// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * dwmac-sun8i.c - Allwinner sun8i DWMAC specific glue layer
 *
 * Copyright (C) 2017 Corentin Labbe <clabbe.montjoie@gmail.com>
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/mdio-mux.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/of_platform.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/regmap.h>
#include <linux/stmmac.h>

#include "stmmac.h"
#include "stmmac_platform.h"

/* General notes on dwmac-sun8i:
 * Locking: no locking is necessary in this file because all necessary locking
 *              is done in the "stmmac files"
 */

/* struct emac_variant - Describe dwmac-sun8i hardware variant
 * @syscon_field                reg_field for the syscon's gmac register
 * @soc_has_internal_phy:       Does the MAC embed an internal PHY
 * @support_mii:                Does the MAC handle MII
 * @support_rmii:               Does the MAC handle RMII
 * @support_rgmii:              Does the MAC handle RGMII
 *
 * @rx_delay_max:               Maximum raw value for RX delay chain
 * @tx_delay_max:               Maximum raw value for TX delay chain
 *                              These two also indicate the bitmask for
 *                              the RX and TX delay chain registers. A
 *                              value of zero indicates this is not supported.
 */
struct emac_variant {
        const struct reg_field *syscon_field;
        bool soc_has_internal_phy;
        bool support_mii;
        bool support_rmii;
        bool support_rgmii;
        u8 rx_delay_max;
        u8 tx_delay_max;
};

/* struct sunxi_priv_data - hold all sunxi private data
 * @ephy_clk:   reference to the optional EPHY clock for the internal PHY
 * @regulator:  reference to the optional regulator
 * @rst_ephy:   reference to the optional EPHY reset for the internal PHY
 * @variant:    reference to the current board variant
 * @regmap:     regmap for using the syscon
 * @internal_phy_powered: Does the internal PHY is enabled
 * @use_internal_phy: Is the internal PHY selected for use
 * @mux_handle: Internal pointer used by mdio-mux lib
 */
struct sunxi_priv_data {
        struct clk *ephy_clk;
        struct regulator *regulator;
        struct reset_control *rst_ephy;
        const struct emac_variant *variant;
        struct regmap_field *regmap_field;
        bool internal_phy_powered;
        bool use_internal_phy;
        void *mux_handle;
};

/* EMAC clock register @ 0x30 in the "system control" address range */
static const struct reg_field sun8i_syscon_reg_field = {
        .reg = 0x30,
        .lsb = 0,
        .msb = 31,
};

/* EMAC clock register @ 0x164 in the CCU address range */
static const struct reg_field sun8i_ccu_reg_field = {
        .reg = 0x164,
        .lsb = 0,
        .msb = 31,
};

static const struct emac_variant emac_variant_h3 = {
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = true,
        .support_mii = true,
        .support_rmii = true,
        .support_rgmii = true,
        .rx_delay_max = 31,
        .tx_delay_max = 7,
};

static const struct emac_variant emac_variant_v3s = {
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = true,
        .support_mii = true
};

static const struct emac_variant emac_variant_a83t = {
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = false,
        .support_mii = true,
        .support_rgmii = true,
        .rx_delay_max = 31,
        .tx_delay_max = 7,
};

static const struct emac_variant emac_variant_r40 = {
        .syscon_field = &sun8i_ccu_reg_field,
        .support_mii = true,
        .support_rgmii = true,
        .rx_delay_max = 7,
};

static const struct emac_variant emac_variant_a64 = {
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = false,
        .support_mii = true,
        .support_rmii = true,
        .support_rgmii = true,
        .rx_delay_max = 31,
        .tx_delay_max = 7,
};

static const struct emac_variant emac_variant_h6 = {
        .syscon_field = &sun8i_syscon_reg_field,
        /* The "Internal PHY" of H6 is not on the die. It's on the
         * co-packaged AC200 chip instead.
         */
        .soc_has_internal_phy = false,
        .support_mii = true,
        .support_rmii = true,
        .support_rgmii = true,
        .rx_delay_max = 31,
        .tx_delay_max = 7,
};

#define EMAC_BASIC_CTL0 0x00
#define EMAC_BASIC_CTL1 0x04
#define EMAC_INT_STA    0x08
#define EMAC_INT_EN     0x0C
#define EMAC_TX_CTL0    0x10
#define EMAC_TX_CTL1    0x14
#define EMAC_TX_FLOW_CTL        0x1C
#define EMAC_TX_DESC_LIST 0x20
#define EMAC_RX_CTL0    0x24
#define EMAC_RX_CTL1    0x28
#define EMAC_RX_DESC_LIST 0x34
#define EMAC_RX_FRM_FLT 0x38
#define EMAC_MDIO_CMD   0x48
#define EMAC_MDIO_DATA  0x4C
#define EMAC_MACADDR_HI(reg) (0x50 + (reg) * 8)
#define EMAC_MACADDR_LO(reg) (0x54 + (reg) * 8)
#define EMAC_TX_DMA_STA 0xB0
#define EMAC_TX_CUR_DESC        0xB4
#define EMAC_TX_CUR_BUF 0xB8
#define EMAC_RX_DMA_STA 0xC0
#define EMAC_RX_CUR_DESC        0xC4
#define EMAC_RX_CUR_BUF 0xC8

/* Use in EMAC_BASIC_CTL0 */
#define EMAC_DUPLEX_FULL        BIT(0)
#define EMAC_LOOPBACK           BIT(1)
#define EMAC_SPEED_1000 0
#define EMAC_SPEED_100 (0x03 << 2)
#define EMAC_SPEED_10 (0x02 << 2)

/* Use in EMAC_BASIC_CTL1 */
#define EMAC_BURSTLEN_SHIFT             24

/* Used in EMAC_RX_FRM_FLT */
#define EMAC_FRM_FLT_RXALL              BIT(0)
#define EMAC_FRM_FLT_CTL                BIT(13)
#define EMAC_FRM_FLT_MULTICAST          BIT(16)

