// SPDX-License-Identifier: GPL-2.0
/* TI K3 AM65x Common Platform Time Sync
 *
 * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com
 *
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/if_vlan.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/net_tstamp.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/ptp_classify.h>
#include <linux/ptp_clock_kernel.h>

#include "am65-cpts.h"

struct am65_genf_regs {
        u32 comp_lo;    /* Comparison Low Value 0:31 */
        u32 comp_hi;    /* Comparison High Value 32:63 */
        u32 control;    /* control */
        u32 length;     /* Length */
        u32 ppm_low;    /* PPM Load Low Value 0:31 */
        u32 ppm_hi;     /* PPM Load High Value 32:63 */
        u32 ts_nudge;   /* Nudge value */
} __aligned(32) __packed;

#define AM65_CPTS_GENF_MAX_NUM 9
#define AM65_CPTS_ESTF_MAX_NUM 8

struct am65_cpts_regs {
        u32 idver;              /* Identification and version */
        u32 control;            /* Time sync control */
        u32 rftclk_sel;         /* Reference Clock Select Register */
        u32 ts_push;            /* Time stamp event push */
        u32 ts_load_val_lo;     /* Time Stamp Load Low Value 0:31 */
        u32 ts_load_en;         /* Time stamp load enable */
        u32 ts_comp_lo;         /* Time Stamp Comparison Low Value 0:31 */
        u32 ts_comp_length;     /* Time Stamp Comparison Length */
        u32 intstat_raw;        /* Time sync interrupt status raw */
        u32 intstat_masked;     /* Time sync interrupt status masked */
        u32 int_enable;         /* Time sync interrupt enable */
        u32 ts_comp_nudge;      /* Time Stamp Comparison Nudge Value */
        u32 event_pop;          /* Event interrupt pop */
        u32 event_0;            /* Event Time Stamp lo 0:31 */
        u32 event_1;            /* Event Type Fields */
        u32 event_2;            /* Event Type Fields domain */
        u32 event_3;            /* Event Time Stamp hi 32:63 */
        u32 ts_load_val_hi;     /* Time Stamp Load High Value 32:63 */
        u32 ts_comp_hi;         /* Time Stamp Comparison High Value 32:63 */
        u32 ts_add_val;         /* Time Stamp Add value */
        u32 ts_ppm_low;         /* Time Stamp PPM Load Low Value 0:31 */
        u32 ts_ppm_hi;          /* Time Stamp PPM Load High Value 32:63 */
        u32 ts_nudge;           /* Time Stamp Nudge value */
        u32 reserv[33];
        struct am65_genf_regs genf[AM65_CPTS_GENF_MAX_NUM];
        struct am65_genf_regs estf[AM65_CPTS_ESTF_MAX_NUM];
};

/* CONTROL_REG */
#define AM65_CPTS_CONTROL_EN                    BIT(0)
#define AM65_CPTS_CONTROL_INT_TEST              BIT(1)
#define AM65_CPTS_CONTROL_TS_COMP_POLARITY      BIT(2)
#define AM65_CPTS_CONTROL_TSTAMP_EN             BIT(3)
#define AM65_CPTS_CONTROL_SEQUENCE_EN           BIT(4)
#define AM65_CPTS_CONTROL_64MODE                BIT(5)
#define AM65_CPTS_CONTROL_TS_COMP_TOG           BIT(6)
#define AM65_CPTS_CONTROL_TS_PPM_DIR            BIT(7)
#define AM65_CPTS_CONTROL_HW1_TS_PUSH_EN        BIT(8)
#define AM65_CPTS_CONTROL_HW2_TS_PUSH_EN        BIT(9)
#define AM65_CPTS_CONTROL_HW3_TS_PUSH_EN        BIT(10)
#define AM65_CPTS_CONTROL_HW4_TS_PUSH_EN        BIT(11)
#define AM65_CPTS_CONTROL_HW5_TS_PUSH_EN        BIT(12)
#define AM65_CPTS_CONTROL_HW6_TS_PUSH_EN        BIT(13)
#define AM65_CPTS_CONTROL_HW7_TS_PUSH_EN        BIT(14)
#define AM65_CPTS_CONTROL_HW8_TS_PUSH_EN        BIT(15)
#define AM65_CPTS_CONTROL_HW1_TS_PUSH_OFFSET    (8)

#define AM65_CPTS_CONTROL_TS_SYNC_SEL_MASK      (0xF)
#define AM65_CPTS_CONTROL_TS_SYNC_SEL_SHIFT     (28)

/* RFTCLK_SEL_REG */
#define AM65_CPTS_RFTCLK_SEL_MASK               (0x1F)

/* TS_PUSH_REG */
#define AM65_CPTS_TS_PUSH                       BIT(0)

/* TS_LOAD_EN_REG */
#define AM65_CPTS_TS_LOAD_EN                    BIT(0)

/* INTSTAT_RAW_REG */
#define AM65_CPTS_INTSTAT_RAW_TS_PEND           BIT(0)

/* INTSTAT_MASKED_REG */
#define AM65_CPTS_INTSTAT_MASKED_TS_PEND        BIT(0)

