[PATCH net-next v2 2/2] net: bcmasp: Keep PHY link during WoL sleep cycle

[Justin Chen <justin.chen@broadcom.com>]

We currently more or less restart all the HW on resume whatever WoL is
enabled or not. The PHY is powered when WoL is enabled which means we
have no reason to re-negotiate the link on resume. So instead of doing
a full restart in this case, we do a partial restart and keep the
negotiated link. That way we can resume network taffic with a much smaller
delay. In the non-WoL case, we do not want to keep the PHY powered, so we
follow the same flow.

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
---
v2
- In the resume case with a HW reset. We trigger a relink by setting the link
  to PHY_UP instead of calling phy_restart_aneg().

 .../net/ethernet/broadcom/asp2/bcmasp_intf.c  | 51 ++++++++++++++-----
 1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c b/drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c
index e2b51ec903af..9ffd0dfa5969 100644
--- a/drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c
+++ b/drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c
@@ -923,7 +923,7 @@ static void bcmasp_phy_hw_unprepare(struct bcmasp_intf *intf)
 		bcmasp_rgmii_mode_en_set(intf, false);
 }
 
-static void bcmasp_netif_deinit(struct net_device *dev)
+static void bcmasp_netif_deinit(struct net_device *dev, bool stop_phy)
 {
 	struct bcmasp_intf *intf = netdev_priv(dev);
 	u32 reg, timeout = 1000;
@@ -946,7 +946,8 @@ static void bcmasp_netif_deinit(struct net_device *dev)
 
 	umac_enable_set(intf, UMC_CMD_TX_EN, 0);
 
-	phy_stop(dev->phydev);
+	if (stop_phy)
+		phy_stop(dev->phydev);
 
 	umac_enable_set(intf, UMC_CMD_RX_EN, 0);
 
@@ -974,7 +975,7 @@ static int bcmasp_stop(struct net_device *dev)
 	/* Stop tx from updating HW */
 	netif_tx_disable(dev);
 
-	bcmasp_netif_deinit(dev);
+	bcmasp_netif_deinit(dev, true);
 
 	bcmasp_reclaim_free_buffers(intf);
 
@@ -1385,15 +1386,20 @@ int bcmasp_interface_suspend(struct bcmasp_intf *intf)
 {
 	struct device *kdev = &intf->parent->pdev->dev;
 	struct net_device *dev = intf->ndev;
+	bool wake;
 
 	if (!netif_running(dev))
 		return 0;
 
 	netif_device_detach(dev);
 
-	bcmasp_netif_deinit(dev);
+	wake = device_may_wakeup(kdev) && intf->wolopts;
 
-	if (!intf->wolopts) {
+	bcmasp_netif_deinit(dev, !wake);
+
+	if (wake) {
+		bcmasp_suspend_to_wol(intf);
+	} else {
 		bcmasp_phy_hw_unprepare(intf);
 
 		/* If Wake-on-LAN is disabled, we can safely
@@ -1402,9 +1408,6 @@ int bcmasp_interface_suspend(struct bcmasp_intf *intf)
 		bcmasp_core_clock_set_intf(intf, false);
 	}
 
-	if (device_may_wakeup(kdev) && intf->wolopts)
-		bcmasp_suspend_to_wol(intf);
-
 	clk_disable_unprepare(intf->parent->clk);
 
 	return 0;
@@ -1428,8 +1431,11 @@ static void bcmasp_resume_from_wol(struct bcmasp_intf *intf)
 
 int bcmasp_interface_resume(struct bcmasp_intf *intf)
 {
+	struct device *kdev = &intf->parent->pdev->dev;
 	struct net_device *dev = intf->ndev;
+	bool wake;
 	int ret;
+	u32 reg;
 
 	if (!netif_running(dev))
 		return 0;
@@ -1438,17 +1444,34 @@ int bcmasp_interface_resume(struct bcmasp_intf *intf)
 	if (ret)
 		return ret;
 
-	bcmasp_core_clock_set_intf(intf, true);
-
-	bcmasp_resume_from_wol(intf);
+	wake = device_may_wakeup(kdev) && intf->wolopts;
 
-	bcmasp_phy_hw_prepare(intf);
+	bcmasp_core_clock_set_intf(intf, true);
 
-	umac_reset_and_init(intf, dev->dev_addr);
+	/* The interface might be HW reset in some suspend modes, so we may
+	 * need to restore the UNIMAC/PHY if that is the case.
+	 */
+	reg = umac_rl(intf, UMC_CMD);
+	if (wake && (reg & UMC_CMD_RX_EN)) {
+		umac_enable_set(intf, UMC_CMD_TX_EN, 1);
+		bcmasp_resume_from_wol(intf);
+	} else {
+		bcmasp_phy_hw_prepare(intf);
+		umac_reset_and_init(intf, dev->dev_addr);
+	}
 
 	bcmasp_netif_init(dev);
 
-	phy_start(dev->phydev);
+	/* If HW was reset, we need to force a relink */
+	if (wake && !(reg & UMC_CMD_RX_EN)) {
+		mutex_lock(&dev->phydev->lock);
+		if (dev->phydev->state == PHY_RUNNING)
+			dev->phydev->state = PHY_UP;
+		mutex_unlock(&dev->phydev->lock);
+		phy_trigger_machine(dev->phydev);
+	} else if (!wake) {
+		phy_start(dev->phydev);
+	}
 
 	netif_device_attach(dev);
 
-- 
2.34.1