/*
 * Driver for the National Semiconductor DP83640 PHYTER
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/ethtool.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/net_tstamp.h>
#include <linux/netdevice.h>
#include <linux/phy.h>
#include <linux/ptp_classify.h>
#include <linux/ptp_clock_kernel.h>

#include "dp83640_reg.h"

#define DP83640_PHY_ID  0x20005ce1
#define PAGESEL         0x13
#define LAYER4          0x02
#define LAYER2          0x01
#define MAX_RXTS        64
#define N_EXT_TS        6
#define PSF_PTPVER      2
#define PSF_EVNT        0x4000
#define PSF_RX          0x2000
#define PSF_TX          0x1000
#define EXT_EVENT       1
#define CAL_EVENT       7
#define CAL_TRIGGER     7
#define PER_TRIGGER     6

#define MII_DP83640_MICR 0x11
#define MII_DP83640_MISR 0x12

#define MII_DP83640_MICR_OE 0x1
#define MII_DP83640_MICR_IE 0x2

#define MII_DP83640_MISR_RHF_INT_EN 0x01
#define MII_DP83640_MISR_FHF_INT_EN 0x02
#define MII_DP83640_MISR_ANC_INT_EN 0x04
#define MII_DP83640_MISR_DUP_INT_EN 0x08
#define MII_DP83640_MISR_SPD_INT_EN 0x10
#define MII_DP83640_MISR_LINK_INT_EN 0x20
#define MII_DP83640_MISR_ED_INT_EN 0x40
#define MII_DP83640_MISR_LQ_INT_EN 0x80

/* phyter seems to miss the mark by 16 ns */
#define ADJTIME_FIX     16

#if defined(__BIG_ENDIAN)
#define ENDIAN_FLAG     0
#elif defined(__LITTLE_ENDIAN)
#define ENDIAN_FLAG     PSF_ENDIAN
#endif

#define SKB_PTP_TYPE(__skb) (*(unsigned int *)((__skb)->cb))

struct phy_rxts {
        u16 ns_lo;   /* ns[15:0] */
        u16 ns_hi;   /* overflow[1:0], ns[29:16] */
        u16 sec_lo;  /* sec[15:0] */
        u16 sec_hi;  /* sec[31:16] */
        u16 seqid;   /* sequenceId[15:0] */
        u16 msgtype; /* messageType[3:0], hash[11:0] */
};

struct phy_txts {
        u16 ns_lo;   /* ns[15:0] */
        u16 ns_hi;   /* overflow[1:0], ns[29:16] */
        u16 sec_lo;  /* sec[15:0] */
        u16 sec_hi;  /* sec[31:16] */
};

struct rxts {
        struct list_head list;
        unsigned long tmo;
        u64 ns;
        u16 seqid;
        u8  msgtype;
        u16 hash;
};

struct dp83640_clock;

struct dp83640_private {
        struct list_head list;
        struct dp83640_clock *clock;
        struct phy_device *phydev;
        struct work_struct ts_work;
        int hwts_tx_en;
        int hwts_rx_en;
        int layer;
        int version;
        /* remember state of cfg0 during calibration */
        int cfg0;
        /* remember the last event time stamp */
        struct phy_txts edata;
        /* list of rx timestamps */
        struct list_head rxts;
        struct list_head rxpool;
        struct rxts rx_pool_data[MAX_RXTS];
        /* protects above three fields from concurrent access */
        spinlock_t rx_lock;
        /* queues of incoming and outgoing packets */
        struct sk_buff_head rx_queue;
        struct sk_buff_head tx_queue;
};

struct dp83640_clock {
        /* keeps the instance in the 'phyter_clocks' list */
        struct list_head list;
        /* we create one clock instance per MII bus */
        struct mii_bus *bus;
        /* protects extended registers from concurrent access */
        struct mutex extreg_lock;
        /* remembers which page was last selected */
        int page;
        /* our advertised capabilities */
        struct ptp_clock_info caps;
        /* protects the three fields below from concurrent access */
        struct mutex clock_lock;
        /* the one phyter from which we shall read */
        struct dp83640_private *chosen;
        /* list of the other attached phyters, not chosen */
        struct list_head phylist;
        /* reference to our PTP hardware clock */
        struct ptp_clock *ptp_clock;
};

/* globals */

enum {
        CALIBRATE_GPIO,
        PEROUT_GPIO,
        EXTTS0_GPIO,
        EXTTS1_GPIO,
        EXTTS2_GPIO,
        EXTTS3_GPIO,
        EXTTS4_GPIO,
        EXTTS5_GPIO,
        GPIO_TABLE_SIZE
};

static int chosen_phy = -1;
static ushort gpio_tab[GPIO_TABLE_SIZE] = {
        1, 2, 3, 4, 8, 9, 10, 11
};

module_param(chosen_phy, int, 0444);
module_param_array(gpio_tab, ushort, NULL, 0444);

MODULE_PARM_DESC(chosen_phy, \
        "The address of the PHY to use for the ancillary clock features");
MODULE_PARM_DESC(gpio_tab, \
        "Which GPIO line to use for which purpose: cal,perout,extts1,...,extts6");

/* a list of clocks and a mutex to protect it */
static LIST_HEAD(phyter_clocks);
static DEFINE_MUTEX(phyter_clocks_lock);

static void rx_timestamp_work(struct work_struct *work);

/* extended register access functions */

#define BROADCAST_ADDR 31

static inline int broadcast_write(struct phy_device *phydev, u32 regnum,
                                  u16 val)
{
        return mdiobus_write(phydev->mdio_bus, BROADCAST_ADDR, regnum, val);
}

