lan78xx: PHY DSP registers initialization to address EEE link drop issues with long cables

The patch is to configure DSP registers of PHY device
to handle Gbe-EEE failures with >40m cable length.

Fixes: 55d7de9d ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Signed-off-by: Raghuram Chary J <raghuramchary.jallipalli@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/microchip.c

@@ -20,6 +20,7 @@
 #include <linux/ethtool.h>
 #include <linux/phy.h>
 #include <linux/microchipphy.h>
+#include <linux/delay.h>
 
 #define DRIVER_AUTHOR	"WOOJUNG HUH <woojung.huh@microchip.com>"
 #define DRIVER_DESC	"Microchip LAN88XX PHY driver"
@@ -30,6 +31,16 @@ struct lan88xx_priv {
 	__u32	wolopts;
 };
 
+static int lan88xx_read_page(struct phy_device *phydev)
+{
+	return __phy_read(phydev, LAN88XX_EXT_PAGE_ACCESS);
+}
+
+static int lan88xx_write_page(struct phy_device *phydev, int page)
+{
+	return __phy_write(phydev, LAN88XX_EXT_PAGE_ACCESS, page);
+}
+
 static int lan88xx_phy_config_intr(struct phy_device *phydev)
 {
 	int rc;
@@ -66,6 +77,150 @@ static int lan88xx_suspend(struct phy_device *phydev)
 	return 0;
 }
 
+static int lan88xx_TR_reg_set(struct phy_device *phydev, u16 regaddr,
+			      u32 data)
+{
+	int val, save_page, ret = 0;
+	u16 buf;
+
+	/* Save current page */
+	save_page = phy_save_page(phydev);
+	if (save_page < 0) {
+		pr_warn("Failed to get current page\n");
+		goto err;
+	}
+
+	/* Switch to TR page */
+	lan88xx_write_page(phydev, LAN88XX_EXT_PAGE_ACCESS_TR);
+
+	ret = __phy_write(phydev, LAN88XX_EXT_PAGE_TR_LOW_DATA,
+			  (data & 0xFFFF));
+	if (ret < 0) {
+		pr_warn("Failed to write TR low data\n");
+		goto err;
+	}
+
+	ret = __phy_write(phydev, LAN88XX_EXT_PAGE_TR_HIGH_DATA,
+			  (data & 0x00FF0000) >> 16);
+	if (ret < 0) {
+		pr_warn("Failed to write TR high data\n");
+		goto err;
+	}
+
+	/* Config control bits [15:13] of register */
+	buf = (regaddr & ~(0x3 << 13));/* Clr [14:13] to write data in reg */
+	buf |= 0x8000; /* Set [15] to Packet transmit */
+
+	ret = __phy_write(phydev, LAN88XX_EXT_PAGE_TR_CR, buf);
+	if (ret < 0) {
+		pr_warn("Failed to write data in reg\n");
+		goto err;
+	}
+
+	usleep_range(1000, 2000);/* Wait for Data to be written */
+	val = __phy_read(phydev, LAN88XX_EXT_PAGE_TR_CR);
+	if (!(val & 0x8000))
+		pr_warn("TR Register[0x%X] configuration failed\n", regaddr);
+err:
+	return phy_restore_page(phydev, save_page, ret);
+}
+
+static void lan88xx_config_TR_regs(struct phy_device *phydev)
+{
+	int err;
+
+	/* Get access to Channel 0x1, Node 0xF , Register 0x01.
+	 * Write 24-bit value 0x12B00A to register. Setting MrvlTrFix1000Kf,
+	 * MrvlTrFix1000Kp, MasterEnableTR bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x0F82, 0x12B00A);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x0F82]\n");
+
+	/* Get access to Channel b'10, Node b'1101, Register 0x06.
+	 * Write 24-bit value 0xD2C46F to register. Setting SSTrKf1000Slv,
+	 * SSTrKp1000Mas bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x168C, 0xD2C46F);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x168C]\n");
+
+	/* Get access to Channel b'10, Node b'1111, Register 0x11.
+	 * Write 24-bit value 0x620 to register. Setting rem_upd_done_thresh
+	 * bits
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x17A2, 0x620);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x17A2]\n");
+
+	/* Get access to Channel b'10, Node b'1101, Register 0x10.
+	 * Write 24-bit value 0xEEFFDD to register. Setting
+	 * eee_TrKp1Long_1000, eee_TrKp2Long_1000, eee_TrKp3Long_1000,
+	 * eee_TrKp1Short_1000,eee_TrKp2Short_1000, eee_TrKp3Short_1000 bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x16A0, 0xEEFFDD);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x16A0]\n");
+
+	/* Get access to Channel b'10, Node b'1101, Register 0x13.
+	 * Write 24-bit value 0x071448 to register. Setting
+	 * slv_lpi_tr_tmr_val1, slv_lpi_tr_tmr_val2 bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x16A6, 0x071448);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x16A6]\n");
+
+	/* Get access to Channel b'10, Node b'1101, Register 0x12.
+	 * Write 24-bit value 0x13132F to register. Setting
+	 * slv_sigdet_timer_val1, slv_sigdet_timer_val2 bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x16A4, 0x13132F);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x16A4]\n");
+
+	/* Get access to Channel b'10, Node b'1101, Register 0x14.
+	 * Write 24-bit value 0x0 to register. Setting eee_3level_delay,
+	 * eee_TrKf_freeze_delay bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x16A8, 0x0);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x16A8]\n");
+
+	/* Get access to Channel b'01, Node b'1111, Register 0x34.
+	 * Write 24-bit value 0x91B06C to register. Setting
+	 * FastMseSearchThreshLong1000, FastMseSearchThreshShort1000,
+	 * FastMseSearchUpdGain1000 bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x0FE8, 0x91B06C);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x0FE8]\n");
+
+	/* Get access to Channel b'01, Node b'1111, Register 0x3E.
+	 * Write 24-bit value 0xC0A028 to register. Setting
+	 * FastMseKp2ThreshLong1000, FastMseKp2ThreshShort1000,
+	 * FastMseKp2UpdGain1000, FastMseKp2ExitEn1000 bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x0FFC, 0xC0A028);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x0FFC]\n");
+
+	/* Get access to Channel b'01, Node b'1111, Register 0x35.
+	 * Write 24-bit value 0x041600 to register. Setting
+	 * FastMseSearchPhShNum1000, FastMseSearchClksPerPh1000,
+	 * FastMsePhChangeDelay1000 bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x0FEA, 0x041600);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x0FEA]\n");
+
+	/* Get access to Channel b'10, Node b'1101, Register 0x03.
+	 * Write 24-bit value 0x000004 to register. Setting TrFreeze bits.
+	 */
+	err = lan88xx_TR_reg_set(phydev, 0x1686, 0x000004);
+	if (err < 0)
+		pr_warn("Failed to Set Register[0x1686]\n");
+}
+
 static int lan88xx_probe(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
@@ -132,6 +287,25 @@ static void lan88xx_set_mdix(struct phy_device *phydev)
 	phy_write(phydev, LAN88XX_EXT_PAGE_ACCESS, LAN88XX_EXT_PAGE_SPACE_0);
 }
 