/* Used in RX_CTL1*/
#define EMAC_RX_MD              BIT(1)
#define EMAC_RX_TH_MASK         GENMASK(5, 4)
#define EMAC_RX_TH_32           0
#define EMAC_RX_TH_64           (0x1 << 4)
#define EMAC_RX_TH_96           (0x2 << 4)
#define EMAC_RX_TH_128          (0x3 << 4)
#define EMAC_RX_DMA_EN  BIT(30)
#define EMAC_RX_DMA_START       BIT(31)

/* Used in TX_CTL1*/
#define EMAC_TX_MD              BIT(1)
#define EMAC_TX_NEXT_FRM        BIT(2)
#define EMAC_TX_TH_MASK         GENMASK(10, 8)
#define EMAC_TX_TH_64           0
#define EMAC_TX_TH_128          (0x1 << 8)
#define EMAC_TX_TH_192          (0x2 << 8)
#define EMAC_TX_TH_256          (0x3 << 8)
#define EMAC_TX_DMA_EN  BIT(30)
#define EMAC_TX_DMA_START       BIT(31)

/* Used in RX_CTL0 */
#define EMAC_RX_RECEIVER_EN             BIT(31)
#define EMAC_RX_DO_CRC BIT(27)
#define EMAC_RX_FLOW_CTL_EN             BIT(16)

/* Used in TX_CTL0 */
#define EMAC_TX_TRANSMITTER_EN  BIT(31)

/* Used in EMAC_TX_FLOW_CTL */
#define EMAC_TX_FLOW_CTL_EN             BIT(0)

/* Used in EMAC_INT_STA */
#define EMAC_TX_INT             BIT(0)
#define EMAC_TX_DMA_STOP_INT    BIT(1)
#define EMAC_TX_BUF_UA_INT      BIT(2)
#define EMAC_TX_TIMEOUT_INT     BIT(3)
#define EMAC_TX_UNDERFLOW_INT   BIT(4)
#define EMAC_TX_EARLY_INT       BIT(5)
#define EMAC_RX_INT             BIT(8)
#define EMAC_RX_BUF_UA_INT      BIT(9)
#define EMAC_RX_DMA_STOP_INT    BIT(10)
#define EMAC_RX_TIMEOUT_INT     BIT(11)
#define EMAC_RX_OVERFLOW_INT    BIT(12)
#define EMAC_RX_EARLY_INT       BIT(13)
#define EMAC_RGMII_STA_INT      BIT(16)

#define EMAC_INT_MSK_COMMON     EMAC_RGMII_STA_INT
#define EMAC_INT_MSK_TX         (EMAC_TX_INT | \
                                 EMAC_TX_DMA_STOP_INT | \
                                 EMAC_TX_BUF_UA_INT | \
                                 EMAC_TX_TIMEOUT_INT | \
                                 EMAC_TX_UNDERFLOW_INT | \
                                 EMAC_TX_EARLY_INT |\
                                 EMAC_INT_MSK_COMMON)
#define EMAC_INT_MSK_RX         (EMAC_RX_INT | \
                                 EMAC_RX_BUF_UA_INT | \
                                 EMAC_RX_DMA_STOP_INT | \
                                 EMAC_RX_TIMEOUT_INT | \
                                 EMAC_RX_OVERFLOW_INT | \
                                 EMAC_RX_EARLY_INT | \
                                 EMAC_INT_MSK_COMMON)

#define MAC_ADDR_TYPE_DST BIT(31)

/* H3 specific bits for EPHY */
#define H3_EPHY_ADDR_SHIFT      20
#define H3_EPHY_CLK_SEL         BIT(18) /* 1: 24MHz, 0: 25MHz */
#define H3_EPHY_LED_POL         BIT(17) /* 1: active low, 0: active high */
#define H3_EPHY_SHUTDOWN        BIT(16) /* 1: shutdown, 0: power up */
#define H3_EPHY_SELECT          BIT(15) /* 1: internal PHY, 0: external PHY */
#define H3_EPHY_MUX_MASK        (H3_EPHY_SHUTDOWN | H3_EPHY_SELECT)
#define DWMAC_SUN8I_MDIO_MUX_INTERNAL_ID        1
#define DWMAC_SUN8I_MDIO_MUX_EXTERNAL_ID        2

/* H3/A64 specific bits */
#define SYSCON_RMII_EN          BIT(13) /* 1: enable RMII (overrides EPIT) */

/* Generic system control EMAC_CLK bits */
#define SYSCON_ETXDC_SHIFT              10
#define SYSCON_ERXDC_SHIFT              5
/* EMAC PHY Interface Type */
#define SYSCON_EPIT                     BIT(2) /* 1: RGMII, 0: MII */
#define SYSCON_ETCS_MASK                GENMASK(1, 0)
#define SYSCON_ETCS_MII         0x0
#define SYSCON_ETCS_EXT_GMII    0x1
#define SYSCON_ETCS_INT_GMII    0x2

/* sun8i_dwmac_dma_reset() - reset the EMAC
 * Called from stmmac via stmmac_dma_ops->reset
 */
static int sun8i_dwmac_dma_reset(void __iomem *ioaddr)
{
        writel(0, ioaddr + EMAC_RX_CTL1);
        writel(0, ioaddr + EMAC_TX_CTL1);
        writel(0, ioaddr + EMAC_RX_FRM_FLT);
        writel(0, ioaddr + EMAC_RX_DESC_LIST);
        writel(0, ioaddr + EMAC_TX_DESC_LIST);
        writel(0, ioaddr + EMAC_INT_EN);
        writel(0x1FFFFFF, ioaddr + EMAC_INT_STA);
        return 0;
}

