[PATCH net-next] net: phy: marvell: wake the system only from the WoL event

[Rosen Penev <rosenp@gmail.com>]

Enable waking the system from a WoL event on the 88E1318S/88E1510.

When WoL is enabled, m88e1318_set_wol() now calls enable_irq_wake()
on the PHY's IRQ and marks the MDIO device as a wakeup source so the
underlying GPIO interrupt raises the system from suspend, and reverses
both on disable.

With WoL active the PHY must stay powered to detect a magic packet,
but without masking, phy_suspend() would leave every interrupt
enabled, so a link status change or any other PHY event would assert
INTn and spuriously wake the system. Set PHY_ALWAYS_CALL_SUSPEND on
the 88E1318S/88E1510 drivers so that phy_suspend() still calls their
suspend callbacks with WoL enabled, and have those callbacks keep the
PHY awake while writing the interrupt enable register (CSIER/IMASK)
down to only the WoL event bit.

marvell_config_intr() rewrites the whole CSIER register with
MII_M1011_IMASK_INIT on resume, clearing the WoL enable bit. Re-arm
WOL_EIE in the resume callbacks so the WoL interrupt stays active for
the next sleep cycle.

Assisted-by: LLM
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/net/phy/marvell.c | 145 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 138 insertions(+), 7 deletions(-)

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index f71cffa88406..70aaa09f2047 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -30,6 +30,8 @@
 #include <linux/ethtool_netlink.h>
 #include <linux/phy.h>
 #include <linux/phy_port.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/property.h>
 #include <linux/marvell_phy.h>
 #include <linux/bitfield.h>
 #include <linux/of.h>
@@ -1902,6 +1904,61 @@ static int marvell_resume(struct phy_device *phydev)
 	return err;
 }
 
+/* marvell_wol_suspend_intrs
+ *
+ * With WoL enabled the PHY has to stay powered to keep detecting a WoL
+ * packet, so instead of entering low power mode, mask all interrupt
+ * sources except the WoL event. On the 88E1318S/88E1510 the interrupt
+ * mask (MII_M1011_IMASK) is the same register as the Copper Specific
+ * Interrupt Enable Register (MII_88E1318S_PHY_CSIER), so writing only
+ * the WoL event enable bit unmask just that event.
+ */
+static int marvell_wol_suspend_intrs(struct phy_device *phydev)
+{
+	int oldpage, ret;
+
+	oldpage = phy_save_page(phydev);
+	if (oldpage < 0)
+		return oldpage;
+
+	ret = marvell_write_page(phydev, MII_MARVELL_COPPER_PAGE);
+	if (ret < 0)
+		goto out;
+
+	ret = __phy_write(phydev, MII_88E1318S_PHY_CSIER,
+			  MII_88E1318S_PHY_CSIER_WOL_EIE);
+out:
+	return phy_restore_page(phydev, oldpage, ret);
+}
+
+/* marvell_wol_resume_intrs
+ *
+ * marvell_config_intr() rewrites the whole MII_M1011_IMASK register
+ * (which is MII_88E1318S_PHY_CSIER) with MII_M1011_IMASK_INIT on
+ * resume, clearing the WoL event interrupt enable bit. Re-arm it if
+ * WoL is still enabled so a later WoL event keeps waking the system.
+ */
+static int marvell_wol_resume_intrs(struct phy_device *phydev)
+{
+	int oldpage, ret;
+
+	if (!phydev->wol_enabled)
+		return 0;
+
+	oldpage = phy_save_page(phydev);
+	if (oldpage < 0)
+		return oldpage;
+
+	ret = marvell_write_page(phydev, MII_MARVELL_COPPER_PAGE);
+	if (ret < 0)
+		goto out;
+
+	ret = __phy_set_bits(phydev, MII_88E1318S_PHY_CSIER,
+			     MII_88E1318S_PHY_CSIER_WOL_EIE);
+out:
+	return phy_restore_page(phydev, oldpage, ret);
+}
+
 /* m88e1510_resume
  *
  * The 88e1510 PHY has an erratum where the phy downshift counter is not cleared
@@ -1934,9 +1991,25 @@ static int m88e1510_resume(struct phy_device *phydev)
 
 		/* downshift enabled, with previous counter value */
 		err = m88e1011_set_downshift(phydev, cnt);
+		if (err < 0)
+			return err;
 	}
 
-	return err;
+	return marvell_wol_resume_intrs(phydev);
+}
+
+/* m88e1510_suspend
+ *
+ * If WoL is enabled the PHY receiver has to keep running to detect a
+ * magic packet, so keep it awake and unmask only the WoL event at the
+ * PHY. Otherwise suspend both the fiber and copper interfaces as usual.
+ */
+static int m88e1510_suspend(struct phy_device *phydev)
+{
+	if (phydev->wol_enabled)
+		return marvell_wol_suspend_intrs(phydev);
+
+	return marvell_suspend(phydev);
 }
 
 static int marvell_aneg_done(struct phy_device *phydev)
@@ -1969,8 +2042,12 @@ static void m88e1318_get_wol(struct phy_device *phydev,
 static int m88e1318_set_wol(struct phy_device *phydev,
 			    struct ethtool_wolinfo *wol)
 {
+	struct device *dev = &phydev->mdio.dev;
+	bool wol_enable;
 	int err = 0, oldpage;
 
