--- /dev/null
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/* Copyright 2020 NXP
+ * Lynx PCS MDIO helpers
+ */
+
+#include <linux/mdio.h>
+#include <linux/phylink.h>
+#include <linux/pcs-lynx.h>
+
+#define SGMII_CLOCK_PERIOD_NS 8 /* PCS is clocked at 125 MHz */
+#define LINK_TIMER_VAL(ns) ((u32)((ns) / SGMII_CLOCK_PERIOD_NS))
+
+#define SGMII_AN_LINK_TIMER_NS 1600000 /* defined by SGMII spec */
+
+#define LINK_TIMER_LO 0x12
+#define LINK_TIMER_HI 0x13
+#define IF_MODE 0x14
+#define IF_MODE_SGMII_EN BIT(0)
+#define IF_MODE_USE_SGMII_AN BIT(1)
+#define IF_MODE_SPEED(x) (((x) << 2) & GENMASK(3, 2))
+#define IF_MODE_SPEED_MSK GENMASK(3, 2)
+#define IF_MODE_HALF_DUPLEX BIT(4)
+
+enum sgmii_speed {
+ SGMII_SPEED_10 = 0,
+ SGMII_SPEED_100 = 1,
+ SGMII_SPEED_1000 = 2,
+ SGMII_SPEED_2500 = 2,
+};
+
+#define phylink_pcs_to_lynx(pl_pcs) container_of((pl_pcs), struct lynx_pcs, pcs)
+
+static void lynx_pcs_get_state_usxgmii(struct mdio_device *pcs,
+ struct phylink_link_state *state)
+{
+ struct mii_bus *bus = pcs->bus;
+ int addr = pcs->addr;
+ int status, lpa;
+
+ status = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_BMSR);
+ if (status < 0)
+ return;
+
+ state->link = !!(status & MDIO_STAT1_LSTATUS);
+ state->an_complete = !!(status & MDIO_AN_STAT1_COMPLETE);
+ if (!state->link || !state->an_complete)
+ return;
+
+ lpa = mdiobus_c45_read(bus, addr, MDIO_MMD_VEND2, MII_LPA);
+ if (lpa < 0)
+ return;
+
+ phylink_decode_usxgmii_word(state, lpa);
+}
+
+static void lynx_pcs_get_state_2500basex(struct mdio_device *pcs,
+ struct phylink_link_state *state)
+{
+ struct mii_bus *bus = pcs->bus;
+ int addr = pcs->addr;
+ int bmsr, lpa;
+
+ bmsr = mdiobus_read(bus, addr, MII_BMSR);
+ lpa = mdiobus_read(bus, addr, MII_LPA);
+ if (bmsr < 0 || lpa < 0) {
+ state->link = false;
+ return;
+ }
+
+ state->link = !!(bmsr & BMSR_LSTATUS);
+ state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
+ if (!state->link)
+ return;
+
+ state->speed = SPEED_2500;
+ state->pause |= MLO_PAUSE_TX | MLO_PAUSE_RX;
+ state->duplex = DUPLEX_FULL;
+}
+
+static void lynx_pcs_get_state(struct phylink_pcs *pcs,
+ struct phylink_link_state *state)
+{
+ struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+
+ switch (state->interface) {
+ case PHY_INTERFACE_MODE_SGMII:
+ case PHY_INTERFACE_MODE_QSGMII:
+ phylink_mii_c22_pcs_get_state(lynx->mdio, state);
+ break;
+ case PHY_INTERFACE_MODE_2500BASEX:
+ lynx_pcs_get_state_2500basex(lynx->mdio, state);
+ break;
+ case PHY_INTERFACE_MODE_USXGMII:
+ lynx_pcs_get_state_usxgmii(lynx->mdio, state);
+ break;
+ default:
+ break;
+ }
+
+ dev_dbg(&lynx->mdio->dev,
+ "mode=%s/%s/%s link=%u an_enabled=%u an_complete=%u\n",
+ phy_modes(state->interface),
+ phy_speed_to_str(state->speed),
+ phy_duplex_to_str(state->duplex),
+ state->link, state->an_enabled, state->an_complete);
+}
+
+static int lynx_pcs_config_sgmii(struct mdio_device *pcs, unsigned int mode,
+ const unsigned long *advertising)
+{
+ struct mii_bus *bus = pcs->bus;
+ int addr = pcs->addr;
