[PATCH net-next v4 3/9] net: dsa: realtek: rtl8365mb: set speed for family D

[Mieczyslaw Nalewaj <namiltd@yahoo.com>]

On family C hardware, forcing a 2.5 Gbps link speed requires relying
strictly on the HSGMII SerDes configuration block, while forcing a dummy
1 Gbps value inside the standard digital interface register. Family D
introduces a dedicated hardware link speed value (5) for 2500M. The speed
bitfield width has been expanded to 3 bits, splitting the most significant
bit into a new separate register field (FORCE_SPEED2), which maps directly
to a distinct per-port digital interface force layout.

On family D the forced-mode configuration (link, duplex, pause, speed)
is written to a per-port register at 0x12c0 + port instead of the
per-extint register. The bit positions of TXPAUSE, RXPAUSE, LINK, DUPLEX
and the low two speed bits are the same as on family C; the upper speed
bits go to bits 13:12 (FORCE_SPEED2), so FORCE_EN (bit 12 on family C)
is not set. A second per-port register at 0x12c8 + port enables the
forced mode: the vendor RTL8367D API writes 0xFFFF there when the MAC
is forced and 0 otherwise. This driver always forces the MAC, as on
family C, so it writes 0xFFFF on every call, including link down.

Signed-off-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
---
 drivers/net/dsa/realtek/rtl8365mb_main.c | 82 ++++++++++++++++++++----
 1 file changed, 69 insertions(+), 13 deletions(-)

diff --git a/drivers/net/dsa/realtek/rtl8365mb_main.c b/drivers/net/dsa/realtek/rtl8365mb_main.c
index 840db5a..2dabc4d 100644
--- a/drivers/net/dsa/realtek/rtl8365mb_main.c
+++ b/drivers/net/dsa/realtek/rtl8365mb_main.c
@@ -344,6 +344,7 @@
 #define RTL8365MB_PORT_SPEED_10M	0
 #define RTL8365MB_PORT_SPEED_100M	1
 #define RTL8365MB_PORT_SPEED_1000M	2
+#define RTL8365MB_D_PORT_SPEED_2500M	5
 
 /* External interface force configuration registers 0~2 */
 #define RTL8365MB_DIGITAL_INTERFACE_FORCE_REG0		0x1310 /* EXT0 */
@@ -361,6 +362,28 @@
 #define   RTL8365MB_DIGITAL_INTERFACE_FORCE_LINK_MASK		BIT(4)
 #define   RTL8365MB_DIGITAL_INTERFACE_FORCE_DUPLEX_MASK		BIT(2)
 #define   RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK		GENMASK(1, 0)
+/* Width of the FORCE_SPEED field, bits[1:0] */
+#define   RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_WIDTH		2
+
+/* bits[13:12]; bit 13 reserved, no defined speed value uses it yet */
+#define   RTL8365MB_D_DIGITAL_INTERFACE_FORCE_SPEED2_MASK	GENMASK(13, 12)
+
+#define RTL8365MB_D_DIGITAL_INTERFACE_FORCE_REG_BASE		0x12c0
+#define RTL8365MB_D_DIGITAL_INTERFACE_FORCE_REG(_port) \
+		(RTL8365MB_D_DIGITAL_INTERFACE_FORCE_REG_BASE + (_port))
+
+#define RTL8365MB_D_DIGITAL_INTERFACE_FORCE_EN_BASE		0x12c8
+#define RTL8365MB_D_DIGITAL_INTERFACE_FORCE_REG_EN(_port) \
+		(RTL8365MB_D_DIGITAL_INTERFACE_FORCE_EN_BASE + (_port))
+
+/* Per-port force-mode enable. The vendor RTL8367D API
+ * (dal_rtl8367d_port_macForceLink_set()) treats it as an on/off switch for
+ * the whole forced configuration: all bits set when the MAC is forced, zero
+ * when it is not. The meaning of the individual bits is not documented.
+ * This driver always forces the MAC, as on family C, so all bits are set
+ * on every call, including link down.
+ */
+#define RTL8365MB_D_DIGITAL_INTERFACE_FORCE_EN_ALL_MASK	GENMASK(15, 0)
 
