Files
linux/drivers/net/phy/microchip.c
Fiona Klute 30a41ed32d net: phy: microchip: force IRQ polling mode for lan88xx
With lan88xx based devices the lan78xx driver can get stuck in an
interrupt loop while bringing the device up, flooding the kernel log
with messages like the following:

lan78xx 2-3:1.0 enp1s0u3: kevent 4 may have been dropped

Removing interrupt support from the lan88xx PHY driver forces the
driver to use polling instead, which avoids the problem.

The issue has been observed with Raspberry Pi devices at least since
4.14 (see [1], bug report for their downstream kernel), as well as
with Nvidia devices [2] in 2020, where disabling interrupts was the
vendor-suggested workaround (together with the claim that phylib
changes in 4.9 made the interrupt handling in lan78xx incompatible).

Iperf reports well over 900Mbits/sec per direction with client in
--dualtest mode, so there does not seem to be a significant impact on
throughput (lan88xx device connected via switch to the peer).

[1] https://github.com/raspberrypi/linux/issues/2447
[2] https://forums.developer.nvidia.com/t/jetson-xavier-and-lan7800-problem/142134/11

Link: https://lore.kernel.org/0901d90d-3f20-4a10-b680-9c978e04ddda@lunn.ch
Fixes: 792aec47d5 ("add microchip LAN88xx phy driver")
Signed-off-by: Fiona Klute <fiona.klute@gmx.de>
Cc: kernel-list@raspberrypi.com
Cc: stable@vger.kernel.org
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250416102413.30654-1-fiona.klute@gmx.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-04-22 12:57:37 +02:00

