[PATCH v2] lan743x: correctly handle chips with internal PHY

[PATCH v2] lan743x: correctly handle chips with internal PHY

[Sven Van Asbroeck]

From: Sven Van Asbroeck <thesven73@gmail.com>

Commit 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
assumes that chips with an internal PHY will never have a devicetree
entry. This is incorrect: even for these chips, a devicetree entry
can be useful e.g. to pass the mac address from bootloader to chip:

    &pcie {
            status = "okay";

            host@0 {
                    reg = <0 0 0 0 0>;

                    #address-cells = <3>;
                    #size-cells = <2>;

                    lan7430: ethernet@0 {
                            /* LAN7430 with internal PHY */
                            compatible = "microchip,lan743x";
                            status = "okay";
                            reg = <0 0 0 0 0>;
                            /* filled in by bootloader */
                            local-mac-address = [00 00 00 00 00 00];
                    };
            };
    };

If a devicetree entry is present, the driver will not attach the chip
to its internal phy, and the chip will be non-operational.

Fix by tweaking the phy connection algorithm:
- first try to connect to a phy specified in the devicetree
  (could be 'real' phy, or just a 'fixed-link')
- if that doesn't succeed, try to connect to an internal phy, even
  if the chip has a devnode

Tested on a LAN7430 with internal PHY. I cannot test a device using
fixed-link, as I do not have access to one.

Fixes: 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
Tested-by: Sven Van Asbroeck <thesven73@gmail.com> # lan7430
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
---

v1 -> v2:
    Andrew Lunn: keep patch minimal and correct, so keep open-coded version
    of of_phy_get_and_connect().

    Jakub Kicinski: fix e-mail address case.

Tree: v5.10-rc2

To: Andrew Lunn <andrew@lunn.ch>
To: Bryan Whitehead <bryan.whitehead@microchip.com>
To: "David S. Miller" <davem@davemloft.net>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
Cc: Roelof Berg <rberg@berg-solutions.de>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

 drivers/net/ethernet/microchip/lan743x_main.c | 21 +++++++++++--------
 drivers/net/ethernet/microchip/lan743x_main.h |  1 -
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index f2d13e8d20f0..65e80d41c9bc 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -957,7 +957,7 @@ static void lan743x_phy_link_status_change(struct net_device *netdev)
 		data = lan743x_csr_read(adapter, MAC_CR);
 
 		/* set interface mode */
-		if (phy_interface_mode_is_rgmii(adapter->phy_mode))
+		if (phy_interface_is_rgmii(phydev))
 			/* RGMII */
 			data &= ~MAC_CR_MII_EN_;
 		else
@@ -1014,17 +1014,18 @@ static void lan743x_phy_close(struct lan743x_adapter *adapter)
 static int lan743x_phy_open(struct lan743x_adapter *adapter)
 {
 	struct lan743x_phy *phy = &adapter->phy;
+	struct phy_device *phydev = NULL;
 	struct device_node *phynode;
-	struct phy_device *phydev;
 	struct net_device *netdev;
+	phy_interface_t phy_mode;
 	int ret = -EIO;
 
 	netdev = adapter->netdev;
 	phynode = of_node_get(adapter->pdev->dev.of_node);
-	adapter->phy_mode = PHY_INTERFACE_MODE_GMII;
 
 	if (phynode) {
-		of_get_phy_mode(phynode, &adapter->phy_mode);
+		/* try devicetree phy, or fixed link */
+		of_get_phy_mode(phynode, &phy_mode);
 
 		if (of_phy_is_fixed_link(phynode)) {
 			ret = of_phy_register_fixed_link(phynode);
@@ -1037,18 +1038,19 @@ static int lan743x_phy_open(struct lan743x_adapter *adapter)
 		}
 		phydev = of_phy_connect(netdev, phynode,
 					lan743x_phy_link_status_change, 0,
-					adapter->phy_mode);
+					phy_mode);
 		of_node_put(phynode);
-		if (!phydev)
-			goto return_error;
-	} else {
+	}
+
+	if (!phydev) {
+		/* try internal phy */
 		phydev = phy_find_first(adapter->mdiobus);
 		if (!phydev)
 			goto return_error;
 
 		ret = phy_connect_direct(netdev, phydev,
 					 lan743x_phy_link_status_change,
-					 adapter->phy_mode);
+					 PHY_INTERFACE_MODE_GMII);
 		if (ret)
 			goto return_error;
 	}
@@ -1063,6 +1065,7 @@ static int lan743x_phy_open(struct lan743x_adapter *adapter)
 
 	phy_start(phydev);
 	phy_start_aneg(phydev);
+	phy_attached_info(phydev);
 	return 0;
 
 return_error:
diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h
index a536f4a4994d..3a0e70daa88f 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.h
+++ b/drivers/net/ethernet/microchip/lan743x_main.h
@@ -703,7 +703,6 @@ struct lan743x_rx {
 struct lan743x_adapter {
 	struct net_device       *netdev;
 	struct mii_bus		*mdiobus;
-	phy_interface_t		phy_mode;
 	int                     msg_enable;
 #ifdef CONFIG_PM
 	u32			wolopts;
-- 
2.17.1

Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

[Andrew Lunn]

On Fri, Nov 06, 2020 at 08:43:24AM -0500, Sven Van Asbroeck wrote:
> From: Sven Van Asbroeck <thesven73@gmail.com>
> 
> Commit 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
> assumes that chips with an internal PHY will never have a devicetree
> entry. This is incorrect: even for these chips, a devicetree entry
> can be useful e.g. to pass the mac address from bootloader to chip:
> 
>     &pcie {
>             status = "okay";
> 
>             host@0 {
>                     reg = <0 0 0 0 0>;
> 
>                     #address-cells = <3>;
>                     #size-cells = <2>;
> 
>                     lan7430: ethernet@0 {
>                             /* LAN7430 with internal PHY */
>                             compatible = "microchip,lan743x";
>                             status = "okay";
>                             reg = <0 0 0 0 0>;
>                             /* filled in by bootloader */
>                             local-mac-address = [00 00 00 00 00 00];
>                     };
>             };
>     };
> 
> If a devicetree entry is present, the driver will not attach the chip
> to its internal phy, and the chip will be non-operational.
> 
> Fix by tweaking the phy connection algorithm:
> - first try to connect to a phy specified in the devicetree
>   (could be 'real' phy, or just a 'fixed-link')
> - if that doesn't succeed, try to connect to an internal phy, even
>   if the chip has a devnode
> 
> Tested on a LAN7430 with internal PHY. I cannot test a device using
> fixed-link, as I do not have access to one.
> 
> Fixes: 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
> Tested-by: Sven Van Asbroeck <thesven73@gmail.com> # lan7430
> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
> ---
> 
> v1 -> v2:
>     Andrew Lunn: keep patch minimal and correct, so keep open-coded version
>     of of_phy_get_and_connect().

Hi Sven

Why is it required to remove adapter->phy_mode? It is not clear to me
what this change has to do with not looking for an internal PHY.

> @@ -1063,6 +1065,7 @@ static int lan743x_phy_open(struct lan743x_adapter *adapter)
>  
>  	phy_start(phydev);
>  	phy_start_aneg(phydev);
> +	phy_attached_info(phydev);

This also has nothing to do with the problem you are fixing. It is a
sensible thing to do, but it should be a separate patch, and target
net-next, since it is not a fix.

	  Andrew

Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

[Roelof Berg]

My last customer has a fixed link setup, contact me if you need one. Maybe they let me have it and I can test all future patches on fixed link as well. I tested the current driver version on a Lan7430 EVM in a PC by the way and it seemed to be working. I have the EVM still here if needed.

Greetings,
Roelof

Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

[Sven Van Asbroeck]

On Sat, Nov 7, 2020 at 11:14 PM Andrew Lunn <andrew@lunn.ch> wrote:
>
> This also has nothing to do with the problem you are fixing. It is a
> sensible thing to do, but it should be a separate patch, and target
> net-next, since it is not a fix.
>

Agreed - I will spin a truly minimal v3.

Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

[Sven Van Asbroeck]

Hi Roelof, great to meet another user of the lan743x !

On Sun, Nov 8, 2020 at 2:43 AM Roelof Berg <rberg@berg-solutions.de> wrote:
>
> My last customer has a fixed link setup, contact me if you need one. Maybe they let me have it and I can test all future patches on fixed link as well.

Is this a commercially available product? I could test this out if it
can be ordered
inexpensively from my location (Canada).

> I tested the current driver version on a Lan7430 EVM in a PC by the way and it seemed to be working. I have the EVM still here if needed.

Yes it will work on a PC, because the device doesn't have a devicetree
entry there.
In my case I am running on ARM, and I'm manually creating a devicetree
entry in the fdt, so that the bootloader can assign a mac address to the chip.

I must be one of the first to use this chip on ARM, because I have
encountered 2 or 3 issues with the current driver, which crash the
kernel on ARM.

I'll try to contribute those changes once this fix is accepted and merged.

Sven

Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

[Sven Van Asbroeck]

Hi Roelof,

On Sun, Nov 8, 2020 at 2:57 PM Roelof Berg <rberg@berg-solutions.de> wrote:
>
> Well, it’s not an easy 4 hours attempt between breakfast and lunch, unfortunately, but it’s based on inexpensive off-the-shelf parts and doable in an experienced team.
>

I would love to test this patch on fixed-link, but unfortunately I
don't have the
resources to create a prototype as per your instructions.

Sven

Re: [PATCH v2] lan743x: correctly handle chips with internal PHY

[Roelof Berg]

.
> I would love to test this patch on fixed-link, but unfortunately

Yes, understandable, it’s quite dome effort. I will e-mail the company that owns the test setup. They have their own pcba‘s ready meanwhile, so maybe they can give me the EVM setup and I can use it for testing your and other patches.