diff mbox series

[V2,net-next] net: fec: fix system hang during suspend/resume

Message ID 20211214105046.31901-1-qiangqing.zhang@nxp.com (mailing list archive)
State Accepted
Commit 0b6f65c707e5ec5e33916820e2a4a628e2b4576c
Delegated to: Netdev Maintainers
Headers show
Series [V2,net-next] net: fec: fix system hang during suspend/resume | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 85 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Joakim Zhang Dec. 14, 2021, 10:50 a.m. UTC
1. During normal suspend (WoL not enabled) process, system has posibility
to hang. The root cause is TXF interrupt coming after clocks disabled,
system hang when accessing registers from interrupt handler. To fix this
issue, disable all interrupts when system suspend.

2. System also has posibility to hang with WoL enabled during suspend,
after entering stop mode, then magic pattern coming after clocks
disabled, system will be waked up, and interrupt handler will be called,
system hang when access registers. To fix this issue, disable wakeup
irq in .suspend(), and enable it in .resume().

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
Send to net-next although this is a bug fix, since there is no suitable
commit to be blamed, can be back ported to stable tree if others need.

ChangeLogs:
V1->V2:
	* remove inline prefix, let the compiler decide.
---
 drivers/net/ethernet/freescale/fec_main.c | 46 +++++++++++++++++------
 1 file changed, 34 insertions(+), 12 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Dec. 15, 2021, 11:10 a.m. UTC | #1
Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Tue, 14 Dec 2021 18:50:46 +0800 you wrote:
> 1. During normal suspend (WoL not enabled) process, system has posibility
> to hang. The root cause is TXF interrupt coming after clocks disabled,
> system hang when accessing registers from interrupt handler. To fix this
> issue, disable all interrupts when system suspend.
> 
> 2. System also has posibility to hang with WoL enabled during suspend,
> after entering stop mode, then magic pattern coming after clocks
> disabled, system will be waked up, and interrupt handler will be called,
> system hang when access registers. To fix this issue, disable wakeup
> irq in .suspend(), and enable it in .resume().
> 
> [...]

Here is the summary with links:
  - [V2,net-next] net: fec: fix system hang during suspend/resume
    https://git.kernel.org/netdev/net-next/c/0b6f65c707e5

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 613b8180a1bd..796133de527e 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1185,6 +1185,21 @@  static void fec_enet_stop_mode(struct fec_enet_private *fep, bool enabled)
 	}
 }
 
+static void fec_irqs_disable(struct net_device *ndev)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+
+	writel(0, fep->hwp + FEC_IMASK);
+}
+
+static void fec_irqs_disable_except_wakeup(struct net_device *ndev)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+
+	writel(0, fep->hwp + FEC_IMASK);
+	writel(FEC_ENET_WAKEUP, fep->hwp + FEC_IMASK);
+}
+
 static void
 fec_stop(struct net_device *ndev)
 {
@@ -1211,15 +1226,13 @@  fec_stop(struct net_device *ndev)
 			writel(1, fep->hwp + FEC_ECNTRL);
 			udelay(10);
 		}
-		writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
 	} else {
-		writel(FEC_DEFAULT_IMASK | FEC_ENET_WAKEUP, fep->hwp + FEC_IMASK);
 		val = readl(fep->hwp + FEC_ECNTRL);
 		val |= (FEC_ECR_MAGICEN | FEC_ECR_SLEEP);
 		writel(val, fep->hwp + FEC_ECNTRL);
-		fec_enet_stop_mode(fep, true);
 	}
 	writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
+	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
 
 	/* We have to keep ENET enabled to have MII interrupt stay working */
 	if (fep->quirks & FEC_QUIRK_ENET_MAC &&
@@ -2877,15 +2890,10 @@  fec_enet_set_wol(struct net_device *ndev, struct ethtool_wolinfo *wol)
 		return -EINVAL;
 
 	device_set_wakeup_enable(&ndev->dev, wol->wolopts & WAKE_MAGIC);
-	if (device_may_wakeup(&ndev->dev)) {
+	if (device_may_wakeup(&ndev->dev))
 		fep->wol_flag |= FEC_WOL_FLAG_ENABLE;
-		if (fep->wake_irq > 0)
-			enable_irq_wake(fep->wake_irq);
-	} else {
+	else
 		fep->wol_flag &= (~FEC_WOL_FLAG_ENABLE);
-		if (fep->wake_irq > 0)
-			disable_irq_wake(fep->wake_irq);
-	}
 
 	return 0;
 }
@@ -4057,9 +4065,19 @@  static int __maybe_unused fec_suspend(struct device *dev)
 		netif_device_detach(ndev);
 		netif_tx_unlock_bh(ndev);
 		fec_stop(ndev);
-		fec_enet_clk_enable(ndev, false);
-		if (!(fep->wol_flag & FEC_WOL_FLAG_ENABLE))
+		if (!(fep->wol_flag & FEC_WOL_FLAG_ENABLE)) {
+			fec_irqs_disable(ndev);
 			pinctrl_pm_select_sleep_state(&fep->pdev->dev);
+		} else {
+			fec_irqs_disable_except_wakeup(ndev);
+			if (fep->wake_irq > 0) {
+				disable_irq(fep->wake_irq);
+				enable_irq_wake(fep->wake_irq);
+			}
+			fec_enet_stop_mode(fep, true);
+		}
+		/* It's safe to disable clocks since interrupts are masked */
+		fec_enet_clk_enable(ndev, false);
 	}
 	rtnl_unlock();
 
@@ -4097,6 +4115,10 @@  static int __maybe_unused fec_resume(struct device *dev)
 		}
 		if (fep->wol_flag & FEC_WOL_FLAG_ENABLE) {
 			fec_enet_stop_mode(fep, false);
+			if (fep->wake_irq) {
+				disable_irq_wake(fep->wake_irq);
+				enable_irq(fep->wake_irq);
+			}
 
 			val = readl(fep->hwp + FEC_ECNTRL);
 			val &= ~(FEC_ECR_MAGICEN | FEC_ECR_SLEEP);