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

[Michal Kubiak <michal.kubiak@intel.com>]

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>