[PATCH net v4 0/3] Fix PHY handle no longer parsing

[PATCH net v4 0/3] Fix PHY handle no longer parsing

[Michael Sit Wei Hong]

After the fixed link support was introduced, it is observed that PHY
no longer attach to the MAC properly. So we introduce a helper
function to determine if the MAC should expect to connect to a PHY
and proceed accordingly.

Michael Sit Wei Hong (3):
  net: phylink: add phylink_expects_phy() method
  net: stmmac: check if MAC needs to attach to a PHY
  net: stmmac: remove redundant fixup to support fixed-link mode

 .../net/ethernet/stmicro/stmmac/dwmac-intel.c   |  1 -
 .../net/ethernet/stmicro/stmmac/stmmac_main.c   |  4 +++-
 drivers/net/phy/phylink.c                       | 17 +++++++++++++++++
 include/linux/phylink.h                         |  1 +
 4 files changed, 21 insertions(+), 2 deletions(-)

v2: Initialize fwnode before using the variable
v3: Introduced phylink_expects_phy() method as suggested by Russell King
    remove xpcs_an_inband fixup instead of moving the fixed-link check
    as suggested by Andrew Lunn
v4: Modify phylink_expects_phy() to check for more complete set of
    conditions when no PHY is needed and return false if met.
-- 
2.34.1

[PATCH net v4 1/3] net: phylink: add phylink_expects_phy() method

[Michael Sit Wei Hong]

Provide phylink_expects_phy() to allow MAC drivers to check if it
is expecting a PHY to attach to. Since fixed-linked setups do not
need to attach to a PHY.

Provides a boolean value as to if the MAC should expect a PHY.
returns true if a PHY is expected.

Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
---
 drivers/net/phy/phylink.c | 17 +++++++++++++++++
 include/linux/phylink.h   |  1 +
 2 files changed, 18 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 1a2f074685fa..4c080656e280 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1586,6 +1586,23 @@ void phylink_destroy(struct phylink *pl)
 }
 EXPORT_SYMBOL_GPL(phylink_destroy);
 
+/**
+ * phylink_expects_phy() - Determine if phylink expects a phy to be attached
+ * @pl: a pointer to a &struct phylink returned from phylink_create()
+ *
+ * Fixed-link mode does not need a PHY, returns a boolean value to check if
+ * phylink will be expecting a PHY to attach.
+ */
+bool phylink_expects_phy(struct phylink *pl)
+{
+	if (pl->cfg_link_an_mode == MLO_AN_FIXED ||
+	    (pl->cfg_link_an_mode == MLO_AN_INBAND &&
+	     phy_interface_mode_is_8023z(pl->link_config.interface)))
+		return false;
+	return true;
+}
+EXPORT_SYMBOL_GPL(phylink_expects_phy);
+
 static void phylink_phy_change(struct phy_device *phydev, bool up)
 {
 	struct phylink *pl = phydev->phylink;
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index c492c26202b5..637698ed5cb6 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -574,6 +574,7 @@ struct phylink *phylink_create(struct phylink_config *, struct fwnode_handle *,
 			       phy_interface_t iface,
 			       const struct phylink_mac_ops *mac_ops);
 void phylink_destroy(struct phylink *);
+bool phylink_expects_phy(struct phylink *pl);
 
 int phylink_connect_phy(struct phylink *, struct phy_device *);
 int phylink_of_phy_connect(struct phylink *, struct device_node *, u32 flags);
-- 
2.34.1

Re: [PATCH net v4 1/3] net: phylink: add phylink_expects_phy() method

[Russell King (Oracle)]

On Thu, Mar 30, 2023 at 04:39:58PM +0800, Michael Sit Wei Hong wrote:
> Provide phylink_expects_phy() to allow MAC drivers to check if it
> is expecting a PHY to attach to. Since fixed-linked setups do not
> need to attach to a PHY.
> 
> Provides a boolean value as to if the MAC should expect a PHY.
> returns true if a PHY is expected.
> 
> Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
> ---
>  drivers/net/phy/phylink.c | 17 +++++++++++++++++
>  include/linux/phylink.h   |  1 +
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index 1a2f074685fa..4c080656e280 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -1586,6 +1586,23 @@ void phylink_destroy(struct phylink *pl)
>  }
>  EXPORT_SYMBOL_GPL(phylink_destroy);
>  
> +/**
> + * phylink_expects_phy() - Determine if phylink expects a phy to be attached
> + * @pl: a pointer to a &struct phylink returned from phylink_create()
> + *
> + * Fixed-link mode does not need a PHY, returns a boolean value to check if
> + * phylink will be expecting a PHY to attach.

This description could be clearer (for example, it isn't just about
fixed-link mode), but apart from that, it's good. I don't think that's
a reason to delay this any further, but please follow-up with a patch
to improve this description.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

[PATCH net v4 2/3] net: stmmac: check if MAC needs to attach to a PHY

[Michael Sit Wei Hong]

After the introduction of the fixed-link support, the MAC driver
no longer attempt to scan for a PHY to attach to. This causes the
non fixed-link setups to stop working.

Using the phylink_expects_phy() to check and determine if the MAC
should expect and attach a PHY.

Fixes: ab21cf920928 ("net: stmmac: make mdio register skips PHY scanning for fixed-link")
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Signed-off-by: Lai Peter Jun Ann <peter.jun.ann.lai@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 8f543c3ab5c5..41f0f3b74933 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1135,6 +1135,7 @@ static int stmmac_init_phy(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 	struct fwnode_handle *fwnode;
+	bool phy_needed;
 	int ret;
 
 	fwnode = of_fwnode_handle(priv->plat->phylink_node);
@@ -1144,10 +1145,11 @@ static int stmmac_init_phy(struct net_device *dev)
 	if (fwnode)
 		ret = phylink_fwnode_phy_connect(priv->phylink, fwnode, 0);
 
+	phy_needed = phylink_expects_phy(priv->phylink);
 	/* Some DT bindings do not set-up the PHY handle. Let's try to
 	 * manually parse it
 	 */
-	if (!fwnode || ret) {
+	if (!fwnode || phy_needed || ret) {
 		int addr = priv->plat->phy_addr;
 		struct phy_device *phydev;
 
-- 
2.34.1

[PATCH net v4 3/3] net: stmmac: remove redundant fixup to support fixed-link mode

[Michael Sit Wei Hong]

Currently, intel_speed_mode_2500() will fix-up xpcs_an_inband
to 1 if the underlying controller has a max speed of 1000Mbps.
The value has been initialized and modified if it is
a fixed-linked setup earlier.

This patch removes the fix-up to allow for fixed-linked setup
support. In stmmac_phy_setup(), ovr_an_inband is set based on
the value of xpcs_an_inband. Which in turn will return an
error in phylink_parse_mode() where MLO_AN_FIXED and
ovr_an_inband are both set.

Fixes: c82386310d95 ("stmmac: intel: prepare to support 1000BASE-X phy interface setting")
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index 7deb1f817dac..6db87184bf75 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
@@ -251,7 +251,6 @@ static void intel_speed_mode_2500(struct net_device *ndev, void *intel_data)
 		priv->plat->mdio_bus_data->xpcs_an_inband = false;
 	} else {
 		priv->plat->max_speed = 1000;
-		priv->plat->mdio_bus_data->xpcs_an_inband = true;
 	}
 }
 
-- 
2.34.1