/* Caller must hold extreg_lock. */
static int ext_read(struct phy_device *phydev, int page, u32 regnum)
{
        struct dp83640_private *dp83640 = phydev->priv;
        int val;

        if (dp83640->clock->page != page) {
                broadcast_write(phydev, PAGESEL, page);
                dp83640->clock->page = page;
        }
        val = phy_read(phydev, regnum);

        return val;
}

/* Caller must hold extreg_lock. */
static void ext_write(int broadcast, struct phy_device *phydev,
                      int page, u32 regnum, u16 val)
{
        struct dp83640_private *dp83640 = phydev->priv;

        if (dp83640->clock->page != page) {
                broadcast_write(phydev, PAGESEL, page);
                dp83640->clock->page = page;
        }
        if (broadcast)
                broadcast_write(phydev, regnum, val);
        else
                phy_write(phydev, regnum, val);
}

/* Caller must hold extreg_lock. */
static int tdr_write(int bc, struct phy_device *dev,
                     const struct timespec *ts, u16 cmd)
{
        ext_write(bc, dev, PAGE4, PTP_TDR, ts->tv_nsec & 0xffff);/* ns[15:0]  */
        ext_write(bc, dev, PAGE4, PTP_TDR, ts->tv_nsec >> 16);   /* ns[31:16] */
        ext_write(bc, dev, PAGE4, PTP_TDR, ts->tv_sec & 0xffff); /* sec[15:0] */
        ext_write(bc, dev, PAGE4, PTP_TDR, ts->tv_sec >> 16);    /* sec[31:16]*/

        ext_write(bc, dev, PAGE4, PTP_CTL, cmd);

        return 0;
}

/* convert phy timestamps into driver timestamps */

static void phy2rxts(struct phy_rxts *p, struct rxts *rxts)
{
        u32 sec;

        sec = p->sec_lo;
        sec |= p->sec_hi << 16;

        rxts->ns = p->ns_lo;
        rxts->ns |= (p->ns_hi & 0x3fff) << 16;
        rxts->ns += ((u64)sec) * 1000000000ULL;
        rxts->seqid = p->seqid;
        rxts->msgtype = (p->msgtype >> 12) & 0xf;
        rxts->hash = p->msgtype & 0x0fff;
        rxts->tmo = jiffies + 2;
}

static u64 phy2txts(struct phy_txts *p)
{
        u64 ns;
        u32 sec;

        sec = p->sec_lo;
        sec |= p->sec_hi << 16;

        ns = p->ns_lo;
        ns |= (p->ns_hi & 0x3fff) << 16;
        ns += ((u64)sec) * 1000000000ULL;

        return ns;
}

static void periodic_output(struct dp83640_clock *clock,
                            struct ptp_clock_request *clkreq, bool on)
{
        struct dp83640_private *dp83640 = clock->chosen;
        struct phy_device *phydev = dp83640->phydev;
        u32 sec, nsec, period;
        u16 gpio, ptp_trig, trigger, val;

        gpio = on ? gpio_tab[PEROUT_GPIO] : 0;
        trigger = PER_TRIGGER;

        ptp_trig = TRIG_WR |
                (trigger & TRIG_CSEL_MASK) << TRIG_CSEL_SHIFT |
                (gpio & TRIG_GPIO_MASK) << TRIG_GPIO_SHIFT |
                TRIG_PER |
                TRIG_PULSE;

        val = (trigger & TRIG_SEL_MASK) << TRIG_SEL_SHIFT;

        if (!on) {
                val |= TRIG_DIS;
                mutex_lock(&clock->extreg_lock);
                ext_write(0, phydev, PAGE5, PTP_TRIG, ptp_trig);
                ext_write(0, phydev, PAGE4, PTP_CTL, val);
                mutex_unlock(&clock->extreg_lock);
                return;
        }

        sec = clkreq->perout.start.sec;
        nsec = clkreq->perout.start.nsec;
        period = clkreq->perout.period.sec * 1000000000UL;
        period += clkreq->perout.period.nsec;

        mutex_lock(&clock->extreg_lock);

        ext_write(0, phydev, PAGE5, PTP_TRIG, ptp_trig);

        /*load trigger*/
        val |= TRIG_LOAD;
        ext_write(0, phydev, PAGE4, PTP_CTL, val);
        ext_write(0, phydev, PAGE4, PTP_TDR, nsec & 0xffff);   /* ns[15:0] */
        ext_write(0, phydev, PAGE4, PTP_TDR, nsec >> 16);      /* ns[31:16] */
        ext_write(0, phydev, PAGE4, PTP_TDR, sec & 0xffff);    /* sec[15:0] */
        ext_write(0, phydev, PAGE4, PTP_TDR, sec >> 16);       /* sec[31:16] */
        ext_write(0, phydev, PAGE4, PTP_TDR, period & 0xffff); /* ns[15:0] */
        ext_write(0, phydev, PAGE4, PTP_TDR, period >> 16);    /* ns[31:16] */

        /*enable trigger*/
        val &= ~TRIG_LOAD;
        val |= TRIG_EN;
        ext_write(0, phydev, PAGE4, PTP_CTL, val);

        mutex_unlock(&clock->extreg_lock);
}

/* ptp clock methods */

static int ptp_dp83640_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
        struct dp83640_clock *clock =
                container_of(ptp, struct dp83640_clock, caps);
        struct phy_device *phydev = clock->chosen->phydev;
        u64 rate;
        int neg_adj = 0;
        u16 hi, lo;

        if (ppb < 0) {
                neg_adj = 1;
                ppb = -ppb;
        }
        rate = ppb;
        rate <<= 26;
        rate = div_u64(rate, 1953125);

        hi = (rate >> 16) & PTP_RATE_HI_MASK;
        if (neg_adj)
                hi |= PTP_RATE_DIR;

        lo = rate & 0xffff;

        mutex_lock(&clock->extreg_lock);

        ext_write(1, phydev, PAGE4, PTP_RATEH, hi);
        ext_write(1, phydev, PAGE4, PTP_RATEL, lo);

