Subject: Re: [net-next PATCH v2 2/3] net: macb: Add support for jumbo frames

From: Nicolas Ferre <[email-masked]>
Date: Mon, 4 May 2015 10:48:39 +0200

Le 04/05/2015 09:52, Harini Katakam a écrit :
> Check for "cdns,zynqmp-gem" compatible string and enable jumbo frame support
> in NWCFG register, update descriptor length masks and registers accordingly.
> Jumbo max length register should be set according to support in SoC; it is
> set to 10240 for Zynq Ultrascale+ MPSoC.
> 
> Signed-off-by: Harini Katakam <[email-masked]>
> Reviewed-by: Punnaiah Choudary Kalluri <[email-masked]>
> ---
> 
> On v1, Michal commented that I should use macb_config for jumbo parameters
> instead of defining them by reading the compatible string directly.
> I can use .caps for isjumbo. But jumbo-max-length needs to be defined.
> Can I add this to the structure? Any suggestions on how to handle this?

Yes, adding it to the "caps" field and adding a field for the max length
is definitively the way to go.

So "NAK" for this implementation.

Thanks, bye.

> v2:
> Add constant definition and update SoC name
> 
> ---
>  drivers/net/ethernet/cadence/macb.c |   21 ++++++++++++++++++---
>  drivers/net/ethernet/cadence/macb.h |    8 ++++++++
>  2 files changed, 26 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index 4104d49..a065283 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -54,6 +54,8 @@
>  #define MACB_MAX_TX_LEN		((unsigned int)((1 << MACB_TX_FRMLEN_SIZE) - 1))
>  #define GEM_MAX_TX_LEN		((unsigned int)((1 << GEM_TX_FRMLEN_SIZE) - 1))
>  
> +#define GEM_ZYNQMP_JUMBO_MAX	10240
> +
>  /*
>   * Graceful stop timeouts in us. We should allow up to
>   * 1 frame time (10 Mbits/s, full-duplex, ignoring collisions)
> @@ -782,7 +784,7 @@ static int gem_rx(struct macb *bp, int budget)
>  		}
>  		/* now everything is ready for receiving packet */
>  		bp->rx_skbuff[entry] = NULL;
> -		len = MACB_BFEXT(RX_FRMLEN, ctrl);
> +		len = ctrl & bp->rx_frm_len_mask;
>  
>  		netdev_vdbg(bp->dev, "gem_rx %u (len %u)\n", entry, len);
>  
> @@ -828,7 +830,7 @@ static int macb_rx_frame(struct macb *bp, unsigned int first_frag,
>  	struct macb_dma_desc *desc;
>  
>  	desc = macb_rx_desc(bp, last_frag);
> -	len = MACB_BFEXT(RX_FRMLEN, desc->ctrl);
> +	len = desc->ctrl & bp->rx_frm_len_mask;
>  
>  	netdev_vdbg(bp->dev, "macb_rx_frame frags %u - %u (len %u)\n",
>  		macb_rx_ring_wrap(first_frag),
> @@ -1633,7 +1635,10 @@ static void macb_init_hw(struct macb *bp)
>  	config |= MACB_BF(RBOF, NET_IP_ALIGN);	/* Make eth data aligned */
>  	config |= MACB_BIT(PAE);		/* PAuse Enable */
>  	config |= MACB_BIT(DRFCS);		/* Discard Rx FCS */
> -	config |= MACB_BIT(BIG);		/* Receive oversized frames */
> +	if (bp->isjumbo)
> +		config |= MACB_BIT(JFRAME);	/* Enable jumbo frames */
> +	else
> +		config |= MACB_BIT(BIG);	/* Receive oversized frames */
>  	if (bp->dev->flags & IFF_PROMISC)
>  		config |= MACB_BIT(CAF);	/* Copy All Frames */
>  	else if (macb_is_gem(bp) && bp->dev->features & NETIF_F_RXCSUM)
> @@ -1642,8 +1647,13 @@ static void macb_init_hw(struct macb *bp)
>  		config |= MACB_BIT(NBC);	/* No BroadCast */
>  	config |= macb_dbw(bp);
>  	macb_writel(bp, NCFGR, config);
> +	if (bp->isjumbo && bp->jumbo_max_len)
> +		gem_writel(bp, JML, bp->jumbo_max_len);
>  	bp->speed = SPEED_10;
>  	bp->duplex = DUPLEX_HALF;
> +	bp->rx_frm_len_mask = MACB_RX_FRMLEN_MASK;
> +	if (bp->isjumbo)
> +		bp->rx_frm_len_mask = MACB_RX_JFRMLEN_MASK;
>  
>  	macb_configure_dma(bp);
>  
> @@ -2762,6 +2772,11 @@ static int macb_probe(struct platform_device *pdev)
>  	bp->pclk = pclk;
>  	bp->hclk = hclk;
>  	bp->tx_clk = tx_clk;
> +	if (of_device_is_compatible(pdev->dev.of_node, "cdns,zynqmp-gem")) {
> +		bp->isjumbo = 1;
> +		bp->jumbo_max_len = GEM_ZYNQMP_JUMBO_MAX;
> +	}
> +
>  	spin_lock_init(&bp->lock);
>  
>  	/* setup capabilities */
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index eb7d76f..e25f77e 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -71,6 +71,7 @@
>  #define GEM_NCFGR		0x0004 /* Network Config */
>  #define GEM_USRIO		0x000c /* User IO */
>  #define GEM_DMACFG		0x0010 /* DMA Configuration */
> +#define GEM_JML			0x0048 /* Jumbo Max Length */
>  #define GEM_HRB			0x0080 /* Hash Bottom */
>  #define GEM_HRT			0x0084 /* Hash Top */
>  #define GEM_SA1B		0x0088 /* Specific1 Bottom */
> @@ -514,6 +515,9 @@ struct macb_dma_desc {
>  #define MACB_RX_BROADCAST_OFFSET		31
>  #define MACB_RX_BROADCAST_SIZE			1
>  
> +#define MACB_RX_FRMLEN_MASK			0xFFF
> +#define MACB_RX_JFRMLEN_MASK			0x3FFF
> +
>  /* RX checksum offload disabled: bit 24 clear in NCFGR */
>  #define GEM_RX_TYPEID_MATCH_OFFSET		22
>  #define GEM_RX_TYPEID_MATCH_SIZE		2
> @@ -826,6 +830,10 @@ struct macb {
>  	unsigned int		max_tx_length;
>  
>  	u64			ethtool_stats[GEM_STATS_LEN];
> +
> +	unsigned int		rx_frm_len_mask;
> +	unsigned int		jumbo_max_len;
> +	bool			isjumbo;
>  };
>  
>  static inline bool macb_is_gem(struct macb *bp)
> 

-- 
Nicolas Ferre