[PATCH v1 net-next 0/3] net: stmmac: re-configure tas basetime after ptp time adjust

If the DWMAC Ethernet device has already set the Qbv EST configuration
before using ptp to synchronize the time adjustment, the Qbv base time
may change to be the past time of the new current time. This is not
allowed by hardware.

This patch calculates and re-configures the Qbv basetime after ptp time
adjustment.

Xiaoliang Yang (3):
  net: stmmac: separate the tas basetime calculation function
  net: stmmac: add mutex lock to protect est parameters
  net: stmmac: ptp: update tas basetime after ptp adjust

 drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  3 ++
 .../net/ethernet/stmicro/stmmac/stmmac_ptp.c  | 41 ++++++++++++++++-
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   | 46 +++++++++++++------
 include/linux/stmmac.h                        |  1 +
 4 files changed, 77 insertions(+), 14 deletions(-)

-- 
2.17.1


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Add a mutex lock to protect est structure parameters so that the
EST parameters can be updated by other threads.

Signed-off-by: Xiaoliang Yang <redacted>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c | 8 ++++++++
 include/linux/stmmac.h                          | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index d7d448c5a72b..8e1f9a18ef59 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c

@@ -798,14 +798,18 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 					 GFP_KERNEL);
 		if (!plat->est)
 			return -ENOMEM;
+
+		mutex_init(&priv->plat->est->lock);
 	} else {
 		memset(plat->est, 0, sizeof(*plat->est));
 	}
 
 	size = qopt->num_entries;
 
+	mutex_lock(&priv->plat->est->lock);
 	priv->plat->est->gcl_size = size;
 	priv->plat->est->enable = qopt->enable;
+	mutex_unlock(&priv->plat->est->lock);
 
 	for (i = 0; i < size; i++) {
 		s64 delta_ns = qopt->entries[i].interval;

@@ -842,6 +846,7 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	time = stmmac_calc_tas_basetime(qopt->base_time, current_time_ns,
 					qopt->cycle_time);
 
+	mutex_lock(&priv->plat->est->lock);
 	priv->plat->est->btr[0] = (u32)time.tv_nsec;
 	priv->plat->est->btr[1] = (u32)time.tv_sec;
 

@@ -859,6 +864,7 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 
 	ret = stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
 				   priv->plat->clk_ptp_rate);
+	mutex_unlock(&priv->plat->est->lock);
 	if (ret) {
 		netdev_err(priv->dev, "failed to configure EST\n");
 		goto disable;

@@ -874,9 +880,11 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	return 0;
 
 disable:
+	mutex_lock(&priv->plat->est->lock);
 	priv->plat->est->enable = false;
 	stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
 			     priv->plat->clk_ptp_rate);
+	mutex_unlock(&priv->plat->est->lock);
 
 	priv->plat->fpe_cfg->enable = false;
 	stmmac_fpe_configure(priv, priv->ioaddr,

diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index e14a12df381b..c38b65aaf8c2 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h

@@ -115,6 +115,7 @@ struct stmmac_axi {
 
 #define EST_GCL		1024
 struct stmmac_est {
+	struct mutex lock;
 	int enable;
 	u32 btr_offset[2];
 	u32 btr[2];

-- 
2.17.1


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Separate the TAS basetime calculation function so that it can be
called by other functions.

Signed-off-by: Xiaoliang Yang <redacted>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  3 ++
 .../net/ethernet/stmicro/stmmac/stmmac_tc.c   | 38 ++++++++++++-------
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index b6cd43eda7ac..1ce25c95cb06 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -355,6 +355,9 @@ void stmmac_selftest_run(struct net_device *dev,
 void stmmac_selftest_get_strings(struct stmmac_priv *priv, u8 *data);
 int stmmac_selftest_get_count(struct stmmac_priv *priv);
 #else
+struct timespec64 stmmac_calc_tas_basetime(ktime_t old_base_time,
+					   ktime_t current_time,
+					   u64 cycle_time);
 static inline void stmmac_selftest_run(struct net_device *dev,
 				       struct ethtool_test *etest, u64 *buf)
 {