/* INT_ENABLE_REG */
#define AM65_CPTS_INT_ENABLE_TS_PEND_EN         BIT(0)

/* TS_COMP_NUDGE_REG */
#define AM65_CPTS_TS_COMP_NUDGE_MASK            (0xFF)

/* EVENT_POP_REG */
#define AM65_CPTS_EVENT_POP                     BIT(0)

/* EVENT_1_REG */
#define AM65_CPTS_EVENT_1_SEQUENCE_ID_MASK      GENMASK(15, 0)

#define AM65_CPTS_EVENT_1_MESSAGE_TYPE_MASK     GENMASK(19, 16)
#define AM65_CPTS_EVENT_1_MESSAGE_TYPE_SHIFT    (16)

#define AM65_CPTS_EVENT_1_EVENT_TYPE_MASK       GENMASK(23, 20)
#define AM65_CPTS_EVENT_1_EVENT_TYPE_SHIFT      (20)

#define AM65_CPTS_EVENT_1_PORT_NUMBER_MASK      GENMASK(28, 24)
#define AM65_CPTS_EVENT_1_PORT_NUMBER_SHIFT     (24)

/* EVENT_2_REG */
#define AM65_CPTS_EVENT_2_REG_DOMAIN_MASK       (0xFF)
#define AM65_CPTS_EVENT_2_REG_DOMAIN_SHIFT      (0)

enum {
        AM65_CPTS_EV_PUSH,      /* Time Stamp Push Event */
        AM65_CPTS_EV_ROLL,      /* Time Stamp Rollover Event */
        AM65_CPTS_EV_HALF,      /* Time Stamp Half Rollover Event */
        AM65_CPTS_EV_HW,                /* Hardware Time Stamp Push Event */
        AM65_CPTS_EV_RX,                /* Ethernet Receive Event */
        AM65_CPTS_EV_TX,                /* Ethernet Transmit Event */
        AM65_CPTS_EV_TS_COMP,   /* Time Stamp Compare Event */
        AM65_CPTS_EV_HOST,      /* Host Transmit Event */
};

struct am65_cpts_event {
        struct list_head list;
        unsigned long tmo;
        u32 event1;
        u32 event2;
        u64 timestamp;
};

#define AM65_CPTS_FIFO_DEPTH            (16)
#define AM65_CPTS_MAX_EVENTS            (32)
#define AM65_CPTS_EVENT_RX_TX_TIMEOUT   (20) /* ms */
#define AM65_CPTS_SKB_TX_WORK_TIMEOUT   1 /* jiffies */
#define AM65_CPTS_MIN_PPM               0x400

struct am65_cpts {
        struct device *dev;
        struct am65_cpts_regs __iomem *reg;
        struct ptp_clock_info ptp_info;
        struct ptp_clock *ptp_clock;
        int phc_index;
        struct clk_hw *clk_mux_hw;
        struct device_node *clk_mux_np;
        struct clk *refclk;
        u32 refclk_freq;
        struct list_head events;
        struct list_head pool;
        struct am65_cpts_event pool_data[AM65_CPTS_MAX_EVENTS];
        spinlock_t lock; /* protects events lists*/
        u32 ext_ts_inputs;
        u32 genf_num;
        u32 ts_add_val;
        int irq;
        struct mutex ptp_clk_lock; /* PHC access sync */
        u64 timestamp;
        u32 genf_enable;
        u32 hw_ts_enable;
        struct sk_buff_head txq;
};

struct am65_cpts_skb_cb_data {
        unsigned long tmo;
        u32 skb_mtype_seqid;
};

#define am65_cpts_write32(c, v, r) writel(v, &(c)->reg->r)
#define am65_cpts_read32(c, r) readl(&(c)->reg->r)

static void am65_cpts_settime(struct am65_cpts *cpts, u64 start_tstamp)
{
        u32 val;

        val = upper_32_bits(start_tstamp);
        am65_cpts_write32(cpts, val, ts_load_val_hi);
        val = lower_32_bits(start_tstamp);
        am65_cpts_write32(cpts, val, ts_load_val_lo);

        am65_cpts_write32(cpts, AM65_CPTS_TS_LOAD_EN, ts_load_en);
}

static void am65_cpts_set_add_val(struct am65_cpts *cpts)
{
        /* select coefficient according to the rate */
        cpts->ts_add_val = (NSEC_PER_SEC / cpts->refclk_freq - 1) & 0x7;

        am65_cpts_write32(cpts, cpts->ts_add_val, ts_add_val);
}

static void am65_cpts_disable(struct am65_cpts *cpts)
{
        am65_cpts_write32(cpts, 0, control);
        am65_cpts_write32(cpts, 0, int_enable);
}

static int am65_cpts_event_get_port(struct am65_cpts_event *event)
{
        return (event->event1 & AM65_CPTS_EVENT_1_PORT_NUMBER_MASK) >>
                AM65_CPTS_EVENT_1_PORT_NUMBER_SHIFT;
}

