root/drivers/net/ethernet/renesas/rtsn.c
// SPDX-License-Identifier: GPL-2.0

/* Renesas Ethernet-TSN device driver
 *
 * Copyright (C) 2022 Renesas Electronics Corporation
 * Copyright (C) 2023 Niklas Söderlund <niklas.soderlund@ragnatech.se>
 */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/module.h>
#include <linux/net_tstamp.h>
#include <linux/of.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/spinlock.h>

#include "rtsn.h"
#include "rcar_gen4_ptp.h"

struct rtsn_private {
        struct net_device *ndev;
        struct platform_device *pdev;
        void __iomem *base;
        struct rcar_gen4_ptp_private *ptp_priv;
        struct clk *clk;
        struct reset_control *reset;

        u32 num_tx_ring;
        u32 num_rx_ring;
        u32 tx_desc_bat_size;
        dma_addr_t tx_desc_bat_dma;
        struct rtsn_desc *tx_desc_bat;
        u32 rx_desc_bat_size;
        dma_addr_t rx_desc_bat_dma;
        struct rtsn_desc *rx_desc_bat;
        dma_addr_t tx_desc_dma;
        dma_addr_t rx_desc_dma;
        struct rtsn_ext_desc *tx_ring;
        struct rtsn_ext_ts_desc *rx_ring;
        struct sk_buff **tx_skb;
        struct sk_buff **rx_skb;
        spinlock_t lock;        /* Register access lock */
        u32 cur_tx;
        u32 dirty_tx;
        u32 cur_rx;
        u32 dirty_rx;
        u8 ts_tag;
        struct napi_struct napi;
        struct rtnl_link_stats64 stats;

        struct mii_bus *mii;
        phy_interface_t iface;
        int link;
        int speed;

        int tx_data_irq;
        int rx_data_irq;

        u32 tstamp_tx_ctrl;
        u32 tstamp_rx_ctrl;
};

static u32 rtsn_read(struct rtsn_private *priv, enum rtsn_reg reg)
{
        return ioread32(priv->base + reg);
}

static void rtsn_write(struct rtsn_private *priv, enum rtsn_reg reg, u32 data)
{
        iowrite32(data, priv->base + reg);
}

static void rtsn_modify(struct rtsn_private *priv, enum rtsn_reg reg,
                        u32 clear, u32 set)
{
        rtsn_write(priv, reg, (rtsn_read(priv, reg) & ~clear) | set);
}

static int rtsn_reg_wait(struct rtsn_private *priv, enum rtsn_reg reg,
                         u32 mask, u32 expected)
{
        u32 val;

        return readl_poll_timeout(priv->base + reg, val,
                                  (val & mask) == expected,
                                  RTSN_INTERVAL_US, RTSN_TIMEOUT_US);
}

static void rtsn_ctrl_data_irq(struct rtsn_private *priv, bool enable)
{
        if (enable) {
                rtsn_write(priv, TDIE0, TDIE_TDID_TDX(TX_CHAIN_IDX));
                rtsn_write(priv, RDIE0, RDIE_RDID_RDX(RX_CHAIN_IDX));
        } else {
                rtsn_write(priv, TDID0, TDIE_TDID_TDX(TX_CHAIN_IDX));
                rtsn_write(priv, RDID0, RDIE_RDID_RDX(RX_CHAIN_IDX));
        }
}

static int rtsn_tx_free(struct net_device *ndev, bool free_txed_only)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        struct rtsn_ext_desc *desc;
        struct sk_buff *skb;
        int free_num = 0;
        int entry, size;

        for (; priv->cur_tx - priv->dirty_tx > 0; priv->dirty_tx++) {
                entry = priv->dirty_tx % priv->num_tx_ring;
                desc = &priv->tx_ring[entry];
                if (free_txed_only && (desc->die_dt & DT_MASK) != DT_FEMPTY)
                        break;

                dma_rmb();
                size = le16_to_cpu(desc->info_ds) & TX_DS;
                skb = priv->tx_skb[entry];
                if (skb) {
                        if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
                                struct skb_shared_hwtstamps shhwtstamps;
                                struct timespec64 ts;

                                rcar_gen4_ptp_gettime64(priv->ptp_priv, &ts);
                                memset(&shhwtstamps, 0, sizeof(shhwtstamps));
                                shhwtstamps.hwtstamp = timespec64_to_ktime(ts);
                                skb_tstamp_tx(skb, &shhwtstamps);
                        }
                        dma_unmap_single(ndev->dev.parent,
                                         le32_to_cpu(desc->dptr),
                                         size, DMA_TO_DEVICE);
                        dev_kfree_skb_any(priv->tx_skb[entry]);
                        free_num++;

                        priv->stats.tx_packets++;
                        priv->stats.tx_bytes += size;
                }

                desc->die_dt = DT_EEMPTY;
        }

        desc = &priv->tx_ring[priv->num_tx_ring];
        desc->die_dt = DT_LINK;

        return free_num;
}

static int rtsn_rx(struct net_device *ndev, int budget)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        unsigned int ndescriptors;
        unsigned int rx_packets;
        unsigned int i;
        bool get_ts;

        get_ts = priv->tstamp_rx_ctrl != HWTSTAMP_FILTER_NONE;

        ndescriptors = priv->dirty_rx + priv->num_rx_ring - priv->cur_rx;
        rx_packets = 0;
        for (i = 0; i < ndescriptors; i++) {
                const unsigned int entry = priv->cur_rx % priv->num_rx_ring;
                struct rtsn_ext_ts_desc *desc = &priv->rx_ring[entry];
                struct sk_buff *skb;
                dma_addr_t dma_addr;
                u16 pkt_len;

