Subject: Re: [PATCH] Prevent interrupt loop with DWMAC MMC RX IPC Counter

From: Giuseppe CAVALLARO <[email-masked]>
Date: Fri, 15 Feb 2013 14:46:16 +0100

Hello Christian

On 2/15/2013 2:15 PM, Christian Ruppert wrote:
> If the DesignWare MAC is synthesised with MMC RX IPC Counter, an unmanaged
> and unacknowledged interrupt is generated after some time of operation. To
> my knowledge there is no way to autodetect this configuration.
>
> This patch adds a Kconfig option to tell the driver about the counter which
> in turn masks the undesired interrupts.
>
> Signed-off-by: Christian Ruppert <[email-masked]>
> ---
>   drivers/net/ethernet/stmicro/stmmac/Kconfig    |    8 ++++++++
>   drivers/net/ethernet/stmicro/stmmac/mmc_core.c |    3 +++
>   2 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index 1164930..60e5130 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -71,5 +71,13 @@ config STMMAC_CHAINED
>
>   endchoice
>
> +config STMMAC_RX_IPC_CTRS
> +	bool "MMC Receive IPC Counters enabled"
> +	depends on STMMAC_ETH
> +	default n
> +	---help---
> +	  Select this option in case MMC Receive IPC counters were enabled at
> +	  synthesis time of the block. If this option is not set correctly,
> +	  system might hang after a certain amount of time.
>
>   endif
> diff --git a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
> index 0c74a70..ae877ee 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/mmc_core.c
> @@ -149,6 +149,9 @@ void dwmac_mmc_intr_all_mask(void __iomem *ioaddr)
>   {
>   	writel(MMC_DEFAULT_MASK, ioaddr + MMC_RX_INTR_MASK);
>   	writel(MMC_DEFAULT_MASK, ioaddr + MMC_TX_INTR_MASK);
> +#ifdef CONFIG_STMMAC_RX_IPC_CTRS
> +	writel(MMC_DEFAULT_MASK, ioaddr + MMC_RX_IPC_INTR_MASK);
> +#endif

your fix makes sense to me; I have never faced this problem because the
MMC RX IPC Counter is not synthesised  on the GMAC chip I used.

Anyway all mmc interrupts are not managed by defsign so I only ask you 
to remove the Kconfig option and add the writel in the 
dwmac_mmc_intr_all_mask.

peppe

>   }
>
>   /* This reads the MAC core counters (if actaully supported).
>