[PATCH net-next] net: stmmac: xgmac3+: add FPE handshaking support

[Serge Semin]

Hi Jianheng, Jakub

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.

Thanks for the patch. No objection about the change:
Reviewed-by: Serge Semin <fancer.lancer at gmail.com>

The only note is that the DW XGMAC v3.x and DW QoS Eth v5.x FPE
implementations are now identical (see the attached diff). What about
factoring out the common parts to a separate file - stmmac_fpe.c
(perhaps together with the handshaking algo from the stmmac_main.c)
and send it out as an additional patch on top of this one? A similar
thing has been recently done for EST:
https://lore.kernel.org/netdev/20231201055252.1302-1-rohan.g.thomas@intel.com/
Although in this case AFAICS the implementation is simpler and the
only difference is in the CSR offset and the frame preemption residue
queue ID setting. All of that can be easily solved in the same way as
it was done for EST (see the link above).

Jakub, what do you think?

-Serge(y)

> 
> Signed-off-by: Jianheng Zhang <Jianheng.Zhang at 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");
>  	}
>  
> -	value = readl(ioaddr + XGMAC_RXQ_CTRL1);
> -	value &= ~XGMAC_RQ;
> -	value |= (num_rxq - 1) << XGMAC_RQ_SHIFT;
> -	writel(value, ioaddr + XGMAC_RXQ_CTRL1);
> +	if (value & XGMAC_TVER) {
> +		status |= FPE_EVENT_TVER;
> +		netdev_info(dev, "FPE: Verify mPacket is transmitted\n");
> +	}
> +
> +	if (value & XGMAC_RRSP) {
> +		status |= FPE_EVENT_RRSP;
> +		netdev_info(dev, "FPE: Respond mPacket is received\n");
> +	}
> +
> +	if (value & XGMAC_RVER) {
> +		status |= FPE_EVENT_RVER;
> +		netdev_info(dev, "FPE: Verify mPacket is received\n");
> +	}
> +
> +	return status;
> +}
> +
> +static void dwxgmac3_fpe_send_mpacket(void __iomem *ioaddr, struct stmmac_fpe_cfg *cfg,
> +				      enum stmmac_mpacket_type type)
> +{
> +	u32 value = cfg->fpe_csr;
> +
> +	if (type == MPACKET_VERIFY)
> +		value |= XGMAC_SVER;
> +	else if (type == MPACKET_RESPONSE)
> +		value |= XGMAC_SRSP;
>  
> -	value = readl(ioaddr + XGMAC_FPE_CTRL_STS);
> -	value |= XGMAC_EFPE;
>  	writel(value, ioaddr + XGMAC_FPE_CTRL_STS);
>  }
>  
> @@ -1503,6 +1544,8 @@ static void dwxgmac3_fpe_configure(void __iomem *ioaddr, struct stmmac_fpe_cfg *
>  	.config_l4_filter = dwxgmac2_config_l4_filter,
>  	.set_arp_offload = dwxgmac2_set_arp_offload,
>  	.fpe_configure = dwxgmac3_fpe_configure,
> +	.fpe_send_mpacket = dwxgmac3_fpe_send_mpacket,
> +	.fpe_irq_status = dwxgmac3_fpe_irq_status,
>  };
>  
>  static void dwxlgmac2_rx_queue_enable(struct mac_device_info *hw, u8 mode,
> -- 
> 1.8.3.1
> 
> 
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