+static int lan88xx_config_init(struct phy_device *phydev)
+{
+	int val;
+
+	genphy_config_init(phydev);
+	/*Zerodetect delay enable */
+	val = phy_read_mmd(phydev, MDIO_MMD_PCS,
+			   PHY_ARDENNES_MMD_DEV_3_PHY_CFG);
+	val |= PHY_ARDENNES_MMD_DEV_3_PHY_CFG_ZD_DLY_EN_;
+
+	phy_write_mmd(phydev, MDIO_MMD_PCS, PHY_ARDENNES_MMD_DEV_3_PHY_CFG,
+		      val);
+
+	/* Config DSP registers */
+	lan88xx_config_TR_regs(phydev);
+
+	return 0;
+}
+
 static int lan88xx_config_aneg(struct phy_device *phydev)
 {
 	lan88xx_set_mdix(phydev);
@@ -151,7 +325,7 @@ static struct phy_driver microchip_phy_driver[] = {
 	.probe		= lan88xx_probe,
 	.remove		= lan88xx_remove,
 
-	.config_init	= genphy_config_init,
+	.config_init	= lan88xx_config_init,
 	.config_aneg	= lan88xx_config_aneg,
 
 	.ack_interrupt	= lan88xx_phy_ack_interrupt,
@@ -160,6 +334,8 @@ static struct phy_driver microchip_phy_driver[] = {
 	.suspend	= lan88xx_suspend,
 	.resume		= genphy_resume,
 	.set_wol	= lan88xx_set_wol,
+	.read_page	= lan88xx_read_page,
+	.write_page	= lan88xx_write_page,
 } };
 
 module_phy_driver(microchip_phy_driver);

include/linux/microchipphy.h

@@ -70,4 +70,12 @@
 #define	LAN88XX_MMD3_CHIP_ID			(32877)
 #define	LAN88XX_MMD3_CHIP_REV			(32878)
 
+/* DSP registers */
+#define PHY_ARDENNES_MMD_DEV_3_PHY_CFG		(0x806A)
+#define PHY_ARDENNES_MMD_DEV_3_PHY_CFG_ZD_DLY_EN_	(0x2000)
+#define LAN88XX_EXT_PAGE_ACCESS_TR		(0x52B5)
+#define LAN88XX_EXT_PAGE_TR_CR			16
+#define LAN88XX_EXT_PAGE_TR_LOW_DATA		17
+#define LAN88XX_EXT_PAGE_TR_HIGH_DATA		18
+
 #endif /* _MICROCHIPPHY_H */