[RFC PATCH net-next 0/4] RGMII Internal delay common property

[RFC PATCH net-next 0/4] RGMII Internal delay common property

[Dan Murphy]

Hello

The RGMII internal delay is a common setting found in most RGMII capable PHY
devices.  It was found that many vendor specific device tree properties exist
to do the same function. This creates a common property to be used for PHY's
that have tunable internal delays for the Rx and Tx paths.

Dan Murphy (4):
  dt-bindings: net: Add tx and rx internal delays
  net: phy: Add a helper to return the index for of the internal delay
  dt-bindings: net: Add RGMII internal delay for DP83869
  net: dp83869: Add RGMII internal delay configuration

 .../bindings/net/ethernet-controller.yaml     |  14 +++
 .../devicetree/bindings/net/ti,dp83869.yaml   |  16 +++
 drivers/net/phy/dp83869.c                     | 101 ++++++++++++++++++
 drivers/net/phy/phy_device.c                  |  45 ++++++++
 include/linux/phy.h                           |   2 +
 5 files changed, 178 insertions(+)

-- 
2.26.2

[RFC PATCH net-next 1/4] dt-bindings: net: Add tx and rx internal delays

[Dan Murphy]

tx-internal-delays and rx-internal-delays are a common setting for RGMII
capable devices.

These properties are used when the phy-mode or phy-controller is set to
rgmii-id, rgmii-rxid or rgmii-txid.  These modes indicate to the
controller that the PHY will add the internal delay for the connection.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---
 .../bindings/net/ethernet-controller.yaml          | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
index ac471b60ed6a..3f25066c339c 100644
--- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
@@ -143,6 +143,20 @@ properties:
       Specifies the PHY management type. If auto is set and fixed-link
       is not specified, it uses MDIO for management.
 
+  rx-internal-delay:
+    $ref: /schemas/types.yaml#definitions/uint32
+    description: |
+      RGMII Receive PHY Clock Delay defined in pico seconds.  This is used for
+      PHY's that have configurable RX internal delays.  This property is only
+      used when the phy-mode or phy-connection-type is rgmii-id or rgmii-rxid.
+
+  tx-internal-delay:
+    $ref: /schemas/types.yaml#definitions/uint32
+    description: |
+      RGMII Transmit PHY Clock Delay defined in pico seconds.  This is used for
+      PHY's that have configurable TX internal delays.  This property is only
+      used when the phy-mode or phy-connection-type is rgmii-id or rgmii-txid.
+
   fixed-link:
     allOf:
       - if:
-- 
2.26.2

[RFC PATCH net-next 2/4] net: phy: Add a helper to return the index for of the internal delay

[Dan Murphy]

Add a helper function that will return the index in the array for the
passed in internal delay value.  The helper requires the array, size and
delay value.

The helper will then return the index for the exact match or return the
index for the index to the closest smaller value.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---
 drivers/net/phy/phy_device.c | 45 ++++++++++++++++++++++++++++++++++++
 include/linux/phy.h          |  2 ++
 2 files changed, 47 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 7481135d27ab..40f53b379d2b 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2661,6 +2661,51 @@ void phy_get_pause(struct phy_device *phydev, bool *tx_pause, bool *rx_pause)
 }
 EXPORT_SYMBOL(phy_get_pause);
 
+/**
+ * phy_get_delay_index - returns the index of the internal delay
+ * @phydev: phy_device struct
+ * @delay_values: array of delays the PHY supports
+ * @size: the size of the delay array
+ * @delay: the delay to be looked up
+ *
+ * Returns the index within the array of internal delay passed in.
+ */
+int phy_get_delay_index(struct phy_device *phydev, int *delay_values, int size,
+			int delay)
+{
+	int i;
+
+	if (size <= 0)
+		return -EINVAL;
+
+	if (delay <= delay_values[0])
+		return 0;
+
+	if (delay > delay_values[size - 1])
+		return size - 1;
+
+	for (i = 0; i < size; i++) {
+		if (delay == delay_values[i])
+			return i;
+
+		/* Find an approximate index by looking up the table */
+		if (delay > delay_values[i - 1] &&
+		    delay < delay_values[i]) {
+			if (delay - delay_values[i - 1] < delay_values[i] - delay)
+				return i - 1;
+			else
+				return i;
+		}
+
+	}
+
+	phydev_err(phydev, "error finding internal delay index for %d\n",
+		   delay);
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(phy_get_delay_index);
+
 static bool phy_drv_supports_irq(struct phy_driver *phydrv)
 {
 	return phydrv->config_intr && phydrv->ack_interrupt;
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 467aa8bf9f64..78b7b77f9a67 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -1406,6 +1406,8 @@ void phy_set_asym_pause(struct phy_device *phydev, bool rx, bool tx);
 bool phy_validate_pause(struct phy_device *phydev,
 			struct ethtool_pauseparam *pp);
 void phy_get_pause(struct phy_device *phydev, bool *tx_pause, bool *rx_pause);
+int phy_get_delay_index(struct phy_device *phydev, int *delay_values,
+			int size, int delay);
 void phy_resolve_pause(unsigned long *local_adv, unsigned long *partner_adv,
 		       bool *tx_pause, bool *rx_pause);
 