                /* Stop processing descriptors if budget is consumed. */
                if (rx_packets >= budget)
                        break;

                /* Stop processing descriptors on first empty. */
                if ((desc->die_dt & DT_MASK) == DT_FEMPTY)
                        break;

                dma_rmb();
                pkt_len = le16_to_cpu(desc->info_ds) & RX_DS;

                skb = priv->rx_skb[entry];
                priv->rx_skb[entry] = NULL;
                dma_addr = le32_to_cpu(desc->dptr);
                dma_unmap_single(ndev->dev.parent, dma_addr, PKT_BUF_SZ,
                                 DMA_FROM_DEVICE);

                /* Get timestamp if enabled. */
                if (get_ts) {
                        struct skb_shared_hwtstamps *shhwtstamps;
                        struct timespec64 ts;

                        shhwtstamps = skb_hwtstamps(skb);
                        memset(shhwtstamps, 0, sizeof(*shhwtstamps));

                        ts.tv_sec = (u64)le32_to_cpu(desc->ts_sec);
                        ts.tv_nsec = le32_to_cpu(desc->ts_nsec & cpu_to_le32(0x3fffffff));

                        shhwtstamps->hwtstamp = timespec64_to_ktime(ts);
                }

                skb_put(skb, pkt_len);
                skb->protocol = eth_type_trans(skb, ndev);
                napi_gro_receive(&priv->napi, skb);

                /* Update statistics. */
                priv->stats.rx_packets++;
                priv->stats.rx_bytes += pkt_len;

                /* Update counters. */
                priv->cur_rx++;
                rx_packets++;
        }

        /* Refill the RX ring buffers */
        for (; priv->cur_rx - priv->dirty_rx > 0; priv->dirty_rx++) {
                const unsigned int entry = priv->dirty_rx % priv->num_rx_ring;
                struct rtsn_ext_ts_desc *desc = &priv->rx_ring[entry];
                struct sk_buff *skb;
                dma_addr_t dma_addr;

                desc->info_ds = cpu_to_le16(PKT_BUF_SZ);

                if (!priv->rx_skb[entry]) {
                        skb = napi_alloc_skb(&priv->napi,
                                             PKT_BUF_SZ + RTSN_ALIGN - 1);
                        if (!skb)
                                break;
                        skb_reserve(skb, NET_IP_ALIGN);
                        dma_addr = dma_map_single(ndev->dev.parent, skb->data,
                                                  le16_to_cpu(desc->info_ds),
                                                  DMA_FROM_DEVICE);
                        if (dma_mapping_error(ndev->dev.parent, dma_addr))
                                desc->info_ds = cpu_to_le16(0);
                        desc->dptr = cpu_to_le32(dma_addr);
                        skb_checksum_none_assert(skb);
                        priv->rx_skb[entry] = skb;
                }

                dma_wmb();
                desc->die_dt = DT_FEMPTY | D_DIE;
        }

        priv->rx_ring[priv->num_rx_ring].die_dt = DT_LINK;

        return rx_packets;
}

static int rtsn_poll(struct napi_struct *napi, int budget)
{
        struct rtsn_private *priv;
        struct net_device *ndev;
        unsigned long flags;
        int work_done;

        ndev = napi->dev;
        priv = netdev_priv(ndev);

        /* Processing RX Descriptor Ring */
        work_done = rtsn_rx(ndev, budget);

        /* Processing TX Descriptor Ring */
        spin_lock_irqsave(&priv->lock, flags);
        rtsn_tx_free(ndev, true);
        netif_wake_subqueue(ndev, 0);
        spin_unlock_irqrestore(&priv->lock, flags);

        /* Re-enable TX/RX interrupts */
        if (work_done < budget && napi_complete_done(napi, work_done)) {
                spin_lock_irqsave(&priv->lock, flags);
                rtsn_ctrl_data_irq(priv, true);
                spin_unlock_irqrestore(&priv->lock, flags);
        }

        return work_done;
}

static int rtsn_desc_alloc(struct rtsn_private *priv)
{
        struct device *dev = &priv->pdev->dev;
        unsigned int i;

        priv->tx_desc_bat_size = sizeof(struct rtsn_desc) * TX_NUM_CHAINS;
        priv->tx_desc_bat = dma_alloc_coherent(dev, priv->tx_desc_bat_size,
                                               &priv->tx_desc_bat_dma,
                                               GFP_KERNEL);

        if (!priv->tx_desc_bat)
                return -ENOMEM;

        for (i = 0; i < TX_NUM_CHAINS; i++)
                priv->tx_desc_bat[i].die_dt = DT_EOS;

        priv->rx_desc_bat_size = sizeof(struct rtsn_desc) * RX_NUM_CHAINS;
        priv->rx_desc_bat = dma_alloc_coherent(dev, priv->rx_desc_bat_size,
                                               &priv->rx_desc_bat_dma,
                                               GFP_KERNEL);

        if (!priv->rx_desc_bat)
                return -ENOMEM;

        for (i = 0; i < RX_NUM_CHAINS; i++)
                priv->rx_desc_bat[i].die_dt = DT_EOS;

        return 0;
}

static void rtsn_desc_free(struct rtsn_private *priv)
{
        if (priv->tx_desc_bat)
                dma_free_coherent(&priv->pdev->dev, priv->tx_desc_bat_size,
                                  priv->tx_desc_bat, priv->tx_desc_bat_dma);
        priv->tx_desc_bat = NULL;

