// SPDX-License-Identifier: GPL-2.0-only
/**
 * 1588 PTP support for Cadence GEM device.
 *
 * Copyright (C) 2017 Cadence Design Systems - http://www.cadence.com
 *
 * Authors: Rafal Ozieblo <rafalo@cadence.com>
 *          Bartosz Folta <bfolta@cadence.com>
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include <linux/platform_device.h>
#include <linux/time64.h>
#include <linux/ptp_classify.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/net_tstamp.h>
#include <linux/circ_buf.h>
#include <linux/spinlock.h>

#include "macb.h"

#define  GEM_PTP_TIMER_NAME "gem-ptp-timer"

static struct macb_dma_desc_ptp *macb_ptp_desc(struct macb *bp,
                                               struct macb_dma_desc *desc)
{
        if (bp->hw_dma_cap == HW_DMA_CAP_PTP)
                return (struct macb_dma_desc_ptp *)
                                ((u8 *)desc + sizeof(struct macb_dma_desc));
        if (bp->hw_dma_cap == HW_DMA_CAP_64B_PTP)
                return (struct macb_dma_desc_ptp *)
                                ((u8 *)desc + sizeof(struct macb_dma_desc)
                                + sizeof(struct macb_dma_desc_64));
        return NULL;
}

static int gem_tsu_get_time(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
        struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
        unsigned long flags;
        long first, second;
        u32 secl, sech;

        spin_lock_irqsave(&bp->tsu_clk_lock, flags);
        first = gem_readl(bp, TN);
        secl = gem_readl(bp, TSL);
        sech = gem_readl(bp, TSH);
        second = gem_readl(bp, TN);

        /* test for nsec rollover */
        if (first > second) {
                /* if so, use later read & re-read seconds
                 * (assume all done within 1s)
                 */
                ts->tv_nsec = gem_readl(bp, TN);
                secl = gem_readl(bp, TSL);
                sech = gem_readl(bp, TSH);
        } else {
                ts->tv_nsec = first;
        }

        spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);
        ts->tv_sec = (((u64)sech << GEM_TSL_SIZE) | secl)
                        & TSU_SEC_MAX_VAL;
        return 0;
}

static int gem_tsu_set_time(struct ptp_clock_info *ptp,
                            const struct timespec64 *ts)
{
        struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
        unsigned long flags;
        u32 ns, sech, secl;

        secl = (u32)ts->tv_sec;
        sech = (ts->tv_sec >> GEM_TSL_SIZE) & ((1 << GEM_TSH_SIZE) - 1);
        ns = ts->tv_nsec;

        spin_lock_irqsave(&bp->tsu_clk_lock, flags);

        /* TSH doesn't latch the time and no atomicity! */
        gem_writel(bp, TN, 0); /* clear to avoid overflow */
        gem_writel(bp, TSH, sech);
        /* write lower bits 2nd, for synchronized secs update */
        gem_writel(bp, TSL, secl);
        gem_writel(bp, TN, ns);

        spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);

        return 0;
}

static int gem_tsu_incr_set(struct macb *bp, struct tsu_incr *incr_spec)
{
        unsigned long flags;

        /* tsu_timer_incr register must be written after
         * the tsu_timer_incr_sub_ns register and the write operation
         * will cause the value written to the tsu_timer_incr_sub_ns register
         * to take effect.
         */
        spin_lock_irqsave(&bp->tsu_clk_lock, flags);
        gem_writel(bp, TISUBN, GEM_BF(SUBNSINCR, incr_spec->sub_ns));
        gem_writel(bp, TI, GEM_BF(NSINCR, incr_spec->ns));
        spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);

        return 0;
}

static int gem_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
{
        struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
        struct tsu_incr incr_spec;
        bool neg_adj = false;
        u32 word;
        u64 adj;

        if (scaled_ppm < 0) {
                neg_adj = true;
                scaled_ppm = -scaled_ppm;
        }

        /* Adjustment is relative to base frequency */
        incr_spec.sub_ns = bp->tsu_incr.sub_ns;
        incr_spec.ns = bp->tsu_incr.ns;

