[PATCH 4/4] net: macb: Add support for suspend/resume with full power down

[Harini Katakam]

When macb device is suspended and system is powered down, the clocks
are removed and hence macb should be closed gracefully and restored
upon resume. This patch does the same by switching off the net device,
suspending phy and performing necessary cleanup of interrupts and BDs.
Upon resume, all these are reinitialized again.

Reset of macb device is done only when GEM is not a wake device.
Even when gem is a wake device, tx queues can be stopped and ptp device
can be closed (tsu clock will be disabled in pm_runtime_suspend) as
wake event detection has no dependency on this.

Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>
Signed-off-by: Harini Katakam <harini.katakam@xxxxxxxxxx>
---
Notes:
I was unable to do a full macb_close/open in this patch as suggested
because it was freeing and allocating the full RX/TX buffers and
this time consuming, also leading to a crash when done continuously
in stress tests. 

 drivers/net/ethernet/cadence/macb_main.c | 38 ++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 09cb4bb..0d1acb4 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4247,16 +4247,33 @@ static int __maybe_unused macb_suspend(struct device *dev)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct net_device *netdev = platform_get_drvdata(pdev);
 	struct macb *bp = netdev_priv(netdev);
+	struct macb_queue *queue = bp->queues;
+	unsigned long flags;
+	unsigned int q;
+
+	if (!netif_running(netdev))
+		return 0;
 
-	netif_carrier_off(netdev);
-	netif_device_detach(netdev);
 
 	if (bp->wol & MACB_WOL_ENABLED) {
 		macb_writel(bp, IER, MACB_BIT(WOL));
 		macb_writel(bp, WOL, MACB_BIT(MAG));
 		enable_irq_wake(bp->queues[0].irq);
+		netif_device_detach(netdev);
+	} else {
+		netif_device_detach(netdev);
+		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
+			napi_disable(&queue->napi);
+		phy_stop(bp->phy_dev);
+		phy_suspend(bp->phy_dev);
+		spin_lock_irqsave(&bp->lock, flags);
+		macb_reset_hw(bp);
+		spin_unlock_irqrestore(&bp->lock, flags);
 	}
 
+	netif_carrier_off(netdev);
+	if (bp->ptp_info)
+		bp->ptp_info->ptp_remove(netdev);
 	pm_runtime_force_suspend(dev);
 
 	return 0;
@@ -4267,6 +4284,11 @@ static int __maybe_unused macb_resume(struct device *dev)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct net_device *netdev = platform_get_drvdata(pdev);
 	struct macb *bp = netdev_priv(netdev);
+	struct macb_queue *queue = bp->queues;
+	unsigned int q;
+
+	if (!netif_running(netdev))
+		return 0;
 
 	pm_runtime_force_resume(dev);
 
@@ -4274,9 +4296,21 @@ static int __maybe_unused macb_resume(struct device *dev)
 		macb_writel(bp, IDR, MACB_BIT(WOL));
 		macb_writel(bp, WOL, 0);
 		disable_irq_wake(bp->queues[0].irq);
+	} else {
+		macb_writel(bp, NCR, MACB_BIT(MPE));
+		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
+			napi_enable(&queue->napi);
+		phy_resume(bp->phy_dev);
+		phy_init_hw(bp->phy_dev);
+		phy_start(bp->phy_dev);
 	}
 
+	bp->macbgem_ops.mog_init_rings(bp);
+	macb_init_hw(bp);
+	macb_set_rx_mode(netdev);
 	netif_device_attach(netdev);
+	if (bp->ptp_info)
+		bp->ptp_info->ptp_init(netdev);
 
 	return 0;
 }
-- 
2.7.4