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 <[email protected]>
---
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 <[email protected]>
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(-)
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index ea8fcce5b2d9..0be57e9463d9 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -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()
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index c492c26202b5..6edfab5f754c 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -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 *);
--
2.34.1
net-next is closed due to the merge window. Please resubmit after
6.3-rc1. Thanks.
On Wed, Feb 22, 2023 at 05:26:35PM +0800, Clark Wang wrote:
> 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 <[email protected]>
> ---
> 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 <[email protected]>
> 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(-)
>
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index ea8fcce5b2d9..0be57e9463d9 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -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()
> diff --git a/include/linux/phylink.h b/include/linux/phylink.h
> index c492c26202b5..6edfab5f754c 100644
> --- a/include/linux/phylink.h
> +++ b/include/linux/phylink.h
> @@ -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 *);
> --
> 2.34.1
>
>
--
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