static int am65_cpts_event_get_type(struct am65_cpts_event *event)
{
        return (event->event1 & AM65_CPTS_EVENT_1_EVENT_TYPE_MASK) >>
                AM65_CPTS_EVENT_1_EVENT_TYPE_SHIFT;
}

static int am65_cpts_cpts_purge_events(struct am65_cpts *cpts)
{
        struct list_head *this, *next;
        struct am65_cpts_event *event;
        int removed = 0;

        list_for_each_safe(this, next, &cpts->events) {
                event = list_entry(this, struct am65_cpts_event, list);
                if (time_after(jiffies, event->tmo)) {
                        list_del_init(&event->list);
                        list_add(&event->list, &cpts->pool);
                        ++removed;
                }
        }

        if (removed)
                dev_dbg(cpts->dev, "event pool cleaned up %d\n", removed);
        return removed ? 0 : -1;
}

static bool am65_cpts_fifo_pop_event(struct am65_cpts *cpts,
                                     struct am65_cpts_event *event)
{
        u32 r = am65_cpts_read32(cpts, intstat_raw);

        if (r & AM65_CPTS_INTSTAT_RAW_TS_PEND) {
                event->timestamp = am65_cpts_read32(cpts, event_0);
                event->event1 = am65_cpts_read32(cpts, event_1);
                event->event2 = am65_cpts_read32(cpts, event_2);
                event->timestamp |= (u64)am65_cpts_read32(cpts, event_3) << 32;
                am65_cpts_write32(cpts, AM65_CPTS_EVENT_POP, event_pop);
                return false;
        }
        return true;
}

static int am65_cpts_fifo_read(struct am65_cpts *cpts)
{
        struct ptp_clock_event pevent;
        struct am65_cpts_event *event;
        bool schedule = false;
        int i, type, ret = 0;
        unsigned long flags;

        spin_lock_irqsave(&cpts->lock, flags);
        for (i = 0; i < AM65_CPTS_FIFO_DEPTH; i++) {
                event = list_first_entry_or_null(&cpts->pool,
                                                 struct am65_cpts_event, list);

                if (!event) {
                        if (am65_cpts_cpts_purge_events(cpts)) {
                                dev_err(cpts->dev, "cpts: event pool empty\n");
                                ret = -1;
                                goto out;
                        }
                        continue;
                }

                if (am65_cpts_fifo_pop_event(cpts, event))
                        break;

                type = am65_cpts_event_get_type(event);
                switch (type) {
                case AM65_CPTS_EV_PUSH:
                        cpts->timestamp = event->timestamp;
                        dev_dbg(cpts->dev, "AM65_CPTS_EV_PUSH t:%llu\n",
                                cpts->timestamp);
                        break;
                case AM65_CPTS_EV_RX:
                case AM65_CPTS_EV_TX:
                        event->tmo = jiffies +
                                msecs_to_jiffies(AM65_CPTS_EVENT_RX_TX_TIMEOUT);

                        list_del_init(&event->list);
                        list_add_tail(&event->list, &cpts->events);

                        dev_dbg(cpts->dev,
                                "AM65_CPTS_EV_TX e1:%08x e2:%08x t:%lld\n",
                                event->event1, event->event2,
                                event->timestamp);
                        schedule = true;
                        break;
                case AM65_CPTS_EV_HW:
                        pevent.index = am65_cpts_event_get_port(event) - 1;
                        pevent.timestamp = event->timestamp;
                        pevent.type = PTP_CLOCK_EXTTS;
                        dev_dbg(cpts->dev, "AM65_CPTS_EV_HW p:%d t:%llu\n",
                                pevent.index, event->timestamp);

                        ptp_clock_event(cpts->ptp_clock, &pevent);
                        break;
                case AM65_CPTS_EV_HOST:
                        break;
                case AM65_CPTS_EV_ROLL:
                case AM65_CPTS_EV_HALF:
                case AM65_CPTS_EV_TS_COMP:
                        dev_dbg(cpts->dev,
                                "AM65_CPTS_EVT: %d e1:%08x e2:%08x t:%lld\n",
                                type,
                                event->event1, event->event2,
                                event->timestamp);
                        break;
                default:
                        dev_err(cpts->dev, "cpts: unknown event type\n");
                        ret = -1;
                        goto out;
                }
        }

out:
        spin_unlock_irqrestore(&cpts->lock, flags);

        if (schedule)
                ptp_schedule_worker(cpts->ptp_clock, 0);

        return ret;
}

static u64 am65_cpts_gettime(struct am65_cpts *cpts,
                             struct ptp_system_timestamp *sts)
{
        unsigned long flags;
        u64 val = 0;

        /* temporarily disable cpts interrupt to avoid intentional
         * doubled read. Interrupt can be in-flight - it's Ok.
         */
        am65_cpts_write32(cpts, 0, int_enable);

