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author | Andrew Halaney <ahalaney@redhat.com> | 2023-11-28 00:41:10 +0300 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2023-12-01 10:11:21 +0300 |
commit | df16c1c51d8166958f533c0c886766f7ee9dd50f (patch) | |
tree | 9b586993540f9634bb5e440d4a734d6b9fd6137b /drivers/net/phy/mdio_device.c | |
parent | 753c8608f3e579307493a63b9242667aee35a751 (diff) | |
download | linux-df16c1c51d8166958f533c0c886766f7ee9dd50f.tar.xz |
net: phy: mdio_device: Reset device only when necessary
Currently the phy reset sequence is as shown below for a
devicetree described mdio phy on boot:
1. Assert the phy_device's reset as part of registering
2. Deassert the phy_device's reset as part of registering
3. Deassert the phy_device's reset as part of phy_probe
4. Deassert the phy_device's reset as part of phy_hw_init
The extra two deasserts include waiting the deassert delay afterwards,
which is adding unnecessary delay.
This applies to both possible types of resets (reset controller
reference and a reset gpio) that can be used.
Here's some snipped tracing output using the following command line
params "trace_event=gpio:* trace_options=stacktrace" illustrating
the reset handling and where its coming from:
/* Assert */
systemd-udevd-283 [002] ..... 6.780434: gpio_value: 544 set 0
systemd-udevd-283 [002] ..... 6.783849: <stack trace>
=> gpiod_set_raw_value_commit
=> gpiod_set_value_nocheck
=> gpiod_set_value_cansleep
=> mdio_device_reset
=> mdiobus_register_device
=> phy_device_register
=> fwnode_mdiobus_phy_device_register
=> fwnode_mdiobus_register_phy
=> __of_mdiobus_register
=> stmmac_mdio_register
=> stmmac_dvr_probe
=> stmmac_pltfr_probe
=> devm_stmmac_pltfr_probe
=> qcom_ethqos_probe
=> platform_probe
/* Deassert */
systemd-udevd-283 [002] ..... 6.802480: gpio_value: 544 set 1
systemd-udevd-283 [002] ..... 6.805886: <stack trace>
=> gpiod_set_raw_value_commit
=> gpiod_set_value_nocheck
=> gpiod_set_value_cansleep
=> mdio_device_reset
=> phy_device_register
=> fwnode_mdiobus_phy_device_register
=> fwnode_mdiobus_register_phy
=> __of_mdiobus_register
=> stmmac_mdio_register
=> stmmac_dvr_probe
=> stmmac_pltfr_probe
=> devm_stmmac_pltfr_probe
=> qcom_ethqos_probe
=> platform_probe
/* Deassert */
systemd-udevd-283 [002] ..... 6.882601: gpio_value: 544 set 1
systemd-udevd-283 [002] ..... 6.886014: <stack trace>
=> gpiod_set_raw_value_commit
=> gpiod_set_value_nocheck
=> gpiod_set_value_cansleep
=> mdio_device_reset
=> phy_probe
=> really_probe
=> __driver_probe_device
=> driver_probe_device
=> __device_attach_driver
=> bus_for_each_drv
=> __device_attach
=> device_initial_probe
=> bus_probe_device
=> device_add
=> phy_device_register
=> fwnode_mdiobus_phy_device_register
=> fwnode_mdiobus_register_phy
=> __of_mdiobus_register
=> stmmac_mdio_register
=> stmmac_dvr_probe
=> stmmac_pltfr_probe
=> devm_stmmac_pltfr_probe
=> qcom_ethqos_probe
=> platform_probe
/* Deassert */
NetworkManager-477 [000] ..... 7.023144: gpio_value: 544 set 1
NetworkManager-477 [000] ..... 7.026596: <stack trace>
=> gpiod_set_raw_value_commit
=> gpiod_set_value_nocheck
=> gpiod_set_value_cansleep
=> mdio_device_reset
=> phy_init_hw
=> phy_attach_direct
=> phylink_fwnode_phy_connect
=> __stmmac_open
=> stmmac_open
There's a lot of paths where the device is getting its reset
asserted and deasserted. Let's track the state and only actually
do the assert/deassert when it changes.
Reported-by: Sagar Cheluvegowda <quic_scheluve@quicinc.com>
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20231127-net-phy-reset-once-v2-1-448e8658779e@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/phy/mdio_device.c')
-rw-r--r-- | drivers/net/phy/mdio_device.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c index 044828d081d2..73f6539b9e50 100644 --- a/drivers/net/phy/mdio_device.c +++ b/drivers/net/phy/mdio_device.c @@ -62,6 +62,7 @@ struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr) mdiodev->device_remove = mdio_device_remove; mdiodev->bus = bus; mdiodev->addr = addr; + mdiodev->reset_state = -1; dev_set_name(&mdiodev->dev, PHY_ID_FMT, bus->id, addr); @@ -122,6 +123,9 @@ void mdio_device_reset(struct mdio_device *mdiodev, int value) if (!mdiodev->reset_gpio && !mdiodev->reset_ctrl) return; + if (mdiodev->reset_state == value) + return; + if (mdiodev->reset_gpio) gpiod_set_value_cansleep(mdiodev->reset_gpio, value); @@ -135,6 +139,8 @@ void mdio_device_reset(struct mdio_device *mdiodev, int value) d = value ? mdiodev->reset_assert_delay : mdiodev->reset_deassert_delay; if (d) fsleep(d); + + mdiodev->reset_state = value; } EXPORT_SYMBOL(mdio_device_reset); |