Re: [PATCH net-next v4 5/5] ravb: Add support for explicit internal clock delay configuration

From: Dan Murphy
Date: Thu Sep 17 2020 - 14:51:40 EST


Geert

On 9/17/20 8:57 AM, Geert Uytterhoeven wrote:
Some EtherAVB variants support internal clock delay configuration, which
can add larger delays than the delays that are typically supported by
the PHY (using an "rgmii-*id" PHY mode, and/or "[rt]xc-skew-ps"
properties).

Historically, the EtherAVB driver configured these delays based on the
"rgmii-*id" PHY mode. This caused issues with PHY drivers that
implement PHY internal delays properly[1]. Hence a backwards-compatible
workaround was added by masking the PHY mode[2].

Add proper support for explicit configuration of the MAC internal clock
delays using the new "[rt]x-internal-delay-ps" properties.
Fall back to the old handling if none of these properties is present.

[1] Commit bcf3440c6dd78bfe ("net: phy: micrel: add phy-mode support for
the KSZ9031 PHY")
[2] Commit 9b23203c32ee02cd ("ravb: Mask PHY mode to avoid inserting
delays twice").

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
v4:
- Add Reviewed-by,

v3:
- No changes,

v2:
- Add Reviewed-by,
- Split long line,
- Replace "renesas,[rt]xc-delay-ps" by "[rt]x-internal-delay-ps",
- Use 1 instead of true when assigning to a single-bit bitfield.
---
drivers/net/ethernet/renesas/ravb.h | 1 +
drivers/net/ethernet/renesas/ravb_main.c | 36 ++++++++++++++++++------
2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index e5ca12ce93c730a9..7453b17a37a2c8d0 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -1038,6 +1038,7 @@ struct ravb_private {
unsigned wol_enabled:1;
unsigned rxcidm:1; /* RX Clock Internal Delay Mode */
unsigned txcidm:1; /* TX Clock Internal Delay Mode */
+ unsigned rgmii_override:1; /* Deprecated rgmii-*id behavior */
int num_tx_desc; /* TX descriptors per packet */
};
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 59dadd971345e0d1..aa120e3f1e4d4da5 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1034,11 +1034,8 @@ static int ravb_phy_init(struct net_device *ndev)
pn = of_node_get(np);
}
- iface = priv->phy_interface;
- if (priv->chip_id != RCAR_GEN2 && phy_interface_mode_is_rgmii(iface)) {
- /* ravb_set_delay_mode() takes care of internal delay mode */
- iface = PHY_INTERFACE_MODE_RGMII;
- }
+ iface = priv->rgmii_override ? PHY_INTERFACE_MODE_RGMII
+ : priv->phy_interface;
phydev = of_phy_connect(ndev, pn, ravb_adjust_link, 0, iface);
of_node_put(pn);
if (!phydev) {
@@ -1989,20 +1986,41 @@ static const struct soc_device_attribute ravb_delay_mode_quirk_match[] = {
};
/* Set tx and rx clock internal delay modes */
-static void ravb_parse_delay_mode(struct net_device *ndev)
+static void ravb_parse_delay_mode(struct device_node *np, struct net_device *ndev)
{
struct ravb_private *priv = netdev_priv(ndev);
+ bool explicit_delay = false;
+ u32 delay;
+
+ if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay)) {
+ /* Valid values are 0 and 1800, according to DT bindings */
+ priv->rxcidm = !!delay;
+ explicit_delay = true;
+ }
+ if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay)) {
+ /* Valid values are 0 and 2000, according to DT bindings */
+ priv->txcidm = !!delay;
+ explicit_delay = true;
+ }
There are helper functions for this

s32 phy_get_internal_delay(struct phy_device *phydev, struct device *dev, const int *delay_values, int size, bool is_rx)