Merge branch 'sja1105-next'

Vladimir Oltean says:

====================
New RGMII delay DT bindings for the SJA1105 DSA driver

During recent reviews I've been telling people that new MAC drivers
should adopt a certain DT binding format for RGMII delays in order to
avoid conflicting interpretations. Some suggestions were better received
than others, and it appears we are still far from a consensus.

Part of the problem seems to be that there are still drivers that apply
RGMII delays based on an incorrect interpretation of the device tree,
and these serve as a bad example for others.
I happen to maintain one of those drivers and I am able to test it, so I
figure that one of the ways in which I can make a change is to stop
providing a bad example.

Therefore, this series adds support for the "rx-internal-delay-ps" and
"tx-internal-delay-ps" properties inside sja1105 switch port DT nodes,
and if these are present, they will decide what RGMII delays will the
driver apply.

The in-tree device trees are also updated to follow the new format, as
well as the schema validator.

I assume it's okay to get all changes merged in through the same tree
(net-next). Although the DTS changes could be split, if needed - the
driver works with or without them. There is one more DTS which should be
changed, which is in Shawn's tree but not in net-next:
https://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git/tree/arch/arm64/boot/dts/freescale/fsl-lx2160a-bluebox3.dts?h=for-next
For that, I'd have to send a separate patch.
====================

Signed-off-by: David S. Miller <[email protected]>

5 files changed, 157 insertions, 47 deletions

diff --git a/Documentation/devicetree/bindings/net/dsa/dsa.yaml b/Documentation/devicetree/bindings/net/dsa/dsa.yaml
index 224cfa45de9a..2ad7f79ad371 100644
--- a/Documentation/devicetree/bindings/net/dsa/dsa.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/dsa.yaml
@@ -46,6 +46,9 @@ patternProperties:
         type: object
         description: Ethernet switch ports
 
+        allOf:
+          - $ref: "http://devicetree.org/schemas/net/ethernet-controller.yaml#"
+
         properties:
           reg:
             description: Port number
@@ -94,6 +97,10 @@ patternProperties:
 
           managed: true
 
+          rx-internal-delay-ps: true
+
+          tx-internal-delay-ps: true
+
         required:
           - reg
 
diff --git a/Documentation/devicetree/bindings/net/dsa/nxp,sja1105.yaml b/Documentation/devicetree/bindings/net/dsa/nxp,sja1105.yaml
index f978f8719d8e..24cd733c11d1 100644
--- a/Documentation/devicetree/bindings/net/dsa/nxp,sja1105.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/nxp,sja1105.yaml
@@ -74,10 +74,42 @@ properties:
           - compatible
           - reg
 
+patternProperties:
+  "^(ethernet-)?ports$":
+    patternProperties:
+      "^(ethernet-)?port@[0-9]+$":
+        allOf:
+          - if:
+              properties:
+                phy-mode:
+                  contains:
+                    enum:
+                      - rgmii
+                      - rgmii-rxid
+                      - rgmii-txid
+                      - rgmii-id
+            then:
+              properties:
+                rx-internal-delay-ps:
+                  $ref: "#/$defs/internal-delay-ps"
+                tx-internal-delay-ps:
+                  $ref: "#/$defs/internal-delay-ps"
+
 required:
   - compatible
   - reg
 
+$defs:
+  internal-delay-ps:
+    description:
+      Disable tunable delay lines using 0 ps, or enable them and select
+      the phase between 1640 ps (73.8 degree shift at 1Gbps) and 2260 ps
+      (101.7 degree shift) in increments of 0.9 degrees (20 ps).
+    enum:
+      [0, 1640, 1660, 1680, 1700, 1720, 1740, 1760, 1780, 1800, 1820, 1840,
+       1860, 1880, 1900, 1920, 1940, 1960, 1980, 2000, 2020, 2040, 2060, 2080,
+       2100, 2120, 2140, 2160, 2180, 2200, 2220, 2240, 2260]
+
 unevaluatedProperties: false
 
 examples:
@@ -97,29 +129,40 @@ examples:
                             port@0 {
                                     phy-handle = <&rgmii_phy6>;
                                     phy-mode = "rgmii-id";
+                                    rx-internal-delay-ps = <0>;
+                                    tx-internal-delay-ps = <0>;
                                     reg = <0>;
                             };
 
                             port@1 {
                                     phy-handle = <&rgmii_phy3>;
                                     phy-mode = "rgmii-id";
+                                    rx-internal-delay-ps = <0>;
+                                    tx-internal-delay-ps = <0>;
                                     reg = <1>;
                             };
 