        /* use spin_lock_irqsave() here as it has to run very fast */
        spin_lock_irqsave(&cpts->lock, flags);
        ptp_read_system_prets(sts);
        am65_cpts_write32(cpts, AM65_CPTS_TS_PUSH, ts_push);
        am65_cpts_read32(cpts, ts_push);
        ptp_read_system_postts(sts);
        spin_unlock_irqrestore(&cpts->lock, flags);

        am65_cpts_fifo_read(cpts);

        am65_cpts_write32(cpts, AM65_CPTS_INT_ENABLE_TS_PEND_EN, int_enable);

        val = cpts->timestamp;

        return val;
}

static irqreturn_t am65_cpts_interrupt(int irq, void *dev_id)
{
        struct am65_cpts *cpts = dev_id;

        if (am65_cpts_fifo_read(cpts))
                dev_dbg(cpts->dev, "cpts: unable to obtain a time stamp\n");

        return IRQ_HANDLED;
}

/* PTP clock operations */
static int am65_cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
        struct am65_cpts *cpts = container_of(ptp, struct am65_cpts, ptp_info);
        int neg_adj = 0;
        u64 adj_period;
        u32 val;

        if (ppb < 0) {
                neg_adj = 1;
                ppb = -ppb;
        }

        /* base freq = 1GHz = 1 000 000 000
         * ppb_norm = ppb * base_freq / clock_freq;
         * ppm_norm = ppb_norm / 1000
         * adj_period = 1 000 000 / ppm_norm
         * adj_period = 1 000 000 000 / ppb_norm
         * adj_period = 1 000 000 000 / (ppb * base_freq / clock_freq)
         * adj_period = (1 000 000 000 * clock_freq) / (ppb * base_freq)
         * adj_period = clock_freq / ppb
         */
        adj_period = div_u64(cpts->refclk_freq, ppb);

        mutex_lock(&cpts->ptp_clk_lock);

        val = am65_cpts_read32(cpts, control);
        if (neg_adj)
                val |= AM65_CPTS_CONTROL_TS_PPM_DIR;
        else
                val &= ~AM65_CPTS_CONTROL_TS_PPM_DIR;
        am65_cpts_write32(cpts, val, control);

        val = upper_32_bits(adj_period) & 0x3FF;
        am65_cpts_write32(cpts, val, ts_ppm_hi);
        val = lower_32_bits(adj_period);
        am65_cpts_write32(cpts, val, ts_ppm_low);

        mutex_unlock(&cpts->ptp_clk_lock);

        return 0;
}

static int am65_cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        struct am65_cpts *cpts = container_of(ptp, struct am65_cpts, ptp_info);
        s64 ns;

        mutex_lock(&cpts->ptp_clk_lock);
        ns = am65_cpts_gettime(cpts, NULL);
        ns += delta;
        am65_cpts_settime(cpts, ns);
        mutex_unlock(&cpts->ptp_clk_lock);

        return 0;
}

static int am65_cpts_ptp_gettimex(struct ptp_clock_info *ptp,
                                  struct timespec64 *ts,
                                  struct ptp_system_timestamp *sts)
{
        struct am65_cpts *cpts = container_of(ptp, struct am65_cpts, ptp_info);
        u64 ns;

        mutex_lock(&cpts->ptp_clk_lock);
        ns = am65_cpts_gettime(cpts, sts);
        mutex_unlock(&cpts->ptp_clk_lock);
        *ts = ns_to_timespec64(ns);

        return 0;
}

u64 am65_cpts_ns_gettime(struct am65_cpts *cpts)
{
        u64 ns;

        /* reuse ptp_clk_lock as it serialize ts push */
        mutex_lock(&cpts->ptp_clk_lock);
        ns = am65_cpts_gettime(cpts, NULL);
        mutex_unlock(&cpts->ptp_clk_lock);

        return ns;
}
EXPORT_SYMBOL_GPL(am65_cpts_ns_gettime);

static int am65_cpts_ptp_settime(struct ptp_clock_info *ptp,
                                 const struct timespec64 *ts)
{
        struct am65_cpts *cpts = container_of(ptp, struct am65_cpts, ptp_info);
        u64 ns;

        ns = timespec64_to_ns(ts);
        mutex_lock(&cpts->ptp_clk_lock);
        am65_cpts_settime(cpts, ns);
        mutex_unlock(&cpts->ptp_clk_lock);

        return 0;
}

static void am65_cpts_extts_enable_hw(struct am65_cpts *cpts, u32 index, int on)
{
        u32 v;

        v = am65_cpts_read32(cpts, control);
        if (on) {
                v |= BIT(AM65_CPTS_CONTROL_HW1_TS_PUSH_OFFSET + index);
                cpts->hw_ts_enable |= BIT(index);
        } else {
                v &= ~BIT(AM65_CPTS_CONTROL_HW1_TS_PUSH_OFFSET + index);
                cpts->hw_ts_enable &= ~BIT(index);
        }
        am65_cpts_write32(cpts, v, control);
}

static int am65_cpts_extts_enable(struct am65_cpts *cpts, u32 index, int on)
{
        if (!!(cpts->hw_ts_enable & BIT(index)) == !!on)
                return 0;

        mutex_lock(&cpts->ptp_clk_lock);
        am65_cpts_extts_enable_hw(cpts, index, on);
        mutex_unlock(&cpts->ptp_clk_lock);

        dev_dbg(cpts->dev, "%s: ExtTS:%u %s\n",
                __func__, index, on ? "enabled" : "disabled");

        return 0;
}

int am65_cpts_estf_enable(struct am65_cpts *cpts, int idx,
                          struct am65_cpts_estf_cfg *cfg)
{
        u64 cycles;
        u32 val;

        cycles = cfg->ns_period * cpts->refclk_freq;
        cycles = DIV_ROUND_UP(cycles, NSEC_PER_SEC);
        if (cycles > U32_MAX)
                return -EINVAL;