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 4e70efc45458..d7d448c5a72b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c

@@ -713,6 +713,29 @@ static int tc_setup_cls(struct stmmac_priv *priv,
 	return ret;
 }
 
+struct timespec64 stmmac_calc_tas_basetime(ktime_t old_base_time,
+					   ktime_t current_time,
+					   u64 cycle_time)
+{
+	struct timespec64 time;
+
+	if (ktime_after(old_base_time, current_time)) {
+		time = ktime_to_timespec64(old_base_time);
+	} else {
+		s64 n;
+		ktime_t base_time;
+
+		n = div64_s64(ktime_sub_ns(current_time, old_base_time),
+			      cycle_time);
+		base_time = ktime_add_ns(old_base_time,
+					 (n + 1) * cycle_time);
+
+		time = ktime_to_timespec64(base_time);
+	}
+
+	return time;
+}
+
 static int tc_setup_taprio(struct stmmac_priv *priv,
 			   struct tc_taprio_qopt_offload *qopt)
 {

@@ -816,19 +839,8 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	/* Adjust for real system time */
 	priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops, &current_time);
 	current_time_ns = timespec64_to_ktime(current_time);
-	if (ktime_after(qopt->base_time, current_time_ns)) {
-		time = ktime_to_timespec64(qopt->base_time);
-	} else {
-		ktime_t base_time;
-		s64 n;
-
-		n = div64_s64(ktime_sub_ns(current_time_ns, qopt->base_time),
-			      qopt->cycle_time);
-		base_time = ktime_add_ns(qopt->base_time,
-					 (n + 1) * qopt->cycle_time);
-
-		time = ktime_to_timespec64(base_time);
-	}
+	time = stmmac_calc_tas_basetime(qopt->base_time, current_time_ns,
+					qopt->cycle_time);
 
 	priv->plat->est->btr[0] = (u32)time.tv_nsec;
 	priv->plat->est->btr[1] = (u32)time.tv_sec;

-- 
2.17.1


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After adjusting the ptp time, the Qbv base time may be the past time
of the new current time. dwmac5 hardware limited the base time cannot
be set as past time. This patch calculate the base time and reset the
Qbv configuration after ptp time adjust.

Signed-off-by: Xiaoliang Yang <redacted>
---
 .../net/ethernet/stmicro/stmmac/stmmac_ptp.c  | 41 ++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 4e86cdf2bc9f..c573bc8b2595 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

@@ -62,7 +62,8 @@ static int stmmac_adjust_time(struct ptp_clock_info *ptp, s64 delta)
 	u32 sec, nsec;
 	u32 quotient, reminder;
 	int neg_adj = 0;
-	bool xmac;
+	bool xmac, est_rst = false;
+	int ret;
 
 	xmac = priv->plat->has_gmac4 || priv->plat->has_xgmac;
 

@@ -75,10 +76,48 @@ static int stmmac_adjust_time(struct ptp_clock_info *ptp, s64 delta)
 	sec = quotient;
 	nsec = reminder;
 
+	/* If EST is enabled, disabled it before adjust ptp time. */
+	if (priv->plat->est && priv->plat->est->enable) {
+		est_rst = true;
+		mutex_lock(&priv->plat->est->lock);
+		priv->plat->est->enable = false;
+		stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
+				     priv->plat->clk_ptp_rate);
+		mutex_unlock(&priv->plat->est->lock);
+	}
+
 	spin_lock_irqsave(&priv->ptp_lock, flags);
 	stmmac_adjust_systime(priv, priv->ptpaddr, sec, nsec, neg_adj, xmac);
 	spin_unlock_irqrestore(&priv->ptp_lock, flags);
 