                             port@2 {
                                     phy-handle = <&rgmii_phy4>;
                                     phy-mode = "rgmii-id";
+                                    rx-internal-delay-ps = <0>;
+                                    tx-internal-delay-ps = <0>;
                                     reg = <2>;
                             };
 
                             port@3 {
+                                    phy-handle = <&rgmii_phy4>;
                                     phy-mode = "rgmii-id";
+                                    rx-internal-delay-ps = <0>;
+                                    tx-internal-delay-ps = <0>;
                                     reg = <3>;
                             };
 
                             port@4 {
                                     ethernet = <&enet2>;
                                     phy-mode = "rgmii";
+                                    rx-internal-delay-ps = <0>;
+                                    tx-internal-delay-ps = <0>;
                                     reg = <4>;
 
                                     fixed-link {
diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h
index 618c8d6a8be1..808419f3b808 100644
--- a/drivers/net/dsa/sja1105/sja1105.h
+++ b/drivers/net/dsa/sja1105/sja1105.h
@@ -20,6 +20,27 @@
 #define SJA1105_AGEING_TIME_MS(ms)	((ms) / 10)
 #define SJA1105_NUM_L2_POLICERS		SJA1110_MAX_L2_POLICING_COUNT
 
+/* Calculated assuming 1Gbps, where the clock has 125 MHz (8 ns period)
+ * To avoid floating point operations, we'll multiply the degrees by 10
+ * to get a "phase" and get 1 decimal point precision.
+ */
+#define SJA1105_RGMII_DELAY_PS_TO_PHASE(ps) \
+	(((ps) * 360) / 800)
+#define SJA1105_RGMII_DELAY_PHASE_TO_PS(phase) \
+	((800 * (phase)) / 360)
+#define SJA1105_RGMII_DELAY_PHASE_TO_HW(phase) \
+	(((phase) - 738) / 9)
+#define SJA1105_RGMII_DELAY_PS_TO_HW(ps) \
+	SJA1105_RGMII_DELAY_PHASE_TO_HW(SJA1105_RGMII_DELAY_PS_TO_PHASE(ps))
+
+/* Valid range in degrees is a value between 73.8 and 101.7
+ * in 0.9 degree increments
+ */
+#define SJA1105_RGMII_DELAY_MIN_PS \
+	SJA1105_RGMII_DELAY_PHASE_TO_PS(738)
+#define SJA1105_RGMII_DELAY_MAX_PS \
+	SJA1105_RGMII_DELAY_PHASE_TO_PS(1017)
+
 typedef enum {
 	SPI_READ = 0,
 	SPI_WRITE = 1,
@@ -222,8 +243,8 @@ struct sja1105_flow_block {
 
 struct sja1105_private {
 	struct sja1105_static_config static_config;
-	bool rgmii_rx_delay[SJA1105_MAX_NUM_PORTS];
-	bool rgmii_tx_delay[SJA1105_MAX_NUM_PORTS];
+	int rgmii_rx_delay_ps[SJA1105_MAX_NUM_PORTS];
+	int rgmii_tx_delay_ps[SJA1105_MAX_NUM_PORTS];
 	phy_interface_t phy_mode[SJA1105_MAX_NUM_PORTS];
 	bool fixed_link[SJA1105_MAX_NUM_PORTS];
 	unsigned long ucast_egress_floods;
diff --git a/drivers/net/dsa/sja1105/sja1105_clocking.c b/drivers/net/dsa/sja1105/sja1105_clocking.c
index 5bbf1707f2af..e3699f76f6d7 100644
--- a/drivers/net/dsa/sja1105/sja1105_clocking.c
+++ b/drivers/net/dsa/sja1105/sja1105_clocking.c
@@ -498,17 +498,6 @@ sja1110_cfg_pad_mii_id_packing(void *buf, struct sja1105_cfg_pad_mii_id *cmd,
 	sja1105_packing(buf, &cmd->txc_pd,          0,  0, size, op);
 }
 
-/* Valid range in degrees is an integer between 73.8 and 101.7 */
-static u64 sja1105_rgmii_delay(u64 phase)
-{
-	/* UM11040.pdf: The delay in degree phase is 73.8 + delay_tune * 0.9.
-	 * To avoid floating point operations we'll multiply by 10
-	 * and get 1 decimal point precision.
-	 */
-	phase *= 10;
-	return (phase - 738) / 9;
-}
-
 /* The RGMII delay setup procedure is 2-step and gets called upon each
  * .phylink_mac_config. Both are strategic.
  * The reason is that the RX Tunable Delay Line of the SJA1105 MAC has issues
@@ -521,13 +510,15 @@ int sja1105pqrs_setup_rgmii_delay(const void *ctx, int port)
 	const struct sja1105_private *priv = ctx;
 	const struct sja1105_regs *regs = priv->info->regs;
 	struct sja1105_cfg_pad_mii_id pad_mii_id = {0};
+	int rx_delay = priv->rgmii_rx_delay_ps[port];
+	int tx_delay = priv->rgmii_tx_delay_ps[port];
 	u8 packed_buf[SJA1105_SIZE_CGU_CMD] = {0};
 	int rc;
 
