netdev - Re: [PATCH net-next 1/2] ravb: Add tx and rx clock internal delays mode of APSR

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Date:   Fri, 27 Jan 2017 17:51:23 +0100
From:   Simon Horman <horms@...ge.net.au>
To:     Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Cc:     David Miller <davem@...emloft.net>,
        Magnus Damm <magnus.damm@...il.com>, netdev@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org,
        Kazuya Mizuguchi <kazuya.mizuguchi.ks@...esas.com>
Subject: Re: [PATCH net-next 1/2] ravb: Add tx and rx clock internal delays
 mode of APSR

On Fri, Jan 27, 2017 at 04:00:27PM +0300, Sergei Shtylyov wrote:
> On 01/27/2017 02:04 PM, Simon Horman wrote:
> 
> >From: Kazuya Mizuguchi <kazuya.mizuguchi.ks@...esas.com>
> >
> >This patch enables tx and rx clock internal delay modes (TDM and RDM).
> >
> >This is to address a failure in the case of 1Gbps communication using the
> >by salvator-x board with the KSZ9031RNX phy. This has been reported to
> >occur with both the r8a7795 (H3) and r8a7796 (M3-W) SoCs.
> >
> >With this change APSR internal delay modes are enabled for
> >"rgmii-id", "rgmii-rxid" and "rgmii-txid" phy modes as follows:
> >
> >phy mode   | ASPR delay mode
> >-----------+----------------
> >rgmii-id   | TDM and RDM
> >rgmii-rxid | RDM
> >rgmii-txid | TDM
> >
> >Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@...esas.com>
> >Signed-off-by: Simon Horman <horms+renesas@...ge.net.au>
> >
> >---
> >v1 [Simon Horman]
> >- Combined patches
> >- Reworded changelog
> >
> >v0 [Kazuya Mizuguchi]
> [...]
> >diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> >index 89ac1e3f6175..9fb4c04c5885 100644
> >--- a/drivers/net/ethernet/renesas/ravb_main.c
> >+++ b/drivers/net/ethernet/renesas/ravb_main.c
> >@@ -1904,6 +1904,29 @@ static void ravb_set_config_mode(struct net_device *ndev)
> > 	}
> > }
> >
> >+static void ravb_set_delay_mode(struct net_device *ndev)
> >+{
> >+	struct ravb_private *priv = netdev_priv(ndev);
> >+
> >+	if (priv->chip_id != RCAR_GEN2) {
> >+		switch (priv->phy_interface) {
> >+		case PHY_INTERFACE_MODE_RGMII_ID:
> >+			ravb_modify(ndev, APSR, APSR_DM, APSR_DM_RDM |
> >+				   APSR_DM_TDM);
> >+			break;
> >+		case PHY_INTERFACE_MODE_RGMII_RXID:
> >+			ravb_modify(ndev, APSR, APSR_DM, APSR_DM_RDM);
> >+			break;
> >+		case PHY_INTERFACE_MODE_RGMII_TXID:
> >+			ravb_modify(ndev, APSR, APSR_DM, APSR_DM_TDM);
> >+			break;
> >+		default:
> >+			ravb_modify(ndev, APSR, APSR_DM, 0);
> >+			break;
> >+		}
> >+	}
> >+}
> >+
> > static int ravb_probe(struct platform_device *pdev)
> > {
> > 	struct device_node *np = pdev->dev.of_node;
> >@@ -2016,6 +2039,9 @@ static int ravb_probe(struct platform_device *pdev)
> > 	/* Request GTI loading */
> > 	ravb_modify(ndev, GCCR, GCCR_LTI, GCCR_LTI);
> >
> >+	/* Set APSR */
> >+	ravb_set_delay_mode(ndev);
> >+
> > 	/* Allocate descriptor base address table */
> > 	priv->desc_bat_size = sizeof(struct ravb_desc) * DBAT_ENTRY_NUM;
> > 	priv->desc_bat = dma_alloc_coherent(ndev->dev.parent, priv->desc_bat_size,
> >@@ -2152,6 +2178,9 @@ static int __maybe_unused ravb_resume(struct device *dev)
> > 	/* Request GTI loading */
> > 	ravb_modify(ndev, GCCR, GCCR_LTI, GCCR_LTI);
> >
> >+	/* Set APSR */
> >+	ravb_set_delay_mode(ndev);
> >+
> 
>    So far the pattern was to first check if gen != 2, then calling a gen3
> specific function. I'd like to keep it, rather than checking in the function
> itself.

So you would like something like?

	/* Set APSR */
	if (priv->chip_id != RCAR_GEN2)
		 ravb_set_delay_mode(ndev);

That does not seem better to me but I can make it so if that is your
preference.