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Date:   Mon, 11 Dec 2023 21:03:36 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Jianheng Zhang <Jianheng.Zhang@synopsys.com>
Cc:     Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <Jose.Abreu@synopsys.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        "open list:STMMAC ETHERNET DRIVER" <netdev@vger.kernel.org>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-stm32@st-md-mailman.stormreply.com>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>,
        James Li <James.Li1@synopsys.com>,
        Martin McKenny <Martin.McKenny@synopsys.com>
Subject: Re: [PATCH net-next] net: stmmac: xgmac3+: add FPE handshaking
 support
Message-ID: <d202770a-3a3a-4ee2-b0de-b86e2f3e83ce@lunn.ch>
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On Mon, Dec 11, 2023 at 06:13:21AM +0000, Jianheng Zhang wrote:
> Adds the HW specific support for Frame Preemption handshaking on XGMAC3+
> cores.
> 
> Signed-off-by: Jianheng Zhang <Jianheng.Zhang@synopsys.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h     |  6 ++
>  .../net/ethernet/stmicro/stmmac/dwxgmac2_core.c    | 65 ++++++++++++++++++----
>  2 files changed, 60 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
> index 207ff17..306d15b 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
> @@ -194,6 +194,12 @@
>  #define XGMAC_MDIO_DATA			0x00000204
>  #define XGMAC_MDIO_C22P			0x00000220
>  #define XGMAC_FPE_CTRL_STS		0x00000280
> +#define XGMAC_TRSP			BIT(19)
> +#define XGMAC_TVER			BIT(18)
> +#define XGMAC_RRSP			BIT(17)
> +#define XGMAC_RVER			BIT(16)
> +#define XGMAC_SRSP			BIT(2)
> +#define XGMAC_SVER			BIT(1)
>  #define XGMAC_EFPE			BIT(0)
>  #define XGMAC_ADDRx_HIGH(x)		(0x00000300 + (x) * 0x8)
>  #define XGMAC_ADDR_MAX			32
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
> index eb48211..091d932 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
> @@ -1439,22 +1439,63 @@ static void dwxgmac3_fpe_configure(void __iomem *ioaddr, struct stmmac_fpe_cfg *
>  {
>  	u32 value;
>  
> -	if (!enable) {
> -		value = readl(ioaddr + XGMAC_FPE_CTRL_STS);
> +	if (enable) {
> +		cfg->fpe_csr = XGMAC_EFPE;
> +		value = readl(ioaddr + XGMAC_RXQ_CTRL1);
> +		value &= ~XGMAC_RQ;
> +		value |= (num_rxq - 1) << XGMAC_RQ_SHIFT;
> +		writel(value, ioaddr + XGMAC_RXQ_CTRL1);
> +	} else {
> +		cfg->fpe_csr = 0;
> +	}
> +	writel(cfg->fpe_csr, ioaddr + XGMAC_FPE_CTRL_STS);
> +}
>  
> -		value &= ~XGMAC_EFPE;
> +static int dwxgmac3_fpe_irq_status(void __iomem *ioaddr, struct net_device *dev)
> +{
> +	u32 value;
> +	int status;
>  
> -		writel(value, ioaddr + XGMAC_FPE_CTRL_STS);
> -		return;
> +	status = FPE_EVENT_UNKNOWN;
> +
> +	/* Reads from the XGMAC_FPE_CTRL_STS register should only be performed
> +	 * here, since the status flags of MAC_FPE_CTRL_STS are "clear on read"
> +	 */
> +	value = readl(ioaddr + XGMAC_FPE_CTRL_STS);
> +
> +	if (value & XGMAC_TRSP) {
> +		status |= FPE_EVENT_TRSP;
> +		netdev_info(dev, "FPE: Respond mPacket is transmitted\n");

netdev_info()?  Is this going to spam the logs? Should it be netdev_dbg()

	Andrew