        /* according to TRM should be zeroed */
        am65_cpts_write32(cpts, 0, estf[idx].length);

        val = upper_32_bits(cfg->ns_start);
        am65_cpts_write32(cpts, val, estf[idx].comp_hi);
        val = lower_32_bits(cfg->ns_start);
        am65_cpts_write32(cpts, val, estf[idx].comp_lo);
        val = lower_32_bits(cycles);
        am65_cpts_write32(cpts, val, estf[idx].length);

        dev_dbg(cpts->dev, "%s: ESTF:%u enabled\n", __func__, idx);

        return 0;
}
EXPORT_SYMBOL_GPL(am65_cpts_estf_enable);

void am65_cpts_estf_disable(struct am65_cpts *cpts, int idx)
{
        am65_cpts_write32(cpts, 0, estf[idx].length);

        dev_dbg(cpts->dev, "%s: ESTF:%u disabled\n", __func__, idx);
}
EXPORT_SYMBOL_GPL(am65_cpts_estf_disable);

static void am65_cpts_perout_enable_hw(struct am65_cpts *cpts,
                                       struct ptp_perout_request *req, int on)
{
        u64 ns_period, ns_start, cycles;
        struct timespec64 ts;
        u32 val;

        if (on) {
                ts.tv_sec = req->period.sec;
                ts.tv_nsec = req->period.nsec;
                ns_period = timespec64_to_ns(&ts);

                cycles = (ns_period * cpts->refclk_freq) / NSEC_PER_SEC;

                ts.tv_sec = req->start.sec;
                ts.tv_nsec = req->start.nsec;
                ns_start = timespec64_to_ns(&ts);

                val = upper_32_bits(ns_start);
                am65_cpts_write32(cpts, val, genf[req->index].comp_hi);
                val = lower_32_bits(ns_start);
                am65_cpts_write32(cpts, val, genf[req->index].comp_lo);
                val = lower_32_bits(cycles);
                am65_cpts_write32(cpts, val, genf[req->index].length);

                cpts->genf_enable |= BIT(req->index);
        } else {
                am65_cpts_write32(cpts, 0, genf[req->index].length);

                cpts->genf_enable &= ~BIT(req->index);
        }
}

static int am65_cpts_perout_enable(struct am65_cpts *cpts,
                                   struct ptp_perout_request *req, int on)
{
        if (!!(cpts->genf_enable & BIT(req->index)) == !!on)
                return 0;

        mutex_lock(&cpts->ptp_clk_lock);
        am65_cpts_perout_enable_hw(cpts, req, on);
        mutex_unlock(&cpts->ptp_clk_lock);

        dev_dbg(cpts->dev, "%s: GenF:%u %s\n",
                __func__, req->index, on ? "enabled" : "disabled");

        return 0;
}

static int am65_cpts_ptp_enable(struct ptp_clock_info *ptp,
                                struct ptp_clock_request *rq, int on)
{
        struct am65_cpts *cpts = container_of(ptp, struct am65_cpts, ptp_info);

        switch (rq->type) {
        case PTP_CLK_REQ_EXTTS:
                return am65_cpts_extts_enable(cpts, rq->extts.index, on);
        case PTP_CLK_REQ_PEROUT:
                return am65_cpts_perout_enable(cpts, &rq->perout, on);
        default:
                break;
        }

        return -EOPNOTSUPP;
}

static long am65_cpts_ts_work(struct ptp_clock_info *ptp);

static struct ptp_clock_info am65_ptp_info = {
        .owner          = THIS_MODULE,
        .name           = "CTPS timer",
        .adjfreq        = am65_cpts_ptp_adjfreq,
        .adjtime        = am65_cpts_ptp_adjtime,
        .gettimex64     = am65_cpts_ptp_gettimex,
        .settime64      = am65_cpts_ptp_settime,
        .enable         = am65_cpts_ptp_enable,
        .do_aux_work    = am65_cpts_ts_work,
};

static bool am65_cpts_match_tx_ts(struct am65_cpts *cpts,
                                  struct am65_cpts_event *event)
{
        struct sk_buff_head txq_list;
        struct sk_buff *skb, *tmp;
        unsigned long flags;
        bool found = false;
        u32 mtype_seqid;

        mtype_seqid = event->event1 &
                      (AM65_CPTS_EVENT_1_MESSAGE_TYPE_MASK |
                       AM65_CPTS_EVENT_1_EVENT_TYPE_MASK |
                       AM65_CPTS_EVENT_1_SEQUENCE_ID_MASK);