/* sun8i_dwmac_dma_init() - initialize the EMAC
 * Called from stmmac via stmmac_dma_ops->init
 */
static void sun8i_dwmac_dma_init(void __iomem *ioaddr,
                                 struct stmmac_dma_cfg *dma_cfg)
{
        writel(EMAC_RX_INT | EMAC_TX_INT, ioaddr + EMAC_INT_EN);
        writel(0x1FFFFFF, ioaddr + EMAC_INT_STA);
}

static void sun8i_dwmac_dma_init_rx(struct stmmac_priv *priv,
                                    void __iomem *ioaddr,
                                    struct stmmac_dma_cfg *dma_cfg,
                                    dma_addr_t dma_rx_phy, u32 chan)
{
        /* Write RX descriptors address */
        writel(lower_32_bits(dma_rx_phy), ioaddr + EMAC_RX_DESC_LIST);
}

static void sun8i_dwmac_dma_init_tx(struct stmmac_priv *priv,
                                    void __iomem *ioaddr,
                                    struct stmmac_dma_cfg *dma_cfg,
                                    dma_addr_t dma_tx_phy, u32 chan)
{
        /* Write TX descriptors address */
        writel(lower_32_bits(dma_tx_phy), ioaddr + EMAC_TX_DESC_LIST);
}

/* sun8i_dwmac_dump_regs() - Dump EMAC address space
 * Called from stmmac_dma_ops->dump_regs
 * Used for ethtool
 */
static void sun8i_dwmac_dump_regs(struct stmmac_priv *priv,
                                  void __iomem *ioaddr, u32 *reg_space)
{
        int i;

        for (i = 0; i < 0xC8; i += 4) {
                if (i == 0x32 || i == 0x3C)
                        continue;
                reg_space[i / 4] = readl(ioaddr + i);
        }
}

/* sun8i_dwmac_dump_mac_regs() - Dump EMAC address space
 * Called from stmmac_ops->dump_regs
 * Used for ethtool
 */
static void sun8i_dwmac_dump_mac_regs(struct mac_device_info *hw,
                                      u32 *reg_space)
{
        int i;
        void __iomem *ioaddr = hw->pcsr;

        for (i = 0; i < 0xC8; i += 4) {
                if (i == 0x32 || i == 0x3C)
                        continue;
                reg_space[i / 4] = readl(ioaddr + i);
        }
}

static void sun8i_dwmac_enable_dma_irq(struct stmmac_priv *priv,
                                       void __iomem *ioaddr, u32 chan,
                                       bool rx, bool tx)
{
        u32 value = readl(ioaddr + EMAC_INT_EN);

        if (rx)
                value |= EMAC_RX_INT;
        if (tx)
                value |= EMAC_TX_INT;

        writel(value, ioaddr + EMAC_INT_EN);
}

static void sun8i_dwmac_disable_dma_irq(struct stmmac_priv *priv,
                                        void __iomem *ioaddr, u32 chan,
                                        bool rx, bool tx)
{
        u32 value = readl(ioaddr + EMAC_INT_EN);

        if (rx)
                value &= ~EMAC_RX_INT;
        if (tx)
                value &= ~EMAC_TX_INT;

        writel(value, ioaddr + EMAC_INT_EN);
}

static void sun8i_dwmac_dma_start_tx(struct stmmac_priv *priv,
                                     void __iomem *ioaddr, u32 chan)
{
        u32 v;

        v = readl(ioaddr + EMAC_TX_CTL1);
        v |= EMAC_TX_DMA_START;
        v |= EMAC_TX_DMA_EN;
        writel(v, ioaddr + EMAC_TX_CTL1);
}

static void sun8i_dwmac_enable_dma_transmission(void __iomem *ioaddr, u32 chan)
{
        u32 v;

        v = readl(ioaddr + EMAC_TX_CTL1);
        v |= EMAC_TX_DMA_START;
        v |= EMAC_TX_DMA_EN;
        writel(v, ioaddr + EMAC_TX_CTL1);
}

static void sun8i_dwmac_dma_stop_tx(struct stmmac_priv *priv,
                                    void __iomem *ioaddr, u32 chan)
{
        u32 v;

        v = readl(ioaddr + EMAC_TX_CTL1);
        v &= ~EMAC_TX_DMA_EN;
        writel(v, ioaddr + EMAC_TX_CTL1);
}

static void sun8i_dwmac_dma_start_rx(struct stmmac_priv *priv,
                                     void __iomem *ioaddr, u32 chan)
{
        u32 v;

        v = readl(ioaddr + EMAC_RX_CTL1);
        v |= EMAC_RX_DMA_START;
        v |= EMAC_RX_DMA_EN;
        writel(v, ioaddr + EMAC_RX_CTL1);
}

static void sun8i_dwmac_dma_stop_rx(struct stmmac_priv *priv,
                                    void __iomem *ioaddr, u32 chan)
{
        u32 v;

        v = readl(ioaddr + EMAC_RX_CTL1);
        v &= ~EMAC_RX_DMA_EN;
        writel(v, ioaddr + EMAC_RX_CTL1);
}

static int sun8i_dwmac_dma_interrupt(struct stmmac_priv *priv,
                                     void __iomem *ioaddr,
                                     struct stmmac_extra_stats *x, u32 chan,
                                     u32 dir)
{
        struct stmmac_pcpu_stats *stats = this_cpu_ptr(priv->xstats.pcpu_stats);
        int ret = 0;
        u32 v;

        v = readl(ioaddr + EMAC_INT_STA);

        if (dir == DMA_DIR_RX)
                v &= EMAC_INT_MSK_RX;
        else if (dir == DMA_DIR_TX)
                v &= EMAC_INT_MSK_TX;

        if (v & EMAC_TX_INT) {
                ret |= handle_tx;
                u64_stats_update_begin(&stats->syncp);
                u64_stats_inc(&stats->tx_normal_irq_n[chan]);
                u64_stats_update_end(&stats->syncp);
        }

        if (v & EMAC_TX_DMA_STOP_INT)
                x->tx_process_stopped_irq++;

        if (v & EMAC_TX_BUF_UA_INT)
                x->tx_process_stopped_irq++;

        if (v & EMAC_TX_TIMEOUT_INT)
                ret |= tx_hard_error;

        if (v & EMAC_TX_UNDERFLOW_INT) {
                ret |= tx_hard_error;
                x->tx_undeflow_irq++;
        }

        if (v & EMAC_TX_EARLY_INT)
                x->tx_early_irq++;

        if (v & EMAC_RX_INT) {
                ret |= handle_rx;
                u64_stats_update_begin(&stats->syncp);
                u64_stats_inc(&stats->rx_normal_irq_n[chan]);
                u64_stats_update_end(&stats->syncp);
        }