-- 
2.26.2

[RFC PATCH net-next 3/4] dt-bindings: net: Add RGMII internal delay for DP83869

[Dan Murphy]

Add the internal delay values into the header and update the binding
with the internal delay properties.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---
 .../devicetree/bindings/net/ti,dp83869.yaml      | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ti,dp83869.yaml b/Documentation/devicetree/bindings/net/ti,dp83869.yaml
index 5b69ef03bbf7..b2547b43e103 100644
--- a/Documentation/devicetree/bindings/net/ti,dp83869.yaml
+++ b/Documentation/devicetree/bindings/net/ti,dp83869.yaml
@@ -64,6 +64,20 @@ properties:
        Operational mode for the PHY.  If this is not set then the operational
        mode is set by the straps. see dt-bindings/net/ti-dp83869.h for values
 
+  rx-internal-delay:
+    $ref: "#/properties/rx-internal-delay"
+    description: Delay is in pico seconds
+    enum: [ 250, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 2750, 3000,
+            3250, 3500, 3750, 4000 ]
+    default: 2000
+
+  tx-internal-delay:
+    $ref: "#/properties/tx-internal-delay"
+    description: Delay is in pico seconds
+    enum: [ 250, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 2750, 3000,
+            3250, 3500, 3750, 4000 ]
+    default: 2000
+
 required:
   - reg
 
@@ -80,5 +94,7 @@ examples:
         ti,op-mode = <DP83869_RGMII_COPPER_ETHERNET>;
         ti,max-output-impedance = "true";
         ti,clk-output-sel = <DP83869_CLK_O_SEL_CHN_A_RCLK>;
+        rx-internal-delay = <2000>;
+        tx-internal-delay = <2000>;
       };
     };
-- 
2.26.2

[RFC PATCH net-next 4/4] net: dp83869: Add RGMII internal delay configuration

[Dan Murphy]

Add RGMII internal delay configuration for Rx and Tx.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---
 drivers/net/phy/dp83869.c | 101 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)

diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
index cfb22a21a2e6..40c34fefffe4 100644
--- a/drivers/net/phy/dp83869.c
+++ b/drivers/net/phy/dp83869.c
@@ -99,6 +99,14 @@
 #define DP83869_OP_MODE_MII			BIT(5)
 #define DP83869_SGMII_RGMII_BRIDGE		BIT(6)
 
+/* RGMIIDCTL bits */
+#define DP83869_RGMII_TX_CLK_DELAY_SHIFT	4
+#define DP83869_RGMII_CLK_DELAY_INV		0
+
+static int dp83869_internal_delay[] = {250, 500, 750, 1000, 1250, 1500, 1750,
+				       2000, 2250, 2500, 2750, 3000, 3250,
+				       3500, 3750, 4000};
+
 enum {
 	DP83869_PORT_MIRRORING_KEEP,
 	DP83869_PORT_MIRRORING_EN,
@@ -108,6 +116,8 @@ enum {
 struct dp83869_private {
 	int tx_fifo_depth;
 	int rx_fifo_depth;
+	u32 rx_id_delay;
+	u32 tx_id_delay;
 	int io_impedance;
 	int port_mirroring;
 	bool rxctrl_strap_quirk;
@@ -182,6 +192,7 @@ static int dp83869_of_init(struct phy_device *phydev)
 	struct dp83869_private *dp83869 = phydev->priv;
 	struct device *dev = &phydev->mdio.dev;
 	struct device_node *of_node = dev->of_node;
+	int delay_size = ARRAY_SIZE(dp83869_internal_delay);
 	int ret;
 
 	if (!of_node)
@@ -232,6 +243,26 @@ static int dp83869_of_init(struct phy_device *phydev)
 				 &dp83869->tx_fifo_depth))
 		dp83869->tx_fifo_depth = DP83869_PHYCR_FIFO_DEPTH_4_B_NIB;
 
