[net-next,V4,1/2] net: phylink: add a function to resume PHY alone to fix resume issue with WoL enabled
Commit Message
Issue we met:
On some platforms, MAC cannot work after resumed from the suspend with WoL
enabled.
The cause of the issue:
1. phylink_resolve() is in a workqueue which will not be executed immediately.
This is the call sequence:
phylink_resolve()->phylink_link_up()->pl->mac_ops->mac_link_up()
For stmmac driver, mac_link_up() will set the correct speed/duplex...
values which are from link_state.
2. In stmmac_resume(), it will call stmmac_hw_setup() after called the
phylink_resume(), because MAC need PHY rx_clk to do the reset.
stmmac_core_init() is called in function stmmac_hw_setup(), which will
reset the MAC and set the speed/duplex... to default value.
Conclusion: Because phylink_resolve() cannot determine when it is called, it
cannot be guaranteed to be called after stmmac_core_init().
Once stmmac_core_init() is called after phylink_resolve(),
the MAC will be misconfigured and cannot be used.
In order to avoid this problem, add a function called phylink_phy_resume()
to resume PHY separately. This eliminates the need to call phylink_resume()
before stmmac_hw_setup().
Add another judgement before called phy_start() in phylink_start(). This way
phy_start() will not be called multiple times when resumes. At the same time,
it may not affect other drivers that do not use phylink_phy_resume().
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
---
V2 change:
- add mac_resume_phy_separately flag to struct phylink to mark if the MAC
driver uses the phylink_phy_resume() first.
V3 change:
- add brace to avoid ambiguous 'else'
Reported-by: kernel test robot <lkp@intel.com>
V4:
Many thanks to Jakub and Russel for their suggestions, here are the changes for V4.
- Unify MAC and PHY in comments and subject to uppercase.
- Add subject of the sentence.
- Move && to the end of the line
- Add notice in the comment of function phylink_phy_resume()
---
drivers/net/phy/phylink.c | 35 +++++++++++++++++++++++++++++++++--
include/linux/phylink.h | 1 +
2 files changed, 34 insertions(+), 2 deletions(-)
@@ -80,6 +80,8 @@ struct phylink {
DECLARE_PHY_INTERFACE_MASK(sfp_interfaces);
__ETHTOOL_DECLARE_LINK_MODE_MASK(sfp_support);
u8 sfp_port;
+
+ bool mac_resume_phy_separately;
};
#define phylink_printk(level, pl, fmt, ...) \
@@ -1509,6 +1511,7 @@ struct phylink *phylink_create(struct phylink_config *config,
return ERR_PTR(-EINVAL);
}
+ pl->mac_resume_phy_separately = false;
pl->using_mac_select_pcs = using_mac_select_pcs;
pl->phy_state.interface = iface;
pl->link_interface = iface;
@@ -1942,8 +1945,12 @@ void phylink_start(struct phylink *pl)
}
if (poll)
mod_timer(&pl->link_poll, jiffies + HZ);
- if (pl->phydev)
- phy_start(pl->phydev);
+ if (pl->phydev) {
+ if (!pl->mac_resume_phy_separately)
+ phy_start(pl->phydev);
+ else
+ pl->mac_resume_phy_separately = false;
+ }
if (pl->sfp_bus)
sfp_upstream_start(pl->sfp_bus);
}
@@ -2023,6 +2030,30 @@ void phylink_suspend(struct phylink *pl, bool mac_wol)
}
EXPORT_SYMBOL_GPL(phylink_suspend);
+/**
+ * phylink_phy_resume() - resume PHY alone
+ * @pl: a pointer to a &struct phylink returned from phylink_create()
+ *
+ * In the MAC driver using phylink, if the MAC needs the clock of the PHY
+ * when it resumes, it can call this function to resume the PHY separately.
+ * Then proceed to MAC resume operations.
+ *
+ * Note: This function MUST ONLY be called before calling phylink_start()
+ * in the MAC resume function.
+ */
+void phylink_phy_resume(struct phylink *pl)
+{
+ ASSERT_RTNL();
+
+ if (!test_bit(PHYLINK_DISABLE_MAC_WOL, &pl->phylink_disable_state) &&
+ pl->phydev) {
+ phy_start(pl->phydev);
+ pl->mac_resume_phy_separately = true;
+ }
+
+}
+EXPORT_SYMBOL_GPL(phylink_phy_resume);
+
/**
* phylink_resume() - handle a network device resume event
* @pl: a pointer to a &struct phylink returned from phylink_create()
@@ -589,6 +589,7 @@ void phylink_stop(struct phylink *);
void phylink_suspend(struct phylink *pl, bool mac_wol);
void phylink_resume(struct phylink *pl);
+void phylink_phy_resume(struct phylink *pl);
void phylink_ethtool_get_wol(struct phylink *, struct ethtool_wolinfo *);
int phylink_ethtool_set_wol(struct phylink *, struct ethtool_wolinfo *);