+	/* Caculate new basetime and re-configured EST after PTP time adjust. */
+	if (est_rst) {
+		struct timespec64 current_time, time;
+		ktime_t current_time_ns, basetime;
+		u64 cycle_time;
+
+		priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops, &current_time);
+		current_time_ns = timespec64_to_ktime(current_time);
+		time.tv_nsec = priv->plat->est->btr[0];
+		time.tv_sec = priv->plat->est->btr[1];
+		basetime = timespec64_to_ktime(time);
+		cycle_time = priv->plat->est->ctr[1] * NSEC_PER_SEC +
+			     priv->plat->est->ctr[0];
+		time = stmmac_calc_tas_basetime(basetime,
+						current_time_ns,
+						cycle_time);
+
+		mutex_lock(&priv->plat->est->lock);
+		priv->plat->est->btr[0] = (u32)time.tv_nsec;
+		priv->plat->est->btr[1] = (u32)time.tv_sec;
+		priv->plat->est->enable = true;
+		ret = stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
+					   priv->plat->clk_ptp_rate);
+		mutex_unlock(&priv->plat->est->lock);
+		if (ret)
+			netdev_err(priv->dev, "failed to configure EST\n");
+	}
+
 	return 0;
 }
 

-- 
2.17.1


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On 6/1/2021 10:38 AM, Xiaoliang Yang wrote:

Hi Xiaoliang,

This time may no longer be what the user specified originally, it was 
adjusted based on the gptp time when the configuration was first made.
IMHO, if we want to respect the user configuration then we need to do 
the calculation here based on the original time.
Typically (using arbitrary units):
a) User configures basetime of 0, at gptp time 1000
b) btr is update to 1000, schedule starts
c) later, gptp time is updated to 500
d-1) with current patch, schedule will restart at 1000 (i.e remains 
disabled for 500)
d-2) with my suggestion, schedule will restart at 500 (which matches the 
user request, "start as soon as possible".

+        basetime = timespec64_to_ktime(time);
+        cycle_time = priv->plat->est->ctr[1] * NSEC_PER_SEC +
+                 priv->plat->est->ctr[0];
+        time = stmmac_calc_tas_basetime(basetime,
+                        current_time_ns,
+                        cycle_time);
+
+        mutex_lock(&priv->plat->est->lock);

Hmm... the locking needs to move up. Reading + writting btr/ctr should 
be atomic.

+        priv->plat->est->btr[0] = (u32)time.tv_nsec;
+        priv->plat->est->btr[1] = (u32)time.tv_sec;
+        priv->plat->est->enable = true;
+        ret = stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
+                       priv->plat->clk_ptp_rate);
+        mutex_unlock(&priv->plat->est->lock);
+        if (ret)
+            netdev_err(priv->dev, "failed to configure EST\n");
+    }
+
     return 0;
}

Br,
Rui Sousa

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Hi Rui,

On 2021-06-02 18:18, Rui Sousa wrote:

quoted

After adjusting the ptp time, the Qbv base time may be the past time
of the new current time. dwmac5 hardware limited the base time cannot
be set as past time. This patch calculate the base time and reset the
Qbv configuration after ptp time adjust.

Signed-off-by: Xiaoliang Yang <redacted>
---
.../net/ethernet/stmicro/stmmac/stmmac_ptp.c  | 41

++++++++++++++++++-

quoted

1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 4e86cdf2bc9f..c573bc8b2595 100644

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

@@ -62,7 +62,8 @@ static int stmmac_adjust_time(struct ptp_clock_info

*ptp, s64 delta)
     u32 sec, nsec;
     u32 quotient, reminder;
     int neg_adj = 0;
-    bool xmac;
+    bool xmac, est_rst = false;
+    int ret;

     xmac = priv->plat->has_gmac4 || priv->plat->has_xgmac;

@@ -75,10 +76,48 @@ static int stmmac_adjust_time(struct

ptp_clock_info *ptp, s64 delta)
     sec = quotient;
     nsec = reminder;

+    /* If EST is enabled, disabled it before adjust ptp time. */
+    if (priv->plat->est && priv->plat->est->enable) {
+        est_rst = true;
+        mutex_lock(&priv->plat->est->lock);
+        priv->plat->est->enable = false;
+        stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
+                     priv->plat->clk_ptp_rate);
+        mutex_unlock(&priv->plat->est->lock);
+    }
+
     spin_lock_irqsave(&priv->ptp_lock, flags);
     stmmac_adjust_systime(priv, priv->ptpaddr, sec, nsec, neg_adj,
xmac);
     spin_unlock_irqrestore(&priv->ptp_lock, flags);