        if (v & EMAC_RX_BUF_UA_INT)
                x->rx_buf_unav_irq++;

        if (v & EMAC_RX_DMA_STOP_INT)
                x->rx_process_stopped_irq++;

        if (v & EMAC_RX_TIMEOUT_INT)
                ret |= tx_hard_error;

        if (v & EMAC_RX_OVERFLOW_INT) {
                ret |= tx_hard_error;
                x->rx_overflow_irq++;
        }

        if (v & EMAC_RX_EARLY_INT)
                x->rx_early_irq++;

        if (v & EMAC_RGMII_STA_INT)
                x->irq_rgmii_n++;

        writel(v, ioaddr + EMAC_INT_STA);

        return ret;
}

static void sun8i_dwmac_dma_operation_mode_rx(struct stmmac_priv *priv,
                                              void __iomem *ioaddr, int mode,
                                              u32 channel, int fifosz, u8 qmode)
{
        u32 v;

        v = readl(ioaddr + EMAC_RX_CTL1);
        if (mode == SF_DMA_MODE) {
                v |= EMAC_RX_MD;
        } else {
                v &= ~EMAC_RX_MD;
                v &= ~EMAC_RX_TH_MASK;
                if (mode < 32)
                        v |= EMAC_RX_TH_32;
                else if (mode < 64)
                        v |= EMAC_RX_TH_64;
                else if (mode < 96)
                        v |= EMAC_RX_TH_96;
                else if (mode < 128)
                        v |= EMAC_RX_TH_128;
        }
        writel(v, ioaddr + EMAC_RX_CTL1);
}

static void sun8i_dwmac_dma_operation_mode_tx(struct stmmac_priv *priv,
                                              void __iomem *ioaddr, int mode,
                                              u32 channel, int fifosz, u8 qmode)
{
        u32 v;

        v = readl(ioaddr + EMAC_TX_CTL1);
        if (mode == SF_DMA_MODE) {
                v |= EMAC_TX_MD;
                /* Undocumented bit (called TX_NEXT_FRM in BSP), the original
                 * comment is
                 * "Operating on second frame increase the performance
                 * especially when transmit store-and-forward is used."
                 */
                v |= EMAC_TX_NEXT_FRM;
        } else {
                v &= ~EMAC_TX_MD;
                v &= ~EMAC_TX_TH_MASK;
                if (mode < 64)
                        v |= EMAC_TX_TH_64;
                else if (mode < 128)
                        v |= EMAC_TX_TH_128;
                else if (mode < 192)
                        v |= EMAC_TX_TH_192;
                else if (mode < 256)
                        v |= EMAC_TX_TH_256;
        }
        writel(v, ioaddr + EMAC_TX_CTL1);
}

static const struct stmmac_dma_ops sun8i_dwmac_dma_ops = {
        .reset = sun8i_dwmac_dma_reset,
        .init = sun8i_dwmac_dma_init,
        .init_rx_chan = sun8i_dwmac_dma_init_rx,
        .init_tx_chan = sun8i_dwmac_dma_init_tx,
        .dump_regs = sun8i_dwmac_dump_regs,
        .dma_rx_mode = sun8i_dwmac_dma_operation_mode_rx,
        .dma_tx_mode = sun8i_dwmac_dma_operation_mode_tx,
        .enable_dma_transmission = sun8i_dwmac_enable_dma_transmission,
        .enable_dma_irq = sun8i_dwmac_enable_dma_irq,
        .disable_dma_irq = sun8i_dwmac_disable_dma_irq,
        .start_tx = sun8i_dwmac_dma_start_tx,
        .stop_tx = sun8i_dwmac_dma_stop_tx,
        .start_rx = sun8i_dwmac_dma_start_rx,
        .stop_rx = sun8i_dwmac_dma_stop_rx,
        .dma_interrupt = sun8i_dwmac_dma_interrupt,
};

static int sun8i_dwmac_power_internal_phy(struct stmmac_priv *priv);

static int sun8i_dwmac_init(struct device *dev, void *priv)
{
        struct net_device *ndev = dev_get_drvdata(dev);
        struct sunxi_priv_data *gmac = priv;
        int ret;

        if (gmac->regulator) {
                ret = regulator_enable(gmac->regulator);
                if (ret) {
                        dev_err(dev, "Fail to enable regulator\n");
                        return ret;
                }
        }

        if (gmac->use_internal_phy) {
                ret = sun8i_dwmac_power_internal_phy(netdev_priv(ndev));
                if (ret)
                        goto err_disable_regulator;
        }

        return 0;

err_disable_regulator:
        if (gmac->regulator)
                regulator_disable(gmac->regulator);

        return ret;
}

static void sun8i_dwmac_core_init(struct mac_device_info *hw,
                                  struct net_device *dev)
{
        void __iomem *ioaddr = hw->pcsr;
        u32 v;

        v = (8 << EMAC_BURSTLEN_SHIFT); /* burst len */
        writel(v, ioaddr + EMAC_BASIC_CTL1);
}

static void sun8i_dwmac_set_mac(void __iomem *ioaddr, bool enable)
{
        u32 t, r;

        t = readl(ioaddr + EMAC_TX_CTL0);
        r = readl(ioaddr + EMAC_RX_CTL0);
        if (enable) {
                t |= EMAC_TX_TRANSMITTER_EN;
                r |= EMAC_RX_RECEIVER_EN;
        } else {
                t &= ~EMAC_TX_TRANSMITTER_EN;
                r &= ~EMAC_RX_RECEIVER_EN;
        }
        writel(t, ioaddr + EMAC_TX_CTL0);
        writel(r, ioaddr + EMAC_RX_CTL0);
}