+	wol_enable = !!(wol->wolopts & (WAKE_MAGIC | WAKE_PHY));
+
 	oldpage = phy_save_page(phydev);
 	if (oldpage < 0)
 		goto error;
@@ -2075,7 +2152,49 @@ static int m88e1318_set_wol(struct phy_device *phydev,
 	}
 
 error:
-	return phy_restore_page(phydev, oldpage, err);
+	err = phy_restore_page(phydev, oldpage, err);
+	if (err < 0)
+		return err;
+
+	if (device_can_wakeup(dev) && wol_enable != device_may_wakeup(dev)) {
+		err = device_set_wakeup_enable(dev, wol_enable);
+		if (err < 0) {
+			/* Roll back the PHY WoL config if the PM state update failed */
+			struct ethtool_wolinfo wol_off = { .wolopts = 0 };
+			int rollback_err = m88e1318_set_wol(phydev, &wol_off);
+
+			if (rollback_err < 0)
+				phydev_err(phydev,
+					   "Failed to disable WoL after wakeup enable error %d\n",
+					   rollback_err);
+		}
+	}
+
+	return err;
+}
+
+/* m88e1318_suspend
+ *
+ * If WoL is enabled keep the PHY awake so it can detect a magic packet
+ * while the system is asleep, unmasking only the WoL event at the PHY.
+ * Otherwise suspend the PHY normally.
+ */
+static int m88e1318_suspend(struct phy_device *phydev)
+{
+	if (phydev->wol_enabled)
+		return marvell_wol_suspend_intrs(phydev);
+
+	return genphy_suspend(phydev);
+}
+
+static int m88e1318_resume(struct phy_device *phydev)
+{
+	int err = genphy_resume(phydev);
+
+	if (err < 0)
+		return err;
+
+	return marvell_wol_resume_intrs(phydev);
 }
 
 static int marvell_get_sset_count(struct phy_device *phydev)
@@ -3587,14 +3706,25 @@ static int m88e1318_led_hw_control_get(struct phy_device *phydev, u8 index,
 
 static int marvell_probe(struct phy_device *phydev)
 {
+	struct device *dev = &phydev->mdio.dev;
 	struct marvell_priv *priv;
 
-	priv = devm_kzalloc(&phydev->mdio.dev, sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
 	phydev->priv = priv;
 
+	if (device_property_present(dev, "wakeup-source") &&
+	    phy_interrupt_is_valid(phydev)) {
+		int ret = devm_pm_set_wake_irq(dev, phydev->irq);
+
+		if (ret)
+			return ret;
+
+		device_set_wakeup_capable(dev, true);
+	}
+
 	return marvell_hwmon_probe(phydev);
 }
 
@@ -3813,6 +3943,7 @@ static struct phy_driver marvell_drivers[] = {
 		.phy_id_mask = MARVELL_PHY_ID_MASK,
 		.name = "Marvell 88E1318S",
 		/* PHY_GBIT_FEATURES */
+		.flags = PHY_ALWAYS_CALL_SUSPEND,
 		.probe = marvell_probe,
 		.config_init = m88e1318_config_init,
 		.config_aneg = m88e1318_config_aneg,
@@ -3821,8 +3952,8 @@ static struct phy_driver marvell_drivers[] = {
 		.handle_interrupt = marvell_handle_interrupt,
 		.get_wol = m88e1318_get_wol,
 		.set_wol = m88e1318_set_wol,
-		.resume = genphy_resume,
-		.suspend = genphy_suspend,
+		.resume = m88e1318_resume,
+		.suspend = m88e1318_suspend,
 		.read_page = marvell_read_page,
 		.write_page = marvell_write_page,
 		.get_sset_count = marvell_get_sset_count,
@@ -3920,7 +4051,7 @@ static struct phy_driver marvell_drivers[] = {
 		.name = "Marvell 88E1510",
 		.driver_data = DEF_MARVELL_HWMON_OPS(m88e1510_hwmon_ops),
 		.features = PHY_GBIT_FIBRE_FEATURES,
-		.flags = PHY_POLL_CABLE_TEST,
+		.flags = PHY_POLL_CABLE_TEST | PHY_ALWAYS_CALL_SUSPEND,
 		.probe = marvell_probe,
 		.config_init = m88e1510_config_init,
 		.config_aneg = m88e1510_config_aneg,
@@ -3930,7 +4061,7 @@ static struct phy_driver marvell_drivers[] = {
 		.get_wol = m88e1318_get_wol,
 		.set_wol = m88e1318_set_wol,
 		.resume = m88e1510_resume,
-		.suspend = marvell_suspend,
+		.suspend = m88e1510_suspend,
 		.read_page = marvell_read_page,
 		.write_page = marvell_write_page,
 		.get_sset_count = marvell_get_sset_count,
-- 
2.55.0