+ u16 if_mode;
+ int err;
+
+ if_mode = IF_MODE_SGMII_EN;
+ if (mode == MLO_AN_INBAND) {
+ u32 link_timer;
+
+ if_mode |= IF_MODE_USE_SGMII_AN;
+
+ /* Adjust link timer for SGMII */
+ link_timer = LINK_TIMER_VAL(SGMII_AN_LINK_TIMER_NS);
+ mdiobus_write(bus, addr, LINK_TIMER_LO, link_timer & 0xffff);
+ mdiobus_write(bus, addr, LINK_TIMER_HI, link_timer >> 16);
+ }
+ err = mdiobus_modify(bus, addr, IF_MODE,
+ IF_MODE_SGMII_EN | IF_MODE_USE_SGMII_AN,
+ if_mode);
+ if (err)
+ return err;
+
+ return phylink_mii_c22_pcs_config(pcs, mode, PHY_INTERFACE_MODE_SGMII,
+ advertising);
+}
+
+static int lynx_pcs_config_usxgmii(struct mdio_device *pcs, unsigned int mode,
+ const unsigned long *advertising)
+{
+ struct mii_bus *bus = pcs->bus;
+ int addr = pcs->addr;
+
+ if (!phylink_autoneg_inband(mode)) {
+ dev_err(&pcs->dev, "USXGMII only supports in-band AN for now\n");
+ return -EOPNOTSUPP;
+ }
+
+ /* Configure device ability for the USXGMII Replicator */
+ return mdiobus_c45_write(bus, addr, MDIO_MMD_VEND2, MII_ADVERTISE,
+ MDIO_USXGMII_10G | MDIO_USXGMII_LINK |
+ MDIO_USXGMII_FULL_DUPLEX |
+ ADVERTISE_SGMII | ADVERTISE_LPACK);
+}
+
+static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
+ phy_interface_t ifmode,
+ const unsigned long *advertising,
+ bool permit)
+{
+ struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+
+ switch (ifmode) {
+ case PHY_INTERFACE_MODE_SGMII:
+ case PHY_INTERFACE_MODE_QSGMII:
+ return lynx_pcs_config_sgmii(lynx->mdio, mode, advertising);
+ case PHY_INTERFACE_MODE_2500BASEX:
+ if (phylink_autoneg_inband(mode)) {
+ dev_err(&lynx->mdio->dev,
+ "AN not supported on 3.125GHz SerDes lane\n");
+ return -EOPNOTSUPP;
+ }
+ break;
+ case PHY_INTERFACE_MODE_USXGMII:
+ return lynx_pcs_config_usxgmii(lynx->mdio, mode, advertising);
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static void lynx_pcs_link_up_sgmii(struct mdio_device *pcs, unsigned int mode,
+ int speed, int duplex)
+{
+ struct mii_bus *bus = pcs->bus;
+ u16 if_mode = 0, sgmii_speed;
+ int addr = pcs->addr;
+
+ /* The PCS needs to be configured manually only
+ * when not operating on in-band mode
+ */
+ if (mode == MLO_AN_INBAND)
+ return;
+
+ if (duplex == DUPLEX_HALF)
+ if_mode |= IF_MODE_HALF_DUPLEX;
+
+ switch (speed) {
+ case SPEED_1000:
+ sgmii_speed = SGMII_SPEED_1000;
+ break;
+ case SPEED_100:
+ sgmii_speed = SGMII_SPEED_100;
+ break;
+ case SPEED_10:
+ sgmii_speed = SGMII_SPEED_10;
+ break;
+ case SPEED_UNKNOWN:
+ /* Silently don't do anything */
+ return;
+ default:
+ dev_err(&pcs->dev, "Invalid PCS speed %d\n", speed);
+ return;
+ }
+ if_mode |= IF_MODE_SPEED(sgmii_speed);
+
+ mdiobus_modify(bus, addr, IF_MODE,
+ IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
+ if_mode);
+}
+
+/* 2500Base-X is SerDes protocol 7 on Felix and 6 on ENETC. It is a SerDes lane
+ * clocked at 3.125 GHz which encodes symbols with 8b/10b and does not have
+ * auto-negotiation of any link parameters. Electrically it is compatible with
+ * a single lane of XAUI.