        mutex_unlock(&clock->extreg_lock);

        return 0;
}

static int ptp_dp83640_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        struct dp83640_clock *clock =
                container_of(ptp, struct dp83640_clock, caps);
        struct phy_device *phydev = clock->chosen->phydev;
        struct timespec ts;
        int err;

        delta += ADJTIME_FIX;

        ts = ns_to_timespec(delta);

        mutex_lock(&clock->extreg_lock);

        err = tdr_write(1, phydev, &ts, PTP_STEP_CLK);

        mutex_unlock(&clock->extreg_lock);

        return err;
}

static int ptp_dp83640_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
{
        struct dp83640_clock *clock =
                container_of(ptp, struct dp83640_clock, caps);
        struct phy_device *phydev = clock->chosen->phydev;
        unsigned int val[4];

        mutex_lock(&clock->extreg_lock);

        ext_write(0, phydev, PAGE4, PTP_CTL, PTP_RD_CLK);

        val[0] = ext_read(phydev, PAGE4, PTP_TDR); /* ns[15:0] */
        val[1] = ext_read(phydev, PAGE4, PTP_TDR); /* ns[31:16] */
        val[2] = ext_read(phydev, PAGE4, PTP_TDR); /* sec[15:0] */
        val[3] = ext_read(phydev, PAGE4, PTP_TDR); /* sec[31:16] */

        mutex_unlock(&clock->extreg_lock);

        ts->tv_nsec = val[0] | (val[1] << 16);
        ts->tv_sec  = val[2] | (val[3] << 16);

        return 0;
}

static int ptp_dp83640_settime(struct ptp_clock_info *ptp,
                               const struct timespec *ts)
{
        struct dp83640_clock *clock =
                container_of(ptp, struct dp83640_clock, caps);
        struct phy_device *phydev = clock->chosen->phydev;
        int err;

        mutex_lock(&clock->extreg_lock);

        err = tdr_write(1, phydev, ts, PTP_LOAD_CLK);

        mutex_unlock(&clock->extreg_lock);

        return err;
}

static int ptp_dp83640_enable(struct ptp_clock_info *ptp,
                              struct ptp_clock_request *rq, int on)
{
        struct dp83640_clock *clock =
                container_of(ptp, struct dp83640_clock, caps);
        struct phy_device *phydev = clock->chosen->phydev;
        int index;
        u16 evnt, event_num, gpio_num;

        switch (rq->type) {
        case PTP_CLK_REQ_EXTTS:
                index = rq->extts.index;
                if (index < 0 || index >= N_EXT_TS)
                        return -EINVAL;
                event_num = EXT_EVENT + index;
                evnt = EVNT_WR | (event_num & EVNT_SEL_MASK) << EVNT_SEL_SHIFT;
                if (on) {
                        gpio_num = gpio_tab[EXTTS0_GPIO + index];
                        evnt |= (gpio_num & EVNT_GPIO_MASK) << EVNT_GPIO_SHIFT;
                        evnt |= EVNT_RISE;
                }
                ext_write(0, phydev, PAGE5, PTP_EVNT, evnt);
                return 0;

        case PTP_CLK_REQ_PEROUT:
                if (rq->perout.index != 0)
                        return -EINVAL;
                periodic_output(clock, rq, on);
                return 0;

        default:
                break;
        }

        return -EOPNOTSUPP;
}

static u8 status_frame_dst[6] = { 0x01, 0x1B, 0x19, 0x00, 0x00, 0x00 };
static u8 status_frame_src[6] = { 0x08, 0x00, 0x17, 0x0B, 0x6B, 0x0F };

static void enable_status_frames(struct phy_device *phydev, bool on)
{
        u16 cfg0 = 0, ver;

        if (on)
                cfg0 = PSF_EVNT_EN | PSF_RXTS_EN | PSF_TXTS_EN | ENDIAN_FLAG;

        ver = (PSF_PTPVER & VERSIONPTP_MASK) << VERSIONPTP_SHIFT;

        ext_write(0, phydev, PAGE5, PSF_CFG0, cfg0);
        ext_write(0, phydev, PAGE6, PSF_CFG1, ver);

        if (!phydev->attached_dev) {
                pr_warn("expected to find an attached netdevice\n");
                return;
        }

        if (on) {
                if (dev_mc_add(phydev->attached_dev, status_frame_dst))
                        pr_warn("failed to add mc address\n");
        } else {
                if (dev_mc_del(phydev->attached_dev, status_frame_dst))
                        pr_warn("failed to delete mc address\n");
        }
}

static bool is_status_frame(struct sk_buff *skb, int type)
{
        struct ethhdr *h = eth_hdr(skb);

        if (PTP_CLASS_V2_L2 == type &&
            !memcmp(h->h_source, status_frame_src, sizeof(status_frame_src)))
                return true;
        else
                return false;
}

static int expired(struct rxts *rxts)
{
        return time_after(jiffies, rxts->tmo);
}

/* Caller must hold rx_lock. */
static void prune_rx_ts(struct dp83640_private *dp83640)
{
        struct list_head *this, *next;
        struct rxts *rxts;

        list_for_each_safe(this, next, &dp83640->rxts) {
                rxts = list_entry(this, struct rxts, list);
                if (expired(rxts)) {
                        list_del_init(&rxts->list);
                        list_add(&rxts->list, &dp83640->rxpool);
                }
        }
}