        if (priv->rx_desc_bat)
                dma_free_coherent(&priv->pdev->dev, priv->rx_desc_bat_size,
                                  priv->rx_desc_bat, priv->rx_desc_bat_dma);
        priv->rx_desc_bat = NULL;
}

static void rtsn_chain_free(struct rtsn_private *priv)
{
        struct device *dev = &priv->pdev->dev;

        dma_free_coherent(dev,
                          sizeof(struct rtsn_ext_desc) * (priv->num_tx_ring + 1),
                          priv->tx_ring, priv->tx_desc_dma);
        priv->tx_ring = NULL;

        dma_free_coherent(dev,
                          sizeof(struct rtsn_ext_ts_desc) * (priv->num_rx_ring + 1),
                          priv->rx_ring, priv->rx_desc_dma);
        priv->rx_ring = NULL;

        kfree(priv->tx_skb);
        priv->tx_skb = NULL;

        kfree(priv->rx_skb);
        priv->rx_skb = NULL;
}

static int rtsn_chain_init(struct rtsn_private *priv, int tx_size, int rx_size)
{
        struct net_device *ndev = priv->ndev;
        struct sk_buff *skb;
        int i;

        priv->num_tx_ring = tx_size;
        priv->num_rx_ring = rx_size;

        priv->tx_skb = kzalloc_objs(*priv->tx_skb, tx_size);
        priv->rx_skb = kzalloc_objs(*priv->rx_skb, rx_size);

        if (!priv->rx_skb || !priv->tx_skb)
                goto error;

        for (i = 0; i < rx_size; i++) {
                skb = netdev_alloc_skb(ndev, PKT_BUF_SZ + RTSN_ALIGN - 1);
                if (!skb)
                        goto error;
                skb_reserve(skb, NET_IP_ALIGN);
                priv->rx_skb[i] = skb;
        }

        /* Allocate TX, RX descriptors */
        priv->tx_ring = dma_alloc_coherent(ndev->dev.parent,
                                           sizeof(struct rtsn_ext_desc) * (tx_size + 1),
                                           &priv->tx_desc_dma, GFP_KERNEL);
        priv->rx_ring = dma_alloc_coherent(ndev->dev.parent,
                                           sizeof(struct rtsn_ext_ts_desc) * (rx_size + 1),
                                           &priv->rx_desc_dma, GFP_KERNEL);

        if (!priv->tx_ring || !priv->rx_ring)
                goto error;

        return 0;
error:
        rtsn_chain_free(priv);

        return -ENOMEM;
}

static void rtsn_chain_format(struct rtsn_private *priv)
{
        struct net_device *ndev = priv->ndev;
        struct rtsn_ext_ts_desc *rx_desc;
        struct rtsn_ext_desc *tx_desc;
        struct rtsn_desc *bat_desc;
        dma_addr_t dma_addr;
        unsigned int i;

        priv->cur_tx = 0;
        priv->cur_rx = 0;
        priv->dirty_rx = 0;
        priv->dirty_tx = 0;

        /* TX */
        memset(priv->tx_ring, 0, sizeof(*tx_desc) * priv->num_tx_ring);
        for (i = 0, tx_desc = priv->tx_ring; i < priv->num_tx_ring; i++, tx_desc++)
                tx_desc->die_dt = DT_EEMPTY | D_DIE;

        tx_desc->dptr = cpu_to_le32((u32)priv->tx_desc_dma);
        tx_desc->die_dt = DT_LINK;

        bat_desc = &priv->tx_desc_bat[TX_CHAIN_IDX];
        bat_desc->die_dt = DT_LINK;
        bat_desc->dptr = cpu_to_le32((u32)priv->tx_desc_dma);

        /* RX */
        memset(priv->rx_ring, 0, sizeof(*rx_desc) * priv->num_rx_ring);
        for (i = 0, rx_desc = priv->rx_ring; i < priv->num_rx_ring; i++, rx_desc++) {
                dma_addr = dma_map_single(ndev->dev.parent,
                                          priv->rx_skb[i]->data, PKT_BUF_SZ,
                                          DMA_FROM_DEVICE);
                if (!dma_mapping_error(ndev->dev.parent, dma_addr))
                        rx_desc->info_ds = cpu_to_le16(PKT_BUF_SZ);
                rx_desc->dptr = cpu_to_le32((u32)dma_addr);
                rx_desc->die_dt = DT_FEMPTY | D_DIE;
        }
        rx_desc->dptr = cpu_to_le32((u32)priv->rx_desc_dma);
        rx_desc->die_dt = DT_LINK;

        bat_desc = &priv->rx_desc_bat[RX_CHAIN_IDX];
        bat_desc->die_dt = DT_LINK;
        bat_desc->dptr = cpu_to_le32((u32)priv->rx_desc_dma);
}

static int rtsn_dmac_init(struct rtsn_private *priv)
{
        int ret;

        ret = rtsn_chain_init(priv, TX_CHAIN_SIZE, RX_CHAIN_SIZE);
        if (ret)
                return ret;

        rtsn_chain_format(priv);

        return 0;
}

static enum rtsn_mode rtsn_read_mode(struct rtsn_private *priv)
{
        return (rtsn_read(priv, OSR) & OSR_OPS) >> 1;
}

static int rtsn_wait_mode(struct rtsn_private *priv, enum rtsn_mode mode)
{
        unsigned int i;

