[PATCH 1/3] net: dsa: qca8k: reduce mgmt ethernet timeout

[PATCH 1/3] net: dsa: qca8k: reduce mgmt ethernet timeout

[Christian Marangi]

The current mgmt ethernet timeout is set to 100ms. This value is too
big and would slow down any mdio command in case the mgmt ethernet
packet have some problems on the receiving part.
Reduce it to just 5ms to handle case when some operation are done on the
master port that would cause the mgmt ethernet to not work temporarily.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/dsa/qca8k.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index 04408e11402a..ec58d0e80a70 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -15,7 +15,7 @@
 
 #define QCA8K_ETHERNET_MDIO_PRIORITY			7
 #define QCA8K_ETHERNET_PHY_PRIORITY			6
-#define QCA8K_ETHERNET_TIMEOUT				100
+#define QCA8K_ETHERNET_TIMEOUT				5
 
 #define QCA8K_NUM_PORTS					7
 #define QCA8K_NUM_CPU_PORTS				2
-- 
2.36.1

[PATCH 2/3] net: dsa: qca8k: change only max_frame_size of mac_frame_size_reg

[Christian Marangi]

Currently we overwrite the entire MAX_FRAME_SIZE reg instead of tweaking
just the MAX_FRAME_SIZE value. Change this and update only the relevant
bits.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/dsa/qca8k.c | 8 ++++++--
 drivers/net/dsa/qca8k.h | 3 ++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 2727d3169c25..eaaf80f96fa9 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -2345,7 +2345,9 @@ qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
 		return 0;
 
 	/* Include L2 header / FCS length */
-	return qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, new_mtu + ETH_HLEN + ETH_FCS_LEN);
+	return regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
+				  QCA8K_MAX_FRAME_SIZE_MASK,
+				  new_mtu + ETH_HLEN + ETH_FCS_LEN);
 }
 
 static int
@@ -3015,7 +3017,9 @@ qca8k_setup(struct dsa_switch *ds)
 	}
 
 	/* Setup our port MTUs to match power on defaults */
-	ret = qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, ETH_FRAME_LEN + ETH_FCS_LEN);
+	ret = regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
+				 QCA8K_MAX_FRAME_SIZE_MASK,
+				 ETH_FRAME_LEN + ETH_FCS_LEN);
 	if (ret)
 		dev_warn(priv->dev, "failed setting MTU settings");
 
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index ec58d0e80a70..1d0c383a95e7 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -87,7 +87,8 @@
 #define   QCA8K_MDIO_MASTER_MAX_REG			32
 #define QCA8K_GOL_MAC_ADDR0				0x60
 #define QCA8K_GOL_MAC_ADDR1				0x64
-#define QCA8K_MAX_FRAME_SIZE				0x78
+#define QCA8K_MAX_FRAME_SIZE_REG			0x78
+#define   QCA8K_MAX_FRAME_SIZE_MASK			GENMASK(13, 0)
 #define QCA8K_REG_PORT_STATUS(_i)			(0x07c + (_i) * 4)
 #define   QCA8K_PORT_STATUS_SPEED			GENMASK(1, 0)
 #define   QCA8K_PORT_STATUS_SPEED_10			0
-- 
2.36.1

[PATCH 3/3] net: dsa: qca8k: reset cpu port on MTU change

[Christian Marangi]

It was discovered that the Documentation lacks of a fundamental detail
on how to correctly change the MAX_FRAME_SIZE of the switch.

In fact if the MAX_FRAME_SIZE is changed while the cpu port is on, the
switch panics and cease to send any packet. This cause the mgmt ethernet
system to not receive any packet (the slow fallback still works) and
makes the device not reachable. To recover from this a switch reset is
required.

To correctly handle this, turn off the cpu ports before changing the
MAX_FRAME_SIZE and turn on again after the value is applied.

Fixes: f58d2598cf70 ("net: dsa: qca8k: implement the port MTU callbacks")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/dsa/qca8k.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index eaaf80f96fa9..0b92b9d5954a 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -2334,6 +2334,7 @@ static int
 qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
 {
 	struct qca8k_priv *priv = ds->priv;
+	int ret;
 
 	/* We have only have a general MTU setting.
 	 * DSA always set the CPU port's MTU to the largest MTU of the slave
@@ -2344,10 +2345,29 @@ qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
 	if (!dsa_is_cpu_port(ds, port))
 		return 0;
 
+	/* To change the MAX_FRAME_SIZE the cpu ports must be off or
+	 * the switch panics.
+	 * Turn off both cpu ports before applying the new value to prevent
+	 * this.
+	 */
+	if (priv->port_enabled_map & BIT(0))
+		qca8k_port_set_status(priv, 0, 0);
+
+	if (priv->port_enabled_map & BIT(6))
+		qca8k_port_set_status(priv, 6, 0);
+
 	/* Include L2 header / FCS length */
-	return regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
-				  QCA8K_MAX_FRAME_SIZE_MASK,
-				  new_mtu + ETH_HLEN + ETH_FCS_LEN);
+	ret = regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
+				 QCA8K_MAX_FRAME_SIZE_MASK,
+				 new_mtu + ETH_HLEN + ETH_FCS_LEN);
+
+	if (priv->port_enabled_map & BIT(0))
+		qca8k_port_set_status(priv, 0, 1);
+
+	if (priv->port_enabled_map & BIT(6))
+		qca8k_port_set_status(priv, 6, 1);
+
+	return ret;
 }
 
 static int
-- 
2.36.1

Re: [PATCH 2/3] net: dsa: qca8k: change only max_frame_size of mac_frame_size_reg

