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From: Sky Huang <SkyLake.Huang@mediatek.com>
To: Andrew Lunn <andrew@lunn.ch>, Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>, "David S. Miller"
	<davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Jakub Kicinski
	<kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, Daniel Golle
	<daniel@makrotopia.org>, Qingfang Deng <dqfext@gmail.com>, SkyLake Huang
	<SkyLake.Huang@mediatek.com>, Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
	<linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <linux-mediatek@lists.infradead.org>
CC: Steven Liu <Steven.Liu@mediatek.com>, SkyLake.Huang
	<skylake.huang@mediatek.com>
Subject: [PATCH net-next v4 4/5] net: phy: mediatek: Extend 1G TX/RX link pulse time
Date: Tue, 21 May 2024 18:15:47 +0800
Message-ID: <20240521101548.9286-5-SkyLake.Huang@mediatek.com>
In-Reply-To: <20240521101548.9286-1-SkyLake.Huang@mediatek.com>
References: <20240521101548.9286-1-SkyLake.Huang@mediatek.com>
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From: "SkyLake.Huang" <skylake.huang@mediatek.com>

We observe that some 10G devices' (mostly Marvell's chips inside) 1G
training time violates specification, which may last 2230ms and affect
later TX/RX link pulse time. This will invalidate MediaTek series
gigabit Ethernet PHYs' hardware auto downshift mechanism.

Without this patch, if someone is trying to use "4-wire" cable to
connect above devices, MediaTek' gigabit Ethernet PHYs may fail
to downshift to 100Mbps. (If partner 10G devices' downshift mechanism
stops at 1G)

This patch extends our 1G TX/RX link pulse time so that we can still
link up with those 10G devices.

Tested device:
- Netgear GS110EMX's 10G port (Marvell 88X3340P)
- QNAP QSW-M408-4C

v3:
Refactor mtk_gphy_cl22_read_status() with genphy_read_status().

v4:
1. Change extend_an_new_lp_cnt_limit()'s return type and all return values
2. Refactor comments in extend_an_new_lp_cnt_limit()

Signed-off-by: SkyLake.Huang <skylake.huang@mediatek.com>
---
 drivers/net/phy/mediatek/mtk-ge-soc.c  |  2 +
 drivers/net/phy/mediatek/mtk-ge.c      |  1 +
 drivers/net/phy/mediatek/mtk-phy-lib.c | 66 ++++++++++++++++++++++++++
 drivers/net/phy/mediatek/mtk.h         | 16 +++++++
 4 files changed, 85 insertions(+)

diff --git a/drivers/net/phy/mediatek/mtk-ge-soc.c b/drivers/net/phy/mediatek/mtk-ge-soc.c
index 8f23137..62424d4 100644
--- a/drivers/net/phy/mediatek/mtk-ge-soc.c
+++ b/drivers/net/phy/mediatek/mtk-ge-soc.c
@@ -1339,6 +1339,7 @@ static struct phy_driver mtk_socphy_driver[] = {
 		PHY_ID_MATCH_EXACT(MTK_GPHY_ID_MT7981),
 		.name		= "MediaTek MT7981 PHY",
 		.config_init	= mt798x_phy_config_init,
+		.read_status	= mtk_gphy_cl22_read_status,
 		.config_intr	= genphy_no_config_intr,
 		.handle_interrupt = genphy_handle_interrupt_no_ack,
 		.probe		= mt7981_phy_probe,
@@ -1356,6 +1357,7 @@ static struct phy_driver mtk_socphy_driver[] = {
 		PHY_ID_MATCH_EXACT(MTK_GPHY_ID_MT7988),
 		.name		= "MediaTek MT7988 PHY",
 		.config_init	= mt798x_phy_config_init,
+		.read_status	= mtk_gphy_cl22_read_status,
 		.config_intr	= genphy_no_config_intr,
 		.handle_interrupt = genphy_handle_interrupt_no_ack,
 		.probe		= mt7988_phy_probe,
diff --git a/drivers/net/phy/mediatek/mtk-ge.c b/drivers/net/phy/mediatek/mtk-ge.c
index 5c0226d..c832c90 100644
--- a/drivers/net/phy/mediatek/mtk-ge.c
+++ b/drivers/net/phy/mediatek/mtk-ge.c
@@ -211,6 +211,7 @@ static struct phy_driver mtk_gephy_driver[] = {
 		.name		= "MediaTek MT7531 PHY",
 		.probe		= mt7531_phy_probe,
 		.config_init	= mt7531_phy_config_init,
+		.read_status	= mtk_gphy_cl22_read_status,
 		/* Interrupts are handled by the switch, not the PHY
 		 * itself.
 		 */
diff --git a/drivers/net/phy/mediatek/mtk-phy-lib.c b/drivers/net/phy/mediatek/mtk-phy-lib.c
index 43547f4..8ec1699 100644
--- a/drivers/net/phy/mediatek/mtk-phy-lib.c
+++ b/drivers/net/phy/mediatek/mtk-phy-lib.c
@@ -106,6 +106,72 @@ int mtk_phy_write_page(struct phy_device *phydev, int page)
 }
 EXPORT_SYMBOL_GPL(mtk_phy_write_page);
 