        /* Need to busy loop as mode changes can happen in atomic context. */
        for (i = 0; i < RTSN_TIMEOUT_US / RTSN_INTERVAL_US; i++) {
                if (rtsn_read_mode(priv) == mode)
                        return 0;

                udelay(RTSN_INTERVAL_US);
        }

        return -ETIMEDOUT;
}

static int rtsn_change_mode(struct rtsn_private *priv, enum rtsn_mode mode)
{
        int ret;

        rtsn_write(priv, OCR, mode);
        ret = rtsn_wait_mode(priv, mode);
        if (ret)
                netdev_err(priv->ndev, "Failed to switch operation mode\n");
        return ret;
}

static int rtsn_get_data_irq_status(struct rtsn_private *priv)
{
        u32 val;

        val = rtsn_read(priv, TDIS0) | TDIS_TDS(TX_CHAIN_IDX);
        val |= rtsn_read(priv, RDIS0) | RDIS_RDS(RX_CHAIN_IDX);

        return val;
}

static irqreturn_t rtsn_irq(int irq, void *dev_id)
{
        struct rtsn_private *priv = dev_id;
        int ret = IRQ_NONE;

        spin_lock(&priv->lock);

        if (rtsn_get_data_irq_status(priv)) {
                /* Clear TX/RX irq status */
                rtsn_write(priv, TDIS0, TDIS_TDS(TX_CHAIN_IDX));
                rtsn_write(priv, RDIS0, RDIS_RDS(RX_CHAIN_IDX));

                if (napi_schedule_prep(&priv->napi)) {
                        /* Disable TX/RX interrupts */
                        rtsn_ctrl_data_irq(priv, false);

                        __napi_schedule(&priv->napi);
                }

                ret = IRQ_HANDLED;
        }

        spin_unlock(&priv->lock);

        return ret;
}

static int rtsn_request_irq(unsigned int irq, irq_handler_t handler,
                            unsigned long flags, struct rtsn_private *priv,
                            const char *ch)
{
        char *name;
        int ret;

        name = devm_kasprintf(&priv->pdev->dev, GFP_KERNEL, "%s:%s",
                              priv->ndev->name, ch);
        if (!name)
                return -ENOMEM;

        ret = request_irq(irq, handler, flags, name, priv);
        if (ret)
                netdev_err(priv->ndev, "Cannot request IRQ %s\n", name);

        return ret;
}

static void rtsn_free_irqs(struct rtsn_private *priv)
{
        free_irq(priv->tx_data_irq, priv);
        free_irq(priv->rx_data_irq, priv);
}

static int rtsn_request_irqs(struct rtsn_private *priv)
{
        int ret;

        priv->rx_data_irq = platform_get_irq_byname(priv->pdev, "rx");
        if (priv->rx_data_irq < 0)
                return priv->rx_data_irq;

        priv->tx_data_irq = platform_get_irq_byname(priv->pdev, "tx");
        if (priv->tx_data_irq < 0)
                return priv->tx_data_irq;

        ret = rtsn_request_irq(priv->tx_data_irq, rtsn_irq, 0, priv, "tx");
        if (ret)
                return ret;

        ret = rtsn_request_irq(priv->rx_data_irq, rtsn_irq, 0, priv, "rx");
        if (ret) {
                free_irq(priv->tx_data_irq, priv);
                return ret;
        }

        return 0;
}

static int rtsn_reset(struct rtsn_private *priv)
{
        reset_control_reset(priv->reset);
        mdelay(1);

        return rtsn_wait_mode(priv, OCR_OPC_DISABLE);
}

static int rtsn_axibmi_init(struct rtsn_private *priv)
{
        int ret;

        ret = rtsn_reg_wait(priv, RR, RR_RST, RR_RST_COMPLETE);
        if (ret)
                return ret;

        /* Set AXIWC */
        rtsn_write(priv, AXIWC, AXIWC_DEFAULT);

        /* Set AXIRC */
        rtsn_write(priv, AXIRC, AXIRC_DEFAULT);

        /* TX Descriptor chain setting */
        rtsn_write(priv, TATLS0, TATLS0_TEDE | TATLS0_TATEN(TX_CHAIN_IDX));
        rtsn_write(priv, TATLS1, priv->tx_desc_bat_dma + TX_CHAIN_ADDR_OFFSET);
        rtsn_write(priv, TATLR, TATLR_TATL);

        ret = rtsn_reg_wait(priv, TATLR, TATLR_TATL, 0);
        if (ret)
                return ret;

        /* RX Descriptor chain setting */
        rtsn_write(priv, RATLS0,
                   RATLS0_RETS | RATLS0_REDE | RATLS0_RATEN(RX_CHAIN_IDX));
        rtsn_write(priv, RATLS1, priv->rx_desc_bat_dma + RX_CHAIN_ADDR_OFFSET);
        rtsn_write(priv, RATLR, RATLR_RATL);

        ret = rtsn_reg_wait(priv, RATLR, RATLR_RATL, 0);
        if (ret)
                return ret;

        /* Enable TX/RX interrupts */
        rtsn_ctrl_data_irq(priv, true);

        return 0;
}

static void rtsn_mhd_init(struct rtsn_private *priv)
{
        /* TX General setting */
        rtsn_write(priv, TGC1, TGC1_STTV_DEFAULT | TGC1_TQTM_SFM);
        rtsn_write(priv, TMS0, TMS_MFS_MAX);

