Re: [PATCH net-next v6 2/5] net: stmmac: introducing support for DWC xPCS logics

From: Florian Fainelli
Date: Tue Jun 04 2019 - 16:50:01 EST

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+Russell,

On 6/4/2019 11:58 AM, Voon Weifeng wrote:
> From: Ong Boon Leong <boon.leong.ong@xxxxxxxxx>
>
> 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.

Assuming this DW xPCS can be found with designs other than STMMAC would
not it make sense to model this as some kind of PHY/MDIO bridge? A
little bit like what drivers/net/phy/xilinx_gmii2rgmii.c tries to do?

>
> 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@xxxxxxxxx>
> Reviewed-by: Voon Weifeng <weifeng.voon@xxxxxxxxx>
> Reviewed-by: Kweh Hock Leong <hock.leong.kweh@xxxxxxxxx>
> Signed-off-by: Ong Boon Leong <boon.leong.ong@xxxxxxxxx>
> Signed-off-by: Voon Weifeng <weifeng.voon@xxxxxxxxx>
> ---
> drivers/net/ethernet/stmicro/stmmac/Makefile | 2 +-
> drivers/net/ethernet/stmicro/stmmac/common.h | 1 +
> drivers/net/ethernet/stmicro/stmmac/dwxpcs.c | 208 +++++++++++++++++++++++++++
> drivers/net/ethernet/stmicro/stmmac/dwxpcs.h | 51 +++++++
> drivers/net/ethernet/stmicro/stmmac/hwif.h | 19 +++
> include/linux/stmmac.h | 1 +
> 6 files changed, 281 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 c59926d96bcc..f007fb873455 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 $(stmmac-y)
>
> stmmac-$(CONFIG_STMMAC_SELFTESTS) += stmmac_selftests.o
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
> index 1961fe9144ca..83df093c4636 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_ops *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..7e850b9dd7b7
> --- /dev/null
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxpcs.c
> @@ -0,0 +1,208 @@
> +// 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;
> + int phydata;
> +
> + xpcs_phy_addr = priv->plat->xpcs_phy_addr;
> +
> + 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;
> + int phydata;
> +
> + xpcs_phy_addr = priv->plat->xpcs_phy_addr;
> + 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;
> + int value;
> +
> + xpcs_phy_addr = priv->plat->xpcs_phy_addr;
> +
> + /* AN Advertisement Ability */
> + 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 ret = IRQ_NONE;
> + int xpcs_phy_addr;
> + int an_stat;
> +
> + xpcs_phy_addr = priv->plat->xpcs_phy_addr;
> +
> + /* AN status */
> + 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_ops 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 2acfbc70e3c8..431cf4261264 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
> @@ -398,6 +398,25 @@ struct stmmac_ops {
> #define stmmac_set_mac_loopback(__priv, __args...) \
> stmmac_do_void_callback(__priv, mac, set_mac_loopback, __args)
>
> +/* Helpers for DW xPCS */
> +struct stmmac_xpcs_ops {
> + 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;
>

--
Florian

Next message: Qian Cai: "[PATCH v2] sched/core: clean up sched_init() a bit"
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In reply to: Voon Weifeng: "[PATCH net-next v6 2/5] net: stmmac: introducing support for DWC xPCS logics"
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