/* Set MAC address at slot reg_n
 * All slot > 0 need to be enabled with MAC_ADDR_TYPE_DST
 * If addr is NULL, clear the slot
 */
static void sun8i_dwmac_set_umac_addr(struct mac_device_info *hw,
                                      const unsigned char *addr,
                                      unsigned int reg_n)
{
        void __iomem *ioaddr = hw->pcsr;
        u32 v;

        if (!addr) {
                writel(0, ioaddr + EMAC_MACADDR_HI(reg_n));
                return;
        }

        stmmac_set_mac_addr(ioaddr, addr, EMAC_MACADDR_HI(reg_n),
                            EMAC_MACADDR_LO(reg_n));
        if (reg_n > 0) {
                v = readl(ioaddr + EMAC_MACADDR_HI(reg_n));
                v |= MAC_ADDR_TYPE_DST;
                writel(v, ioaddr + EMAC_MACADDR_HI(reg_n));
        }
}

static void sun8i_dwmac_get_umac_addr(struct mac_device_info *hw,
                                      unsigned char *addr,
                                      unsigned int reg_n)
{
        void __iomem *ioaddr = hw->pcsr;

        stmmac_get_mac_addr(ioaddr, addr, EMAC_MACADDR_HI(reg_n),
                            EMAC_MACADDR_LO(reg_n));
}

/* caution this function must return non 0 to work */
static int sun8i_dwmac_rx_ipc_enable(struct mac_device_info *hw)
{
        void __iomem *ioaddr = hw->pcsr;
        u32 v;

        v = readl(ioaddr + EMAC_RX_CTL0);
        v |= EMAC_RX_DO_CRC;
        writel(v, ioaddr + EMAC_RX_CTL0);

        return 1;
}

static void sun8i_dwmac_set_filter(struct mac_device_info *hw,
                                   struct net_device *dev)
{
        void __iomem *ioaddr = hw->pcsr;
        u32 v;
        int i = 1;
        struct netdev_hw_addr *ha;
        int macaddrs = netdev_uc_count(dev) + netdev_mc_count(dev) + 1;

        v = EMAC_FRM_FLT_CTL;

        if (dev->flags & IFF_PROMISC) {
                v = EMAC_FRM_FLT_RXALL;
        } else if (dev->flags & IFF_ALLMULTI) {
                v |= EMAC_FRM_FLT_MULTICAST;
        } else if (macaddrs <= hw->unicast_filter_entries) {
                if (!netdev_mc_empty(dev)) {
                        netdev_for_each_mc_addr(ha, dev) {
                                sun8i_dwmac_set_umac_addr(hw, ha->addr, i);
                                i++;
                        }
                }
                if (!netdev_uc_empty(dev)) {
                        netdev_for_each_uc_addr(ha, dev) {
                                sun8i_dwmac_set_umac_addr(hw, ha->addr, i);
                                i++;
                        }
                }
        } else {
                if (!(readl(ioaddr + EMAC_RX_FRM_FLT) & EMAC_FRM_FLT_RXALL))
                        netdev_info(dev, "Too many address, switching to promiscuous\n");
                v = EMAC_FRM_FLT_RXALL;
        }

        /* Disable unused address filter slots */
        while (i < hw->unicast_filter_entries)
                sun8i_dwmac_set_umac_addr(hw, NULL, i++);

        writel(v, ioaddr + EMAC_RX_FRM_FLT);
}

static void sun8i_dwmac_flow_ctrl(struct mac_device_info *hw,
                                  unsigned int duplex, unsigned int fc,
                                  unsigned int pause_time, u32 tx_cnt)
{
        void __iomem *ioaddr = hw->pcsr;
        u32 v;

        v = readl(ioaddr + EMAC_RX_CTL0);
        if (fc == FLOW_AUTO)
                v |= EMAC_RX_FLOW_CTL_EN;
        else
                v &= ~EMAC_RX_FLOW_CTL_EN;
        writel(v, ioaddr + EMAC_RX_CTL0);

        v = readl(ioaddr + EMAC_TX_FLOW_CTL);
        if (fc == FLOW_AUTO)
                v |= EMAC_TX_FLOW_CTL_EN;
        else
                v &= ~EMAC_TX_FLOW_CTL_EN;
        writel(v, ioaddr + EMAC_TX_FLOW_CTL);
}

static int sun8i_dwmac_reset(struct stmmac_priv *priv)
{
        u32 v;
        int err;

        v = readl(priv->ioaddr + EMAC_BASIC_CTL1);
        writel(v | 0x01, priv->ioaddr + EMAC_BASIC_CTL1);

        /* The timeout was previously set to 10ms, but some board (OrangePI0)
         * need more if no cable plugged. 100ms seems OK
         */
        err = readl_poll_timeout(priv->ioaddr + EMAC_BASIC_CTL1, v,
                                 !(v & 0x01), 100, 100000);

        if (err) {
                dev_err(priv->device, "EMAC reset timeout\n");
                return err;
        }
        return 0;
}

/* Search in mdio-mux node for internal PHY node and get its clk/reset */
static int get_ephy_nodes(struct stmmac_priv *priv)
{
        struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
        struct device_node *mdio_internal;
        struct device_node *mdio_mux;
        int ret;

        mdio_mux = of_get_child_by_name(priv->device->of_node, "mdio-mux");
        if (!mdio_mux) {
                dev_err(priv->device, "Cannot get mdio-mux node\n");
                return -ENODEV;
        }

        mdio_internal = of_get_compatible_child(mdio_mux,
                                                "allwinner,sun8i-h3-mdio-internal");
        of_node_put(mdio_mux);
        if (!mdio_internal) {
                dev_err(priv->device, "Cannot get internal_mdio node\n");
                return -ENODEV;
        }

        /* Seek for internal PHY */
        for_each_child_of_node_scoped(mdio_internal, iphynode) {
                gmac->ephy_clk = of_clk_get(iphynode, 0);
                if (IS_ERR(gmac->ephy_clk))
                        continue;
                gmac->rst_ephy = of_reset_control_get_exclusive(iphynode, NULL);
                if (IS_ERR(gmac->rst_ephy)) {
                        ret = PTR_ERR(gmac->rst_ephy);
                        if (ret == -EPROBE_DEFER) {
                                of_node_put(mdio_internal);
                                return ret;
                        }
                        continue;
                }
                dev_info(priv->device, "Found internal PHY node\n");
                of_node_put(mdio_internal);
                return 0;
        }

        of_node_put(mdio_internal);
        return -ENODEV;
}

static int sun8i_dwmac_power_internal_phy(struct stmmac_priv *priv)
{
        struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
        int ret;

        if (gmac->internal_phy_powered) {
                dev_warn(priv->device, "Internal PHY already powered\n");
                return 0;
        }

        dev_info(priv->device, "Powering internal PHY\n");
        ret = clk_prepare_enable(gmac->ephy_clk);
        if (ret) {
                dev_err(priv->device, "Cannot enable internal PHY\n");
                return ret;
        }

