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Subject[PATCH 1/2] net: phylink: add sync flag mac_ready to fix resume issue with WoL enabled
Date
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(). 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 solve this problem, the mac_ready flag is added to the phylink
structure to synchronize the state of the mac in the phylink_resolve()
function. To prevent the correct configuration from being overwritten.

By default, mac_ready will be configured as true, that is, it will not affect
other drivers that do not use this flag.

Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
---
drivers/net/phy/phylink.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/phylink.h | 2 ++
2 files changed, 38 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 09cc65c0da93..312b47fdc12b 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -74,6 +74,7 @@ struct phylink {

bool mac_link_dropped;
bool using_mac_select_pcs;
+ bool mac_ready;

struct sfp_bus *sfp_bus;
bool sfp_may_have_phy;
@@ -1276,6 +1277,12 @@ static void phylink_resolve(struct work_struct *w)
bool retrigger = false;
bool cur_link_state;

+ /* If mac is not ready, retrigger this work queue to wait it ready*/
+ if (!pl->mac_ready) {
+ queue_work(system_power_efficient_wq, &pl->resolve);
+ return;
+ }
+
mutex_lock(&pl->state_mutex);
if (pl->netdev)
cur_link_state = netif_carrier_ok(ndev);
@@ -1450,6 +1457,34 @@ static int phylink_register_sfp(struct phylink *pl,
return ret;
}

+/**
+ * phylink_clear_mac_ready() - clear mac_ready flag
+ * @pl: a pointer to a &struct phylink returned from phylink_create()
+ *
+ * set mac_ready to false, which means the mac is not ready,
+ * if the pl->mac_ops->mac_link_up function in resolve is called at this time,
+ * the correct speed/duplex and other parameters set in this function will
+ * be reset to the default values by mac.
+ */
+void phylink_clear_mac_ready(struct phylink *pl)
+{
+ pl->mac_ready = false;
+}
+EXPORT_SYMBOL_GPL(phylink_clear_mac_ready);
+
+/**
+ * phylink_set_mac_ready() - set mac_ready flag
+ * @pl: a pointer to a &struct phylink returned from phylink_create()
+ *
+ * set mac_ready to true, which means the mac is ready now, can reslove the
+ * phylink and set the correct speed/duplex settings for mac.
+ */
+void phylink_set_mac_ready(struct phylink *pl)
+{
+ pl->mac_ready = true;
+}
+EXPORT_SYMBOL_GPL(phylink_set_mac_ready);
+
/**
* phylink_create() - create a phylink instance
* @config: a pointer to the target &struct phylink_config
@@ -1518,6 +1553,7 @@ struct phylink *phylink_create(struct phylink_config *config,
pl->link_config.duplex = DUPLEX_UNKNOWN;
pl->link_config.an_enabled = true;
pl->mac_ops = mac_ops;
+ pl->mac_ready = true;
__set_bit(PHYLINK_DISABLE_STOPPED, &pl->phylink_disable_state);
timer_setup(&pl->link_poll, phylink_fixed_poll, 0);

diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index c492c26202b5..759c8041f3d2 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -570,6 +570,8 @@ void phylink_generic_validate(struct phylink_config *config,
unsigned long *supported,
struct phylink_link_state *state);

+void phylink_clear_mac_ready(struct phylink *pl);
+void phylink_set_mac_ready(struct phylink *pl);
struct phylink *phylink_create(struct phylink_config *, struct fwnode_handle *,
phy_interface_t iface,
const struct phylink_mac_ops *mac_ops);
--
2.34.1
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