+static int extend_an_new_lp_cnt_limit(struct phy_device *phydev)
+{
+	int mmd_read_ret;
+	u32 reg_val;
+	int timeout;
+
+	timeout = read_poll_timeout(mmd_read_ret = phy_read_mmd, reg_val,
+			  (mmd_read_ret < 0) || reg_val & MTK_PHY_FINAL_SPEED_1000,
+			  10000, 1000000, false, phydev,
+			  MDIO_MMD_VEND1, MTK_PHY_LINK_STATUS_MISC);
+	if (mmd_read_ret < 0)
+		return mmd_read_ret;
+
+	/* [When cable is plugged in]
+	 * We expect final_speed_1000 will be set, which means this phy starts 1G link-up
+	 * training. In this case, try to extend timeout period of auto downshift.
+	 * [When cable is unplugged]
+	 * We expect that reading MTK_PHY_FINAL_SPEED_1000 will time out. Do nothing but
+	 * return.
+	 */
+	if (!timeout) {
+		tr_modify(phydev, 0x0, 0xf, 0x3c, AN_NEW_LP_CNT_LIMIT_MASK,
+			  FIELD_PREP(AN_NEW_LP_CNT_LIMIT_MASK, 0xf));
+		mdelay(1500);
+
+		timeout = read_poll_timeout(tr_read, reg_val,
+					    (reg_val & AN_STATE_MASK) !=
+					    (AN_STATE_TX_DISABLE << AN_STATE_SHIFT),
+					    10000, 1000000, false, phydev,
+					    0x0, 0xf, 0x2);
+		if (!timeout) {
+			mdelay(625);
+			tr_modify(phydev, 0x0, 0xf, 0x3c, AN_NEW_LP_CNT_LIMIT_MASK,
+				  FIELD_PREP(AN_NEW_LP_CNT_LIMIT_MASK, 0x8));
+			mdelay(500);
+			tr_modify(phydev, 0x0, 0xf, 0x3c, AN_NEW_LP_CNT_LIMIT_MASK,
+				  FIELD_PREP(AN_NEW_LP_CNT_LIMIT_MASK, 0xf));
+		} else {
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+int mtk_gphy_cl22_read_status(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = genphy_read_status(phydev);
+	if (ret)
+		return ret;
+
+	if (phydev->autoneg == AUTONEG_ENABLE && !phydev->autoneg_complete) {
+		ret = phy_read(phydev, MII_CTRL1000);
+		if ((ret & ADVERTISE_1000FULL) || (ret & ADVERTISE_1000HALF)) {
+			ret = extend_an_new_lp_cnt_limit(phydev);
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtk_gphy_cl22_read_status);
+
 int mtk_phy_led_hw_is_supported(struct phy_device *phydev, u8 index, unsigned long rules,
 				unsigned long supported_triggers)
 {
diff --git a/drivers/net/phy/mediatek/mtk.h b/drivers/net/phy/mediatek/mtk.h
index 10ee9be..32fa3f1 100644
--- a/drivers/net/phy/mediatek/mtk.h
+++ b/drivers/net/phy/mediatek/mtk.h
@@ -12,6 +12,20 @@
 #define MTK_PHY_PAGE_STANDARD			0x0000
 #define MTK_PHY_PAGE_EXTENDED_52B5		0x52b5
 
+/* Registers on Token Ring debug nodes */
+/* ch_addr = 0x0, node_addr = 0xf, data_addr = 0x2 */
+#define   AN_STATE_MASK			GENMASK(22, 19)
+#define   AN_STATE_SHIFT		19
+#define   AN_STATE_TX_DISABLE		1
+
+/* ch_addr = 0x0, node_addr = 0xf, data_addr = 0x3c */
+#define AN_NEW_LP_CNT_LIMIT_MASK		GENMASK(23, 20)
+#define AUTO_NP_10XEN				BIT(6)
+
+/* Registers on MDIO_MMD_VEND1 */
+#define MTK_PHY_LINK_STATUS_MISC	(0xa2)
+#define   MTK_PHY_FINAL_SPEED_1000	BIT(3)
+
 /* Registers on MDIO_MMD_VEND2 */
 #define MTK_PHY_LED0_ON_CTRL			0x24
 #define MTK_PHY_LED1_ON_CTRL			0x26
@@ -75,6 +89,8 @@ void __tr_clr_bits(struct phy_device *phydev, u8 ch_addr, u8 node_addr, u8 data_
 int mtk_phy_read_page(struct phy_device *phydev);
 int mtk_phy_write_page(struct phy_device *phydev, int page);
 
+int mtk_gphy_cl22_read_status(struct phy_device *phydev);
+
 int mtk_phy_led_hw_is_supported(struct phy_device *phydev, u8 index, unsigned long rules,
 				unsigned long supported_triggers);
 int mtk_phy_led_hw_ctrl_set(struct phy_device *phydev, u8 index, unsigned long rules,
-- 
2.18.0