[PATCH net-next 04/12] net: mtk_eth_soc: correct 802.3z speed setting

From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: "Marek Behún" <kabel@kernel.org>, "Felix Fietkau" <nbd@nbd.name>,
	"John Crispin" <john@phrozen.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	"Mark Lee" <Mark-MC.Lee@mediatek.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	netdev@vger.kernel.org, "Paolo Abeni" <pabeni@redhat.com>,
	"Sean Wang" <sean.wang@mediatek.com>,
	"Eric Dumazet" <edumazet@google.com>
Subject: [PATCH net-next 04/12] net: mtk_eth_soc: correct 802.3z speed setting
Date: Wed, 18 May 2022 15:54:47 +0100	[thread overview]
Message-ID: <E1nrL4Z-00AM4w-5V@rmk-PC.armlinux.org.uk> (raw)
In-Reply-To: <YoUIX+BN/ZbyXzTT@shell.armlinux.org.uk>

Phylink does not guarantee that state->speed will be set correctly in
the mac_config() call, so it's a bug that the driver makes use of it.
Moreover, it is making use of it in a function that is only ever called
for 1000BASE-X and 2500BASE-X which operate at a fixed speed which
happens to be the same setting irrespective of the interface mode. We
can simply remove the switch statement and just set the SGMII interface
speed.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/mediatek/mtk_sgmii.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
index 5897940a418b..d378ecdf56cc 100644
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -34,6 +34,7 @@ int mtk_sgmii_init(struct mtk_sgmii *ss, struct device_node *r, u32 ana_rgc3)
 	return 0;
 }
 
+/* For SGMII interface mode */
 int mtk_sgmii_setup_mode_an(struct mtk_sgmii *ss, int id)
 {
 	unsigned int val;
@@ -60,6 +61,9 @@ int mtk_sgmii_setup_mode_an(struct mtk_sgmii *ss, int id)
 	return 0;
 }
 
+/* For 1000BASE-X and 2500BASE-X interface modes, which operate at a
+ * fixed speed.
+ */
 int mtk_sgmii_setup_mode_force(struct mtk_sgmii *ss, int id,
 			       const struct phylink_link_state *state)
 {
@@ -82,19 +86,7 @@ int mtk_sgmii_setup_mode_force(struct mtk_sgmii *ss, int id,
 	/* SGMII force mode setting */
 	regmap_read(ss->regmap[id], SGMSYS_SGMII_MODE, &val);
 	val &= ~SGMII_IF_MODE_MASK;
-
-	switch (state->speed) {
-	case SPEED_10:
-		val |= SGMII_SPEED_10;
-		break;
-	case SPEED_100:
-		val |= SGMII_SPEED_100;
-		break;
-	case SPEED_2500:
-	case SPEED_1000:
-		val |= SGMII_SPEED_1000;
-		break;
-	}
+	val |= SGMII_SPEED_1000;
 
 	if (state->duplex == DUPLEX_FULL)
 		val |= SGMII_DUPLEX_FULL;
-- 
2.30.2