        __skb_queue_head_init(&txq_list);

        spin_lock_irqsave(&cpts->txq.lock, flags);
        skb_queue_splice_init(&cpts->txq, &txq_list);
        spin_unlock_irqrestore(&cpts->txq.lock, flags);

        /* no need to grab txq.lock as access is always done under cpts->lock */
        skb_queue_walk_safe(&txq_list, skb, tmp) {
                struct skb_shared_hwtstamps ssh;
                struct am65_cpts_skb_cb_data *skb_cb =
                                        (struct am65_cpts_skb_cb_data *)skb->cb;

                if (mtype_seqid == skb_cb->skb_mtype_seqid) {
                        u64 ns = event->timestamp;

                        memset(&ssh, 0, sizeof(ssh));
                        ssh.hwtstamp = ns_to_ktime(ns);
                        skb_tstamp_tx(skb, &ssh);
                        found = true;
                        __skb_unlink(skb, &txq_list);
                        dev_consume_skb_any(skb);
                        dev_dbg(cpts->dev,
                                "match tx timestamp mtype_seqid %08x\n",
                                mtype_seqid);
                        break;
                }

                if (time_after(jiffies, skb_cb->tmo)) {
                        /* timeout any expired skbs over 100 ms */
                        dev_dbg(cpts->dev,
                                "expiring tx timestamp mtype_seqid %08x\n",
                                mtype_seqid);
                        __skb_unlink(skb, &txq_list);
                        dev_consume_skb_any(skb);
                }
        }

        spin_lock_irqsave(&cpts->txq.lock, flags);
        skb_queue_splice(&txq_list, &cpts->txq);
        spin_unlock_irqrestore(&cpts->txq.lock, flags);

        return found;
}

static void am65_cpts_find_ts(struct am65_cpts *cpts)
{
        struct am65_cpts_event *event;
        struct list_head *this, *next;
        LIST_HEAD(events_free);
        unsigned long flags;
        LIST_HEAD(events);

        spin_lock_irqsave(&cpts->lock, flags);
        list_splice_init(&cpts->events, &events);
        spin_unlock_irqrestore(&cpts->lock, flags);

        list_for_each_safe(this, next, &events) {
                event = list_entry(this, struct am65_cpts_event, list);
                if (am65_cpts_match_tx_ts(cpts, event) ||
                    time_after(jiffies, event->tmo)) {
                        list_del_init(&event->list);
                        list_add(&event->list, &events_free);
                }
        }

        spin_lock_irqsave(&cpts->lock, flags);
        list_splice_tail(&events, &cpts->events);
        list_splice_tail(&events_free, &cpts->pool);
        spin_unlock_irqrestore(&cpts->lock, flags);
}

static long am65_cpts_ts_work(struct ptp_clock_info *ptp)
{
        struct am65_cpts *cpts = container_of(ptp, struct am65_cpts, ptp_info);
        unsigned long flags;
        long delay = -1;

        am65_cpts_find_ts(cpts);

        spin_lock_irqsave(&cpts->txq.lock, flags);
        if (!skb_queue_empty(&cpts->txq))
                delay = AM65_CPTS_SKB_TX_WORK_TIMEOUT;
        spin_unlock_irqrestore(&cpts->txq.lock, flags);

        return delay;
}

/**
 * am65_cpts_rx_enable - enable rx timestamping
 * @cpts: cpts handle
 * @skb: packet
 *
 * This functions enables rx packets timestamping. The CPTS can timestamp all
 * rx packets.
 */
void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en)
{
        u32 val;

        mutex_lock(&cpts->ptp_clk_lock);
        val = am65_cpts_read32(cpts, control);
        if (en)
                val |= AM65_CPTS_CONTROL_TSTAMP_EN;
        else
                val &= ~AM65_CPTS_CONTROL_TSTAMP_EN;
        am65_cpts_write32(cpts, val, control);
        mutex_unlock(&cpts->ptp_clk_lock);
}
EXPORT_SYMBOL_GPL(am65_cpts_rx_enable);

static int am65_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
{
        unsigned int ptp_class = ptp_classify_raw(skb);
        u8 *msgtype, *data = skb->data;
        unsigned int offset = 0;
        __be16 *seqid;

        if (ptp_class == PTP_CLASS_NONE)
                return 0;

        if (ptp_class & PTP_CLASS_VLAN)
                offset += VLAN_HLEN;

        switch (ptp_class & PTP_CLASS_PMASK) {
        case PTP_CLASS_IPV4:
                offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
                break;
        case PTP_CLASS_IPV6:
                offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
                break;
        case PTP_CLASS_L2:
                offset += ETH_HLEN;
                break;
        default:
                return 0;
        }

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

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

        seqid = (__be16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
        *mtype_seqid = (*msgtype << AM65_CPTS_EVENT_1_MESSAGE_TYPE_SHIFT) &
                        AM65_CPTS_EVENT_1_MESSAGE_TYPE_MASK;
        *mtype_seqid |= (ntohs(*seqid) & AM65_CPTS_EVENT_1_SEQUENCE_ID_MASK);

        return 1;
}

/**
 * am65_cpts_tx_timestamp - save tx packet for timestamping
 * @cpts: cpts handle
 * @skb: packet
 *
 * This functions saves tx packet for timestamping if packet can be timestamped.
 * The future processing is done in from PTP auxiliary worker.
 */
void am65_cpts_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb)
{
        struct am65_cpts_skb_cb_data *skb_cb = (void *)skb->cb;

        if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
                return;