/* synchronize the phyters so they act as one clock */

static void enable_broadcast(struct phy_device *phydev, int init_page, int on)
{
        int val;
        phy_write(phydev, PAGESEL, 0);
        val = phy_read(phydev, PHYCR2);
        if (on)
                val |= BC_WRITE;
        else
                val &= ~BC_WRITE;
        phy_write(phydev, PHYCR2, val);
        phy_write(phydev, PAGESEL, init_page);
}

static void recalibrate(struct dp83640_clock *clock)
{
        s64 now, diff;
        struct phy_txts event_ts;
        struct timespec ts;
        struct list_head *this;
        struct dp83640_private *tmp;
        struct phy_device *master = clock->chosen->phydev;
        u16 cal_gpio, cfg0, evnt, ptp_trig, trigger, val;

        trigger = CAL_TRIGGER;
        cal_gpio = gpio_tab[CALIBRATE_GPIO];

        mutex_lock(&clock->extreg_lock);

        /*
         * enable broadcast, disable status frames, enable ptp clock
         */
        list_for_each(this, &clock->phylist) {
                tmp = list_entry(this, struct dp83640_private, list);
                enable_broadcast(tmp->phydev, clock->page, 1);
                tmp->cfg0 = ext_read(tmp->phydev, PAGE5, PSF_CFG0);
                ext_write(0, tmp->phydev, PAGE5, PSF_CFG0, 0);
                ext_write(0, tmp->phydev, PAGE4, PTP_CTL, PTP_ENABLE);
        }
        enable_broadcast(master, clock->page, 1);
        cfg0 = ext_read(master, PAGE5, PSF_CFG0);
        ext_write(0, master, PAGE5, PSF_CFG0, 0);
        ext_write(0, master, PAGE4, PTP_CTL, PTP_ENABLE);

        /*
         * enable an event timestamp
         */
        evnt = EVNT_WR | EVNT_RISE | EVNT_SINGLE;
        evnt |= (CAL_EVENT & EVNT_SEL_MASK) << EVNT_SEL_SHIFT;
        evnt |= (cal_gpio & EVNT_GPIO_MASK) << EVNT_GPIO_SHIFT;

        list_for_each(this, &clock->phylist) {
                tmp = list_entry(this, struct dp83640_private, list);
                ext_write(0, tmp->phydev, PAGE5, PTP_EVNT, evnt);
        }
        ext_write(0, master, PAGE5, PTP_EVNT, evnt);

        /*
         * configure a trigger
         */
        ptp_trig = TRIG_WR | TRIG_IF_LATE | TRIG_PULSE;
        ptp_trig |= (trigger  & TRIG_CSEL_MASK) << TRIG_CSEL_SHIFT;
        ptp_trig |= (cal_gpio & TRIG_GPIO_MASK) << TRIG_GPIO_SHIFT;
        ext_write(0, master, PAGE5, PTP_TRIG, ptp_trig);

        /* load trigger */
        val = (trigger & TRIG_SEL_MASK) << TRIG_SEL_SHIFT;
        val |= TRIG_LOAD;
        ext_write(0, master, PAGE4, PTP_CTL, val);

        /* enable trigger */
        val &= ~TRIG_LOAD;
        val |= TRIG_EN;
        ext_write(0, master, PAGE4, PTP_CTL, val);

        /* disable trigger */
        val = (trigger & TRIG_SEL_MASK) << TRIG_SEL_SHIFT;
        val |= TRIG_DIS;
        ext_write(0, master, PAGE4, PTP_CTL, val);

        /*
         * read out and correct offsets
         */
        val = ext_read(master, PAGE4, PTP_STS);
        pr_info("master PTP_STS  0x%04hx\n", val);
        val = ext_read(master, PAGE4, PTP_ESTS);
        pr_info("master PTP_ESTS 0x%04hx\n", val);
        event_ts.ns_lo  = ext_read(master, PAGE4, PTP_EDATA);
        event_ts.ns_hi  = ext_read(master, PAGE4, PTP_EDATA);
        event_ts.sec_lo = ext_read(master, PAGE4, PTP_EDATA);
        event_ts.sec_hi = ext_read(master, PAGE4, PTP_EDATA);
        now = phy2txts(&event_ts);

        list_for_each(this, &clock->phylist) {
                tmp = list_entry(this, struct dp83640_private, list);
                val = ext_read(tmp->phydev, PAGE4, PTP_STS);
                pr_info("slave  PTP_STS  0x%04hx\n", val);
                val = ext_read(tmp->phydev, PAGE4, PTP_ESTS);
                pr_info("slave  PTP_ESTS 0x%04hx\n", val);
                event_ts.ns_lo  = ext_read(tmp->phydev, PAGE4, PTP_EDATA);
                event_ts.ns_hi  = ext_read(tmp->phydev, PAGE4, PTP_EDATA);
                event_ts.sec_lo = ext_read(tmp->phydev, PAGE4, PTP_EDATA);
                event_ts.sec_hi = ext_read(tmp->phydev, PAGE4, PTP_EDATA);
                diff = now - (s64) phy2txts(&event_ts);
                pr_info("slave offset %lld nanoseconds\n", diff);
                diff += ADJTIME_FIX;
                ts = ns_to_timespec(diff);
                tdr_write(0, tmp->phydev, &ts, PTP_STEP_CLK);
        }

        /*
         * restore status frames
         */
        list_for_each(this, &clock->phylist) {
                tmp = list_entry(this, struct dp83640_private, list);
                ext_write(0, tmp->phydev, PAGE5, PSF_CFG0, tmp->cfg0);
        }
        ext_write(0, master, PAGE5, PSF_CFG0, cfg0);

        mutex_unlock(&clock->extreg_lock);
}

/* time stamping methods */

static inline u16 exts_chan_to_edata(int ch)
{
        return 1 << ((ch + EXT_EVENT) * 2);
}

static int decode_evnt(struct dp83640_private *dp83640,
                       void *data, u16 ests)
{
        struct phy_txts *phy_txts;
        struct ptp_clock_event event;
        int i, parsed;
        int words = (ests >> EVNT_TS_LEN_SHIFT) & EVNT_TS_LEN_MASK;
        u16 ext_status = 0;

        if (ests & MULT_EVNT) {
                ext_status = *(u16 *) data;
                data += sizeof(ext_status);
        }