522 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2015 Microchip Technology
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/phy.h>
#include <linux/microchipphy.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <dt-bindings/net/microchip-lan78xx.h>
#define PHY_ID_LAN937X_TX 0x0007c190
#define LAN937X_MODE_CTRL_STATUS_REG 0x11
#define LAN937X_AUTOMDIX_EN BIT(7)
#define LAN937X_MDI_MODE BIT(6)
#define DRIVER_AUTHOR "WOOJUNG HUH <woojung.huh@microchip.com>"
#define DRIVER_DESC "Microchip LAN88XX/LAN937X TX PHY driver"
struct lan88xx_priv {
int chip_id;
int chip_rev;
__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_suspend(struct phy_device *phydev)
{
struct lan88xx_priv *priv = phydev->priv;
/* do not power down PHY when WOL is enabled */
if (!priv->wolopts)
genphy_suspend(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) {
phydev_warn(phydev, "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) {
phydev_warn(phydev, "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) {
phydev_warn(phydev, "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) {
phydev_warn(phydev, "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))
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "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)
phydev_warn(phydev, "Failed to Set Register[0x1686]\n");
}
static int lan88xx_probe(struct phy_device *phydev)
{
struct device *dev = &phydev->mdio.dev;
struct lan88xx_priv *priv;
u32 led_modes[4];
int len;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->wolopts = 0;
len = of_property_read_variable_u32_array(dev->of_node,
"microchip,led-modes",
led_modes,
0,
ARRAY_SIZE(led_modes));
if (len >= 0) {
u32 reg = 0;
int i;
for (i = 0; i < len; i++) {
if (led_modes[i] > 15)
return -EINVAL;
reg |= led_modes[i] << (i * 4);
}
for (; i < ARRAY_SIZE(led_modes); i++)
reg |= LAN78XX_FORCE_LED_OFF << (i * 4);
(void)phy_write(phydev, LAN78XX_PHY_LED_MODE_SELECT, reg);
} else if (len == -EOVERFLOW) {
return -EINVAL;
}
/* these values can be used to identify internal PHY */
priv->chip_id = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_ID);
priv->chip_rev = phy_read_mmd(phydev, 3, LAN88XX_MMD3_CHIP_REV);
phydev->priv = priv;
return 0;
}
static void lan88xx_remove(struct phy_device *phydev)
{
struct device *dev = &phydev->mdio.dev;
struct lan88xx_priv *priv = phydev->priv;
if (priv)
devm_kfree(dev, priv);
}
static int lan88xx_set_wol(struct phy_device *phydev,
struct ethtool_wolinfo *wol)
{
struct lan88xx_priv *priv = phydev->priv;
priv->wolopts = wol->wolopts;
return 0;
}
static void lan88xx_set_mdix(struct phy_device *phydev)
{
int buf;
int val;
switch (phydev->mdix_ctrl) {
case ETH_TP_MDI:
val = LAN88XX_EXT_MODE_CTRL_MDI_;
break;
case ETH_TP_MDI_X:
val = LAN88XX_EXT_MODE_CTRL_MDI_X_;
break;
case ETH_TP_MDI_AUTO:
val = LAN88XX_EXT_MODE_CTRL_AUTO_MDIX_;
break;
default:
return;
}
phy_write(phydev, LAN88XX_EXT_PAGE_ACCESS, LAN88XX_EXT_PAGE_SPACE_1);
buf = phy_read(phydev, LAN88XX_EXT_MODE_CTRL);
buf &= ~LAN88XX_EXT_MODE_CTRL_MDIX_MASK_;
buf |= val;
phy_write(phydev, LAN88XX_EXT_MODE_CTRL, buf);
phy_write(phydev, LAN88XX_EXT_PAGE_ACCESS, LAN88XX_EXT_PAGE_SPACE_0);
}
static int lan88xx_config_init(struct phy_device *phydev)
{
int val;
/*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);
return genphy_config_aneg(phydev);
}
static void lan88xx_link_change_notify(struct phy_device *phydev)
{
int temp;
int ret;
/* Reset PHY to ensure MII_LPA provides up-to-date information. This
* issue is reproducible only after parallel detection, as described
* in IEEE 802.3-2022, Section 28.2.3.1 ("Parallel detection function"),
* where the link partner does not support auto-negotiation.
*/
if (phydev->state == PHY_NOLINK) {
ret = phy_init_hw(phydev);
if (ret < 0)
goto link_change_notify_failed;
ret = _phy_start_aneg(phydev);
if (ret < 0)
goto link_change_notify_failed;
}
/* At forced 100 F/H mode, chip may fail to set mode correctly
* when cable is switched between long(~50+m) and short one.
* As workaround, set to 10 before setting to 100
* at forced 100 F/H mode.
*/
if (!phydev->autoneg && phydev->speed == 100) {
/* disable phy interrupt */
temp = phy_read(phydev, LAN88XX_INT_MASK);
temp &= ~LAN88XX_INT_MASK_MDINTPIN_EN_;
phy_write(phydev, LAN88XX_INT_MASK, temp);
temp = phy_read(phydev, MII_BMCR);
temp &= ~(BMCR_SPEED100 | BMCR_SPEED1000);
phy_write(phydev, MII_BMCR, temp); /* set to 10 first */
