2021-10-24 17:54:43

by Trevor Woerner

Subject: [PATCH] net: nxp: lpc_eth.c: avoid hang when bringing interface down

A hard hang is observed whenever the ethernet interface is brought
down. If the PHY is stopped before the LPC core block is reset,
the SoC will hang. Comparing lpc_eth_close() and lpc_eth_open() I
re-arranged the ordering of the functions calls in lpc_eth_close() to
reset the hardware before stopping the PHY.

Signed-off-by: Trevor Woerner <[email protected]>
---
drivers/net/ethernet/nxp/lpc_eth.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/nxp/lpc_eth.c b/drivers/net/ethernet/nxp/lpc_eth.c
index d29fe562b3de..c910fa2f40a4 100644
--- a/drivers/net/ethernet/nxp/lpc_eth.c
+++ b/drivers/net/ethernet/nxp/lpc_eth.c
@@ -1015,9 +1015,6 @@ static int lpc_eth_close(struct net_device *ndev)
napi_disable(&pldat->napi);
netif_stop_queue(ndev);

- if (ndev->phydev)
- phy_stop(ndev->phydev);
-
spin_lock_irqsave(&pldat->lock, flags);
__lpc_eth_reset(pldat);
netif_carrier_off(ndev);
@@ -1025,6 +1022,8 @@ static int lpc_eth_close(struct net_device *ndev)
writel(0, LPC_ENET_MAC2(pldat->net_base));
spin_unlock_irqrestore(&pldat->lock, flags);

+ if (ndev->phydev)
+ phy_stop(ndev->phydev);
clk_disable_unprepare(pldat->clk);

return 0;
--
2.30.0.rc0

2021-10-24 21:36:15

by Vladimir Zapolskiy

Subject: Re: [PATCH] net: nxp: lpc_eth.c: avoid hang when bringing interface down

Hi Trevor,

On 10/24/21 8:50 PM, Trevor Woerner wrote:
> A hard hang is observed whenever the ethernet interface is brought
> down. If the PHY is stopped before the LPC core block is reset,
> the SoC will hang. Comparing lpc_eth_close() and lpc_eth_open() I
> re-arranged the ordering of the functions calls in lpc_eth_close() to
> reset the hardware before stopping the PHY.
>
> Signed-off-by: Trevor Woerner <[email protected]>
> ---
> drivers/net/ethernet/nxp/lpc_eth.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/nxp/lpc_eth.c b/drivers/net/ethernet/nxp/lpc_eth.c
> index d29fe562b3de..c910fa2f40a4 100644
> --- a/drivers/net/ethernet/nxp/lpc_eth.c
> +++ b/drivers/net/ethernet/nxp/lpc_eth.c
> @@ -1015,9 +1015,6 @@ static int lpc_eth_close(struct net_device *ndev)
> napi_disable(&pldat->napi);
> netif_stop_queue(ndev);
>
> - if (ndev->phydev)
> - phy_stop(ndev->phydev);
> -
> spin_lock_irqsave(&pldat->lock, flags);
> __lpc_eth_reset(pldat);
> netif_carrier_off(ndev);
> @@ -1025,6 +1022,8 @@ static int lpc_eth_close(struct net_device *ndev)
> writel(0, LPC_ENET_MAC2(pldat->net_base));
> spin_unlock_irqrestore(&pldat->lock, flags);
>
> + if (ndev->phydev)
> + phy_stop(ndev->phydev);
> clk_disable_unprepare(pldat->clk);
>
> return 0;
>

thank you for the fix!

Fixes: b7370112f519 ("lpc32xx: Added ethernet driver")
Acked-by: Vladimir Zapolskiy <[email protected]>

--
Best wishes,
Vladimir

2021-10-25 14:54:13

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] net: nxp: lpc_eth.c: avoid hang when bringing interface down

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

On Sun, 24 Oct 2021 13:50:02 -0400 you wrote:
> A hard hang is observed whenever the ethernet interface is brought
> down. If the PHY is stopped before the LPC core block is reset,
> the SoC will hang. Comparing lpc_eth_close() and lpc_eth_open() I
> re-arranged the ordering of the functions calls in lpc_eth_close() to
> reset the hardware before stopping the PHY.
>
> Signed-off-by: Trevor Woerner <[email protected]>
>
> [...]

Here is the summary with links:
- net: nxp: lpc_eth.c: avoid hang when bringing interface down
https://git.kernel.org/netdev/net/c/ace19b992436

You are awesome, thank you!
--
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