From: Khoa Hoang <admin@khoahoang.com>
Date: Fri, 8 Nov 2024 05:51:35 +0000 (-0800)
Subject: eth: asix88179: Fix ASIX AX88179A PHY hang
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eth: asix88179: Fix ASIX AX88179A PHY hang

The ASIX AX88179A locks up when the ADVERTISE_NPAGE bit is set in the
MII_ADVERTISE register, suggesting that this feature may be broken or
unsupported on this chip. In the Linux kernel, this bit is not set,
and enabling it also causes the PHY to lock up and stay in a
link-down state.

Additionally, the AX88179 and AX88179A variants do not appear to
support the ADVERTISE_LPACK bit, as setting it consistently reads
back as 0.

This patch removes the ADVERTISE_NPAGE and ADVERTISE_LPACK bits from
the MII_ADVERTISE register configuration. It also resets the PHY
before modifying the MII_ADVERTISE register, then restarts
auto-negotiation, following the same flow used in the U-Boot asix.c
driver.

Signed-off-by: Khoa Hoang <admin@khoahoang.com>
Reviewed-by: Marek Vasut <marex@denx.de>
---

diff --git a/drivers/usb/eth/asix88179.c b/drivers/usb/eth/asix88179.c
index 4bd3b9d10d..4bd353b93a 100644
--- a/drivers/usb/eth/asix88179.c
+++ b/drivers/usb/eth/asix88179.c
@@ -176,6 +176,7 @@
 #define AX_RX_URB_SIZE 1024 * 0x12
 #define BLK_FRAME_SIZE 0x200
 #define PHY_CONNECT_TIMEOUT 5000
+#define PHY_RESET_TIMEOUT 500
 
 #define TIMEOUT_RESOLUTION 50	/* ms */
 
@@ -285,6 +286,26 @@ static int asix_write_mac(struct ueth_data *dev, uint8_t *enetaddr)
 	return ret;
 }
 
+static int asix_reset_phy(struct ueth_data *dev)
+{
+	u16 bmcr;
+	u32 t;
+
+	/* Reset the PHY */
+	bmcr = BMCR_RESET;
+	asix_write_cmd(dev, AX_ACCESS_PHY, 0x03, MII_BMCR, 2, &bmcr);
+
+	for (t = 0; t < PHY_RESET_TIMEOUT; t += TIMEOUT_RESOLUTION) {
+		asix_read_cmd(dev, AX_ACCESS_PHY, 0x03, MII_BMCR, 2, &bmcr);
+		if (!(bmcr & BMCR_RESET))
+			return 0;
+		mdelay(TIMEOUT_RESOLUTION);
+	}
+
+	debug("Reset PHY timeout\n");
+	return -ETIMEDOUT;
+}
+
 static int asix_basic_reset(struct ueth_data *dev,
 			struct asix_private *dev_priv)
 {
@@ -344,14 +365,22 @@ static int asix_basic_reset(struct ueth_data *dev,
 		 AX_MEDIUM_GIGAMODE | AX_MEDIUM_JUMBO_EN;
 	asix_write_cmd(dev, AX_ACCESS_MAC, AX_MEDIUM_STATUS_MODE, 2, 2, tmp16);
 
+	asix_reset_phy(dev);
+
 	u16 adv = 0;
-	adv = ADVERTISE_ALL | ADVERTISE_CSMA | ADVERTISE_LPACK |
-	      ADVERTISE_NPAGE | ADVERTISE_PAUSE_ASYM | ADVERTISE_PAUSE_CAP;
+	adv = ADVERTISE_ALL | ADVERTISE_CSMA |
+	      ADVERTISE_PAUSE_ASYM | ADVERTISE_PAUSE_CAP;
 	asix_write_cmd(dev, AX_ACCESS_PHY, 0x03, MII_ADVERTISE, 2, &adv);
 
 	adv = ADVERTISE_1000FULL;
 	asix_write_cmd(dev, AX_ACCESS_PHY, 0x03, MII_CTRL1000, 2, &adv);
 
+	/* Restart auto-negotiation */
+	u16 bmcr = 0;
+	asix_read_cmd(dev, AX_ACCESS_PHY, 0x03, MII_BMCR, 2, &bmcr);
+	bmcr |= BMCR_ANENABLE | BMCR_ANRESTART;
+	asix_write_cmd(dev, AX_ACCESS_PHY, 0x03, MII_BMCR, 2, &bmcr);
+
 	return 0;
 }