[PATCH net.git] net: bgmac: postpone turning IRQs off to avoid SoC hangs

[PATCH net.git] net: bgmac: postpone turning IRQs off to avoid SoC hangs

[Rafał Miłecki]

From: Rafał Miłecki <rafal@milecki.pl>

Turning IRQs off is done by accessing Ethernet controller registers.
That can't be done until device's clock is enabled. It results in a SoC
hang otherwise.

This bug remained unnoticed for years as most bootloaders keep all
Ethernet interfaces turned on. It seems to only affect a niche SoC
family BCM47189. It has two Ethernet controllers but CFE bootloader uses
only the first one.

Fixes: 34322615cbaa ("net: bgmac: Mask interrupts during probe")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 drivers/net/ethernet/broadcom/bgmac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 1761df8fb7f9..10c7c232cc4e 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -1492,8 +1492,6 @@ int bgmac_enet_probe(struct bgmac *bgmac)
 
 	bgmac->in_init = true;
 
-	bgmac_chip_intrs_off(bgmac);
-
 	net_dev->irq = bgmac->irq;
 	SET_NETDEV_DEV(net_dev, bgmac->dev);
 	dev_set_drvdata(bgmac->dev, bgmac);
@@ -1511,6 +1509,8 @@ int bgmac_enet_probe(struct bgmac *bgmac)
 	 */
 	bgmac_clk_enable(bgmac, 0);
 
+	bgmac_chip_intrs_off(bgmac);
+
 	/* This seems to be fixing IRQ by assigning OOB #6 to the core */
 	if (!(bgmac->feature_flags & BGMAC_FEAT_IDM_MASK)) {
 		if (bgmac->feature_flags & BGMAC_FEAT_IRQ_ID_OOB_6)
-- 
2.35.3

Re: [PATCH net.git] net: bgmac: postpone turning IRQs off to avoid SoC hangs

[Michal Kubiak]

On Fri, Jul 07, 2023 at 08:53:25AM +0200, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> Turning IRQs off is done by accessing Ethernet controller registers.
> That can't be done until device's clock is enabled. It results in a SoC
> hang otherwise.
> 
> This bug remained unnoticed for years as most bootloaders keep all
> Ethernet interfaces turned on. It seems to only affect a niche SoC
> family BCM47189. It has two Ethernet controllers but CFE bootloader uses
> only the first one.
> 
> Fixes: 34322615cbaa ("net: bgmac: Mask interrupts during probe")
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
> ---
>  drivers/net/ethernet/broadcom/bgmac.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
> index 1761df8fb7f9..10c7c232cc4e 100644
> --- a/drivers/net/ethernet/broadcom/bgmac.c
> +++ b/drivers/net/ethernet/broadcom/bgmac.c
> @@ -1492,8 +1492,6 @@ int bgmac_enet_probe(struct bgmac *bgmac)
>  
>  	bgmac->in_init = true;
>  
> -	bgmac_chip_intrs_off(bgmac);
> -
>  	net_dev->irq = bgmac->irq;
>  	SET_NETDEV_DEV(net_dev, bgmac->dev);
>  	dev_set_drvdata(bgmac->dev, bgmac);
> @@ -1511,6 +1509,8 @@ int bgmac_enet_probe(struct bgmac *bgmac)
>  	 */
>  	bgmac_clk_enable(bgmac, 0);
>  
> +	bgmac_chip_intrs_off(bgmac);
> +
>  	/* This seems to be fixing IRQ by assigning OOB #6 to the core */
>  	if (!(bgmac->feature_flags & BGMAC_FEAT_IDM_MASK)) {
>  		if (bgmac->feature_flags & BGMAC_FEAT_IRQ_ID_OOB_6)
> -- 
> 2.35.3
> 
>

Looks like a good catch!

Thanks,
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>

Re: [PATCH net.git] net: bgmac: postpone turning IRQs off to avoid SoC hangs

[patchwork-bot+netdevbpf]

Hello:

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

On Fri,  7 Jul 2023 08:53:25 +0200 you wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> Turning IRQs off is done by accessing Ethernet controller registers.
> That can't be done until device's clock is enabled. It results in a SoC
> hang otherwise.
> 
> This bug remained unnoticed for years as most bootloaders keep all
> Ethernet interfaces turned on. It seems to only affect a niche SoC
> family BCM47189. It has two Ethernet controllers but CFE bootloader uses
> only the first one.
> 
> [...]

Here is the summary with links:
  - [net.git] net: bgmac: postpone turning IRQs off to avoid SoC hangs
    https://git.kernel.org/netdev/net/c/e7731194fdf0

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html