mult_dem);
+	diff = div_u64(adj, ptp_ops->cc_coeffs->cc_mult_dem);
 
 	mv88e6xxx_reg_lock(chip);
 
@@ -364,10 +377,7 @@ const struct mv88e6xxx_ptp_ops mv88e6165_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_shift = MV88E6XXX_CC_SHIFT,
-	.cc_mult = MV88E6XXX_CC_MULT,
-	.cc_mult_num = MV88E6XXX_CC_MULT_NUM,
-	.cc_mult_dem = MV88E6XXX_CC_MULT_DEM,
+	.cc_coeffs = &mv88e6xxx_cc_coeffs
 };
 
 const struct mv88e6xxx_ptp_ops mv88e6250_ptp_ops = {
@@ -391,10 +401,7 @@ const struct mv88e6xxx_ptp_ops mv88e6250_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_shift = MV88E6250_CC_SHIFT,
-	.cc_mult = MV88E6250_CC_MULT,
-	.cc_mult_num = MV88E6250_CC_MULT_NUM,
-	.cc_mult_dem = MV88E6250_CC_MULT_DEM,
+	.cc_coeffs = &mv88e6250_cc_coeffs,
 };
 
 const struct mv88e6xxx_ptp_ops mv88e6352_ptp_ops = {
@@ -418,10 +425,7 @@ const struct mv88e6xxx_ptp_ops mv88e6352_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_shift = MV88E6XXX_CC_SHIFT,
-	.cc_mult = MV88E6XXX_CC_MULT,
-	.cc_mult_num = MV88E6XXX_CC_MULT_NUM,
-	.cc_mult_dem = MV88E6XXX_CC_MULT_DEM,
+	.cc_coeffs = &mv88e6xxx_cc_coeffs,
 };
 
 const struct mv88e6xxx_ptp_ops mv88e6390_ptp_ops = {
@@ -446,10 +450,7 @@ const struct mv88e6xxx_ptp_ops mv88e6390_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_shift = MV88E6XXX_CC_SHIFT,
-	.cc_mult = MV88E6XXX_CC_MULT,
-	.cc_mult_num = MV88E6XXX_CC_MULT_NUM,
-	.cc_mult_dem = MV88E6XXX_CC_MULT_DEM,
+	.cc_coeffs = &mv88e6xxx_cc_coeffs,
 };
 
 static u64 mv88e6xxx_ptp_clock_read(const struct cyclecounter *cc)
@@ -487,8 +488,8 @@ int mv88e6xxx_ptp_setup(struct mv88e6xxx_chip *chip)
 	memset(&chip->tstamp_cc, 0, sizeof(chip->tstamp_cc));
 	chip->tstamp_cc.read	= mv88e6xxx_ptp_clock_read;
 	chip->tstamp_cc.mask	= CYCLECOUNTER_MASK(32);
-	chip->tstamp_cc.mult	= ptp_ops->cc_mult;
-	chip->tstamp_cc.shift	= ptp_ops->cc_shift;
+	chip->tstamp_cc.mult	= ptp_ops->cc_coeffs->cc_mult;
+	chip->tstamp_cc.shift	= ptp_ops->cc_coeffs->cc_shift;
 
 	timecounter_init(&chip->tstamp_tc, &chip->tstamp_cc,
 			 ktime_to_ns(ktime_get_real()));
-- 
2.47.0

[PATCH net v3 2/3] net: dsa: mv88e6xxx: read cycle counter period from hardware

[Shenghao Yang]

Instead of relying on a fixed mapping of hardware family to cycle
counter frequency, pull this information from the
MV88E6XXX_TAI_CLOCK_PERIOD register.

This lets us support switches whose cycle counter frequencies depend on
board design.

