[PATCH net-next v3 2/5] net: stmmac: introducing support for DWC xPCS logics

[Voon Weifeng <weifeng.voon@intel.com>]

From: Ong Boon Leong <boon.leong.ong@intel.com>

xPCS is DWC Ethernet Physical Coding Sublayer that may be integrated
into a GbE controller that uses DWC EQoS MAC controller. An example of
HW configuration is shown below:-

  <-----------------GBE Controller---------->|<--External PHY chip-->

  +----------+         +----+    +---+               +--------------+
  |   EQoS   | <-GMII->| DW |<-->|PHY| <-- SGMII --> | External GbE |
  |   MAC    |         |xPCS|    |IF |               | PHY Chip     |
  +----------+         +----+    +---+               +--------------+
         ^               ^                                  ^
         |               |                                  |
         +---------------------MDIO-------------------------+

xPCS is a Clause-45 MDIO Manageable Device (MMD) and we need a way to
differentiate it from external PHY chip that is discovered over MDIO.
Therefore, xpcs_phy_addr is introduced in stmmac platform data
(plat_stmmacenet_data) for differentiating xPCS from 'phy_addr' that
belongs to external PHY.

Basic functionalities for initializing xPCS and configuring auto
negotiation (AN), loopback, link status, AN advertisement and Link
Partner ability are implemented. The implementation supports the C37
AN for 1000BASE-X and SGMII (MAC side SGMII only).

Tested-by: Tan, Tee Min <tee.min.tan@intel.com>
Reviewed-by: Voon Weifeng <weifeng.voon@intel.com>
Reviewed-by: Kweh Hock Leong <hock.leong.kweh@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: Voon Weifeng <weifeng.voon@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/Makefile |   2 +-
 drivers/net/ethernet/stmicro/stmmac/common.h |   1 +
 drivers/net/ethernet/stmicro/stmmac/dwxpcs.c | 198 +++++++++++++++++++++++++++
 drivers/net/ethernet/stmicro/stmmac/dwxpcs.h |  51 +++++++
 drivers/net/ethernet/stmicro/stmmac/hwif.h   |  19 +++
 include/linux/stmmac.h                       |   1 +
 6 files changed, 271 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwxpcs.c
 create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwxpcs.h

diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
index c529c21e9bdd..57ca648fae4e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Makefile
+++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
@@ -6,7 +6,7 @@ stmmac-objs:= stmmac_main.o stmmac_ethtool.o stmmac_mdio.o ring_mode.o	\
 	      mmc_core.o stmmac_hwtstamp.o stmmac_ptp.o dwmac4_descs.o	\
 	      dwmac4_dma.o dwmac4_lib.o dwmac4_core.o dwmac5.o hwif.o \
 	      stmmac_tc.o dwxgmac2_core.o dwxgmac2_dma.o dwxgmac2_descs.o \
-	      $(stmmac-y)
+	      dwxpcs.o $(stmmac-y)
 
 # Ordering matters. Generic driver must be last.
 obj-$(CONFIG_STMMAC_PLATFORM)	+= stmmac-platform.o
diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 272b9ca66314..67d03a5a21af 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -419,6 +419,7 @@ struct mii_regs {
 