+ * The hardware reference manual wants to call this mode SGMII, but it isn't
+ * really, since the fundamental features of SGMII:
+ * - Downgrading the link speed by duplicating symbols
+ * - Auto-negotiation
+ * are not there.
+ * The speed is configured at 1000 in the IF_MODE because the clock frequency
+ * is actually given by a PLL configured in the Reset Configuration Word (RCW).
+ * Since there is no difference between fixed speed SGMII w/o AN and 802.3z w/o
+ * AN, we call this PHY interface type 2500Base-X. In case a PHY negotiates a
+ * lower link speed on line side, the system-side interface remains fixed at
+ * 2500 Mbps and we do rate adaptation through pause frames.
+ */
+static void lynx_pcs_link_up_2500basex(struct mdio_device *pcs,
+ unsigned int mode,
+ int speed, int duplex)
+{
+ struct mii_bus *bus = pcs->bus;
+ int addr = pcs->addr;
+ u16 if_mode = 0;
+
+ if (mode == MLO_AN_INBAND) {
+ dev_err(&pcs->dev, "AN not supported for 2500BaseX\n");
+ return;
+ }
+
+ if (duplex == DUPLEX_HALF)
+ if_mode |= IF_MODE_HALF_DUPLEX;
+ if_mode |= IF_MODE_SPEED(SGMII_SPEED_2500);
+
+ mdiobus_modify(bus, addr, IF_MODE,
+ IF_MODE_HALF_DUPLEX | IF_MODE_SPEED_MSK,
+ if_mode);
+}
+
+static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
+ phy_interface_t interface,
+ int speed, int duplex)
+{
+ struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+
+ switch (interface) {
+ case PHY_INTERFACE_MODE_SGMII:
+ case PHY_INTERFACE_MODE_QSGMII:
+ lynx_pcs_link_up_sgmii(lynx->mdio, mode, speed, duplex);
+ break;
+ case PHY_INTERFACE_MODE_2500BASEX:
+ lynx_pcs_link_up_2500basex(lynx->mdio, mode, speed, duplex);
+ break;
+ case PHY_INTERFACE_MODE_USXGMII:
+ /* At the moment, only in-band AN is supported for USXGMII
+ * so nothing to do in link_up
+ */
+ break;
+ default:
+ break;
+ }
+}
+
+static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
+ .pcs_get_state = lynx_pcs_get_state,
+ .pcs_config = lynx_pcs_config,
+ .pcs_link_up = lynx_pcs_link_up,
+};
+
+struct lynx_pcs *lynx_pcs_create(struct mdio_device *mdio)
+{
+ struct lynx_pcs *lynx_pcs;
+
+ lynx_pcs = kzalloc(sizeof(*lynx_pcs), GFP_KERNEL);
+ if (!lynx_pcs)
+ return NULL;
+
+ lynx_pcs->mdio = mdio;
+ lynx_pcs->pcs.ops = &lynx_pcs_phylink_ops;
+ lynx_pcs->pcs.poll = true;
+
+ return lynx_pcs;
+}
+EXPORT_SYMBOL(lynx_pcs_create);
+
+void lynx_pcs_destroy(struct lynx_pcs *pcs)
+{
+ kfree(pcs);
+}
+EXPORT_SYMBOL(lynx_pcs_destroy);
+
+MODULE_LICENSE("Dual BSD/GPL");
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