temp |= BMCR_SPEED100;
phy_write(phydev, MII_BMCR, temp); /* set to 100 later */
/* clear pending interrupt generated while workaround */
temp = phy_read(phydev, LAN88XX_INT_STS);
/* enable phy interrupt back */
temp = phy_read(phydev, LAN88XX_INT_MASK);
temp |= LAN88XX_INT_MASK_MDINTPIN_EN_;
phy_write(phydev, LAN88XX_INT_MASK, temp);
}
return;
link_change_notify_failed:
phydev_err(phydev, "Link change process failed %pe\n", ERR_PTR(ret));
}
/**
* lan937x_tx_read_mdix_status - Read the MDIX status for the LAN937x TX PHY.
* @phydev: Pointer to the phy_device structure.
*
* This function reads the MDIX status of the LAN937x TX PHY and sets the
* mdix_ctrl and mdix fields of the phy_device structure accordingly.
* Note that MDIX status is not supported in AUTO mode, and will be set
* to invalid in such cases.
*
* Return: 0 on success, a negative error code on failure.
*/
static int lan937x_tx_read_mdix_status(struct phy_device *phydev)
{
int ret;
ret = phy_read(phydev, LAN937X_MODE_CTRL_STATUS_REG);
if (ret < 0)
return ret;
if (ret & LAN937X_AUTOMDIX_EN) {
phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
/* MDI/MDIX status is unknown */
phydev->mdix = ETH_TP_MDI_INVALID;
} else if (ret & LAN937X_MDI_MODE) {
phydev->mdix_ctrl = ETH_TP_MDI_X;
phydev->mdix = ETH_TP_MDI_X;
} else {
phydev->mdix_ctrl = ETH_TP_MDI;
phydev->mdix = ETH_TP_MDI;
}
return 0;
}
/**
* lan937x_tx_read_status - Read the status for the LAN937x TX PHY.
* @phydev: Pointer to the phy_device structure.
*
* This function reads the status of the LAN937x TX PHY and updates the
* phy_device structure accordingly.
*
* Return: 0 on success, a negative error code on failure.
*/
static int lan937x_tx_read_status(struct phy_device *phydev)
{
int ret;
ret = genphy_read_status(phydev);
if (ret < 0)
return ret;
return lan937x_tx_read_mdix_status(phydev);
}
/**
* lan937x_tx_set_mdix - Set the MDIX mode for the LAN937x TX PHY.
* @phydev: Pointer to the phy_device structure.
*
* This function configures the MDIX mode of the LAN937x TX PHY based on the
* mdix_ctrl field of the phy_device structure. The MDIX mode can be set to
* MDI (straight-through), MDIX (crossover), or AUTO (auto-MDIX). If the mode
* is not recognized, it returns 0 without making any changes.
*
* Return: 0 on success, a negative error code on failure.
*/
static int lan937x_tx_set_mdix(struct phy_device *phydev)
{
u16 val;
switch (phydev->mdix_ctrl) {
case ETH_TP_MDI:
val = 0;
break;
case ETH_TP_MDI_X:
val = LAN937X_MDI_MODE;
break;
case ETH_TP_MDI_AUTO:
val = LAN937X_AUTOMDIX_EN;
break;
default:
return 0;
}
return phy_modify(phydev, LAN937X_MODE_CTRL_STATUS_REG,
LAN937X_AUTOMDIX_EN | LAN937X_MDI_MODE, val);
}
/**
* lan937x_tx_config_aneg - Configure auto-negotiation and fixed modes for the
* LAN937x TX PHY.
* @phydev: Pointer to the phy_device structure.
*
* This function configures the MDIX mode for the LAN937x TX PHY and then
* proceeds to configure the auto-negotiation or fixed mode settings
* based on the phy_device structure.
*
* Return: 0 on success, a negative error code on failure.
*/
static int lan937x_tx_config_aneg(struct phy_device *phydev)
{
int ret;
ret = lan937x_tx_set_mdix(phydev);
if (ret < 0)
return ret;
return genphy_config_aneg(phydev);
}
static struct phy_driver microchip_phy_driver[] = {
{
.phy_id = 0x0007c132,
/* This mask (0xfffffff2) is to differentiate from
* LAN8742 (phy_id 0x0007c130 and 0x0007c131)
* and allows future phy_id revisions.
*/
.phy_id_mask = 0xfffffff2,
.name = "Microchip LAN88xx",
/* PHY_GBIT_FEATURES */
.probe = lan88xx_probe,
.remove = lan88xx_remove,
.config_init = lan88xx_config_init,
.config_aneg = lan88xx_config_aneg,
.link_change_notify = lan88xx_link_change_notify,
/* Interrupt handling is broken, do not define related
* functions to force polling.
*/
.suspend = lan88xx_suspend,
.resume = genphy_resume,
.set_wol = lan88xx_set_wol,
.read_page = lan88xx_read_page,
.write_page = lan88xx_write_page,
},
{
PHY_ID_MATCH_MODEL(PHY_ID_LAN937X_TX),
.name = "Microchip LAN937x TX",
.suspend = genphy_suspend,
.resume = genphy_resume,
.config_aneg = lan937x_tx_config_aneg,
.read_status = lan937x_tx_read_status,
} };
module_phy_driver(microchip_phy_driver);
static const struct mdio_device_id __maybe_unused microchip_tbl[] = {
{ 0x0007c132, 0xfffffff2 },
{ PHY_ID_MATCH_MODEL(PHY_ID_LAN937X_TX) },
{ }
};
MODULE_DEVICE_TABLE(mdio, microchip_tbl);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");