 struct mac_device_info {
 	const struct stmmac_ops *mac;
+	const struct stmmac_xpcs *xpcs;
 	const struct stmmac_desc_ops *desc;
 	const struct stmmac_dma_ops *dma;
 	const struct stmmac_mode_ops *mode;
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxpcs.c b/drivers/net/ethernet/stmicro/stmmac/dwxpcs.c
new file mode 100644
index 000000000000..081d3631afd2
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxpcs.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019, Intel Corporation.
+ * DWC Ethernet Physical Coding Sublayer
+ */
+#include <linux/bitops.h>
+#include <linux/mdio.h>
+#include "dwxpcs.h"
+#include "stmmac.h"
+
+/* DW xPCS mdiobus_read and mdiobus_write helper functions */
+#define xpcs_read(dev, reg) \
+	mdiobus_read(priv->mii, xpcs_phy_addr, \
+		     MII_ADDR_C45 | (reg) | \
+		     ((dev) << MII_DEVADDR_C45_SHIFT))
+#define xpcs_write(dev, reg, val) \
+	mdiobus_write(priv->mii, xpcs_phy_addr, \
+		      MII_ADDR_C45 | (reg) | \
+		      ((dev) << MII_DEVADDR_C45_SHIFT), val)
+
+static void dw_xpcs_init(struct net_device *ndev, int pcs_mode)
+{
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	int xpcs_phy_addr = priv->plat->xpcs_phy_addr;
+	int phydata;
+
+	if (pcs_mode == AN_CTRL_PCS_MD_C37_SGMII) {
+		/* For AN for SGMII mode, the settings are :-
+		 * 1) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 10b (SGMII AN)
+		 * 2) VR_MII_AN_CTRL Bit(3) [TX_CONFIG] = 0b (MAC side SGMII)
+		 *    DW xPCS used with DW EQoS MAC is always MAC
+		 *    side SGMII.
+		 * 3) VR_MII_AN_CTRL Bit(0) [AN_INTR_EN] = 1b (AN Interrupt
+		 *    enabled)
+		 * 4) VR_MII_DIG_CTRL1 Bit(9) [MAC_AUTO_SW] = 1b (Automatic
+		 *    speed mode change after SGMII AN complete)
+		 * Note: Since it is MAC side SGMII, there is no need to set
+		 *	 SR_MII_AN_ADV. MAC side SGMII receives AN Tx Config
+		 *	 from PHY about the link state change after C28 AN
+		 *	 is completed between PHY and Link Partner.
+		 */
+		phydata = xpcs_read(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_AN_CTRL);
+		phydata &= ~MDIO_MII_MMD_AN_CTRL_PCS_MD;
+		phydata |= MDIO_MII_MMD_AN_CTRL_AN_INTR_EN |
+			   (AN_CTRL_PCS_MD_C37_SGMII <<
+			    MDIO_MII_MMD_AN_CTRL_PCS_MD_SHIFT &
+			    MDIO_MII_MMD_AN_CTRL_PCS_MD) |
+			   (AN_CTRL_TX_CONF_MAC_SIDE_SGMII <<
+			    MDIO_MII_MMD_AN_CTRL_TX_CONFIG_SHIFT);
+		xpcs_write(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_AN_CTRL, phydata);
+
+		phydata = xpcs_read(XPCS_MDIO_MII_MMD,
+				    MDIO_MII_MMD_DIGITAL_CTRL_1);
+		phydata |= MDIO_MII_MMD_DIGI_CTRL_1_MAC_AUTO_SW;
+		xpcs_write(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_DIGITAL_CTRL_1,
+			   phydata);
+	} else {
+		/* For AN for 1000BASE-X mode, the settings are :-
+		 * 1) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 00b (1000BASE-X C37)
+		 * 2) VR_MII_AN_CTRL Bit(0) [AN_INTR_EN] = 1b (AN Interrupt
+		 *    enabled)
+		 * 3) SR_MII_AN_ADV Bit(6)[FD] = 1b (Full Duplex)
+		 *    Note: Half Duplex is rarely used, so don't advertise.
+		 * 4) SR_MII_AN_ADV Bit(8:7)[PSE] = 11b (Sym & Asym Pause)
+		 */
+		phydata = xpcs_read(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_AN_CTRL);
+		phydata &= ~MDIO_MII_MMD_AN_CTRL_PCS_MD;
+		phydata |= MDIO_MII_MMD_AN_CTRL_AN_INTR_EN |
+			   (AN_CTRL_PCS_MD_C37_1000BASEX <<
+			    MDIO_MII_MMD_AN_CTRL_PCS_MD_SHIFT &
+			    MDIO_MII_MMD_AN_CTRL_PCS_MD);
+		xpcs_write(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_AN_CTRL, phydata);
+
+		phydata = xpcs_read(XPCS_MDIO_MII_MMD, MII_ADVERTISE);
+		phydata |= MDIO_MII_MMD_FD |
+			   (MDIO_MII_MMD_PSE_BOTH << MDIO_MII_MMD_PSE_SHIFT);
+		xpcs_write(XPCS_MDIO_MII_MMD, MII_ADVERTISE, phydata);
+	}
+}
+
+static void dw_xpcs_ctrl_ane(struct net_device *ndev, bool ane,
+			     bool loopback)
+{
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	int xpcs_phy_addr = priv->plat->xpcs_phy_addr;
+
+	int phydata = xpcs_read(XPCS_MDIO_MII_MMD, MII_BMCR);
+
+	if (ane)
+		phydata |= (BMCR_ANENABLE | BMCR_ANRESTART);
+
+	if (loopback)
+		phydata |= BMCR_LOOPBACK;
+
+	xpcs_write(XPCS_MDIO_MII_MMD, MII_BMCR, phydata);
+}
+
+static void dw_xpcs_get_adv_lp(struct net_device *ndev,
+			       struct rgmii_adv *adv_lp,
+			       int pcs_mode)
+{
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	int xpcs_phy_addr = priv->plat->xpcs_phy_addr;
+
+	/* AN Advertisement Ability */
+	int value = xpcs_read(XPCS_MDIO_MII_MMD, MII_ADVERTISE);
+
+	if (value & MDIO_MII_MMD_FD)
+		adv_lp->duplex = DUPLEX_FULL;
+	if (value & MDIO_MII_MMD_HD)
+		adv_lp->duplex = DUPLEX_HALF;
+	adv_lp->pause = (u32)((value & MDIO_MII_MMD_PSE) >>
+			      MDIO_MII_MMD_PSE_SHIFT);
+
+	/* Link Partner Ability - 1000BASE-X only*/
+	if (pcs_mode == AN_CTRL_PCS_MD_C37_1000BASEX) {
+		value = xpcs_read(XPCS_MDIO_MII_MMD, MII_LPA);
+		if (value & MDIO_MII_MMD_FD)
+			adv_lp->lp_duplex = DUPLEX_FULL;
+		if (value & MDIO_MII_MMD_HD)
