6.14-stable review patch. If anyone has any objections, please let me know.
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From: Russell King (Oracle) rmk+kernel@armlinux.org.uk
commit ef43e5132895ad59b45e38855d32e966bb7434d9 upstream.
The Synopsys Designware GMAC core databook requires all clocks to be active in order to complete software reset, which we perform during resume.
However, IEEE 802.3 allows a PHY to stop its clocks when placed in low-power mode, which happens when the system is suspended and WoL is not enabled.
As an attempt to work around this, commit 36d18b5664ef ("net: stmmac: start phylink instance before stmmac_hw_setup()") started phylink early, but this has the side effect that the mac_link_up() method may be called before or during the initialisation of GMAC hardware.
We also have the socfpga glue driver directly calling phy_resume() also as an attempt to work around this.
In a previous commit, phylink_prepare_resume() has been introduced to give MAC drivers a way to ensure that the PHY is resumed prior to their initialisation of their MAC hardware. This commit adds the call, and moves the phylink_resume() call back to where it should be before the aforementioned commit.
Signed-off-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk Link: https://patch.msgid.link/E1tvO6a-008Vjh-FG@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski kuba@kernel.org Cc: Jon Hunter jonathanh@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -7907,12 +7907,12 @@ int stmmac_resume(struct device *dev) }
rtnl_lock(); - phylink_resume(priv->phylink); - if (device_may_wakeup(priv->device) && !priv->plat->pmt) - phylink_speed_up(priv->phylink); - rtnl_unlock();
- rtnl_lock(); + /* Prepare the PHY to resume, ensuring that its clocks which are + * necessary for the MAC DMA reset to complete are running + */ + phylink_prepare_resume(priv->phylink); + mutex_lock(&priv->lock);
stmmac_reset_queues_param(priv); @@ -7930,6 +7930,15 @@ int stmmac_resume(struct device *dev) stmmac_enable_all_dma_irq(priv);
mutex_unlock(&priv->lock); + + /* phylink_resume() must be called after the hardware has been + * initialised because it may bring the link up immediately in a + * workqueue thread, which will race with initialisation. + */ + phylink_resume(priv->phylink); + if (device_may_wakeup(priv->device) && !priv->plat->pmt) + phylink_speed_up(priv->phylink); + rtnl_unlock();
netif_device_attach(ndev);