linux-kernel - [PATCH net-next v5 6/6] net: dsa: microchip: Disable PTP function of KSZ8463

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250723022612.38535-7-Tristram.Ha@microchip.com>
Date: Tue, 22 Jul 2025 19:26:12 -0700
From: <Tristram.Ha@...rochip.com>
To: Woojung Huh <woojung.huh@...rochip.com>, Andrew Lunn <andrew@...n.ch>,
	Vladimir Oltean <olteanv@...il.com>, Rob Herring <robh@...nel.org>,
	"Krzysztof Kozlowski" <krzk+dt@...nel.org>, Conor Dooley
	<conor+dt@...nel.org>
CC: Maxime Chevallier <maxime.chevallier@...tlin.com>, Simon Horman
	<horms@...nel.org>, "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>, Marek Vasut <marex@...x.de>,
	<UNGLinuxDriver@...rochip.com>, <devicetree@...r.kernel.org>,
	<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Tristram Ha
	<tristram.ha@...rochip.com>
Subject: [PATCH net-next v5 6/6] net: dsa: microchip: Disable PTP function of KSZ8463

From: Tristram Ha <tristram.ha@...rochip.com>

The PTP function of KSZ8463 is on by default.  However, its proprietary
way of storing timestamp directly in a reserved field inside the PTP
message header is not suitable for use with the current Linux PTP stack
implementation.  It is necessary to disable the PTP function to not
interfere the normal operation of the MAC.

Note the PTP driver for KSZ switches does not work for KSZ8463 and is not
activated for it.

Signed-off-by: Tristram Ha <tristram.ha@...rochip.com>
---
 drivers/net/dsa/microchip/ksz8.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz8.c b/drivers/net/dsa/microchip/ksz8.c
index 62224426a9bd..c400e1c0369e 100644
--- a/drivers/net/dsa/microchip/ksz8.c
+++ b/drivers/net/dsa/microchip/ksz8.c
@@ -1760,6 +1760,17 @@ void ksz8_config_cpu_port(struct dsa_switch *ds)
 					   KSZ8463_REG_DSP_CTRL_6,
 					   COPPER_RECEIVE_ADJUSTMENT, 0);
 		}
+
+		/* Turn off PTP function as the switch's proprietary way of
+		 * handling timestamp is not supported in current Linux PTP
+		 * stack implementation.
+		 */
+		regmap_update_bits(ksz_regmap_16(dev),
+				   KSZ8463_PTP_MSG_CONF1,
+				   PTP_ENABLE, 0);
+		regmap_update_bits(ksz_regmap_16(dev),
+				   KSZ8463_PTP_CLK_CTRL,
+				   PTP_CLK_ENABLE, 0);
 	}
 }
 
-- 
2.34.1