+			adv_lp->lp_duplex = DUPLEX_HALF;
+		adv_lp->lp_pause = (u32)((value & MDIO_MII_MMD_PSE) >>
+					 MDIO_MII_MMD_PSE_SHIFT);
+	}
+}
+
+static void dw_xpcs_get_linkstatus(struct net_device *ndev,
+				   u16 an_stat,
+				   struct stmmac_extra_stats *x)
+{
+	/* Check the SGMII AN link status */
+	if (an_stat & AN_STAT_SGMII_AN_LNKSTS) {
+		int speed_value;
+
+		x->pcs_link = 1;
+
+		speed_value = ((an_stat & AN_STAT_SGMII_AN_SPEED) >>
+				AN_STAT_SGMII_AN_SPEED_SHIFT);
+		if (speed_value == AN_STAT_SGMII_AN_1000MBPS)
+			x->pcs_speed = SPEED_1000;
+		else if (speed_value == AN_STAT_SGMII_AN_100MBPS)
+			x->pcs_speed = SPEED_100;
+		else
+			x->pcs_speed = SPEED_10;
+
+		if (an_stat & AN_STAT_SGMII_AN_FD)
+			x->pcs_duplex = 1;
+		else
+			x->pcs_duplex = 0;
+
+		netdev_info(ndev, "Link is Up - %d/%s\n", (int)x->pcs_speed,
+			    x->pcs_duplex ? "Full" : "Half");
+	} else {
+		x->pcs_link = 0;
+		netdev_info(ndev, "Link is Down\n");
+	}
+}
+
+static int dw_xpcs_irq_status(struct net_device *ndev,
+			      struct stmmac_extra_stats *x,
+			      int pcs_mode)
+{
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	int xpcs_phy_addr = priv->plat->xpcs_phy_addr;
+	int ret = IRQ_NONE;
+
+	/* AN status */
+	int an_stat = xpcs_read(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_AN_STAT);
+
+	if (an_stat & AN_STAT_SGMII_AN_CMPLT) {
+		x->irq_pcs_ane_n++;
+
+		if (pcs_mode == AN_CTRL_PCS_MD_C37_SGMII) {
+			dw_xpcs_get_linkstatus(ndev, an_stat, x);
+		} else {
+			/* For 1000BASE-X AN, DW xPCS does not have register
+			 * to read the link state of 1000BASE-X C37 AN and
+			 * since 1000BASE-X is always 1000Mbps and FD, we
+			 * just set the default link here.
+			 */
+			x->pcs_link = 1;
+			x->pcs_duplex = 1;
+			x->pcs_speed = SPEED_1000;
+		}
+
+		/* Clear C37 AN complete status by writing zero */
+		xpcs_write(XPCS_MDIO_MII_MMD, MDIO_MII_MMD_AN_STAT, 0);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+const struct stmmac_xpcs stmmac_xpcs_ops = {
+	.xpcs_init = dw_xpcs_init,
+	.xpcs_ctrl_ane = dw_xpcs_ctrl_ane,
+	.xpcs_get_adv_lp = dw_xpcs_get_adv_lp,
+	.xpcs_irq_status = dw_xpcs_irq_status,
+};
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxpcs.h b/drivers/net/ethernet/stmicro/stmmac/dwxpcs.h
new file mode 100644
index 000000000000..bd52ce80bf4e
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxpcs.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2019, Intel Corporation.
+ * DWC Ethernet Physical Coding Sublayer
+ */
+#ifndef __DW_XPCS_H__
+#define __DW_XPCS_H__
+
+/* XPCS MII MMD Device Addresses */
+#define XPCS_MDIO_MII_MMD	MDIO_MMD_VEND2
+
+/* MII MMD registers offsets */
+#define MDIO_MII_MMD_DIGITAL_CTRL_1	0x8000	/* Digital Control 1 */
+#define MDIO_MII_MMD_AN_CTRL		0x8001	/* AN Control */
+#define MDIO_MII_MMD_AN_STAT		0x8002	/* AN Status */
+
+/* MII MMD SR AN Advertisement & Link Partner Ability are slightly
+ * different from MII_ADVERTISEMENT & MII_LPA in below fields:
+ */
+#define MDIO_MII_MMD_HD			BIT(6)	/* Half duplex */
+#define MDIO_MII_MMD_FD			BIT(5)	/* Full duplex */
+#define MDIO_MII_MMD_PSE_SHIFT		7	/* Pause Ability shift */
+#define MDIO_MII_MMD_PSE		GENMASK(8, 7)	/* Pause Ability */
+#define MDIO_MII_MMD_PSE_NO		0x0
+#define MDIO_MII_MMD_PSE_ASYM		0x1
+#define MDIO_MII_MMD_PSE_SYM		0x2
+#define MDIO_MII_MMD_PSE_BOTH		0x3
+
+/* Automatic Speed Mode Change for MAC side SGMII AN */
+#define MDIO_MII_MMD_DIGI_CTRL_1_MAC_AUTO_SW	BIT(9)
+
+/* MII MMD AN Control defines */
+#define MDIO_MII_MMD_AN_CTRL_TX_CONFIG_SHIFT	3 /* TX Config shift */
+#define AN_CTRL_TX_CONF_PHY_SIDE_SGMII		0x1 /* PHY side SGMII mode */
+#define AN_CTRL_TX_CONF_MAC_SIDE_SGMII		0x0 /* MAC side SGMII mode */
+#define MDIO_MII_MMD_AN_CTRL_PCS_MD_SHIFT	1  /* PCS Mode shift */
+#define MDIO_MII_MMD_AN_CTRL_PCS_MD	GENMASK(2, 1) /* PCS Mode */
+#define AN_CTRL_PCS_MD_C37_1000BASEX	0x0	/* C37 AN for 1000BASE-X */
+#define AN_CTRL_PCS_MD_C37_SGMII	0x2	/* C37 AN for SGMII */
+#define MDIO_MII_MMD_AN_CTRL_AN_INTR_EN	BIT(0)	/* AN Complete Intr Enable */
+
+/* MII MMD AN Status defines for SGMII AN Status */
+#define AN_STAT_SGMII_AN_CMPLT		BIT(0)	/* AN Complete Intr */
+#define AN_STAT_SGMII_AN_FD		BIT(1)	/* Full Duplex */
+#define AN_STAT_SGMII_AN_SPEED_SHIFT	2	/* AN Speed shift */
+#define AN_STAT_SGMII_AN_SPEED		GENMASK(3, 2)	/* AN Speed */
+#define AN_STAT_SGMII_AN_10MBPS		0x0	/* 10 Mbps */
+#define AN_STAT_SGMII_AN_100MBPS	0x1	/* 100 Mbps */
+#define AN_STAT_SGMII_AN_1000MBPS	0x2	/* 1000 Mbps */
+#define AN_STAT_SGMII_AN_LNKSTS		BIT(4)	/* Link Status */
+
+#endif /* __DW_XPCS_H__ */
diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 5bb00234d961..4ee6a69c922b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -393,6 +393,25 @@ struct stmmac_ops {
 #define stmmac_flex_pps_config(__priv, __args...) \
 	stmmac_do_callback(__priv, mac, flex_pps_config, __args)
 