        /* add frame to queue for processing later.
         * The periodic FIFO check will handle this.
         */
        skb_get(skb);
        /* get the timestamp for timeouts */
        skb_cb->tmo = jiffies + msecs_to_jiffies(100);
        skb_queue_tail(&cpts->txq, skb);
        ptp_schedule_worker(cpts->ptp_clock, 0);
}
EXPORT_SYMBOL_GPL(am65_cpts_tx_timestamp);

/**
 * am65_cpts_prep_tx_timestamp - check and prepare tx packet for timestamping
 * @cpts: cpts handle
 * @skb: packet
 *
 * This functions should be called from .xmit().
 * It checks if packet can be timestamped, fills internal cpts data
 * in skb-cb and marks packet as SKBTX_IN_PROGRESS.
 */
void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb)
{
        struct am65_cpts_skb_cb_data *skb_cb = (void *)skb->cb;
        int ret;

        if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
                return;

        ret = am65_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
        if (!ret)
                return;
        skb_cb->skb_mtype_seqid |= (AM65_CPTS_EV_TX <<
                                   AM65_CPTS_EVENT_1_EVENT_TYPE_SHIFT);

        skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
}
EXPORT_SYMBOL_GPL(am65_cpts_prep_tx_timestamp);

int am65_cpts_phc_index(struct am65_cpts *cpts)
{
        return cpts->phc_index;
}
EXPORT_SYMBOL_GPL(am65_cpts_phc_index);

static void cpts_free_clk_mux(void *data)
{
        struct am65_cpts *cpts = data;

        of_clk_del_provider(cpts->clk_mux_np);
        clk_hw_unregister_mux(cpts->clk_mux_hw);
        of_node_put(cpts->clk_mux_np);
}

static int cpts_of_mux_clk_setup(struct am65_cpts *cpts,
                                 struct device_node *node)
{
        unsigned int num_parents;
        const char **parent_names;
        char *clk_mux_name;
        void __iomem *reg;
        int ret = -EINVAL;

        cpts->clk_mux_np = of_get_child_by_name(node, "refclk-mux");
        if (!cpts->clk_mux_np)
                return 0;

        num_parents = of_clk_get_parent_count(cpts->clk_mux_np);
        if (num_parents < 1) {
                dev_err(cpts->dev, "mux-clock %pOF must have parents\n",
                        cpts->clk_mux_np);
                goto mux_fail;
        }

        parent_names = devm_kcalloc(cpts->dev, sizeof(char *), num_parents,
                                    GFP_KERNEL);
        if (!parent_names) {
                ret = -ENOMEM;
                goto mux_fail;
        }

        of_clk_parent_fill(cpts->clk_mux_np, parent_names, num_parents);

        clk_mux_name = devm_kasprintf(cpts->dev, GFP_KERNEL, "%s.%pOFn",
                                      dev_name(cpts->dev), cpts->clk_mux_np);
        if (!clk_mux_name) {
                ret = -ENOMEM;
                goto mux_fail;
        }

        reg = &cpts->reg->rftclk_sel;
        /* dev must be NULL to avoid recursive incrementing
         * of module refcnt
         */
        cpts->clk_mux_hw = clk_hw_register_mux(NULL, clk_mux_name,
                                               parent_names, num_parents,
                                               0, reg, 0, 5, 0, NULL);
        if (IS_ERR(cpts->clk_mux_hw)) {
                ret = PTR_ERR(cpts->clk_mux_hw);
                goto mux_fail;
        }

        ret = of_clk_add_hw_provider(cpts->clk_mux_np, of_clk_hw_simple_get,
                                     cpts->clk_mux_hw);
        if (ret)
                goto clk_hw_register;

        ret = devm_add_action_or_reset(cpts->dev, cpts_free_clk_mux, cpts);
        if (ret)
                dev_err(cpts->dev, "failed to add clkmux reset action %d", ret);

        return ret;

clk_hw_register:
        clk_hw_unregister_mux(cpts->clk_mux_hw);
mux_fail:
        of_node_put(cpts->clk_mux_np);
        return ret;
}

static int am65_cpts_of_parse(struct am65_cpts *cpts, struct device_node *node)
{
        u32 prop[2];

        if (!of_property_read_u32(node, "ti,cpts-ext-ts-inputs", &prop[0]))
                cpts->ext_ts_inputs = prop[0];

        if (!of_property_read_u32(node, "ti,cpts-periodic-outputs", &prop[0]))
                cpts->genf_num = prop[0];

        return cpts_of_mux_clk_setup(cpts, node);
}

static void am65_cpts_release(void *data)
{
        struct am65_cpts *cpts = data;

        ptp_clock_unregister(cpts->ptp_clock);
        am65_cpts_disable(cpts);
        clk_disable_unprepare(cpts->refclk);
}

struct am65_cpts *am65_cpts_create(struct device *dev, void __iomem *regs,
                                   struct device_node *node)
{
        struct am65_cpts *cpts;
        int ret, i;

