Thread (26 messages) 26 messages, 4 authors, 3d ago

Re: [PATCH 3/3] net: stmmac: dwmac-socfpga: Add mac-mode DT property support

From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2026-07-01 06:50:12
Also in: linux-arm-kernel, linux-devicetree, lkml

Hi,

On 6/30/26 15:31, muhammad.nazim.amirul.nazle.asmade@altera.com wrote:
From: Nazim Amirul <redacted>

Russell King's commit de696c63c1dc ("net: stmmac: socfpga: convert to
use phy_interface") replaced mac_interface with phy_interface in
socfpga_get_plat_phymode(), noting that no upstream DTS files set the
"mac-mode" property, making the two values identical.

The Agilex5 SoCDK TSN Config2 board is an exception: its gmac1 TSN
port uses GMII internally in the MAC while the PHY-side interface is
RGMII, so mac-mode and phy-mode differ. Without restoring mac_interface
support, the MAC is configured with RGMII instead of GMII, causing
connectivity failures on this board.

Add socfpga_of_get_mac_mode() to read the optional "mac-mode" DT
property and store it in a new mac_interface field. When the property
is absent, mac_interface falls back to phy_interface, preserving
the existing behaviour for all other boards.
After our discussions, indeed mac-mode seems to be the way to go, however
I have some remarks on how it's handled right now.
quoted hunk ↗ jump to hunk
Fixes: de696c63c1dc ("net: stmmac: socfpga: convert to use phy_interface")
Signed-off-by: Nazim Amirul <redacted>
---
 .../ethernet/stmicro/stmmac/dwmac-socfpga.c   | 23 ++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
index 1d7f0a57d288..6a6837c4a414 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c
@@ -69,12 +69,30 @@ struct socfpga_dwmac {
 	void __iomem *tse_pcs_base;
 	void __iomem *sgmii_adapter_base;
 	bool f2h_ptp_ref_clk;
+	phy_interface_t mac_interface;
 	const struct socfpga_dwmac_ops *ops;
 };
 
+static int socfpga_of_get_mac_mode(struct device_node *np)
+{
+	const char *pm;
+	int err, i;
+
+	err = of_property_read_string(np, "mac-mode", &pm);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < PHY_INTERFACE_MODE_MAX; i++) {
+		if (!strcasecmp(pm, phy_modes(i)))
+			return i;
+	}
+
+	return -ENODEV;
+}
+
 static phy_interface_t socfpga_get_plat_phymode(struct socfpga_dwmac *dwmac)
 {
-	return dwmac->plat_dat->phy_interface;
+	return dwmac->mac_interface;
 }
Taking a look at the logic in socfpga_gen{5|10}_set_phy_mode(), we have :

  phy_interface_t phymode = socfpga_get_plat_phymode(dwmac);
  u32 val;

  socfpga_set_phy_mode_common(phymode, &val)

  if (dwmac->splitter_base)
	  val = SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_GMII_MII;

[...]

  if (phymode == PHY_INTERFACE_MODE_SGMII)
	  socfpga_sgmii_config(dwmac, true);



With this new patch, we now have 2 different ways of handling this
converter block (splitter presence, and mac-mode presence in DT)

Can you unify this a bit ?

One thing could be adding a helper to get the macmode such as
socfpga_get_plat_macmode()

I think we should move the splitter handling before calling 
socfpga_get_plat_macmode() :

 if (dwmac->splitter_base)
   	dwmav->mac_interface = PHY_INTERFACE_MODE_GMII

We'd get the intf_sel value based on the macmode, and also calls to
helpers such as socfpga_sgmii_config(phymode, xxx) need the actual
phymode as a parameter, not the macmode.

Thanks :)

Maxime

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