+/* Helpers for DW xPCS */
+struct stmmac_xpcs {
+	void (*xpcs_init)(struct net_device *ndev, int pcs_mode);
+	void (*xpcs_ctrl_ane)(struct net_device *ndev, bool ane, bool loopback);
+	void (*xpcs_get_adv_lp)(struct net_device *ndev, struct rgmii_adv *adv,
+				int pcs_mode);
+	int (*xpcs_irq_status)(struct net_device *ndev,
+			       struct stmmac_extra_stats *x, int pcs_mode);
+};
+
+#define stmmac_xpcs_init(__priv, __args...) \
+	stmmac_do_void_callback(__priv, xpcs, xpcs_init, __args)
+#define stmmac_xpcs_ctrl_ane(__priv, __args...) \
+	stmmac_do_void_callback(__priv, xpcs, xpcs_ctrl_ane, __args)
+#define stmmac_xpcs_get_adv_lp(__priv, __args...) \
+	stmmac_do_void_callback(__priv, xpcs, xpcs_get_adv_lp, __args)
+#define stmmac_xpcs_irq_status(__priv, __args...) \
+	stmmac_do_callback(__priv, xpcs, xpcs_irq_status, __args)
+
 /* PTP and HW Timer helpers */
 struct stmmac_hwtimestamp {
 	void (*config_hw_tstamping) (void __iomem *ioaddr, u32 data);
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 4335bd771ce5..b00e7951a66d 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -148,6 +148,7 @@ struct stmmac_txq_cfg {
 struct plat_stmmacenet_data {
 	int bus_id;
 	int phy_addr;
+	int xpcs_phy_addr;
 	int interface;
 	struct stmmac_mdio_bus_data *mdio_bus_data;
 	struct device_node *phy_node;
-- 
1.9.1