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

        cpts->dev = dev;
        cpts->reg = (struct am65_cpts_regs __iomem *)regs;

        cpts->irq = of_irq_get_byname(node, "cpts");
        if (cpts->irq <= 0) {
                ret = cpts->irq ?: -ENXIO;
                if (ret != -EPROBE_DEFER)
                        dev_err(dev, "Failed to get IRQ number (err = %d)\n",
                                ret);
                return ERR_PTR(ret);
        }

        ret = am65_cpts_of_parse(cpts, node);
        if (ret)
                return ERR_PTR(ret);

        mutex_init(&cpts->ptp_clk_lock);
        INIT_LIST_HEAD(&cpts->events);
        INIT_LIST_HEAD(&cpts->pool);
        spin_lock_init(&cpts->lock);
        skb_queue_head_init(&cpts->txq);

        for (i = 0; i < AM65_CPTS_MAX_EVENTS; i++)
                list_add(&cpts->pool_data[i].list, &cpts->pool);

        cpts->refclk = devm_get_clk_from_child(dev, node, "cpts");
        if (IS_ERR(cpts->refclk)) {
                ret = PTR_ERR(cpts->refclk);
                if (ret != -EPROBE_DEFER)
                        dev_err(dev, "Failed to get refclk %d\n", ret);
                return ERR_PTR(ret);
        }

        ret = clk_prepare_enable(cpts->refclk);
        if (ret) {
                dev_err(dev, "Failed to enable refclk %d\n", ret);
                return ERR_PTR(ret);
        }

        cpts->refclk_freq = clk_get_rate(cpts->refclk);

        am65_ptp_info.max_adj = cpts->refclk_freq / AM65_CPTS_MIN_PPM;
        cpts->ptp_info = am65_ptp_info;

        if (cpts->ext_ts_inputs)
                cpts->ptp_info.n_ext_ts = cpts->ext_ts_inputs;
        if (cpts->genf_num)
                cpts->ptp_info.n_per_out = cpts->genf_num;

        am65_cpts_set_add_val(cpts);

        am65_cpts_write32(cpts, AM65_CPTS_CONTROL_EN | AM65_CPTS_CONTROL_64MODE,
                          control);
        am65_cpts_write32(cpts, AM65_CPTS_INT_ENABLE_TS_PEND_EN, int_enable);

        /* set time to the current system time */
        am65_cpts_settime(cpts, ktime_to_ns(ktime_get_real()));

        cpts->ptp_clock = ptp_clock_register(&cpts->ptp_info, cpts->dev);
        if (IS_ERR_OR_NULL(cpts->ptp_clock)) {
                dev_err(dev, "Failed to register ptp clk %ld\n",
                        PTR_ERR(cpts->ptp_clock));
                if (!cpts->ptp_clock)
                        ret = -ENODEV;
                goto refclk_disable;
        }
        cpts->phc_index = ptp_clock_index(cpts->ptp_clock);

        ret = devm_add_action_or_reset(dev, am65_cpts_release, cpts);
        if (ret) {
                dev_err(dev, "failed to add ptpclk reset action %d", ret);
                return ERR_PTR(ret);
        }

        ret = devm_request_threaded_irq(dev, cpts->irq, NULL,
                                        am65_cpts_interrupt,
                                        IRQF_ONESHOT, dev_name(dev), cpts);
        if (ret < 0) {
                dev_err(cpts->dev, "error attaching irq %d\n", ret);
                return ERR_PTR(ret);
        }

        dev_info(dev, "CPTS ver 0x%08x, freq:%u, add_val:%u\n",
                 am65_cpts_read32(cpts, idver),
                 cpts->refclk_freq, cpts->ts_add_val);

        return cpts;

refclk_disable:
        clk_disable_unprepare(cpts->refclk);
        return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(am65_cpts_create);

static int am65_cpts_probe(struct platform_device *pdev)
{
        struct device_node *node = pdev->dev.of_node;
        struct device *dev = &pdev->dev;
        struct am65_cpts *cpts;
        struct resource *res;
        void __iomem *base;

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cpts");
        base = devm_ioremap_resource(dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);

        cpts = am65_cpts_create(dev, base, node);
        return PTR_ERR_OR_ZERO(cpts);
}

static const struct of_device_id am65_cpts_of_match[] = {
        { .compatible = "ti,am65-cpts", },
        { .compatible = "ti,j721e-cpts", },
        {},
};
MODULE_DEVICE_TABLE(of, am65_cpts_of_match);

static struct platform_driver am65_cpts_driver = {
        .probe          = am65_cpts_probe,
        .driver         = {
                .name   = "am65-cpts",
                .of_match_table = am65_cpts_of_match,
        },
};
module_platform_driver(am65_cpts_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Grygorii Strashko <grygorii.strashko@ti.com>");
MODULE_DESCRIPTION("TI K3 AM65 CPTS driver");