        phy_txts = data;

        switch (words) { /* fall through in every case */
        case 3:
                dp83640->edata.sec_hi = phy_txts->sec_hi;
        case 2:
                dp83640->edata.sec_lo = phy_txts->sec_lo;
        case 1:
                dp83640->edata.ns_hi = phy_txts->ns_hi;
        case 0:
                dp83640->edata.ns_lo = phy_txts->ns_lo;
        }

        if (ext_status) {
                parsed = words + 2;
        } else {
                parsed = words + 1;
                i = ((ests >> EVNT_NUM_SHIFT) & EVNT_NUM_MASK) - EXT_EVENT;
                ext_status = exts_chan_to_edata(i);
        }

        event.type = PTP_CLOCK_EXTTS;
        event.timestamp = phy2txts(&dp83640->edata);

        for (i = 0; i < N_EXT_TS; i++) {
                if (ext_status & exts_chan_to_edata(i)) {
                        event.index = i;
                        ptp_clock_event(dp83640->clock->ptp_clock, &event);
                }
        }

        return parsed * sizeof(u16);
}

static void decode_rxts(struct dp83640_private *dp83640,
                        struct phy_rxts *phy_rxts)
{
        struct rxts *rxts;
        unsigned long flags;

        spin_lock_irqsave(&dp83640->rx_lock, flags);

        prune_rx_ts(dp83640);

        if (list_empty(&dp83640->rxpool)) {
                pr_debug("rx timestamp pool is empty\n");
                goto out;
        }
        rxts = list_first_entry(&dp83640->rxpool, struct rxts, list);
        list_del_init(&rxts->list);
        phy2rxts(phy_rxts, rxts);
        list_add_tail(&rxts->list, &dp83640->rxts);
out:
        spin_unlock_irqrestore(&dp83640->rx_lock, flags);
}

static void decode_txts(struct dp83640_private *dp83640,
                        struct phy_txts *phy_txts)
{
        struct skb_shared_hwtstamps shhwtstamps;
        struct sk_buff *skb;
        u64 ns;

        /* We must already have the skb that triggered this. */

        skb = skb_dequeue(&dp83640->tx_queue);

        if (!skb) {
                pr_debug("have timestamp but tx_queue empty\n");
                return;
        }
        ns = phy2txts(phy_txts);
        memset(&shhwtstamps, 0, sizeof(shhwtstamps));
        shhwtstamps.hwtstamp = ns_to_ktime(ns);
        skb_complete_tx_timestamp(skb, &shhwtstamps);
}

static void decode_status_frame(struct dp83640_private *dp83640,
                                struct sk_buff *skb)
{
        struct phy_rxts *phy_rxts;
        struct phy_txts *phy_txts;
        u8 *ptr;
        int len, size;
        u16 ests, type;

        ptr = skb->data + 2;

        for (len = skb_headlen(skb) - 2; len > sizeof(type); len -= size) {

                type = *(u16 *)ptr;
                ests = type & 0x0fff;
                type = type & 0xf000;
                len -= sizeof(type);
                ptr += sizeof(type);

                if (PSF_RX == type && len >= sizeof(*phy_rxts)) {

                        phy_rxts = (struct phy_rxts *) ptr;
                        decode_rxts(dp83640, phy_rxts);
                        size = sizeof(*phy_rxts);

                } else if (PSF_TX == type && len >= sizeof(*phy_txts)) {

                        phy_txts = (struct phy_txts *) ptr;
                        decode_txts(dp83640, phy_txts);
                        size = sizeof(*phy_txts);

                } else if (PSF_EVNT == type && len >= sizeof(*phy_txts)) {

                        size = decode_evnt(dp83640, ptr, ests);

                } else {
                        size = 0;
                        break;
                }
                ptr += size;
        }
}

static int is_sync(struct sk_buff *skb, int type)
{
        u8 *data = skb->data, *msgtype;
        unsigned int offset = 0;

        switch (type) {
        case PTP_CLASS_V1_IPV4:
        case PTP_CLASS_V2_IPV4:
                offset = ETH_HLEN + IPV4_HLEN(data) + UDP_HLEN;
                break;
        case PTP_CLASS_V1_IPV6:
        case PTP_CLASS_V2_IPV6:
                offset = OFF_PTP6;
                break;
        case PTP_CLASS_V2_L2:
                offset = ETH_HLEN;
                break;
        case PTP_CLASS_V2_VLAN:
                offset = ETH_HLEN + VLAN_HLEN;
                break;
        default:
                return 0;
        }

        if (type & PTP_CLASS_V1)
                offset += OFF_PTP_CONTROL;

        if (skb->len < offset + 1)
                return 0;

        msgtype = data + offset;

        return (*msgtype & 0xf) == 0;
}

static int match(struct sk_buff *skb, unsigned int type, struct rxts *rxts)
{
        u16 *seqid;
        unsigned int offset;
        u8 *msgtype, *data = skb_mac_header(skb);

