net: phy: meson-gxl: improve link-up behavior

[ Upstream commit 2c87c6f9fb ]

Sometimes the link comes up but no data flows. This patch fixes
this behavior. It's not clear what's the root cause of the issue.

According to the tests one other link-up issue remains.
In very rare cases the link isn't even reported as up.

Fixes: 84c8f773d2 ("net: phy: meson-gxl: remove the use of .ack_callback()")
Tested-by: Erico Nunes <nunes.erico@gmail.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/e3473452-a1f9-efcf-5fdd-02b6f44c3fcd@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/phy/meson-gxl.c

@@ -243,7 +243,13 @@ static irqreturn_t meson_gxl_handle_interrupt(struct phy_device *phydev)
 	    irq_status == INTSRC_ENERGY_DETECT)
 		return IRQ_HANDLED;
 
-	phy_trigger_machine(phydev);
+	/* Give PHY some time before MAC starts sending data. This works
+	 * around an issue where network doesn't come up properly.
+	 */
+	if (!(irq_status & INTSRC_LINK_DOWN))
+		phy_queue_state_machine(phydev, msecs_to_jiffies(100));
+	else
+		phy_trigger_machine(phydev);
 
 	return IRQ_HANDLED;
 }