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6a23c555f7
Marek reports that a deadlock occurs with the AX88772A PHY used on the
ASIX USB network driver:
asix 1-1.4:1.0 (unnamed net_device) (uninitialized): PHY [usb-001:003:10] driver [Asix Electronics AX88772A] (irq=POLL)
Asix Electronics AX88772A usb-001:003:10: attached PHY driver(mii_bus:phy_addr=usb-001:003:10, irq=POLL)
asix 1-1.4:1.0 eth0: register 'asix' at usb-12110000.usb-1.4, ASIX AX88772 USB 2.0 Ethernet, a2:99:b6💿11:eb
asix 1-1.4:1.0 eth0: configuring for phy/internal link mode
============================================
WARNING: possible recursive locking detected
6.6.0-rc1-00239-g8da77df649c4-dirty #13949 Not tainted
--------------------------------------------
kworker/3:3/71 is trying to acquire lock:
c6c704cc (&dev->lock){+.+.}-{3:3}, at: phy_start_aneg+0x1c/0x38
but task is already holding lock:
c6c704cc (&dev->lock){+.+.}-{3:3}, at: phy_state_machine+0x100/0x2b8
This is because we now consistently call phy_process_state_change()
while holding phydev->lock, but the AX88772A PHY driver then goes on
to call phy_start_aneg() which tries to grab the same lock - causing
deadlock.
Fix this by exporting the unlocked version, and use this in the PHY
driver instead.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: ef113a60d0 ("net: phy: call phy_error_precise() while holding the lock")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/E1qiEFs-007g7b-Lq@rmk-PC.armlinux.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/* Driver for Asix PHYs
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*
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* Author: Michael Schmitz <schmitzmic@gmail.com>
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mii.h>
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#include <linux/phy.h>
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#define PHY_ID_ASIX_AX88772A 0x003b1861
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#define PHY_ID_ASIX_AX88772C 0x003b1881
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#define PHY_ID_ASIX_AX88796B 0x003b1841
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MODULE_DESCRIPTION("Asix PHY driver");
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MODULE_AUTHOR("Michael Schmitz <schmitzmic@gmail.com>");
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MODULE_LICENSE("GPL");
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/**
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* asix_soft_reset - software reset the PHY via BMCR_RESET bit
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* @phydev: target phy_device struct
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*
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* Description: Perform a software PHY reset using the standard
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* BMCR_RESET bit and poll for the reset bit to be cleared.
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* Toggle BMCR_RESET bit off to accommodate broken AX8796B PHY implementation
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* such as used on the Individual Computers' X-Surf 100 Zorro card.
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*
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* Returns: 0 on success, < 0 on failure
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*/
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static int asix_soft_reset(struct phy_device *phydev)
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{
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int ret;
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/* Asix PHY won't reset unless reset bit toggles */
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ret = phy_write(phydev, MII_BMCR, 0);
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if (ret < 0)
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return ret;
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return genphy_soft_reset(phydev);
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}
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/* AX88772A is not working properly with some old switches (NETGEAR EN 108TP):
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* after autoneg is done and the link status is reported as active, the MII_LPA
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* register is 0. This issue is not reproducible on AX88772C.
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*/
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static int asix_ax88772a_read_status(struct phy_device *phydev)
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{
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int ret, val;
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ret = genphy_update_link(phydev);
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if (ret)
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return ret;
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if (!phydev->link)
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return 0;
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/* If MII_LPA is 0, phy_resolve_aneg_linkmode() will fail to resolve
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* linkmode so use MII_BMCR as default values.
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*/
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val = phy_read(phydev, MII_BMCR);
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if (val < 0)
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return val;
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if (val & BMCR_SPEED100)
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phydev->speed = SPEED_100;
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else
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phydev->speed = SPEED_10;
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if (val & BMCR_FULLDPLX)
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phydev->duplex = DUPLEX_FULL;
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else
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phydev->duplex = DUPLEX_HALF;
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ret = genphy_read_lpa(phydev);
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if (ret < 0)
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return ret;
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if (phydev->autoneg == AUTONEG_ENABLE && phydev->autoneg_complete)
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phy_resolve_aneg_linkmode(phydev);
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return 0;
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}
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static void asix_ax88772a_link_change_notify(struct phy_device *phydev)
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{
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/* Reset PHY, otherwise MII_LPA will provide outdated information.
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* This issue is reproducible only with some link partner PHYs
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*/
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if (phydev->state == PHY_NOLINK) {
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phy_init_hw(phydev);
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_phy_start_aneg(phydev);
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}
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}
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static struct phy_driver asix_driver[] = {
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{
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PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772A),
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.name = "Asix Electronics AX88772A",
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.flags = PHY_IS_INTERNAL,
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.read_status = asix_ax88772a_read_status,
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.suspend = genphy_suspend,
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.resume = genphy_resume,
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.soft_reset = asix_soft_reset,
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.link_change_notify = asix_ax88772a_link_change_notify,
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}, {
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PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772C),
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.name = "Asix Electronics AX88772C",
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.flags = PHY_IS_INTERNAL,
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.suspend = genphy_suspend,
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.resume = genphy_resume,
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.soft_reset = asix_soft_reset,
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}, {
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.phy_id = PHY_ID_ASIX_AX88796B,
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.name = "Asix Electronics AX88796B",
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.phy_id_mask = 0xfffffff0,
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/* PHY_BASIC_FEATURES */
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.soft_reset = asix_soft_reset,
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} };
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module_phy_driver(asix_driver);
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static struct mdio_device_id __maybe_unused asix_tbl[] = {
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{ PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772A) },
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{ PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772C) },
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{ PHY_ID_ASIX_AX88796B, 0xfffffff0 },
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{ }
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};
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MODULE_DEVICE_TABLE(mdio, asix_tbl);
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