+	dp83869->rx_id_delay = DP83869_RGMII_CLK_DELAY_INV;
+	ret = of_property_read_u32(of_node, "rx-internal-delay",
+				   &dp83869->rx_id_delay);
+	if (!ret && dp83869->rx_id_delay > dp83869_internal_delay[delay_size]) {
+		phydev_err(phydev,
+			   "rx-internal-delay value of %u out of range\n",
+			   dp83869->rx_id_delay);
+		return -EINVAL;
+	}
+
+	dp83869->tx_id_delay = DP83869_RGMII_CLK_DELAY_INV;
+	ret = of_property_read_u32(of_node, "tx-internal-delay",
+				   &dp83869->tx_id_delay);
+	if (!ret && dp83869->tx_id_delay > dp83869_internal_delay[delay_size]) {
+		phydev_err(phydev,
+			   "tx-internal-delay value of %u out of range\n",
+			   dp83869->tx_id_delay);
+		return -EINVAL;
+	}
+
 	return ret;
 }
 #else
@@ -270,6 +301,29 @@ static int dp83869_configure_rgmii(struct phy_device *phydev,
 	return ret;
 }
 
+static int dp83869_verify_rgmii_cfg(struct phy_device *phydev)
+{
+	struct dp83869_private *dp83869 = phydev->priv;
+
+	/* RX delay *must* be specified if internal delay of RX is used. */
+	if ((phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
+	     phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID) &&
+	     dp83869->rx_id_delay == DP83869_RGMII_CLK_DELAY_INV) {
+		phydev_err(phydev, "ti,rx-internal-delay must be specified\n");
+		return -EINVAL;
+	}
+
+	/* TX delay *must* be specified if internal delay of TX is used. */
+	if ((phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
+	     phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID) &&
+	     dp83869->tx_id_delay == DP83869_RGMII_CLK_DELAY_INV) {
+		phydev_err(phydev, "ti,tx-internal-delay must be specified\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int dp83869_configure_mode(struct phy_device *phydev,
 				  struct dp83869_private *dp83869)
 {
@@ -371,6 +425,12 @@ static int dp83869_config_init(struct phy_device *phydev)
 {
 	struct dp83869_private *dp83869 = phydev->priv;
 	int ret, val;
+	int delay_size = ARRAY_SIZE(dp83869_internal_delay);
+	int delay = 0;
+
+	ret = dp83869_verify_rgmii_cfg(phydev);
+	if (ret)
+		return ret;
 
 	ret = dp83869_configure_mode(phydev, dp83869);
 	if (ret)
@@ -394,6 +454,47 @@ static int dp83869_config_init(struct phy_device *phydev)
 				     dp83869->clk_output_sel <<
 				     DP83869_IO_MUX_CFG_CLK_O_SEL_SHIFT);
 
+	if (phy_interface_is_rgmii(phydev)) {
+		val = phy_read_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIICTL);
+
+		val &= ~(DP83869_RGMII_TX_CLK_DELAY_EN | DP83869_RGMII_RX_CLK_DELAY_EN);
+		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
+			val |= (DP83869_RGMII_TX_CLK_DELAY_EN | DP83869_RGMII_RX_CLK_DELAY_EN);
+
+		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)
+			val |= DP83869_RGMII_TX_CLK_DELAY_EN;
+
+		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID)
+			val |= DP83869_RGMII_RX_CLK_DELAY_EN;
+
+		phy_write_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIICTL, val);
+
+		if (dp83869->rx_id_delay) {
+			val = phy_get_delay_index(phydev,
+						  &dp83869_internal_delay[0],
+						  delay_size,
+						  dp83869->rx_id_delay);
+			if (val < 0)
+				return val;
+
+			delay |= val;
+		}
+
+		if (dp83869->tx_id_delay) {
+			val = phy_get_delay_index(phydev,
+						  &dp83869_internal_delay[0],
+						  delay_size,
+						  dp83869->tx_id_delay);
+			if (val < 0)
+				return val;
+
+			delay |= val << DP83869_RGMII_TX_CLK_DELAY_SHIFT;
+		}
+
+		phy_write_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIIDCTL,
+			      delay);
+	}
+
 	return ret;
 }
 
-- 
2.26.2

Re: [RFC PATCH net-next 1/4] dt-bindings: net: Add tx and rx internal delays

[Florian Fainelli]

On 5/21/2020 10:48 AM, Dan Murphy wrote:
> tx-internal-delays and rx-internal-delays are a common setting for RGMII
> capable devices.
> 
> These properties are used when the phy-mode or phy-controller is set to
> rgmii-id, rgmii-rxid or rgmii-txid.  These modes indicate to the
> controller that the PHY will add the internal delay for the connection.
> 
> Signed-off-by: Dan Murphy <dmurphy@ti.com>
> ---
>  .../bindings/net/ethernet-controller.yaml          | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
> index ac471b60ed6a..3f25066c339c 100644
> --- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
> +++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
> @@ -143,6 +143,20 @@ properties:
>        Specifies the PHY management type. If auto is set and fixed-link
>        is not specified, it uses MDIO for management.
>  
> +  rx-internal-delay:

Please name this 'rx-internal-delay-ps'

> +    $ref: /schemas/types.yaml#definitions/uint32
> +    description: |
> +      RGMII Receive PHY Clock Delay defined in pico seconds.  This is used for
> +      PHY's that have configurable RX internal delays.  This property is only
> +      used when the phy-mode or phy-connection-type is rgmii-id or rgmii-rxid.
> +
> +  tx-internal-delay:

Likewise

> +    $ref: /schemas/types.yaml#definitions/uint32
> +    description: |
> +      RGMII Transmit PHY Clock Delay defined in pico seconds.  This is used for
> +      PHY's that have configurable TX internal delays.  This property is only
> +      used when the phy-mode or phy-connection-type is rgmii-id or rgmii-txid.
> +
>    fixed-link:
>      allOf:
>        - if:
> 

-- 
Florian

Re: [RFC PATCH net-next 4/4] net: dp83869: Add RGMII internal delay configuration

[Andrew Lunn]

On Thu, May 21, 2020 at 12:48:34PM -0500, Dan Murphy wrote:
> Add RGMII internal delay configuration for Rx and Tx.
> 
> Signed-off-by: Dan Murphy <dmurphy@ti.com>
> ---
>  drivers/net/phy/dp83869.c | 101 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 101 insertions(+)
> 
> diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
> index cfb22a21a2e6..40c34fefffe4 100644
> --- a/drivers/net/phy/dp83869.c
> +++ b/drivers/net/phy/dp83869.c
> @@ -99,6 +99,14 @@
>  #define DP83869_OP_MODE_MII			BIT(5)
>  #define DP83869_SGMII_RGMII_BRIDGE		BIT(6)
>  
> +/* RGMIIDCTL bits */
> +#define DP83869_RGMII_TX_CLK_DELAY_SHIFT	4
> +#define DP83869_RGMII_CLK_DELAY_INV		0
> +
> +static int dp83869_internal_delay[] = {250, 500, 750, 1000, 1250, 1500, 1750,
> +				       2000, 2250, 2500, 2750, 3000, 3250,
> +				       3500, 3750, 4000};
> +
>  enum {
>  	DP83869_PORT_MIRRORING_KEEP,
>  	DP83869_PORT_MIRRORING_EN,
> @@ -108,6 +116,8 @@ enum {
>  struct dp83869_private {
>  	int tx_fifo_depth;
>  	int rx_fifo_depth;
> +	u32 rx_id_delay;
> +	u32 tx_id_delay;
>  	int io_impedance;
>  	int port_mirroring;
>  	bool rxctrl_strap_quirk;
> @@ -182,6 +192,7 @@ static int dp83869_of_init(struct phy_device *phydev)
>  	struct dp83869_private *dp83869 = phydev->priv;
>  	struct device *dev = &phydev->mdio.dev;
>  	struct device_node *of_node = dev->of_node;
> +	int delay_size = ARRAY_SIZE(dp83869_internal_delay);
>  	int ret;
>  
>  	if (!of_node)
> @@ -232,6 +243,26 @@ static int dp83869_of_init(struct phy_device *phydev)
>  				 &dp83869->tx_fifo_depth))
>  		dp83869->tx_fifo_depth = DP83869_PHYCR_FIFO_DEPTH_4_B_NIB;
>  
> +	dp83869->rx_id_delay = DP83869_RGMII_CLK_DELAY_INV;
> +	ret = of_property_read_u32(of_node, "rx-internal-delay",
> +				   &dp83869->rx_id_delay);
> +	if (!ret && dp83869->rx_id_delay > dp83869_internal_delay[delay_size]) {
> +		phydev_err(phydev,
> +			   "rx-internal-delay value of %u out of range\n",
> +			   dp83869->rx_id_delay);
> +		return -EINVAL;
> +	}

Hi Dan

Seems like the helper should be doing the range check, and printing
the message. It should be common to all PHY drivers using delays
looked up in a list.

I also wonder about putting the of_property_read_u32 inside a
helper. Something like

of_get_phy_rgmii_delays(struct device_node *np, phy_interface_t interface,
			u32 *rx_delay, u32 *tx_delay)

And maybe a third helper which combines phy_get_delay_index() and
of_get_phy_rgmii_delays().

> +static int dp83869_verify_rgmii_cfg(struct phy_device *phydev)
> +{
> +	struct dp83869_private *dp83869 = phydev->priv;
> +
> +	/* RX delay *must* be specified if internal delay of RX is used. */

No. As i said last time, default to 2ns, if there is no specific delay
value in DT.

    Andrew