+    /* Caculate new basetime and re-configured EST after PTP time
adjust. */
+    if (est_rst) {
+        struct timespec64 current_time, time;
+        ktime_t current_time_ns, basetime;
+        u64 cycle_time;
+
+        priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops,
&current_time);
+        current_time_ns = timespec64_to_ktime(current_time);
+        time.tv_nsec = priv->plat->est->btr[0];
+        time.tv_sec = priv->plat->est->btr[1];

This time may no longer be what the user specified originally, it was adjusted
based on the gptp time when the configuration was first made.
IMHO, if we want to respect the user configuration then we need to do the
calculation here based on the original time.
Typically (using arbitrary units):
a) User configures basetime of 0, at gptp time 1000
b) btr is update to 1000, schedule starts
c) later, gptp time is updated to 500
d-1) with current patch, schedule will restart at 1000 (i.e remains disabled for
500)
d-2) with my suggestion, schedule will restart at 500 (which matches the user
request, "start as soon as possible".

It is not the correct operation sequence for the user to configure Qbv before ptp clock synchronization. After adjusting the ptp clock time, it is no longer possible to determine whether the previously set basetime is what the user wants. I think our driver only needs to ensure that the set basetime meets the hardware regulations, and the hardware can work normally. So I only updated the past basetime. I am not sure if it is appropriate to reset EST configure in the PTP driver, but this case will cause the hardware to not work.

quoted

+        basetime = timespec64_to_ktime(time);
+        cycle_time = priv->plat->est->ctr[1] * NSEC_PER_SEC +
+                 priv->plat->est->ctr[0];
+        time = stmmac_calc_tas_basetime(basetime,
+                        current_time_ns,
+                        cycle_time);
+
+        mutex_lock(&priv->plat->est->lock);

Hmm... the locking needs to move up. Reading + writting btr/ctr should be
atomic.

I will modify this.

quoted

+        priv->plat->est->btr[0] = (u32)time.tv_nsec;
+        priv->plat->est->btr[1] = (u32)time.tv_sec;
+        priv->plat->est->enable = true;
+        ret = stmmac_est_configure(priv, priv->ioaddr,
+priv->plat->est,
+                       priv->plat->clk_ptp_rate);
+        mutex_unlock(&priv->plat->est->lock);
+        if (ret)
+            netdev_err(priv->dev, "failed to configure EST\n");
+    }
+
     return 0;
}

Thanks,
xiaoliang
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On 6/9/2021 11:03 AM, Xiaoliang Yang wrote:

Hi Rui,

Hi,

On 2021-06-02 18:18, Rui Sousa wrote:

quoted

quoted

After adjusting the ptp time, the Qbv base time may be the past time
of the new current time. dwmac5 hardware limited the base time cannot
be set as past time. This patch calculate the base time and reset the
Qbv configuration after ptp time adjust.

Signed-off-by: Xiaoliang Yang <redacted>
---
.../net/ethernet/stmicro/stmmac/stmmac_ptp.c  | 41

++++++++++++++++++-

quoted

1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 4e86cdf2bc9f..c573bc8b2595 100644

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

@@ -62,7 +62,8 @@ static int stmmac_adjust_time(struct ptp_clock_info

*ptp, s64 delta)
      u32 sec, nsec;
      u32 quotient, reminder;
      int neg_adj = 0;
-    bool xmac;
+    bool xmac, est_rst = false;
+    int ret;

      xmac = priv->plat->has_gmac4 || priv->plat->has_xgmac;

@@ -75,10 +76,48 @@ static int stmmac_adjust_time(struct

ptp_clock_info *ptp, s64 delta)
      sec = quotient;
      nsec = reminder;