        /* check sequenceID, messageType, 12 bit hash of offset 20-29 */

        switch (type) {
        case PTP_CLASS_V1_IPV4:
        case PTP_CLASS_V2_IPV4:
                offset = ETH_HLEN + IPV4_HLEN(data) + UDP_HLEN;
                break;
        case PTP_CLASS_V1_IPV6:
        case PTP_CLASS_V2_IPV6:
                offset = OFF_PTP6;
                break;
        case PTP_CLASS_V2_L2:
                offset = ETH_HLEN;
                break;
        case PTP_CLASS_V2_VLAN:
                offset = ETH_HLEN + VLAN_HLEN;
                break;
        default:
                return 0;
        }

        if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
                return 0;

        if (unlikely(type & PTP_CLASS_V1))
                msgtype = data + offset + OFF_PTP_CONTROL;
        else
                msgtype = data + offset;

        seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);

        return (rxts->msgtype == (*msgtype & 0xf) &&
                rxts->seqid   == ntohs(*seqid));
}

static void dp83640_free_clocks(void)
{
        struct dp83640_clock *clock;
        struct list_head *this, *next;

        mutex_lock(&phyter_clocks_lock);

        list_for_each_safe(this, next, &phyter_clocks) {
                clock = list_entry(this, struct dp83640_clock, list);
                if (!list_empty(&clock->phylist)) {
                        pr_warn("phy list non-empty while unloading\n");
                        BUG();
                }
                list_del(&clock->list);
                mutex_destroy(&clock->extreg_lock);
                mutex_destroy(&clock->clock_lock);
                put_device(&clock->bus->dev);
                kfree(clock);
        }

        mutex_unlock(&phyter_clocks_lock);
}

static void dp83640_clock_init(struct dp83640_clock *clock, struct mii_bus *bus)
{
        INIT_LIST_HEAD(&clock->list);
        clock->bus = bus;
        mutex_init(&clock->extreg_lock);
        mutex_init(&clock->clock_lock);
        INIT_LIST_HEAD(&clock->phylist);
        clock->caps.owner = THIS_MODULE;
        sprintf(clock->caps.name, "dp83640 timer");
        clock->caps.max_adj     = 1953124;
        clock->caps.n_alarm     = 0;
        clock->caps.n_ext_ts    = N_EXT_TS;
        clock->caps.n_per_out   = 1;
        clock->caps.pps         = 0;
        clock->caps.adjfreq     = ptp_dp83640_adjfreq;
        clock->caps.adjtime     = ptp_dp83640_adjtime;
        clock->caps.gettime     = ptp_dp83640_gettime;
        clock->caps.settime     = ptp_dp83640_settime;
        clock->caps.enable      = ptp_dp83640_enable;
        /*
         * Get a reference to this bus instance.
         */
        get_device(&bus->dev);
}

static int choose_this_phy(struct dp83640_clock *clock,
                           struct phy_device *phydev)
{
        if (chosen_phy == -1 && !clock->chosen)
                return 1;

        if (chosen_phy == phydev->mdio_addr)
                return 1;

        return 0;
}

static struct dp83640_clock *dp83640_clock_get(struct dp83640_clock *clock)
{
        if (clock)
                mutex_lock(&clock->clock_lock);
        return clock;
}

/*
 * Look up and lock a clock by bus instance.
 * If there is no clock for this bus, then create it first.
 */
static struct dp83640_clock *dp83640_clock_get_bus(struct mii_bus *bus)
{
        struct dp83640_clock *clock = NULL, *tmp;
        struct list_head *this;

        mutex_lock(&phyter_clocks_lock);

        list_for_each(this, &phyter_clocks) {
                tmp = list_entry(this, struct dp83640_clock, list);
                if (tmp->bus == bus) {
                        clock = tmp;
                        break;
                }
        }
        if (clock)
                goto out;

        clock = kzalloc(sizeof(struct dp83640_clock), GFP_KERNEL);
        if (!clock)
                goto out;

        dp83640_clock_init(clock, bus);
        list_add_tail(&phyter_clocks, &clock->list);
out:
        mutex_unlock(&phyter_clocks_lock);

        return dp83640_clock_get(clock);
}

static void dp83640_clock_put(struct dp83640_clock *clock)
{
        mutex_unlock(&clock->clock_lock);
}

static int dp83640_probe(struct phy_device *phydev)
{
        struct dp83640_clock *clock;
        struct dp83640_private *dp83640;
        int err = -ENOMEM, i;

        if (phydev->mdio_addr == BROADCAST_ADDR)
                return 0;

        clock = dp83640_clock_get_bus(phydev->mdio_bus);
        if (!clock)
                goto no_clock;

        dp83640 = kzalloc(sizeof(struct dp83640_private), GFP_KERNEL);
        if (!dp83640)
                goto no_memory;

        dp83640->phydev = phydev;
        INIT_WORK(&dp83640->ts_work, rx_timestamp_work);

        INIT_LIST_HEAD(&dp83640->rxts);
        INIT_LIST_HEAD(&dp83640->rxpool);
        for (i = 0; i < MAX_RXTS; i++)
                list_add(&dp83640->rx_pool_data[i].list, &dp83640->rxpool);

        phydev->priv = dp83640;

        spin_lock_init(&dp83640->rx_lock);
        skb_queue_head_init(&dp83640->rx_queue);
        skb_queue_head_init(&dp83640->tx_queue);

        dp83640->clock = clock;

        if (choose_this_phy(clock, phydev)) {
                clock->chosen = dp83640;
                clock->ptp_clock = ptp_clock_register(&clock->caps,
                                                      &phydev->mdio_dev);

                if (IS_ERR(clock->ptp_clock)) {
                        err = PTR_ERR(clock->ptp_clock);
                        goto no_register;
                }
        } else
                list_add_tail(&dp83640->list, &clock->phylist);

        if (clock->chosen && !list_empty(&clock->phylist))
                recalibrate(clock);
        else
                enable_broadcast(dp83640->phydev, clock->page, 1);

        dp83640_clock_put(clock);
        return 0;

no_register:
        clock->chosen = NULL;
        kfree(dp83640);
no_memory:
        dp83640_clock_put(clock);
no_clock:
        return err;
}

static void dp83640_remove(struct phy_device *phydev)
{
        struct dp83640_clock *clock;
        struct list_head *this, *next;
        struct dp83640_private *tmp, *dp83640 = phydev->priv;
        struct sk_buff *skb;

        if (phydev->mdio_addr == BROADCAST_ADDR)
                return;

        enable_status_frames(phydev, false);
        cancel_work_sync(&dp83640->ts_work);