        /* RX Filter IP */
        rtsn_write(priv, CFCR0, CFCR_SDID(RX_CHAIN_IDX));
        rtsn_write(priv, FMSCR, FMSCR_FMSIE(RX_CHAIN_IDX));
}

static int rtsn_get_phy_params(struct rtsn_private *priv)
{
        int ret;

        ret = of_get_phy_mode(priv->pdev->dev.of_node, &priv->iface);
        if (ret)
                return ret;

        switch (priv->iface) {
        case PHY_INTERFACE_MODE_MII:
                priv->speed = 100;
                break;
        case PHY_INTERFACE_MODE_RGMII:
        case PHY_INTERFACE_MODE_RGMII_ID:
        case PHY_INTERFACE_MODE_RGMII_RXID:
        case PHY_INTERFACE_MODE_RGMII_TXID:
                priv->speed = 1000;
                break;
        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

static void rtsn_set_phy_interface(struct rtsn_private *priv)
{
        u32 val;

        switch (priv->iface) {
        case PHY_INTERFACE_MODE_MII:
                val = MPIC_PIS_MII;
                break;
        case PHY_INTERFACE_MODE_RGMII:
        case PHY_INTERFACE_MODE_RGMII_ID:
        case PHY_INTERFACE_MODE_RGMII_RXID:
        case PHY_INTERFACE_MODE_RGMII_TXID:
                val = MPIC_PIS_GMII;
                break;
        default:
                return;
        }

        rtsn_modify(priv, MPIC, MPIC_PIS_MASK, val);
}

static void rtsn_set_rate(struct rtsn_private *priv)
{
        u32 val;

        switch (priv->speed) {
        case 10:
                val = MPIC_LSC_10M;
                break;
        case 100:
                val = MPIC_LSC_100M;
                break;
        case 1000:
                val = MPIC_LSC_1G;
                break;
        default:
                return;
        }

        rtsn_modify(priv, MPIC, MPIC_LSC_MASK, val);
}

static int rtsn_rmac_init(struct rtsn_private *priv)
{
        const u8 *mac_addr = priv->ndev->dev_addr;
        int ret;

        /* Set MAC address */
        rtsn_write(priv, MRMAC0, (mac_addr[0] << 8) | mac_addr[1]);
        rtsn_write(priv, MRMAC1, (mac_addr[2] << 24) | (mac_addr[3] << 16) |
                   (mac_addr[4] << 8) | mac_addr[5]);

        /* Set xMII type */
        rtsn_set_phy_interface(priv);
        rtsn_set_rate(priv);

        /* Enable MII */
        rtsn_modify(priv, MPIC, MPIC_PSMCS_MASK | MPIC_PSMHT_MASK,
                    MPIC_PSMCS_DEFAULT | MPIC_PSMHT_DEFAULT);

        /* Link verification */
        rtsn_modify(priv, MLVC, MLVC_PLV, MLVC_PLV);
        ret = rtsn_reg_wait(priv, MLVC, MLVC_PLV, 0);
        if (ret)
                return ret;

        return ret;
}

static int rtsn_hw_init(struct rtsn_private *priv)
{
        int ret;

        ret = rtsn_reset(priv);
        if (ret)
                return ret;

        /* Change to CONFIG mode */
        ret = rtsn_change_mode(priv, OCR_OPC_CONFIG);
        if (ret)
                return ret;

        ret = rtsn_axibmi_init(priv);
        if (ret)
                return ret;

        rtsn_mhd_init(priv);

        ret = rtsn_rmac_init(priv);
        if (ret)
                return ret;

        ret = rtsn_change_mode(priv, OCR_OPC_DISABLE);
        if (ret)
                return ret;

        /* Change to OPERATION mode */
        ret = rtsn_change_mode(priv, OCR_OPC_OPERATION);

        return ret;
}

static int rtsn_mii_access(struct mii_bus *bus, bool read, int phyad,
                           int regad, u16 data)
{
        struct rtsn_private *priv = bus->priv;
        u32 val;
        int ret;

        val = MPSM_PDA(phyad) | MPSM_PRA(regad) | MPSM_PSME;

        if (!read)
                val |= MPSM_PSMAD | MPSM_PRD_SET(data);

        rtsn_write(priv, MPSM, val);

        ret = rtsn_reg_wait(priv, MPSM, MPSM_PSME, 0);
        if (ret)
                return ret;

        if (read)
                ret = MPSM_PRD_GET(rtsn_read(priv, MPSM));

        return ret;
}

static int rtsn_mii_read(struct mii_bus *bus, int addr, int regnum)
{
        return rtsn_mii_access(bus, true, addr, regnum, 0);
}

static int rtsn_mii_write(struct mii_bus *bus, int addr, int regnum, u16 val)
{
        return rtsn_mii_access(bus, false, addr, regnum, val);
}

static int rtsn_mdio_alloc(struct rtsn_private *priv)
{
        struct platform_device *pdev = priv->pdev;
        struct device *dev = &pdev->dev;
        struct device_node *mdio_node;
        struct mii_bus *mii;
        int ret;

        mii = mdiobus_alloc();
        if (!mii)
                return -ENOMEM;

        mdio_node = of_get_child_by_name(dev->of_node, "mdio");
        if (!mdio_node) {
                ret = -ENODEV;
                goto out_free_bus;
        }

        /* Enter config mode before registering the MDIO bus */
        ret = rtsn_reset(priv);
        if (ret)
                goto out_free_bus;

        ret = rtsn_change_mode(priv, OCR_OPC_CONFIG);
        if (ret)
                goto out_free_bus;

        rtsn_modify(priv, MPIC, MPIC_PSMCS_MASK | MPIC_PSMHT_MASK,
                    MPIC_PSMCS_DEFAULT | MPIC_PSMHT_DEFAULT);

