@@ -7936,12 +7936,12 @@ 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);
@@ -7959,6 +7959,15 @@ 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);
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> --- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)