        while ((skb = skb_dequeue(&dp83640->rx_queue)) != NULL)
                kfree_skb(skb);

        while ((skb = skb_dequeue(&dp83640->tx_queue)) != NULL)
                skb_complete_tx_timestamp(skb, NULL);

        clock = dp83640_clock_get(dp83640->clock);

        if (dp83640 == clock->chosen) {
                ptp_clock_unregister(clock->ptp_clock);
                clock->chosen = NULL;
        } else {
                list_for_each_safe(this, next, &clock->phylist) {
                        tmp = list_entry(this, struct dp83640_private, list);
                        if (tmp == dp83640) {
                                list_del_init(&tmp->list);
                                break;
                        }
                }
        }

        dp83640_clock_put(clock);
        kfree(dp83640);
}

static int dp83640_ack_interrupt(struct phy_device *phydev)
{
        int err = phy_read(phydev, MII_DP83640_MISR);

        if (err < 0)
                return err;

        return 0;
}

static int dp83640_config_intr(struct phy_device *phydev)
{
        int micr;
        int misr;
        int err;

        if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
                misr = phy_read(phydev, MII_DP83640_MISR);
                if (misr < 0)
                        return misr;
                misr |=
                        (MII_DP83640_MISR_ANC_INT_EN |
                        MII_DP83640_MISR_DUP_INT_EN |
                        MII_DP83640_MISR_SPD_INT_EN |
                        MII_DP83640_MISR_LINK_INT_EN);
                err = phy_write(phydev, MII_DP83640_MISR, misr);
                if (err < 0)
                        return err;

                micr = phy_read(phydev, MII_DP83640_MICR);
                if (micr < 0)
                        return micr;
                micr |=
                        (MII_DP83640_MICR_OE |
                        MII_DP83640_MICR_IE);
                return phy_write(phydev, MII_DP83640_MICR, micr);
        } else {
                micr = phy_read(phydev, MII_DP83640_MICR);
                if (micr < 0)
                        return micr;
                micr &=
                        ~(MII_DP83640_MICR_OE |
                        MII_DP83640_MICR_IE);
                err = phy_write(phydev, MII_DP83640_MICR, micr);
                if (err < 0)
                        return err;

                misr = phy_read(phydev, MII_DP83640_MISR);
                if (misr < 0)
                        return misr;
                misr &=
                        ~(MII_DP83640_MISR_ANC_INT_EN |
                        MII_DP83640_MISR_DUP_INT_EN |
                        MII_DP83640_MISR_SPD_INT_EN |
                        MII_DP83640_MISR_LINK_INT_EN);
                return phy_write(phydev, MII_DP83640_MISR, misr);
        }
}

static int dp83640_hwtstamp(struct phy_device *phydev, struct ifreq *ifr)
{
        struct dp83640_private *dp83640 = phydev->priv;
        struct hwtstamp_config cfg;
        u16 txcfg0, rxcfg0;

        if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
                return -EFAULT;

        if (cfg.flags) /* reserved for future extensions */
                return -EINVAL;

        if (cfg.tx_type < 0 || cfg.tx_type > HWTSTAMP_TX_ONESTEP_SYNC)
                return -ERANGE;

        dp83640->hwts_tx_en = cfg.tx_type;

        switch (cfg.rx_filter) {
        case HWTSTAMP_FILTER_NONE:
                dp83640->hwts_rx_en = 0;
                dp83640->layer = 0;
                dp83640->version = 0;
                break;
        case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
        case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
                dp83640->hwts_rx_en = 1;
                dp83640->layer = LAYER4;
                dp83640->version = 1;
                break;
        case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
                dp83640->hwts_rx_en = 1;
                dp83640->layer = LAYER4;
                dp83640->version = 2;
                break;
        case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
                dp83640->hwts_rx_en = 1;
                dp83640->layer = LAYER2;
                dp83640->version = 2;
                break;
        case HWTSTAMP_FILTER_PTP_V2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
                dp83640->hwts_rx_en = 1;
                dp83640->layer = LAYER4|LAYER2;
                dp83640->version = 2;
                break;
        default:
                return -ERANGE;
        }

        txcfg0 = (dp83640->version & TX_PTP_VER_MASK) << TX_PTP_VER_SHIFT;
        rxcfg0 = (dp83640->version & TX_PTP_VER_MASK) << TX_PTP_VER_SHIFT;

        if (dp83640->layer & LAYER2) {
                txcfg0 |= TX_L2_EN;
                rxcfg0 |= RX_L2_EN;
        }
        if (dp83640->layer & LAYER4) {
                txcfg0 |= TX_IPV6_EN | TX_IPV4_EN;
                rxcfg0 |= RX_IPV6_EN | RX_IPV4_EN;
        }

        if (dp83640->hwts_tx_en)
                txcfg0 |= TX_TS_EN;

        if (dp83640->hwts_tx_en == HWTSTAMP_TX_ONESTEP_SYNC)
                txcfg0 |= SYNC_1STEP | CHK_1STEP;

        if (dp83640->hwts_rx_en)
                rxcfg0 |= RX_TS_EN;

        mutex_lock(&dp83640->clock->extreg_lock);

        if (dp83640->hwts_tx_en || dp83640->hwts_rx_en) {
                enable_status_frames(phydev, true);
                ext_write(0, phydev, PAGE4, PTP_CTL, PTP_ENABLE);
        }

        ext_write(0, phydev, PAGE5, PTP_TXCFG0, txcfg0);
        ext_write(0, phydev, PAGE5, PTP_RXCFG0, rxcfg0);

        mutex_unlock(&dp83640->clock->extreg_lock);

        return copy_to_user(ifr->ifr_data, &cfg, sizeof(cfg)) ? -EFAULT : 0;
}

static void rx_timestamp_work(struct work_struct *work)
{
        struct dp83640_private *dp83640 =
                container_of(work, struct dp83640_private, ts_work);
        struct list_head *this, *next;
        struct rxts *rxts;
        struct skb_shared_hwtstamps *shhwtstamps;
        struct sk_buff *skb;
        unsigned int type;
        unsigned long flags;

