[PATCH net-next v10 04/12] 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.

Add the family D implementation as rtl8365mb_d_ext_config_forcemode().
The shared code reaches it through the ext_config_forcemode pointer in
struct rtl8365mb_family_info, so it needs no is_d() check.

Nothing points to it until the family D info is added together with the
chip table entry in the last patch. Until then it is not static and is
declared in rtl8365mb.h, so that the build does not warn about an unused
function.

Tested-by: Gustavo Foletto Mora <gusfmora@gmail.com>
Signed-off-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
---
 drivers/net/dsa/realtek/rtl8365mb.h      |   4 +
 drivers/net/dsa/realtek/rtl8365mb_main.c | 110 +++++++++++++++++++++++
 2 files changed, 114 insertions(+)

diff --git a/drivers/net/dsa/realtek/rtl8365mb.h b/drivers/net/dsa/realtek/rtl8365mb.h
index 664bddb..3d607bd 100644
--- a/drivers/net/dsa/realtek/rtl8365mb.h
+++ b/drivers/net/dsa/realtek/rtl8365mb.h
@@ -24,6 +24,10 @@ struct rtl8365mb_family_info {
 const struct rtl8365mb_family_info *
 rtl8365mb_get_family_info(struct realtek_priv *priv);
 
+int rtl8365mb_d_ext_config_forcemode(struct realtek_priv *priv, int port,
+				     bool link, int speed, int duplex,
+				     bool tx_pause, bool rx_pause);
+
 static inline bool rtl8365mb_is_d(struct realtek_priv *priv)
 {
 	return rtl8365mb_get_family_info(priv)->family == RTL8365MB_FAMILY_D;
diff --git a/drivers/net/dsa/realtek/rtl8365mb_main.c b/drivers/net/dsa/realtek/rtl8365mb_main.c
index ef75dc2..27a6917 100644
--- a/drivers/net/dsa/realtek/rtl8365mb_main.c
+++ b/drivers/net/dsa/realtek/rtl8365mb_main.c
@@ -346,6 +346,8 @@
 #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
+#define RTL8365MB_D_PORT_SPEED_MSB_MASK	BIT(2)
 
 /* External interface force configuration registers 0~2 */
 #define RTL8365MB_C_DIGITAL_INTERFACE_FORCE_REG0		0x1310 /* EXT0 */
@@ -364,6 +366,26 @@
 #define   RTL8365MB_DIGITAL_INTERFACE_FORCE_DUPLEX_MASK		BIT(2)
 #define   RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK		GENMASK(1, 0)
 
+/* 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
 #define   RTL8365MB_CPU_PORT_MASK_MASK	RTL8365MB_PORT_MASK
@@ -1713,6 +1735,94 @@ static int rtl8365mb_c_ext_config_forcemode(struct realtek_priv *priv, int port,
 	return 0;
 }
 
+int rtl8365mb_d_ext_config_forcemode(struct realtek_priv *priv, int port,
+				     bool link, int speed, int duplex,
+				     bool tx_pause, bool rx_pause)
+{
+	const struct rtl8365mb_extint *extint =
+		rtl8365mb_get_port_extint(priv, port);
+	u32 r_tx_pause;
+	u32 r_rx_pause;
+	u32 r_duplex;
+	u32 r_speed;
+	u32 r_link;
+	int val;
+	int ret;
+
+	if (!extint)
+		return -ENODEV;
+
+	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;
+
+		if (speed == SPEED_2500) {
+			r_speed = RTL8365MB_D_PORT_SPEED_2500M;
+		} else if (speed == SPEED_1000) {
+			r_speed = RTL8365MB_PORT_SPEED_1000M;
+		} else if (speed == SPEED_100) {
+			r_speed = RTL8365MB_PORT_SPEED_100M;
+		} else if (speed == SPEED_10) {
+			r_speed = RTL8365MB_PORT_SPEED_10M;
+		} else {
+			dev_err(priv->dev, "unsupported port speed %s\n",
+				phy_speed_to_str(speed));
+			return -EINVAL;
+		}
+
+		if (duplex == DUPLEX_FULL) {
+			r_duplex = 1;
+		} else if (duplex == DUPLEX_HALF) {
+			r_duplex = 0;
+		} else {
+			dev_err(priv->dev, "unsupported duplex %s\n",
+				phy_duplex_to_str(duplex));
+			return -EINVAL;
+		}
+	} else {
+		/* Force the link down and reset any programmed configuration */
+		r_link = 0;
+		r_tx_pause = 0;
+		r_rx_pause = 0;
+		r_speed = 0;
+		r_duplex = 0;
+	}
+
+	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 &
+			 RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK);
+
+	/* Speed is 3 bits on family D: bits[1:0] go into FORCE_SPEED,
+	 * bit[2] goes into FORCE_SPEED2 (register bit 12); only 2500M
+	 * sets it. Register bit 13 is reserved.
+	 */
+	val |= FIELD_PREP(RTL8365MB_D_DIGITAL_INTERFACE_FORCE_SPEED2_MASK,
+			  FIELD_GET(RTL8365MB_D_PORT_SPEED_MSB_MASK,
+				    r_speed));
+	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;
+
+	return 0;
+}
+
 static void rtl8365mb_phylink_get_caps(struct dsa_switch *ds, int port,
 				       struct phylink_config *config)
 {
-- 
2.53.0