-	if (priv->rgmii_rx_delay[port])
-		pad_mii_id.rxc_delay = sja1105_rgmii_delay(90);
-	if (priv->rgmii_tx_delay[port])
-		pad_mii_id.txc_delay = sja1105_rgmii_delay(90);
+	if (rx_delay)
+		pad_mii_id.rxc_delay = SJA1105_RGMII_DELAY_PS_TO_HW(rx_delay);
+	if (tx_delay)
+		pad_mii_id.txc_delay = SJA1105_RGMII_DELAY_PS_TO_HW(tx_delay);
 
 	/* Stage 1: Turn the RGMII delay lines off. */
 	pad_mii_id.rxc_bypass = 1;
@@ -542,11 +533,11 @@ int sja1105pqrs_setup_rgmii_delay(const void *ctx, int port)
 		return rc;
 
 	/* Stage 2: Turn the RGMII delay lines on. */
-	if (priv->rgmii_rx_delay[port]) {
+	if (rx_delay) {
 		pad_mii_id.rxc_bypass = 0;
 		pad_mii_id.rxc_pd = 0;
 	}
-	if (priv->rgmii_tx_delay[port]) {
+	if (tx_delay) {
 		pad_mii_id.txc_bypass = 0;
 		pad_mii_id.txc_pd = 0;
 	}
@@ -561,20 +552,22 @@ int sja1110_setup_rgmii_delay(const void *ctx, int port)
 	const struct sja1105_private *priv = ctx;
 	const struct sja1105_regs *regs = priv->info->regs;
 	struct sja1105_cfg_pad_mii_id pad_mii_id = {0};
+	int rx_delay = priv->rgmii_rx_delay_ps[port];
+	int tx_delay = priv->rgmii_tx_delay_ps[port];
 	u8 packed_buf[SJA1105_SIZE_CGU_CMD] = {0};
 
 	pad_mii_id.rxc_pd = 1;
 	pad_mii_id.txc_pd = 1;
 
-	if (priv->rgmii_rx_delay[port]) {
-		pad_mii_id.rxc_delay = sja1105_rgmii_delay(90);
+	if (rx_delay) {
+		pad_mii_id.rxc_delay = SJA1105_RGMII_DELAY_PS_TO_HW(rx_delay);
 		/* The "BYPASS" bit in SJA1110 is actually a "don't bypass" */
 		pad_mii_id.rxc_bypass = 1;
 		pad_mii_id.rxc_pd = 0;
 	}
 
-	if (priv->rgmii_tx_delay[port]) {
-		pad_mii_id.txc_delay = sja1105_rgmii_delay(90);
+	if (tx_delay) {
+		pad_mii_id.txc_delay = SJA1105_RGMII_DELAY_PS_TO_HW(tx_delay);
 		pad_mii_id.txc_bypass = 1;
 		pad_mii_id.txc_pd = 0;
 	}
diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 0f1bba0076a8..1832d4bd3440 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1109,27 +1109,78 @@ static int sja1105_static_config_load(struct sja1105_private *priv)
 	return sja1105_static_config_upload(priv);
 }
 
-static int sja1105_parse_rgmii_delays(struct sja1105_private *priv)
+/* This is the "new way" for a MAC driver to configure its RGMII delay lines,
+ * based on the explicit "rx-internal-delay-ps" and "tx-internal-delay-ps"
+ * properties. It has the advantage of working with fixed links and with PHYs
+ * that apply RGMII delays too, and the MAC driver needs not perform any
+ * special checks.
+ *
+ * Previously we were acting upon the "phy-mode" property when we were
+ * operating in fixed-link, basically acting as a PHY, but with a reversed
+ * interpretation: PHY_INTERFACE_MODE_RGMII_TXID means that the MAC should
+ * behave as if it is connected to a PHY which has applied RGMII delays in the
+ * TX direction. So if anything, RX delays should have been added by the MAC,
+ * but we were adding TX delays.
+ *
+ * If the "{rx,tx}-internal-delay-ps" properties are not specified, we fall
+ * back to the legacy behavior and apply delays on fixed-link ports based on
+ * the reverse interpretation of the phy-mode. This is a deviation from the
+ * expected default behavior which is to simply apply no delays. To achieve
+ * that behavior with the new bindings, it is mandatory to specify
+ * "{rx,tx}-internal-delay-ps" with a value of 0.
+ */
+static int sja1105_parse_rgmii_delays(struct sja1105_private *priv, int port,
+				      struct device_node *port_dn)
 {
-	struct dsa_switch *ds = priv->ds;
-	int port;
+	phy_interface_t phy_mode = priv->phy_mode[port];
+	struct device *dev = &priv->spidev->dev;
+	int rx_delay = -1, tx_delay = -1;
 