        /* Make sure the EPHY is properly reset, as U-Boot may leave
         * it at deasserted state, and thus it may fail to reset EMAC.
         *
         * This assumes the driver has exclusive access to the EPHY reset.
         */
        ret = reset_control_reset(gmac->rst_ephy);
        if (ret) {
                dev_err(priv->device, "Cannot reset internal PHY\n");
                clk_disable_unprepare(gmac->ephy_clk);
                return ret;
        }

        gmac->internal_phy_powered = true;

        return 0;
}

static void sun8i_dwmac_unpower_internal_phy(struct sunxi_priv_data *gmac)
{
        if (!gmac->internal_phy_powered)
                return;

        clk_disable_unprepare(gmac->ephy_clk);
        reset_control_assert(gmac->rst_ephy);
        gmac->internal_phy_powered = false;
}

/* MDIO multiplexing switch function
 * This function is called by the mdio-mux layer when it thinks the mdio bus
 * multiplexer needs to switch.
 * 'current_child' is the current value of the mux register
 * 'desired_child' is the value of the 'reg' property of the target child MDIO
 * node.
 * The first time this function is called, current_child == -1.
 * If current_child == desired_child, then the mux is already set to the
 * correct bus.
 */
static int mdio_mux_syscon_switch_fn(int current_child, int desired_child,
                                     void *data)
{
        struct stmmac_priv *priv = data;
        struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
        u32 reg, val;
        int ret = 0;

        if (current_child ^ desired_child) {
                regmap_field_read(gmac->regmap_field, &reg);
                switch (desired_child) {
                case DWMAC_SUN8I_MDIO_MUX_INTERNAL_ID:
                        dev_info(priv->device, "Switch mux to internal PHY");
                        val = (reg & ~H3_EPHY_MUX_MASK) | H3_EPHY_SELECT;
                        gmac->use_internal_phy = true;
                        break;
                case DWMAC_SUN8I_MDIO_MUX_EXTERNAL_ID:
                        dev_info(priv->device, "Switch mux to external PHY");
                        val = (reg & ~H3_EPHY_MUX_MASK) | H3_EPHY_SHUTDOWN;
                        gmac->use_internal_phy = false;
                        break;
                default:
                        dev_err(priv->device, "Invalid child ID %x\n",
                                desired_child);
                        return -EINVAL;
                }
                regmap_field_write(gmac->regmap_field, val);
                if (gmac->use_internal_phy) {
                        ret = sun8i_dwmac_power_internal_phy(priv);
                        if (ret)
                                return ret;
                } else {
                        sun8i_dwmac_unpower_internal_phy(gmac);
                }
                /* After changing syscon value, the MAC need reset or it will
                 * use the last value (and so the last PHY set).
                 */
                ret = sun8i_dwmac_reset(priv);
        }
        return ret;
}

static int sun8i_dwmac_register_mdio_mux(struct stmmac_priv *priv)
{
        int ret;
        struct device_node *mdio_mux;
        struct sunxi_priv_data *gmac = priv->plat->bsp_priv;

        mdio_mux = of_get_child_by_name(priv->device->of_node, "mdio-mux");
        if (!mdio_mux)
                return -ENODEV;

        ret = mdio_mux_init(priv->device, mdio_mux, mdio_mux_syscon_switch_fn,
                            &gmac->mux_handle, priv, priv->mii);
        of_node_put(mdio_mux);
        return ret;
}

static int sun8i_dwmac_set_syscon(struct device *dev,
                                  struct plat_stmmacenet_data *plat)
{
        struct sunxi_priv_data *gmac = plat->bsp_priv;
        struct device_node *node = dev->of_node;
        int ret;
        u32 reg = 0, val;

        if (gmac->variant->soc_has_internal_phy) {
                if (of_property_read_bool(node, "allwinner,leds-active-low"))
                        reg |= H3_EPHY_LED_POL;

                /* Force EPHY xtal frequency to 24MHz. */
                reg |= H3_EPHY_CLK_SEL;

                ret = of_mdio_parse_addr(dev, plat->phy_node);
                if (ret < 0) {
                        dev_err(dev, "Could not parse MDIO addr\n");
                        return ret;
                }
                /* of_mdio_parse_addr returns a valid (0 ~ 31) PHY
                 * address. No need to mask it again.
                 */
                reg |= ret << H3_EPHY_ADDR_SHIFT;
        }

        if (!of_property_read_u32(node, "allwinner,tx-delay-ps", &val)) {
                if (val % 100) {
                        dev_err(dev, "tx-delay must be a multiple of 100\n");
                        return -EINVAL;
                }
                val /= 100;
                dev_dbg(dev, "set tx-delay to %x\n", val);
                if (val <= gmac->variant->tx_delay_max) {
                        reg |= (val << SYSCON_ETXDC_SHIFT);
                } else {
                        dev_err(dev, "Invalid TX clock delay: %d\n",
                                val);
                        return -EINVAL;
                }
        }

        if (!of_property_read_u32(node, "allwinner,rx-delay-ps", &val)) {
                if (val % 100) {
                        dev_err(dev, "rx-delay must be a multiple of 100\n");
                        return -EINVAL;
                }
                val /= 100;
                dev_dbg(dev, "set rx-delay to %x\n", val);
                if (val <= gmac->variant->rx_delay_max) {
                        reg |= (val << SYSCON_ERXDC_SHIFT);
                } else {
                        dev_err(dev, "Invalid RX clock delay: %d\n",
                                val);
                        return -EINVAL;
                }
        }

