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From: Alex Elder <elder@riscstar•com>
To: andrew+netdev@lunn•ch, davem@davemloft•net, edumazet@google•com,
	kuba@kernel•org, pabeni@redhat•com,
	maxime.chevallier@bootlin•com, rmk+kernel@armlinux•org.uk,
	andersson@kernel•org, konradybcio@kernel•org, robh@kernel•org,
	krzk+dt@kernel•org, conor+dt@kernel•org, linusw@kernel•org,
	brgl@kernel•org, arnd@arndb•de, gregkh@linuxfoundation•org
Cc: Daniel Thompson <daniel@riscstar•com>,
	elder@riscstar•com, mohd.anwar@oss•qualcomm.com,
	a0987203069@gmail•com, alexandre.torgue@foss•st.com,
	ast@kernel•org, boon.khai.ng@altera•com, chenchuangyu@xiaomi•com,
	chenhuacai@kernel•org, daniel@iogearbox•net, hawk@kernel•org,
	hkallweit1@gmail•com, inochiama@gmail•com,
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	prabhakar.mahadev-lad.rj@bp•renesas.com,
	richardcochran@gmail•com, rohan.g.thomas@altera•com,
	sdf@fomichev•me, siyanteng@cqsoftware•com.cn,
	weishangjuan@eswincomputing•com, wens@kernel•org,
	netdev@vger•kernel.org, bpf@vger•kernel.org,
	linux-arm-msm@vger•kernel.org, devicetree@vger•kernel.org,
	linux-gpio@vger•kernel.org,
	linux-stm32@st-md-mailman•stormreply.com,
	linux-arm-kernel@lists•infradead.org,
	linux-kernel@vger•kernel.org
Subject: [PATCH net-next v2 04/14] net: pcs: xpcs: re-order xpcs_pre_config() to update after the reset
Date: Thu,  4 Jun 2026 20:00:11 -0500	[thread overview]
Message-ID: <20260605010022.968612-5-elder@riscstar.com> (raw)
In-Reply-To: <20260605010022.968612-1-elder@riscstar.com>

From: Daniel Thompson <daniel@riscstar•com>

Currently, on Wangxun platforms, the XPCS is configured during the call
to xpcs_switch_interface_mode() and, if the need_reset flag is set, the
XPCS is reset and the configuration will be lost. This is harmless at
present because need_reset will never actually be set on these platforms.

Nevertheless having xpcs_switch_interface_mode() on the wrong side of
the reset is an obstacle for future changes where wiping out programmed
configuration with a reset could be harmful.

Reorder xpcs_pre_config() to allow the reset can happen before we
switch interface mode. To make this work we have to hoist the special
case logic for SGMII into the parent function.

Signed-off-by: Daniel Thompson <daniel@riscstar•com>
Signed-off-by: Alex Elder <elder@riscstar•com>
---
 drivers/net/pcs/pcs-xpcs.c | 56 ++++++++++++++++++++------------------
 1 file changed, 30 insertions(+), 26 deletions(-)

diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index e69fa2f0a0e8d..76c04372b5b50 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c
@@ -705,46 +705,50 @@ static void xpcs_get_interfaces(struct dw_xpcs *xpcs, unsigned long *interfaces)
 static int xpcs_switch_interface_mode(struct dw_xpcs *xpcs,
 				      phy_interface_t interface)
 {
-	int ret = 0;
+	/* Wangxun provides a full alternative implementation to handle quirks */
+	if (xpcs->info.pma == WX_TXGBE_XPCS_PMA_10G_ID)
+		return txgbe_xpcs_switch_mode(xpcs, interface);
 
-	if (xpcs->info.pma == WX_TXGBE_XPCS_PMA_10G_ID) {
-		ret = txgbe_xpcs_switch_mode(xpcs, interface);
-	} else if (xpcs->interface != interface) {
-		if (interface == PHY_INTERFACE_MODE_SGMII)
-			xpcs->need_reset = true;
-		xpcs->interface = interface;
-	}
+	xpcs->interface = interface;
 
-	return ret;
+	return 0;
 }
 
 static void xpcs_pre_config(struct phylink_pcs *pcs, phy_interface_t interface)
 {
 	struct dw_xpcs *xpcs = phylink_pcs_to_xpcs(pcs);
 	const struct dw_xpcs_compat *compat;
+	bool force_reset;
 	int ret;
 
+	/*
+	 * According to the XPCS datasheet, a soft reset is required to initiate
+	 * Clause 37 auto-negotiation when the XPCS switches interface modes.
+	 */
+	force_reset = interface == PHY_INTERFACE_MODE_SGMII;
+
+	if (force_reset || xpcs->need_reset) {
+		compat = xpcs_find_compat(xpcs, interface);
+		if (!compat) {
+			dev_err(&xpcs->mdiodev->dev, "unsupported interface %s\n",
+				phy_modes(interface));
+			return;
+		}
+
+		ret = xpcs_soft_reset(xpcs, compat);
+		if (ret) {
+			dev_err(&xpcs->mdiodev->dev, "soft reset failed: %pe\n",
+				ERR_PTR(ret));
+			return;
+		}
+
+		xpcs->need_reset = false;
+	}
+
 	ret = xpcs_switch_interface_mode(xpcs, interface);
 	if (ret)
 		dev_err(&xpcs->mdiodev->dev, "switch interface failed: %pe\n",
 			ERR_PTR(ret));
-
-	if (!xpcs->need_reset)
-		return;
-
-	compat = xpcs_find_compat(xpcs, interface);
-	if (!compat) {
-		dev_err(&xpcs->mdiodev->dev, "unsupported interface %s\n",
-			phy_modes(interface));
-		return;
-	}
-
-	ret = xpcs_soft_reset(xpcs, compat);
-	if (ret)
-		dev_err(&xpcs->mdiodev->dev, "soft reset failed: %pe\n",
-			ERR_PTR(ret));
-
-	xpcs->need_reset = false;
 }
 
 static int xpcs_config_aneg_c37_sgmii(struct dw_xpcs *xpcs,
-- 
2.51.0



  parent reply	other threads:[~2026-06-05  1:00 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-05  1:00 [PATCH net-next v2 00/14] net: enable TC956x support Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 01/14] dt-bindings: net: qca,qca808x: Add regulator properties Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 02/14] net: phy: qcom: qca808x: Add regulator management Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 03/14] net: pcs: pcs-xpcs-regmap: support XPCS memory-mapped MDIO bus via regmap Alex Elder
2026-06-05  1:00 ` Alex Elder [this message]
2026-06-05  1:00 ` [PATCH net-next v2 05/14] net: pcs: pcs-xpcs: select operating mode for 10G-baseR capable PCS Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 06/14] net: stmmac: dma: create a separate dma_device pointer Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 07/14] net: stmmac: dwxgmac2: Add multi MSI interrupt mode Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 08/14] net: stmmac: dwxgmac2: Add XGMAC 3.01a support Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 09/14] net: stmmac: dwxgmac2: export symbols for XGMAC 3.01a DMA Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 10/14] dt-bindings: net: toshiba,tc9654-dwmac: add TC9564 Ethernet bridge Alex Elder
2026-06-05  2:40   ` Rob Herring (Arm)
2026-06-05  1:00 ` [PATCH net-next v2 11/14] misc: tc956x_pci: add TC956x/QPS615 support Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 12/14] gpio: tc956x: " Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 13/14] net: stmmac: " Alex Elder
2026-06-05  1:00 ` [PATCH net-next v2 14/14] arm64: dts: qcom: qcs6490-rb3gen2: enable TC9564 with a single QCA8081 phy Alex Elder

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