        /* Register the MDIO bus */
        mii->name = "rtsn_mii";
        snprintf(mii->id, MII_BUS_ID_SIZE, "%s-%x",
                 pdev->name, pdev->id);
        mii->priv = priv;
        mii->read = rtsn_mii_read;
        mii->write = rtsn_mii_write;
        mii->parent = dev;

        ret = of_mdiobus_register(mii, mdio_node);
        of_node_put(mdio_node);
        if (ret)
                goto out_free_bus;

        priv->mii = mii;

        return 0;

out_free_bus:
        mdiobus_free(mii);
        return ret;
}

static void rtsn_mdio_free(struct rtsn_private *priv)
{
        mdiobus_unregister(priv->mii);
        mdiobus_free(priv->mii);
        priv->mii = NULL;
}

static void rtsn_adjust_link(struct net_device *ndev)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        struct phy_device *phydev = ndev->phydev;
        bool new_state = false;
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);

        if (phydev->link) {
                if (phydev->speed != priv->speed) {
                        new_state = true;
                        priv->speed = phydev->speed;
                }

                if (!priv->link) {
                        new_state = true;
                        priv->link = phydev->link;
                }
        } else if (priv->link) {
                new_state = true;
                priv->link = 0;
                priv->speed = 0;
        }

        if (new_state) {
                /* Need to transition to CONFIG mode before reconfiguring and
                 * then back to the original mode. Any state change to/from
                 * CONFIG or OPERATION must go over DISABLED to stop Rx/Tx.
                 */
                enum rtsn_mode orgmode = rtsn_read_mode(priv);

                /* Transit to CONFIG */
                if (orgmode != OCR_OPC_CONFIG) {
                        if (orgmode != OCR_OPC_DISABLE &&
                            rtsn_change_mode(priv, OCR_OPC_DISABLE))
                                goto out;
                        if (rtsn_change_mode(priv, OCR_OPC_CONFIG))
                                goto out;
                }

                rtsn_set_rate(priv);

                /* Transition to original mode */
                if (orgmode != OCR_OPC_CONFIG) {
                        if (rtsn_change_mode(priv, OCR_OPC_DISABLE))
                                goto out;
                        if (orgmode != OCR_OPC_DISABLE &&
                            rtsn_change_mode(priv, orgmode))
                                goto out;
                }
        }
out:
        spin_unlock_irqrestore(&priv->lock, flags);

        if (new_state)
                phy_print_status(phydev);
}

static int rtsn_phy_init(struct rtsn_private *priv)
{
        struct device_node *np = priv->ndev->dev.parent->of_node;
        struct phy_device *phydev;
        struct device_node *phy;

        priv->link = 0;

        phy = of_parse_phandle(np, "phy-handle", 0);
        if (!phy)
                return -ENOENT;

        phydev = of_phy_connect(priv->ndev, phy, rtsn_adjust_link, 0,
                                priv->iface);
        of_node_put(phy);
        if (!phydev)
                return -ENOENT;

        /* Only support full-duplex mode */
        phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_10baseT_Half_BIT);
        phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_100baseT_Half_BIT);
        phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_1000baseT_Half_BIT);

        phy_attached_info(phydev);

        return 0;
}

static void rtsn_phy_deinit(struct rtsn_private *priv)
{
        phy_disconnect(priv->ndev->phydev);
        priv->ndev->phydev = NULL;
}

static int rtsn_init(struct rtsn_private *priv)
{
        int ret;

        ret = rtsn_desc_alloc(priv);
        if (ret)
                return ret;

        ret = rtsn_dmac_init(priv);
        if (ret)
                goto error_free_desc;

        ret = rtsn_hw_init(priv);
        if (ret)
                goto error_free_chain;

        ret = rtsn_phy_init(priv);
        if (ret)
                goto error_free_chain;

        ret = rtsn_request_irqs(priv);
        if (ret)
                goto error_free_phy;

        return 0;
error_free_phy:
        rtsn_phy_deinit(priv);
error_free_chain:
        rtsn_chain_free(priv);
error_free_desc:
        rtsn_desc_free(priv);
        return ret;
}

static void rtsn_deinit(struct rtsn_private *priv)
{
        rtsn_free_irqs(priv);
        rtsn_phy_deinit(priv);
        rtsn_chain_free(priv);
        rtsn_desc_free(priv);
}

static void rtsn_parse_mac_address(struct device_node *np,
                                   struct net_device *ndev)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        u8 addr[ETH_ALEN];
        u32 mrmac0;
        u32 mrmac1;

        /* Try to read address from Device Tree. */
        if (!of_get_mac_address(np, addr)) {
                eth_hw_addr_set(ndev, addr);
                return;
        }

        /* Try to read address from device. */
        mrmac0 = rtsn_read(priv, MRMAC0);
        mrmac1 = rtsn_read(priv, MRMAC1);

        addr[0] = (mrmac0 >>  8) & 0xff;
        addr[1] = (mrmac0 >>  0) & 0xff;
        addr[2] = (mrmac1 >> 24) & 0xff;
        addr[3] = (mrmac1 >> 16) & 0xff;
        addr[4] = (mrmac1 >>  8) & 0xff;
        addr[5] = (mrmac1 >>  0) & 0xff;

        if (is_valid_ether_addr(addr)) {
                eth_hw_addr_set(ndev, addr);
                return;
        }