 /* CPU port mask register - controls which ports are treated as CPU ports */
 #define RTL8365MB_CPU_PORT_MASK_REG	0x1219
@@ -1646,23 +1669,32 @@ static int rtl8365mb_ext_config_forcemode(struct realtek_priv *priv, int port,
 	u32 r_duplex;
 	u32 r_speed;
 	u32 r_link;
+	bool is_d;
 	int val;
 	int ret;
 
 	if (!extint)
 		return -ENODEV;
 
+	is_d = rtl8365mb_get_family(priv) == RTL8365MB_FAMILY_D;
 	if (link) {
 		/* Force the link up with the desired configuration */
 		r_link = 1;
 		r_rx_pause = rx_pause ? 1 : 0;
 		r_tx_pause = tx_pause ? 1 : 0;
 
-		/* The speed field has no value for 2.5 Gbps: the rate is
-		 * determined by the HSGMII SerDes configuration, and the
-		 * vendor driver programs the 1 Gbps value here.
-		 */
-		if (speed == SPEED_2500 || speed == SPEED_1000) {
+		if (speed == SPEED_2500) {
+			if (is_d) {
+				r_speed = RTL8365MB_D_PORT_SPEED_2500M;
+			} else {
+				/* The speed field has no value for 2.5 Gbps:
+				 * the rate is determined by the HSGMII SerDes
+				 * configuration, and the vendor driver programs
+				 * the 1 Gbps value here.
+				 */
+				r_speed = RTL8365MB_PORT_SPEED_1000M;
+			}
+		} else if (speed == SPEED_1000) {
 			r_speed = RTL8365MB_PORT_SPEED_1000M;
 		} else if (speed == SPEED_100) {
 			r_speed = RTL8365MB_PORT_SPEED_100M;
@@ -1692,20 +1724,44 @@ static int rtl8365mb_ext_config_forcemode(struct realtek_priv *priv, int port,
 		r_duplex = 0;
 	}
 
-	val = FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_EN_MASK, 1) |
-	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_TXPAUSE_MASK,
+	val = FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_TXPAUSE_MASK,
 			 r_tx_pause) |
 	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_RXPAUSE_MASK,
 			 r_rx_pause) |
 	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_LINK_MASK, r_link) |
 	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_DUPLEX_MASK,
 			 r_duplex) |
-	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK, r_speed);
-	ret = regmap_write(priv->map,
-			   RTL8365MB_DIGITAL_INTERFACE_FORCE_REG(extint->id),
-			   val);
-	if (ret)
-		return ret;
+	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK,
+			 r_speed &
+			 RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK);
+
+	if (is_d) {
+		/* Speed is 3 bits on family D: bits[1:0] go into FORCE_SPEED,
+		 * bit[2] goes into FORCE_SPEED2 (bit 12); only 2500M sets it,
+		 * bit 13 of the field is unused.
+		 */
+		val |= FIELD_PREP(RTL8365MB_D_DIGITAL_INTERFACE_FORCE_SPEED2_MASK,
+				  r_speed >>
+				  RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_WIDTH);
+		ret = regmap_write(priv->map,
+				   RTL8365MB_D_DIGITAL_INTERFACE_FORCE_REG(port),
+				   val);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(priv->map,
+				   RTL8365MB_D_DIGITAL_INTERFACE_FORCE_REG_EN(port),
+				   RTL8365MB_D_DIGITAL_INTERFACE_FORCE_EN_ALL_MASK);
+		if (ret)
+			return ret;
+	} else {
+		val |= FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_EN_MASK, 1);
+		ret = regmap_write(priv->map,
+				   RTL8365MB_DIGITAL_INTERFACE_FORCE_REG(extint->id),
+				   val);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
-- 
2.53.0