Fixes: de776d0d316f ("net: dsa: mv88e6xxx: add support for mv88e6393x family")
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Shenghao Yang <me@shenghaoyang.info>
---
 drivers/net/dsa/mv88e6xxx/chip.h |  2 +-
 drivers/net/dsa/mv88e6xxx/ptp.c  | 60 ++++++++++++++++++++++----------
 2 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 1d003a9deafa..a54682240839 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -409,6 +409,7 @@ struct mv88e6xxx_chip {
 	struct cyclecounter	tstamp_cc;
 	struct timecounter	tstamp_tc;
 	struct delayed_work	overflow_work;
+	const struct mv88e6xxx_cc_coeffs *cc_coeffs;
 
 	struct ptp_clock	*ptp_clock;
 	struct ptp_clock_info	ptp_clock_info;
@@ -732,7 +733,6 @@ struct mv88e6xxx_ptp_ops {
 	int arr1_sts_reg;
 	int dep_sts_reg;
 	u32 rx_filters;
-	const struct mv88e6xxx_cc_coeffs *cc_coeffs;
 };
 
 struct mv88e6xxx_pcs_ops {
diff --git a/drivers/net/dsa/mv88e6xxx/ptp.c b/drivers/net/dsa/mv88e6xxx/ptp.c
index 641af44e00af..a409b8661fad 100644
--- a/drivers/net/dsa/mv88e6xxx/ptp.c
+++ b/drivers/net/dsa/mv88e6xxx/ptp.c
@@ -32,10 +32,10 @@ struct mv88e6xxx_cc_coeffs {
  * simplifies to
  * clkadj = scaled_ppm * 2^7 / 5^5
  */
-#define MV88E6250_CC_SHIFT 28
-static const struct mv88e6xxx_cc_coeffs mv88e6250_cc_coeffs = {
-	.cc_shift = MV88E6250_CC_SHIFT,
-	.cc_mult = 10 << MV88E6250_CC_SHIFT,
+#define MV88E6XXX_CC_10NS_SHIFT 28
+static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_10ns_coeffs = {
+	.cc_shift = MV88E6XXX_CC_10NS_SHIFT,
+	.cc_mult = 10 << MV88E6XXX_CC_10NS_SHIFT,
 	.cc_mult_num = 1 << 7,
 	.cc_mult_dem = 3125ULL,
 };
@@ -47,10 +47,10 @@ static const struct mv88e6xxx_cc_coeffs mv88e6250_cc_coeffs = {
  * simplifies to
  * clkadj = scaled_ppm * 2^9 / 5^6
  */
-#define MV88E6XXX_CC_SHIFT 28
-static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_coeffs = {
-	.cc_shift = MV88E6XXX_CC_SHIFT,
-	.cc_mult = 8 << MV88E6XXX_CC_SHIFT,
+#define MV88E6XXX_CC_8NS_SHIFT 28
+static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_8ns_coeffs = {
+	.cc_shift = MV88E6XXX_CC_8NS_SHIFT,
+	.cc_mult = 8 << MV88E6XXX_CC_8NS_SHIFT,
 	.cc_mult_num = 1 << 9,
 	.cc_mult_dem = 15625ULL
 };
@@ -96,6 +96,31 @@ static int mv88e6352_set_gpio_func(struct mv88e6xxx_chip *chip, int pin,
 	return chip->info->ops->gpio_ops->set_pctl(chip, pin, func);
 }
 
+static const struct mv88e6xxx_cc_coeffs *
+mv88e6xxx_cc_coeff_get(struct mv88e6xxx_chip *chip)
+{
+	u16 period_ps;
+	int err;
+
+	err = mv88e6xxx_tai_read(chip, MV88E6XXX_TAI_CLOCK_PERIOD, &period_ps, 1);
+	if (err) {
+		dev_err(chip->dev, "failed to read cycle counter period: %d\n",
+			err);
+		return ERR_PTR(err);
+	}
+
+	switch (period_ps) {
+	case 8000:
+		return &mv88e6xxx_cc_8ns_coeffs;
+	case 10000:
+		return &mv88e6xxx_cc_10ns_coeffs;
+	default:
+		dev_err(chip->dev, "unexpected cycle counter period of %u ps\n",
+			period_ps);
+		return ERR_PTR(-ENODEV);
+	}
+}
+
 static u64 mv88e6352_ptp_clock_read(const struct cyclecounter *cc)
 {
 	struct mv88e6xxx_chip *chip = cc_to_chip(cc);
@@ -217,7 +242,6 @@ static void mv88e6352_tai_event_work(struct work_struct *ugly)
 static int mv88e6xxx_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 {
 	struct mv88e6xxx_chip *chip = ptp_to_chip(ptp);
-	const struct mv88e6xxx_ptp_ops *ptp_ops = chip->info->ops->ptp_ops;
 	int neg_adj = 0;
 	u32 diff, mult;
 	u64 adj;
@@ -227,10 +251,10 @@ static int mv88e6xxx_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 		scaled_ppm = -scaled_ppm;
 	}
 