+    /* If EST is enabled, disabled it before adjust ptp time. */
+    if (priv->plat->est && priv->plat->est->enable) {
+        est_rst = true;
+        mutex_lock(&priv->plat->est->lock);
+        priv->plat->est->enable = false;
+        stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
+                     priv->plat->clk_ptp_rate);
+        mutex_unlock(&priv->plat->est->lock);
+    }
+
      spin_lock_irqsave(&priv->ptp_lock, flags);
      stmmac_adjust_systime(priv, priv->ptpaddr, sec, nsec, neg_adj,
xmac);
      spin_unlock_irqrestore(&priv->ptp_lock, flags);

+    /* Caculate new basetime and re-configured EST after PTP time
adjust. */
+    if (est_rst) {
+        struct timespec64 current_time, time;
+        ktime_t current_time_ns, basetime;
+        u64 cycle_time;
+
+        priv->ptp_clock_ops.gettime64(&priv->ptp_clock_ops,
&current_time);
+        current_time_ns = timespec64_to_ktime(current_time);
+        time.tv_nsec = priv->plat->est->btr[0];
+        time.tv_sec = priv->plat->est->btr[1];

This time may no longer be what the user specified originally, it was adjusted
based on the gptp time when the configuration was first made.
IMHO, if we want to respect the user configuration then we need to do the
calculation here based on the original time.
Typically (using arbitrary units):
a) User configures basetime of 0, at gptp time 1000
b) btr is update to 1000, schedule starts
c) later, gptp time is updated to 500
d-1) with current patch, schedule will restart at 1000 (i.e remains disabled for
500)
d-2) with my suggestion, schedule will restart at 500 (which matches the user
request, "start as soon as possible".

It is not the correct operation sequence for the user to configure Qbv before ptp clock synchronization.

The way I see it, a ptp clock discontinuity may happen at any time 
(change of grand master, grand master discontinuity, ...) outside of the 
user control. So having the driver handle all corner cases looked like a 
good solution to me.

After adjusting the ptp clock time, it is no longer possible to determine whether the previously set basetime is what the user wants.

I may be assuming too much, but usually a Qbv schedule is determined by 
some central identity based on an absolute time (not related to the 
current time in the endpoint). So with this assumption I was considering 
the time specified by the user as "correct", independently of the 
current local ptp time.

I think our driver only needs to ensure that the set basetime meets the hardware regulations, and the hardware can work normally. So I only updated the past basetime.

Understood, but from the point of view of the user I think the case you 
are already handling and the one I mentioned are very similar. Qbv 
schedule doesn't work as intended after the clock jump. Also, my 
suggestion simplifies a bit the code (no conversion from hardware to 
ktime), at the cost of adding extra data (software backup of the 
original user ktime).

I am not sure if it is appropriate to reset EST configure in the PTP driver,

I'm not 100% sure either and I was hoping to see other people comments 
(and I haven't checked yet how other drivers are handling this).
That said, to handle this properly in userspace, IMHO you would need:
- some process monitoring the ptp clock and detecting jumps
- the process would need to be aware of the current Qbv schedule
- when a jump is detected, re-do the Qbv configuration

Overall, handling the issue transparently in the driver, seems like a 
better solution.

but this case will cause the hardware to not work.

quoted

quoted

+        basetime = timespec64_to_ktime(time);
+        cycle_time = priv->plat->est->ctr[1] * NSEC_PER_SEC +
+                 priv->plat->est->ctr[0];
+        time = stmmac_calc_tas_basetime(basetime,
+                        current_time_ns,
+                        cycle_time);
+
+        mutex_lock(&priv->plat->est->lock);

Hmm... the locking needs to move up. Reading + writting btr/ctr should be
atomic.

I will modify this.

quoted

quoted

+        priv->plat->est->btr[0] = (u32)time.tv_nsec;
+        priv->plat->est->btr[1] = (u32)time.tv_sec;
+        priv->plat->est->enable = true;
+        ret = stmmac_est_configure(priv, priv->ioaddr,
+priv->plat->est,
+                       priv->plat->clk_ptp_rate);
+        mutex_unlock(&priv->plat->est->lock);
+        if (ret)
+            netdev_err(priv->dev, "failed to configure EST\n");
+    }
+
      return 0;
}

Thanks,
xiaoliang

Br,
Rui

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