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

On 01/27/2017 07:49 PM, Simon Horman wrote:

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From: Kazuya Mizuguchi <redacted>

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 <redacted>
Signed-off-by: Simon Horman <redacted>

---
v1 [Simon Horman]
- Combined patches
- Reworded changelog

v0 [Kazuya Mizuguchi]
---
drivers/net/ethernet/renesas/ravb.h      | 10 ++++++++++
drivers/net/ethernet/renesas/ravb_main.c | 29 +++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index f1109661a533..d7c91d48cc48 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h

[...]

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@@ -248,6 +249,15 @@ enum ESR_BIT {

	ESR_EIL		= 0x00001000,
};

+/* APSR */
+enum APSR_BIT {
+	APSR_MEMS		= 0x00000002,

   Not documented in the revision 0.5 of the gen3 manual...

It is in version 0.53 of the documentation but I think it can be dropped
from this patch as its unused.

    No need to drop, let it be. :-)

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+	APSR_CMSW		= 0x00000010,

I think the above can also be dropped as it is unused.

    No need.

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+	APSR_DM			= 0x00006000,

   ... and neither this field. Are these documented in the latter revs?

This one is not. I can ask Mizuguchi-san to confirm it exists (with himself).

    The whole patch depends on it! If it's not documented, I'd like a comment 
added, like I did for the other undocumented things in this driver...

[...]

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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;
+		}

   How about doing ravb_modify() only once?

Something like this?

		int set = 0;

		if (priv->phy_interface == PHY_INTERFACE_MODE_RGMII_ID ||
		    priv->phy_interface == PHY_INTERFACE_MODE_RGMII_RXID)
		    set |= APSR_DM_RDM;

		if (priv->phy_interface == PHY_INTERFACE_MODE_RGMII_ID ||
		    priv->phy_interface == PHY_INTERFACE_MODE_RGMII_TXID)
		    set |= APSR_DM_TDM;

		ravb_modify(ndev, APSR, APSR_DM, set);

I don't really see any advantage to it but I can change things around
however you like.

    I didn't mean to replace *switch*, actually -- just to move ravb_modify() 
out of it.

MBR, Sergei