        switch (plat->phy_interface) {
        case PHY_INTERFACE_MODE_MII:
                /* default */
                break;
        case PHY_INTERFACE_MODE_RGMII:
        case PHY_INTERFACE_MODE_RGMII_ID:
        case PHY_INTERFACE_MODE_RGMII_RXID:
        case PHY_INTERFACE_MODE_RGMII_TXID:
                reg |= SYSCON_EPIT | SYSCON_ETCS_INT_GMII;
                break;
        case PHY_INTERFACE_MODE_RMII:
                reg |= SYSCON_RMII_EN | SYSCON_ETCS_EXT_GMII;
                break;
        default:
                dev_err(dev, "Unsupported interface mode: %s",
                        phy_modes(plat->phy_interface));
                return -EINVAL;
        }

        regmap_field_write(gmac->regmap_field, reg);

        return 0;
}

static void sun8i_dwmac_unset_syscon(struct sunxi_priv_data *gmac)
{
        if (gmac->variant->soc_has_internal_phy)
                regmap_field_write(gmac->regmap_field,
                                   (H3_EPHY_SHUTDOWN | H3_EPHY_SELECT));
}

static void sun8i_dwmac_exit(struct device *dev, void *priv)
{
        struct sunxi_priv_data *gmac = priv;

        if (gmac->variant->soc_has_internal_phy)
                sun8i_dwmac_unpower_internal_phy(gmac);

        if (gmac->regulator)
                regulator_disable(gmac->regulator);
}

static void sun8i_dwmac_set_mac_loopback(void __iomem *ioaddr, bool enable)
{
        u32 value = readl(ioaddr + EMAC_BASIC_CTL0);

        if (enable)
                value |= EMAC_LOOPBACK;
        else
                value &= ~EMAC_LOOPBACK;

        writel(value, ioaddr + EMAC_BASIC_CTL0);
}

static const struct stmmac_ops sun8i_dwmac_ops = {
        .core_init = sun8i_dwmac_core_init,
        .set_mac = sun8i_dwmac_set_mac,
        .dump_regs = sun8i_dwmac_dump_mac_regs,
        .rx_ipc = sun8i_dwmac_rx_ipc_enable,
        .set_filter = sun8i_dwmac_set_filter,
        .flow_ctrl = sun8i_dwmac_flow_ctrl,
        .set_umac_addr = sun8i_dwmac_set_umac_addr,
        .get_umac_addr = sun8i_dwmac_get_umac_addr,
        .set_mac_loopback = sun8i_dwmac_set_mac_loopback,
};

static int sun8i_dwmac_setup(void *ppriv, struct mac_device_info *mac)
{
        struct stmmac_priv *priv = ppriv;

        mac->pcsr = priv->ioaddr;
        mac->mac = &sun8i_dwmac_ops;
        mac->dma = &sun8i_dwmac_dma_ops;

        priv->dev->priv_flags |= IFF_UNICAST_FLT;

        mac->link.caps = MAC_ASYM_PAUSE | MAC_SYM_PAUSE |
                         MAC_10 | MAC_100 | MAC_1000;
        /* The loopback bit seems to be re-set when link change
         * Simply mask it each time
         * Speed 10/100/1000 are set in BIT(2)/BIT(3)
         */
        mac->link.speed_mask = GENMASK(3, 2) | EMAC_LOOPBACK;
        mac->link.speed10 = EMAC_SPEED_10;
        mac->link.speed100 = EMAC_SPEED_100;
        mac->link.speed1000 = EMAC_SPEED_1000;
        mac->link.duplex = EMAC_DUPLEX_FULL;
        mac->mii.addr = EMAC_MDIO_CMD;
        mac->mii.data = EMAC_MDIO_DATA;
        mac->mii.reg_shift = 4;
        mac->mii.reg_mask = GENMASK(8, 4);
        mac->mii.addr_shift = 12;
        mac->mii.addr_mask = GENMASK(16, 12);
        mac->mii.clk_csr_shift = 20;
        mac->mii.clk_csr_mask = GENMASK(22, 20);
        mac->unicast_filter_entries = 8;

        /* Synopsys Id is not available */
        priv->synopsys_id = 0;

        return 0;
}

static struct regmap *sun8i_dwmac_get_syscon_from_dev(struct device_node *node)
{
        struct device_node *syscon_node;
        struct platform_device *syscon_pdev;
        struct regmap *regmap = NULL;

        syscon_node = of_parse_phandle(node, "syscon", 0);
        if (!syscon_node)
                return ERR_PTR(-ENODEV);

        syscon_pdev = of_find_device_by_node(syscon_node);
        if (!syscon_pdev) {
                /* platform device might not be probed yet */
                regmap = ERR_PTR(-EPROBE_DEFER);
                goto out_put_node;
        }

        /* If no regmap is found then the other device driver is at fault */
        regmap = dev_get_regmap(&syscon_pdev->dev, NULL);
        if (!regmap)
                regmap = ERR_PTR(-EINVAL);

        platform_device_put(syscon_pdev);
out_put_node:
        of_node_put(syscon_node);
        return regmap;
}

static int sun8i_dwmac_probe(struct platform_device *pdev)
{
        struct plat_stmmacenet_data *plat_dat;
        struct stmmac_resources stmmac_res;
        struct sunxi_priv_data *gmac;
        struct device *dev = &pdev->dev;
        struct stmmac_priv *priv;
        struct net_device *ndev;
        struct regmap *regmap;
        int ret;

        ret = stmmac_get_platform_resources(pdev, &stmmac_res);
        if (ret)
                return ret;

        gmac = devm_kzalloc(dev, sizeof(*gmac), GFP_KERNEL);
        if (!gmac)
                return -ENOMEM;

        gmac->variant = of_device_get_match_data(&pdev->dev);
        if (!gmac->variant) {
                dev_err(&pdev->dev, "Missing dwmac-sun8i variant\n");
                return -EINVAL;
        }

        /* Optional regulator for PHY */
        gmac->regulator = devm_regulator_get_optional(dev, "phy");
        if (IS_ERR(gmac->regulator)) {
                if (PTR_ERR(gmac->regulator) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;
                dev_info(dev, "No regulator found\n");
                gmac->regulator = NULL;
        }