        /* Deliver each deferred packet, with or without a time stamp. */

        while ((skb = skb_dequeue(&dp83640->rx_queue)) != NULL) {
                type = SKB_PTP_TYPE(skb);
                spin_lock_irqsave(&dp83640->rx_lock, flags);
                list_for_each_safe(this, next, &dp83640->rxts) {
                        rxts = list_entry(this, struct rxts, list);
                        if (match(skb, type, rxts)) {
                                shhwtstamps = skb_hwtstamps(skb);
                                memset(shhwtstamps, 0, sizeof(*shhwtstamps));
                                shhwtstamps->hwtstamp = ns_to_ktime(rxts->ns);
                                list_del_init(&rxts->list);
                                list_add(&rxts->list, &dp83640->rxpool);
                                break;
                        }
                }
                spin_unlock_irqrestore(&dp83640->rx_lock, flags);
                netif_rx_ni(skb);
        }

        /* Clear out expired time stamps. */

        spin_lock_irqsave(&dp83640->rx_lock, flags);
        prune_rx_ts(dp83640);
        spin_unlock_irqrestore(&dp83640->rx_lock, flags);
}

static bool dp83640_rxtstamp(struct phy_device *phydev,
                             struct sk_buff *skb, int type)
{
        struct dp83640_private *dp83640 = phydev->priv;

        if (!dp83640->hwts_rx_en)
                return false;

        if (is_status_frame(skb, type)) {
                decode_status_frame(dp83640, skb);
                kfree_skb(skb);
                return true;
        }

        SKB_PTP_TYPE(skb) = type;
        skb_queue_tail(&dp83640->rx_queue, skb);
        schedule_work(&dp83640->ts_work);

        return true;
}

static void dp83640_txtstamp(struct phy_device *phydev,
                             struct sk_buff *skb, int type)
{
        struct dp83640_private *dp83640 = phydev->priv;

        switch (dp83640->hwts_tx_en) {

        case HWTSTAMP_TX_ONESTEP_SYNC:
                if (is_sync(skb, type)) {
                        skb_complete_tx_timestamp(skb, NULL);
                        return;
                }
                /* fall through */
        case HWTSTAMP_TX_ON:
                skb_queue_tail(&dp83640->tx_queue, skb);
                schedule_work(&dp83640->ts_work);
                break;

        case HWTSTAMP_TX_OFF:
        default:
                skb_complete_tx_timestamp(skb, NULL);
                break;
        }
}

static int dp83640_ts_info(struct phy_device *dev, struct ethtool_ts_info *info)
{
        struct dp83640_private *dp83640 = dev->priv;

        info->so_timestamping =
                SOF_TIMESTAMPING_TX_HARDWARE |
                SOF_TIMESTAMPING_RX_HARDWARE |
                SOF_TIMESTAMPING_RAW_HARDWARE;
        info->phc_index = ptp_clock_index(dp83640->clock->ptp_clock);
        info->tx_types =
                (1 << HWTSTAMP_TX_OFF) |
                (1 << HWTSTAMP_TX_ON) |
                (1 << HWTSTAMP_TX_ONESTEP_SYNC);
        info->rx_filters =
                (1 << HWTSTAMP_FILTER_NONE) |
                (1 << HWTSTAMP_FILTER_PTP_V1_L4_EVENT) |
                (1 << HWTSTAMP_FILTER_PTP_V1_L4_SYNC) |
                (1 << HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ) |
                (1 << HWTSTAMP_FILTER_PTP_V2_L4_EVENT) |
                (1 << HWTSTAMP_FILTER_PTP_V2_L4_SYNC) |
                (1 << HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ) |
                (1 << HWTSTAMP_FILTER_PTP_V2_L2_EVENT) |
                (1 << HWTSTAMP_FILTER_PTP_V2_L2_SYNC) |
                (1 << HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ) |
                (1 << HWTSTAMP_FILTER_PTP_V2_EVENT) |
                (1 << HWTSTAMP_FILTER_PTP_V2_SYNC) |
                (1 << HWTSTAMP_FILTER_PTP_V2_DELAY_REQ);
        return 0;
}

static struct phy_driver dp83640_driver = {
        .phy_id         = DP83640_PHY_ID,
        .phy_id_mask    = 0xfffffff0,
        .name           = "NatSemi DP83640",
        .features       = PHY_BASIC_FEATURES,
        .flags          = PHY_HAS_INTERRUPT,
        .probe          = dp83640_probe,
        .remove         = dp83640_remove,
        .config_aneg    = genphy_config_aneg,
        .read_status    = genphy_read_status,
        .ack_interrupt  = dp83640_ack_interrupt,
        .config_intr    = dp83640_config_intr,
        .ts_info        = dp83640_ts_info,
        .hwtstamp       = dp83640_hwtstamp,
        .rxtstamp       = dp83640_rxtstamp,
        .txtstamp       = dp83640_txtstamp,
        .driver         = {.owner = THIS_MODULE,}
};

static int __init dp83640_init(void)
{
        return phy_driver_register(&dp83640_driver);
}

static void __exit dp83640_exit(void)
{
        dp83640_free_clocks();
        phy_driver_unregister(&dp83640_driver);
}

MODULE_DESCRIPTION("National Semiconductor DP83640 PHY driver");
MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.at>");
MODULE_LICENSE("GPL");

module_init(dp83640_init);
module_exit(dp83640_exit);

static struct mdio_device_id __maybe_unused dp83640_tbl[] = {
        { DP83640_PHY_ID, 0xfffffff0 },
        { }
};

MODULE_DEVICE_TABLE(mdio, dp83640_tbl);