[Vladimir Oltean]

On Sat, Jun 18, 2022 at 08:22:59AM +0200, Christian Marangi wrote:
> Currently we overwrite the entire MAX_FRAME_SIZE reg instead of tweaking
> just the MAX_FRAME_SIZE value. Change this and update only the relevant
> bits.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/net/dsa/qca8k.c | 8 ++++++--
>  drivers/net/dsa/qca8k.h | 3 ++-
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
> index 2727d3169c25..eaaf80f96fa9 100644
> --- a/drivers/net/dsa/qca8k.c
> +++ b/drivers/net/dsa/qca8k.c
> @@ -2345,7 +2345,9 @@ qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
>  		return 0;
>  
>  	/* Include L2 header / FCS length */
> -	return qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, new_mtu + ETH_HLEN + ETH_FCS_LEN);
> +	return regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
> +				  QCA8K_MAX_FRAME_SIZE_MASK,
> +				  new_mtu + ETH_HLEN + ETH_FCS_LEN);
>  }
>  
>  static int
> @@ -3015,7 +3017,9 @@ qca8k_setup(struct dsa_switch *ds)
>  	}
>  
>  	/* Setup our port MTUs to match power on defaults */
> -	ret = qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, ETH_FRAME_LEN + ETH_FCS_LEN);
> +	ret = regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
> +				 QCA8K_MAX_FRAME_SIZE_MASK,
> +				 ETH_FRAME_LEN + ETH_FCS_LEN);
>  	if (ret)
>  		dev_warn(priv->dev, "failed setting MTU settings");
>  
> diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
> index ec58d0e80a70..1d0c383a95e7 100644
> --- a/drivers/net/dsa/qca8k.h
> +++ b/drivers/net/dsa/qca8k.h
> @@ -87,7 +87,8 @@
>  #define   QCA8K_MDIO_MASTER_MAX_REG			32
>  #define QCA8K_GOL_MAC_ADDR0				0x60
>  #define QCA8K_GOL_MAC_ADDR1				0x64
> -#define QCA8K_MAX_FRAME_SIZE				0x78
> +#define QCA8K_MAX_FRAME_SIZE_REG			0x78
> +#define   QCA8K_MAX_FRAME_SIZE_MASK			GENMASK(13, 0)

What's at bits 14 and beyond? Trying to understand the impact of this change.

>  #define QCA8K_REG_PORT_STATUS(_i)			(0x07c + (_i) * 4)
>  #define   QCA8K_PORT_STATUS_SPEED			GENMASK(1, 0)
>  #define   QCA8K_PORT_STATUS_SPEED_10			0
> -- 
> 2.36.1
> 

Re: [PATCH 1/3] net: dsa: qca8k: reduce mgmt ethernet timeout

[Vladimir Oltean]

On Sat, Jun 18, 2022 at 08:22:58AM +0200, Christian Marangi wrote:
> The current mgmt ethernet timeout is set to 100ms. This value is too
> big and would slow down any mdio command in case the mgmt ethernet
> packet have some problems on the receiving part.
> Reduce it to just 5ms to handle case when some operation are done on the
> master port that would cause the mgmt ethernet to not work temporarily.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---

I think this could very well qualify as a regression and have a tag of:

Fixes: 5950c7c0a68c ("net: dsa: qca8k: add support for mgmt read/write in Ethernet packet")

if it was presented along with a situation where users could hit some
real life conditions where the Ethernet management interface isn't
functional.

>  drivers/net/dsa/qca8k.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
> index 04408e11402a..ec58d0e80a70 100644
> --- a/drivers/net/dsa/qca8k.h
> +++ b/drivers/net/dsa/qca8k.h
> @@ -15,7 +15,7 @@
>  
>  #define QCA8K_ETHERNET_MDIO_PRIORITY			7
>  #define QCA8K_ETHERNET_PHY_PRIORITY			6
> -#define QCA8K_ETHERNET_TIMEOUT				100
> +#define QCA8K_ETHERNET_TIMEOUT				5
>  
>  #define QCA8K_NUM_PORTS					7
>  #define QCA8K_NUM_CPU_PORTS				2
> -- 
> 2.36.1
> 

Re: [PATCH 2/3] net: dsa: qca8k: change only max_frame_size of mac_frame_size_reg

[Christian Marangi]