        /* Fallback to a random address */
        eth_hw_addr_random(ndev);
}

static int rtsn_open(struct net_device *ndev)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        int ret;

        napi_enable(&priv->napi);

        ret = rtsn_init(priv);
        if (ret) {
                napi_disable(&priv->napi);
                return ret;
        }

        phy_start(ndev->phydev);

        netif_start_queue(ndev);

        return 0;
}

static int rtsn_stop(struct net_device *ndev)
{
        struct rtsn_private *priv = netdev_priv(ndev);

        phy_stop(priv->ndev->phydev);
        napi_disable(&priv->napi);
        rtsn_change_mode(priv, OCR_OPC_DISABLE);
        rtsn_deinit(priv);

        return 0;
}

static netdev_tx_t rtsn_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        struct rtsn_ext_desc *desc;
        int ret = NETDEV_TX_OK;
        unsigned long flags;
        dma_addr_t dma_addr;
        int entry;

        spin_lock_irqsave(&priv->lock, flags);

        /* Drop packet if it won't fit in a single descriptor. */
        if (skb->len >= TX_DS) {
                priv->stats.tx_dropped++;
                priv->stats.tx_errors++;
                dev_kfree_skb_any(skb);
                goto out;
        }

        if (priv->cur_tx - priv->dirty_tx > priv->num_tx_ring) {
                netif_stop_subqueue(ndev, 0);
                ret = NETDEV_TX_BUSY;
                goto out;
        }

        if (skb_put_padto(skb, ETH_ZLEN))
                goto out;

        dma_addr = dma_map_single(ndev->dev.parent, skb->data, skb->len,
                                  DMA_TO_DEVICE);
        if (dma_mapping_error(ndev->dev.parent, dma_addr)) {
                dev_kfree_skb_any(skb);
                goto out;
        }

        entry = priv->cur_tx % priv->num_tx_ring;
        priv->tx_skb[entry] = skb;
        desc = &priv->tx_ring[entry];
        desc->dptr = cpu_to_le32(dma_addr);
        desc->info_ds = cpu_to_le16(skb->len);
        desc->info1 = cpu_to_le64(skb->len);

        if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
                skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
                priv->ts_tag++;
                desc->info_ds |= cpu_to_le16(TXC);
                desc->info = priv->ts_tag;
        }

        skb_tx_timestamp(skb);
        dma_wmb();

        desc->die_dt = DT_FSINGLE | D_DIE;
        priv->cur_tx++;

        /* Start xmit */
        rtsn_write(priv, TRCR0, BIT(TX_CHAIN_IDX));
out:
        spin_unlock_irqrestore(&priv->lock, flags);
        return ret;
}

static void rtsn_get_stats64(struct net_device *ndev,
                             struct rtnl_link_stats64 *storage)
{
        struct rtsn_private *priv = netdev_priv(ndev);
        *storage = priv->stats;
}

static int rtsn_do_ioctl(struct net_device *ndev, struct ifreq *ifr, int cmd)
{
        if (!netif_running(ndev))
                return -ENODEV;

        return phy_do_ioctl_running(ndev, ifr, cmd);
}

static int rtsn_hwtstamp_get(struct net_device *ndev,
                             struct kernel_hwtstamp_config *config)
{
        struct rtsn_private *priv;

        if (!netif_running(ndev))
                return -ENODEV;

        priv = netdev_priv(ndev);

        config->flags = 0;
        config->tx_type = priv->tstamp_tx_ctrl;
        config->rx_filter = priv->tstamp_rx_ctrl;

        return 0;
}

static int rtsn_hwtstamp_set(struct net_device *ndev,
                             struct kernel_hwtstamp_config *config,
                             struct netlink_ext_ack *extack)
{
        enum hwtstamp_rx_filters tstamp_rx_ctrl;
        enum hwtstamp_tx_types tstamp_tx_ctrl;
        struct rtsn_private *priv;

        if (!netif_running(ndev))
                return -ENODEV;

        priv = netdev_priv(ndev);

        if (config->flags)
                return -EINVAL;

        switch (config->tx_type) {
        case HWTSTAMP_TX_OFF:
        case HWTSTAMP_TX_ON:
                tstamp_tx_ctrl = config->tx_type;
                break;
        default:
                return -ERANGE;
        }

        switch (config->rx_filter) {
        case HWTSTAMP_FILTER_NONE:
        case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
                tstamp_rx_ctrl = config->rx_filter;
                break;
        default:
                config->rx_filter = HWTSTAMP_FILTER_ALL;
                tstamp_rx_ctrl = HWTSTAMP_FILTER_ALL;
                break;
        }

        priv->tstamp_tx_ctrl = tstamp_tx_ctrl;
        priv->tstamp_rx_ctrl = tstamp_rx_ctrl;

        return 0;
}

static const struct net_device_ops rtsn_netdev_ops = {
        .ndo_open               = rtsn_open,
        .ndo_stop               = rtsn_stop,
        .ndo_start_xmit         = rtsn_start_xmit,
        .ndo_get_stats64        = rtsn_get_stats64,
        .ndo_eth_ioctl          = rtsn_do_ioctl,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = eth_mac_addr,
        .ndo_hwtstamp_set       = rtsn_hwtstamp_set,
        .ndo_hwtstamp_get       = rtsn_hwtstamp_get,
};

static int rtsn_get_ts_info(struct net_device *ndev,
                            struct kernel_ethtool_ts_info *info)
{
        struct rtsn_private *priv = netdev_priv(ndev);