        /* The "GMAC clock control" register might be located in the
         * CCU address range (on the R40), or the system control address
         * range (on most other sun8i and later SoCs).
         *
         * The former controls most if not all clocks in the SoC. The
         * latter has an SoC identification register, and on some SoCs,
         * controls to map device specific SRAM to either the intended
         * peripheral, or the CPU address space.
         *
         * In either case, there should be a coordinated and restricted
         * method of accessing the register needed here. This is done by
         * having the device export a custom regmap, instead of a generic
         * syscon, which grants all access to all registers.
         *
         * To support old device trees, we fall back to using the syscon
         * interface if possible.
         */
        regmap = sun8i_dwmac_get_syscon_from_dev(pdev->dev.of_node);
        if (IS_ERR(regmap))
                regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
                                                         "syscon");
        if (IS_ERR(regmap)) {
                ret = PTR_ERR(regmap);
                dev_err(&pdev->dev, "Unable to map syscon: %d\n", ret);
                return ret;
        }

        gmac->regmap_field = devm_regmap_field_alloc(dev, regmap,
                                                     *gmac->variant->syscon_field);
        if (IS_ERR(gmac->regmap_field)) {
                ret = PTR_ERR(gmac->regmap_field);
                dev_err(dev, "Unable to map syscon register: %d\n", ret);
                return ret;
        }

        plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
        if (IS_ERR(plat_dat))
                return PTR_ERR(plat_dat);

        /* platform data specifying hardware features and callbacks.
         * hardware features were copied from Allwinner drivers.
         */
        plat_dat->rx_coe = STMMAC_RX_COE_TYPE2;
        plat_dat->tx_coe = 1;
        plat_dat->flags |= STMMAC_FLAG_HAS_SUN8I;
        plat_dat->bsp_priv = gmac;
        plat_dat->init = sun8i_dwmac_init;
        plat_dat->exit = sun8i_dwmac_exit;
        plat_dat->mac_setup = sun8i_dwmac_setup;
        plat_dat->tx_fifo_size = 4096;
        plat_dat->rx_fifo_size = 16384;

        ret = sun8i_dwmac_set_syscon(&pdev->dev, plat_dat);
        if (ret)
                return ret;

        ret = stmmac_pltfr_probe(pdev, plat_dat, &stmmac_res);
        if (ret)
                goto dwmac_syscon;

        ndev = dev_get_drvdata(&pdev->dev);
        priv = netdev_priv(ndev);

        /* the MAC is runtime suspended after stmmac_dvr_probe(), so we
         * need to ensure the MAC resume back before other operations such
         * as reset.
         */
        pm_runtime_get_sync(&pdev->dev);

        /* The mux must be registered after parent MDIO
         * so after stmmac_dvr_probe()
         */
        if (gmac->variant->soc_has_internal_phy) {
                ret = get_ephy_nodes(priv);
                if (ret)
                        goto dwmac_remove;
                ret = sun8i_dwmac_register_mdio_mux(priv);
                if (ret) {
                        dev_err(&pdev->dev, "Failed to register mux\n");
                        goto dwmac_mux;
                }
        } else {
                ret = sun8i_dwmac_reset(priv);
                if (ret)
                        goto dwmac_remove;
        }

        pm_runtime_put(&pdev->dev);

        return 0;

dwmac_mux:
        reset_control_put(gmac->rst_ephy);
        clk_put(gmac->ephy_clk);
dwmac_remove:
        pm_runtime_put_noidle(&pdev->dev);
        stmmac_pltfr_remove(pdev);
dwmac_syscon:
        sun8i_dwmac_unset_syscon(gmac);

        return ret;
}

static void sun8i_dwmac_remove(struct platform_device *pdev)
{
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct stmmac_priv *priv = netdev_priv(ndev);
        struct sunxi_priv_data *gmac = priv->plat->bsp_priv;

        if (gmac->variant->soc_has_internal_phy) {
                mdio_mux_uninit(gmac->mux_handle);
                sun8i_dwmac_unpower_internal_phy(gmac);
                reset_control_put(gmac->rst_ephy);
                clk_put(gmac->ephy_clk);
        }

        stmmac_pltfr_remove(pdev);
        sun8i_dwmac_unset_syscon(gmac);
}

static void sun8i_dwmac_shutdown(struct platform_device *pdev)
{
        struct net_device *ndev = platform_get_drvdata(pdev);
        struct stmmac_priv *priv = netdev_priv(ndev);
        struct sunxi_priv_data *gmac = priv->plat->bsp_priv;

        sun8i_dwmac_exit(&pdev->dev, gmac);
}

static const struct of_device_id sun8i_dwmac_match[] = {
        { .compatible = "allwinner,sun8i-h3-emac",
                .data = &emac_variant_h3 },
        { .compatible = "allwinner,sun8i-v3s-emac",
                .data = &emac_variant_v3s },
        { .compatible = "allwinner,sun8i-a83t-emac",
                .data = &emac_variant_a83t },
        { .compatible = "allwinner,sun8i-r40-gmac",
                .data = &emac_variant_r40 },
        { .compatible = "allwinner,sun50i-a64-emac",
                .data = &emac_variant_a64 },
        { .compatible = "allwinner,sun50i-h6-emac",
                .data = &emac_variant_h6 },
        { }
};
MODULE_DEVICE_TABLE(of, sun8i_dwmac_match);

static struct platform_driver sun8i_dwmac_driver = {
        .probe  = sun8i_dwmac_probe,
        .remove = sun8i_dwmac_remove,
        .shutdown = sun8i_dwmac_shutdown,
        .driver = {
                .name           = "dwmac-sun8i",
                .pm             = &stmmac_pltfr_pm_ops,
                .of_match_table = sun8i_dwmac_match,
        },
};
module_platform_driver(sun8i_dwmac_driver);

MODULE_AUTHOR("Corentin Labbe <clabbe.montjoie@gmail.com>");
MODULE_DESCRIPTION("Allwinner sun8i DWMAC specific glue layer");
MODULE_LICENSE("GPL");