Re: [PATCH net] net: stmmac: xgmac: fix handling of DPP safety error for DMA channels

[Serge Semin]

On Tue, Jan 23, 2024 at 05:50:06PM +0800, Furong Xu wrote:
> Commit 56e58d6c8a56 ("net: stmmac: Implement Safety Features in
> XGMAC core") checks and reports safety errors, but leaves the
> Data Path Parity Errors for each channel in DMA unhandled at all, lead to
> a storm of interrupt.
> Fix it by checking and clearing the DMA_DPP_Interrupt_Status register.
> 
> Fixes: 56e58d6c8a56 ("net: stmmac: Implement Safety Features in XGMAC core")
> Signed-off-by: Furong Xu <0x1207@xxxxxxxxx>
> ---
>  drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h      | 1 +
>  drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c | 6 ++++++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
> index 207ff1799f2c..188e11683136 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
> @@ -385,6 +385,7 @@
>  #define XGMAC_DCEIE			BIT(1)
>  #define XGMAC_TCEIE			BIT(0)
>  #define XGMAC_DMA_ECC_INT_STATUS	0x0000306c
> +#define XGMAC_DMA_DPP_INT_STATUS	0x00003074
>  #define XGMAC_DMA_CH_CONTROL(x)		(0x00003100 + (0x80 * (x)))
>  #define XGMAC_SPH			BIT(24)
>  #define XGMAC_PBLx8			BIT(16)
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
> index eb48211d9b0e..874e85b499e2 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
> @@ -745,6 +745,12 @@ static void dwxgmac3_handle_mac_err(struct net_device *ndev,
>  
>  	dwxgmac3_log_error(ndev, value, correctable, "MAC",
>  			   dwxgmac3_mac_errors, STAT_OFF(mac_errors), stats);
> +
> +	value = readl(ioaddr + XGMAC_DMA_DPP_INT_STATUS);
> +	writel(value, ioaddr + XGMAC_DMA_DPP_INT_STATUS);
> +
> +	if (value)
> +		netdev_err(ndev, "Found DMA_DPP error, status: 0x%x\n", value);

1. Why not to implement this in the same way as the rest of the safety
errors handle code? (with the flags described by the
dwxgmac3_error_desc-based table and the respective counters being
incremented should the errors were detected)

2. I don't see this IRQ being enabled in the dwxgmac3_safety_feat_config()
method. How come the respective event has turned to be triggered
anyway?

-Serge(y) 

>  }
>  
>  static const struct dwxgmac3_error_desc dwxgmac3_mtl_errors[32]= {
> -- 
> 2.34.1
> 
>