-	mult = ptp_ops->cc_coeffs->cc_mult;
-	adj = ptp_ops->cc_coeffs->cc_mult_num;
+	mult = chip->cc_coeffs->cc_mult;
+	adj = chip->cc_coeffs->cc_mult_num;
 	adj *= scaled_ppm;
-	diff = div_u64(adj, ptp_ops->cc_coeffs->cc_mult_dem);
+	diff = div_u64(adj, chip->cc_coeffs->cc_mult_dem);
 
 	mv88e6xxx_reg_lock(chip);
 
@@ -377,7 +401,6 @@ const struct mv88e6xxx_ptp_ops mv88e6165_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_coeffs = &mv88e6xxx_cc_coeffs
 };
 
 const struct mv88e6xxx_ptp_ops mv88e6250_ptp_ops = {
@@ -401,7 +424,6 @@ const struct mv88e6xxx_ptp_ops mv88e6250_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_coeffs = &mv88e6250_cc_coeffs,
 };
 
 const struct mv88e6xxx_ptp_ops mv88e6352_ptp_ops = {
@@ -425,7 +447,6 @@ const struct mv88e6xxx_ptp_ops mv88e6352_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_coeffs = &mv88e6xxx_cc_coeffs,
 };
 
 const struct mv88e6xxx_ptp_ops mv88e6390_ptp_ops = {
@@ -450,7 +471,6 @@ const struct mv88e6xxx_ptp_ops mv88e6390_ptp_ops = {
 		(1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
 		(1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ),
-	.cc_coeffs = &mv88e6xxx_cc_coeffs,
 };
 
 static u64 mv88e6xxx_ptp_clock_read(const struct cyclecounter *cc)
@@ -485,11 +505,15 @@ int mv88e6xxx_ptp_setup(struct mv88e6xxx_chip *chip)
 	int i;
 
 	/* Set up the cycle counter */
+	chip->cc_coeffs = mv88e6xxx_cc_coeff_get(chip);
+	if (IS_ERR(chip->cc_coeffs))
+		return PTR_ERR(chip->cc_coeffs);
+
 	memset(&chip->tstamp_cc, 0, sizeof(chip->tstamp_cc));
 	chip->tstamp_cc.read	= mv88e6xxx_ptp_clock_read;
 	chip->tstamp_cc.mask	= CYCLECOUNTER_MASK(32);
-	chip->tstamp_cc.mult	= ptp_ops->cc_coeffs->cc_mult;
-	chip->tstamp_cc.shift	= ptp_ops->cc_coeffs->cc_shift;
+	chip->tstamp_cc.mult	= chip->cc_coeffs->cc_mult;
+	chip->tstamp_cc.shift	= chip->cc_coeffs->cc_shift;
 
 	timecounter_init(&chip->tstamp_tc, &chip->tstamp_cc,
 			 ktime_to_ns(ktime_get_real()));
-- 
2.47.0

[PATCH net v3 3/3] net: dsa: mv88e6xxx: support 4000ps cycle counter period

[Shenghao Yang]

The MV88E6393X family of devices can run its cycle counter off
an internal 250MHz clock instead of an external 125MHz one.

Add support for this cycle counter period by adding another set
of coefficients and lowering the periodic cycle counter read interval
to compensate for faster overflows at the increased frequency.

Otherwise, the PHC runs at 2x real time in userspace and cannot be
synchronized.

Fixes: de776d0d316f ("net: dsa: mv88e6xxx: add support for mv88e6393x family")
Signed-off-by: Shenghao Yang <me@shenghaoyang.info>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/mv88e6xxx/ptp.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/ptp.c b/drivers/net/dsa/mv88e6xxx/ptp.c
index a409b8661fad..aed4a4b07f34 100644
--- a/drivers/net/dsa/mv88e6xxx/ptp.c
+++ b/drivers/net/dsa/mv88e6xxx/ptp.c
@@ -40,7 +40,7 @@ static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_10ns_coeffs = {
 	.cc_mult_dem = 3125ULL,
 };
 
