netdev - [PATCH net-next v6 6/7] net: phy: qcom: at803x: Avoid hibernating if MAC requires RX clock

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Message-Id: <20240311-rxc_bugfix-v6-6-adf5133829a2@bootlin.com>
Date: Mon, 11 Mar 2024 10:55:49 +0100
From: Romain Gantois <romain.gantois@...tlin.com>
To: Russell King <linux@...linux.org.uk>, Andrew Lunn <andrew@...n.ch>, 
 Heiner Kallweit <hkallweit1@...il.com>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Alexandre Torgue <alexandre.torgue@...s.st.com>, 
 Jose Abreu <joabreu@...opsys.com>, 
 Maxime Coquelin <mcoquelin.stm32@...il.com>, 
 Clément Léger <clement.leger@...tlin.com>
Cc: Maxime Chevallier <maxime.chevallier@...tlin.com>, 
 Miquel Raynal <miquel.raynal@...tlin.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, netdev@...r.kernel.org, 
 linux-stm32@...md-mailman.stormreply.com, 
 linux-arm-kernel@...ts.infradead.org, linux-renesas-soc@...r.kernel.org, 
 "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>, 
 Clark Wang <xiaoning.wang@....com>, 
 Romain Gantois <romain.gantois@...tlin.com>
Subject: [PATCH net-next v6 6/7] net: phy: qcom: at803x: Avoid hibernating
 if MAC requires RX clock

From: "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>

Stmmac controllers connected to an at803x PHY cannot resume properly after
suspend when WoL is enabled. This happens because the MAC requires an RX
clock generated by the PHY to initialize its hardware properly. But the RX
clock is cut when the PHY suspends and isn't brought up until the MAC
driver resumes the phylink.

Prevent the at803x PHY driver from going into suspend if the attached MAC
driver always requires an RX clock signal.

Reported-by: Clark Wang <xiaoning.wang@....com>
Link: https://lore.kernel.org/all/20230202081559.3553637-1-xiaoning.wang@nxp.com/
Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
[rgantois: commit log]
Signed-off-by: Romain Gantois <romain.gantois@...tlin.com>
Reviewed-by: Andrew Lunn <andrew@...n.ch>
---
 drivers/net/phy/qcom/at803x.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/qcom/at803x.c b/drivers/net/phy/qcom/at803x.c
index 4717c59d51d0..2a221b81cf37 100644
--- a/drivers/net/phy/qcom/at803x.c
+++ b/drivers/net/phy/qcom/at803x.c
@@ -426,7 +426,8 @@ static int at803x_hibernation_mode_config(struct phy_device *phydev)
 	/* The default after hardware reset is hibernation mode enabled. After
 	 * software reset, the value is retained.
 	 */
-	if (!(priv->flags & AT803X_DISABLE_HIBERNATION_MODE))
+	if (!(priv->flags & AT803X_DISABLE_HIBERNATION_MODE) &&
+	    !(phydev->dev_flags & PHY_F_RXC_ALWAYS_ON))
 		return 0;

 	return at803x_debug_reg_mask(phydev, AT803X_DEBUG_REG_HIB_CTRL,

-- 
2.44.0