        info->phc_index = rcar_gen4_ptp_clock_index(priv->ptp_priv);
        info->so_timestamping = SOF_TIMESTAMPING_TX_SOFTWARE |
                SOF_TIMESTAMPING_TX_HARDWARE |
                SOF_TIMESTAMPING_RX_HARDWARE |
                SOF_TIMESTAMPING_RAW_HARDWARE;
        info->tx_types = BIT(HWTSTAMP_TX_OFF) | BIT(HWTSTAMP_TX_ON);
        info->rx_filters = BIT(HWTSTAMP_FILTER_NONE) | BIT(HWTSTAMP_FILTER_ALL);

        return 0;
}

static const struct ethtool_ops rtsn_ethtool_ops = {
        .nway_reset             = phy_ethtool_nway_reset,
        .get_link               = ethtool_op_get_link,
        .get_ts_info            = rtsn_get_ts_info,
        .get_link_ksettings     = phy_ethtool_get_link_ksettings,
        .set_link_ksettings     = phy_ethtool_set_link_ksettings,
};

static const struct of_device_id rtsn_match_table[] = {
        { .compatible = "renesas,r8a779g0-ethertsn", },
        { /* Sentinel */ }
};

MODULE_DEVICE_TABLE(of, rtsn_match_table);

static int rtsn_probe(struct platform_device *pdev)
{
        struct rtsn_private *priv;
        struct net_device *ndev;
        void __iomem *ptpaddr;
        struct resource *res;
        int ret;

        ndev = alloc_etherdev_mqs(sizeof(struct rtsn_private), TX_NUM_CHAINS,
                                  RX_NUM_CHAINS);
        if (!ndev)
                return -ENOMEM;

        priv = netdev_priv(ndev);
        priv->pdev = pdev;
        priv->ndev = ndev;

        spin_lock_init(&priv->lock);
        platform_set_drvdata(pdev, priv);

        priv->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(priv->clk)) {
                ret = PTR_ERR(priv->clk);
                goto error_free;
        }

        priv->reset = devm_reset_control_get(&pdev->dev, NULL);
        if (IS_ERR(priv->reset)) {
                ret = PTR_ERR(priv->reset);
                goto error_free;
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tsnes");
        if (!res) {
                dev_err(&pdev->dev, "Can't find tsnes resource\n");
                ret = -EINVAL;
                goto error_free;
        }

        priv->base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(priv->base)) {
                ret = PTR_ERR(priv->base);
                goto error_free;
        }

        SET_NETDEV_DEV(ndev, &pdev->dev);

        ndev->features = NETIF_F_RXCSUM;
        ndev->hw_features = NETIF_F_RXCSUM;
        ndev->base_addr = res->start;
        ndev->netdev_ops = &rtsn_netdev_ops;
        ndev->ethtool_ops = &rtsn_ethtool_ops;

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gptp");
        if (!res) {
                dev_err(&pdev->dev, "Can't find gptp resource\n");
                ret = -EINVAL;
                goto error_free;
        }

        ptpaddr = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(ptpaddr)) {
                ret = PTR_ERR(ptpaddr);
                goto error_free;
        }

        priv->ptp_priv = rcar_gen4_ptp_alloc(pdev, ptpaddr);
        if (!priv->ptp_priv) {
                ret = -ENOMEM;
                goto error_free;
        }

        ret = rtsn_get_phy_params(priv);
        if (ret)
                goto error_free;

        pm_runtime_enable(&pdev->dev);
        pm_runtime_get_sync(&pdev->dev);

        netif_napi_add(ndev, &priv->napi, rtsn_poll);

        rtsn_parse_mac_address(pdev->dev.of_node, ndev);

        dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));

        device_set_wakeup_capable(&pdev->dev, 1);

        ret = rcar_gen4_ptp_register(priv->ptp_priv, clk_get_rate(priv->clk));
        if (ret)
                goto error_pm;

        ret = rtsn_mdio_alloc(priv);
        if (ret)
                goto error_ptp;

        ret = register_netdev(ndev);
        if (ret)
                goto error_mdio;

        netdev_info(ndev, "MAC address %pM\n", ndev->dev_addr);

        return 0;

error_mdio:
        rtsn_mdio_free(priv);
error_ptp:
        rcar_gen4_ptp_unregister(priv->ptp_priv);
error_pm:
        netif_napi_del(&priv->napi);
        rtsn_change_mode(priv, OCR_OPC_DISABLE);
        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
error_free:
        free_netdev(ndev);

        return ret;
}

static void rtsn_remove(struct platform_device *pdev)
{
        struct rtsn_private *priv = platform_get_drvdata(pdev);

        unregister_netdev(priv->ndev);
        rtsn_mdio_free(priv);
        rcar_gen4_ptp_unregister(priv->ptp_priv);
        rtsn_change_mode(priv, OCR_OPC_DISABLE);
        netif_napi_del(&priv->napi);

        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        free_netdev(priv->ndev);
}

static struct platform_driver rtsn_driver = {
        .probe          = rtsn_probe,
        .remove         = rtsn_remove,
        .driver = {
                .name   = "rtsn",
                .of_match_table = rtsn_match_table,
        }
};
module_platform_driver(rtsn_driver);

MODULE_AUTHOR("Phong Hoang, Niklas Söderlund");
MODULE_DESCRIPTION("Renesas Ethernet-TSN device driver");
MODULE_LICENSE("GPL");