On Tue, Jun 21, 2022 at 03:30:41PM +0300, Vladimir Oltean wrote:
> On Sat, Jun 18, 2022 at 08:22:59AM +0200, Christian Marangi wrote:
> > Currently we overwrite the entire MAX_FRAME_SIZE reg instead of tweaking
> > just the MAX_FRAME_SIZE value. Change this and update only the relevant
> > bits.
> > 
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >  drivers/net/dsa/qca8k.c | 8 ++++++--
> >  drivers/net/dsa/qca8k.h | 3 ++-
> >  2 files changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
> > index 2727d3169c25..eaaf80f96fa9 100644
> > --- a/drivers/net/dsa/qca8k.c
> > +++ b/drivers/net/dsa/qca8k.c
> > @@ -2345,7 +2345,9 @@ qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
> >  		return 0;
> >  
> >  	/* Include L2 header / FCS length */
> > -	return qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, new_mtu + ETH_HLEN + ETH_FCS_LEN);
> > +	return regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
> > +				  QCA8K_MAX_FRAME_SIZE_MASK,
> > +				  new_mtu + ETH_HLEN + ETH_FCS_LEN);
> >  }
> >  
> >  static int
> > @@ -3015,7 +3017,9 @@ qca8k_setup(struct dsa_switch *ds)
> >  	}
> >  
> >  	/* Setup our port MTUs to match power on defaults */
> > -	ret = qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, ETH_FRAME_LEN + ETH_FCS_LEN);
> > +	ret = regmap_update_bits(priv->regmap, QCA8K_MAX_FRAME_SIZE_REG,
> > +				 QCA8K_MAX_FRAME_SIZE_MASK,
> > +				 ETH_FRAME_LEN + ETH_FCS_LEN);
> >  	if (ret)
> >  		dev_warn(priv->dev, "failed setting MTU settings");
> >  
> > diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
> > index ec58d0e80a70..1d0c383a95e7 100644
> > --- a/drivers/net/dsa/qca8k.h
> > +++ b/drivers/net/dsa/qca8k.h
> > @@ -87,7 +87,8 @@
> >  #define   QCA8K_MDIO_MASTER_MAX_REG			32
> >  #define QCA8K_GOL_MAC_ADDR0				0x60
> >  #define QCA8K_GOL_MAC_ADDR1				0x64
> > -#define QCA8K_MAX_FRAME_SIZE				0x78
> > +#define QCA8K_MAX_FRAME_SIZE_REG			0x78
> > +#define   QCA8K_MAX_FRAME_SIZE_MASK			GENMASK(13, 0)
> 
> What's at bits 14 and beyond? Trying to understand the impact of this change.
>

Most of them are reserved bits (from Documentation).
The few we have Documentation of are debug bits about CRC handling, IPG
and special mode where the MAC send pause frames based on the signal.

It's a cleanup and seems a nice change now that we are touching this
part.

> >  #define QCA8K_REG_PORT_STATUS(_i)			(0x07c + (_i) * 4)
> >  #define   QCA8K_PORT_STATUS_SPEED			GENMASK(1, 0)
> >  #define   QCA8K_PORT_STATUS_SPEED_10			0
> > -- 
> > 2.36.1
> > 

-- 
	Ansuel

Re: [PATCH 1/3] net: dsa: qca8k: reduce mgmt ethernet timeout

[Christian Marangi]

On Tue, Jun 21, 2022 at 03:33:35PM +0300, Vladimir Oltean wrote:
> On Sat, Jun 18, 2022 at 08:22:58AM +0200, Christian Marangi wrote:
> > The current mgmt ethernet timeout is set to 100ms. This value is too
> > big and would slow down any mdio command in case the mgmt ethernet
> > packet have some problems on the receiving part.
> > Reduce it to just 5ms to handle case when some operation are done on the
> > master port that would cause the mgmt ethernet to not work temporarily.
> > 
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> 
> I think this could very well qualify as a regression and have a tag of:
> 
> Fixes: 5950c7c0a68c ("net: dsa: qca8k: add support for mgmt read/write in Ethernet packet")
> 
> if it was presented along with a situation where users could hit some
> real life conditions where the Ethernet management interface isn't
> functional.
>

It's really to handle corner case... In testing the MTU change (and
noticing the mgmt ethernet going "macheroni") I notice the timeout was
absurdly high. In a situation where something goes wrong at least you
can have access to it after some time.

Ok I will add the fixes tag.

> >  drivers/net/dsa/qca8k.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
> > index 04408e11402a..ec58d0e80a70 100644
> > --- a/drivers/net/dsa/qca8k.h
> > +++ b/drivers/net/dsa/qca8k.h
> > @@ -15,7 +15,7 @@
> >  
> >  #define QCA8K_ETHERNET_MDIO_PRIORITY			7
> >  #define QCA8K_ETHERNET_PHY_PRIORITY			6
> > -#define QCA8K_ETHERNET_TIMEOUT				100
> > +#define QCA8K_ETHERNET_TIMEOUT				5
> >  
> >  #define QCA8K_NUM_PORTS					7
> >  #define QCA8K_NUM_CPU_PORTS				2
> > -- 
> > 2.36.1
> > 

-- 
	Ansuel