-	for (port = 0; port < ds->num_ports; port++) {
-		if (!priv->fixed_link[port])
-			continue;
+	if (!phy_interface_mode_is_rgmii(phy_mode))
+		return 0;
 
-		if (priv->phy_mode[port] == PHY_INTERFACE_MODE_RGMII_RXID ||
-		    priv->phy_mode[port] == PHY_INTERFACE_MODE_RGMII_ID)
-			priv->rgmii_rx_delay[port] = true;
+	of_property_read_u32(port_dn, "rx-internal-delay-ps", &rx_delay);
+	of_property_read_u32(port_dn, "tx-internal-delay-ps", &tx_delay);
 
-		if (priv->phy_mode[port] == PHY_INTERFACE_MODE_RGMII_TXID ||
-		    priv->phy_mode[port] == PHY_INTERFACE_MODE_RGMII_ID)
-			priv->rgmii_tx_delay[port] = true;
+	if (rx_delay == -1 && tx_delay == -1 && priv->fixed_link[port]) {
+		dev_warn(dev,
+			 "Port %d interpreting RGMII delay settings based on \"phy-mode\" property, "
+			 "please update device tree to specify \"rx-internal-delay-ps\" and "
+			 "\"tx-internal-delay-ps\"",
+			 port);
 
-		if ((priv->rgmii_rx_delay[port] || priv->rgmii_tx_delay[port]) &&
-		    !priv->info->setup_rgmii_delay)
-			return -EINVAL;
+		if (phy_mode == PHY_INTERFACE_MODE_RGMII_RXID ||
+		    phy_mode == PHY_INTERFACE_MODE_RGMII_ID)
+			rx_delay = 2000;
+
+		if (phy_mode == PHY_INTERFACE_MODE_RGMII_TXID ||
+		    phy_mode == PHY_INTERFACE_MODE_RGMII_ID)
+			tx_delay = 2000;
 	}
+
+	if (rx_delay < 0)
+		rx_delay = 0;
+	if (tx_delay < 0)
+		tx_delay = 0;
+
+	if ((rx_delay || tx_delay) && !priv->info->setup_rgmii_delay) {
+		dev_err(dev, "Chip cannot apply RGMII delays\n");
+		return -EINVAL;
+	}
+
+	if ((rx_delay && rx_delay < SJA1105_RGMII_DELAY_MIN_PS) ||
+	    (tx_delay && tx_delay < SJA1105_RGMII_DELAY_MIN_PS) ||
+	    (rx_delay > SJA1105_RGMII_DELAY_MAX_PS) ||
+	    (tx_delay > SJA1105_RGMII_DELAY_MAX_PS)) {
+		dev_err(dev,
+			"port %d RGMII delay values out of range, must be between %d and %d ps\n",
+			port, SJA1105_RGMII_DELAY_MIN_PS, SJA1105_RGMII_DELAY_MAX_PS);
+		return -ERANGE;
+	}
+
+	priv->rgmii_rx_delay_ps[port] = rx_delay;
+	priv->rgmii_tx_delay_ps[port] = tx_delay;
+
 	return 0;
 }
 
@@ -1180,6 +1231,10 @@ static int sja1105_parse_ports_node(struct sja1105_private *priv,
 		}
 
 		priv->phy_mode[index] = phy_mode;
+
+		err = sja1105_parse_rgmii_delays(priv, index, child);
+		if (err)
+			return err;
 	}
 
 	return 0;
@@ -3317,15 +3372,6 @@ static int sja1105_probe(struct spi_device *spi)
 		return rc;
 	}
 
-	/* Error out early if internal delays are required through DT
-	 * and we can't apply them.
-	 */
-	rc = sja1105_parse_rgmii_delays(priv);
-	if (rc < 0) {
-		dev_err(ds->dev, "RGMII delay not supported\n");
-		return rc;
-	}
-
 	if (IS_ENABLED(CONFIG_NET_SCH_CBS)) {
 		priv->cbs = devm_kcalloc(dev, priv->info->num_cbs_shapers,
 					 sizeof(struct sja1105_cbs_entry),