-/* Other families:
+/* Other families except MV88E6393X in internal clock mode:
  * Raw timestamps are in units of 8-ns clock periods.
  *
  * clkadj = scaled_ppm * 8*2^28 / (10^6 * 2^16)
@@ -55,6 +55,21 @@ static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_8ns_coeffs = {
 	.cc_mult_dem = 15625ULL
 };
 
+/* Family MV88E6393X using internal clock:
+ * Raw timestamps are in units of 4-ns clock periods.
+ *
+ * clkadj = scaled_ppm * 4*2^28 / (10^6 * 2^16)
+ * simplifies to
+ * clkadj = scaled_ppm * 2^8 / 5^6
+ */
+#define MV88E6XXX_CC_4NS_SHIFT 28
+static const struct mv88e6xxx_cc_coeffs mv88e6xxx_cc_4ns_coeffs = {
+	.cc_shift = MV88E6XXX_CC_4NS_SHIFT,
+	.cc_mult = 4 << MV88E6XXX_CC_4NS_SHIFT,
+	.cc_mult_num = 1 << 8,
+	.cc_mult_dem = 15625ULL
+};
+
 #define TAI_EVENT_WORK_INTERVAL msecs_to_jiffies(100)
 
 #define cc_to_chip(cc) container_of(cc, struct mv88e6xxx_chip, tstamp_cc)
@@ -110,6 +125,8 @@ mv88e6xxx_cc_coeff_get(struct mv88e6xxx_chip *chip)
 	}
 
 	switch (period_ps) {
+	case 4000:
+		return &mv88e6xxx_cc_4ns_coeffs;
 	case 8000:
 		return &mv88e6xxx_cc_8ns_coeffs;
 	case 10000:
@@ -483,10 +500,10 @@ static u64 mv88e6xxx_ptp_clock_read(const struct cyclecounter *cc)
 	return 0;
 }
 
-/* With a 125MHz input clock, the 32-bit timestamp counter overflows in ~34.3
+/* With a 250MHz input clock, the 32-bit timestamp counter overflows in ~17.2
  * seconds; this task forces periodic reads so that we don't miss any.
  */
-#define MV88E6XXX_TAI_OVERFLOW_PERIOD (HZ * 16)
+#define MV88E6XXX_TAI_OVERFLOW_PERIOD (HZ * 8)
 static void mv88e6xxx_ptp_overflow_check(struct work_struct *work)
 {
 	struct delayed_work *dw = to_delayed_work(work);
-- 
2.47.0

Re: [PATCH net v3 2/3] net: dsa: mv88e6xxx: read cycle counter period from hardware

[Andrew Lunn]

On Sun, Oct 20, 2024 at 02:38:29PM +0800, Shenghao Yang wrote:
> Instead of relying on a fixed mapping of hardware family to cycle
> counter frequency, pull this information from the
> MV88E6XXX_TAI_CLOCK_PERIOD register.
> 
> This lets us support switches whose cycle counter frequencies depend on
> board design.
> 
> Fixes: de776d0d316f ("net: dsa: mv88e6xxx: add support for mv88e6393x family")
> Suggested-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Shenghao Yang <me@shenghaoyang.info>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH net v3 0/3] net: dsa: mv88e6xxx: fix MV88E6393X PHC frequency on internal clock

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Sun, 20 Oct 2024 14:38:27 +0800 you wrote:
> The MV88E6393X family of switches can additionally run their cycle
> counters using a 250MHz internal clock instead of the usual 125MHz
> external clock [1].
> 
> The driver currently assumes all designs utilize that external clock,
> but MikroTik's RB5009 uses the internal source - causing the PHC to be
> seen running at 2x real time in userspace, making synchronization
> with ptp4l impossible.
> 
> [...]

Here is the summary with links:
  - [net,v3,1/3] net: dsa: mv88e6xxx: group cycle counter coefficients
    https://git.kernel.org/netdev/net/c/67af86afff74
  - [net,v3,2/3] net: dsa: mv88e6xxx: read cycle counter period from hardware
    https://git.kernel.org/netdev/net/c/7e3c18097a70
  - [net,v3,3/3] net: dsa: mv88e6xxx: support 4000ps cycle counter period
    https://git.kernel.org/netdev/net/c/3e65ede526cf

You are awesome, thank you!
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