[PATCH net-next v5 4/5] net: phy: mediatek: Extend 1G TX/RX link pulse time

From: Sky Huang
Date: Wed May 29 2024 - 23:51:28 EST


From: "SkyLake.Huang" <skylake.huang@xxxxxxxxxxxx>

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@xxxxxxxxxxxx>
---
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 c566bf9..d7b7fb2 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 3f1a24c..41bd1b0 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