        /* scaling: unused(8bit) | ns(8bit) | fractions(16bit) */
        word = ((u64)incr_spec.ns << GEM_SUBNSINCR_SIZE) + incr_spec.sub_ns;
        adj = (u64)scaled_ppm * word;
        /* Divide with rounding, equivalent to floating dividing:
         * (temp / USEC_PER_SEC) + 0.5
         */
        adj += (USEC_PER_SEC >> 1);
        adj >>= GEM_SUBNSINCR_SIZE; /* remove fractions */
        adj = div_u64(adj, USEC_PER_SEC);
        adj = neg_adj ? (word - adj) : (word + adj);

        incr_spec.ns = (adj >> GEM_SUBNSINCR_SIZE)
                        & ((1 << GEM_NSINCR_SIZE) - 1);
        incr_spec.sub_ns = adj & ((1 << GEM_SUBNSINCR_SIZE) - 1);
        gem_tsu_incr_set(bp, &incr_spec);
        return 0;
}

static int gem_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
        struct timespec64 now, then = ns_to_timespec64(delta);
        u32 adj, sign = 0;

        if (delta < 0) {
                sign = 1;
                delta = -delta;
        }

        if (delta > TSU_NSEC_MAX_VAL) {
                gem_tsu_get_time(&bp->ptp_clock_info, &now);
                now = timespec64_add(now, then);

                gem_tsu_set_time(&bp->ptp_clock_info,
                                 (const struct timespec64 *)&now);
        } else {
                adj = (sign << GEM_ADDSUB_OFFSET) | delta;

                gem_writel(bp, TA, adj);
        }

        return 0;
}

static int gem_ptp_enable(struct ptp_clock_info *ptp,
                          struct ptp_clock_request *rq, int on)
{
        return -EOPNOTSUPP;
}

static const struct ptp_clock_info gem_ptp_caps_template = {
        .owner          = THIS_MODULE,
        .name           = GEM_PTP_TIMER_NAME,
        .max_adj        = 0,
        .n_alarm        = 0,
        .n_ext_ts       = 0,
        .n_per_out      = 0,
        .n_pins         = 0,
        .pps            = 1,
        .adjfine        = gem_ptp_adjfine,
        .adjtime        = gem_ptp_adjtime,
        .gettime64      = gem_tsu_get_time,
        .settime64      = gem_tsu_set_time,
        .enable         = gem_ptp_enable,
};

static void gem_ptp_init_timer(struct macb *bp)
{
        u32 rem = 0;
        u64 adj;

        bp->tsu_incr.ns = div_u64_rem(NSEC_PER_SEC, bp->tsu_rate, &rem);
        if (rem) {
                adj = rem;
                adj <<= GEM_SUBNSINCR_SIZE;
                bp->tsu_incr.sub_ns = div_u64(adj, bp->tsu_rate);
        } else {
                bp->tsu_incr.sub_ns = 0;
        }
}

static void gem_ptp_init_tsu(struct macb *bp)
{
        struct timespec64 ts;

        /* 1. get current system time */
        ts = ns_to_timespec64(ktime_to_ns(ktime_get_real()));

        /* 2. set ptp timer */
        gem_tsu_set_time(&bp->ptp_clock_info, &ts);

        /* 3. set PTP timer increment value to BASE_INCREMENT */
        gem_tsu_incr_set(bp, &bp->tsu_incr);

        gem_writel(bp, TA, 0);
}

static void gem_ptp_clear_timer(struct macb *bp)
{
        bp->tsu_incr.sub_ns = 0;
        bp->tsu_incr.ns = 0;

        gem_writel(bp, TISUBN, GEM_BF(SUBNSINCR, 0));
        gem_writel(bp, TI, GEM_BF(NSINCR, 0));
        gem_writel(bp, TA, 0);
}

static int gem_hw_timestamp(struct macb *bp, u32 dma_desc_ts_1,
                            u32 dma_desc_ts_2, struct timespec64 *ts)
{
        struct timespec64 tsu;

        ts->tv_sec = (GEM_BFEXT(DMA_SECH, dma_desc_ts_2) << GEM_DMA_SECL_SIZE) |
                        GEM_BFEXT(DMA_SECL, dma_desc_ts_1);
        ts->tv_nsec = GEM_BFEXT(DMA_NSEC, dma_desc_ts_1);

        /* TSU overlapping workaround
         * The timestamp only contains lower few bits of seconds,
         * so add value from 1588 timer
         */
        gem_tsu_get_time(&bp->ptp_clock_info, &tsu);

        /* If the top bit is set in the timestamp,
         * but not in 1588 timer, it has rolled over,
         * so subtract max size
         */
        if ((ts->tv_sec & (GEM_DMA_SEC_TOP >> 1)) &&
            !(tsu.tv_sec & (GEM_DMA_SEC_TOP >> 1)))
                ts->tv_sec -= GEM_DMA_SEC_TOP;

        ts->tv_sec += ((~GEM_DMA_SEC_MASK) & tsu.tv_sec);

        return 0;
}

void gem_ptp_rxstamp(struct macb *bp, struct sk_buff *skb,
                     struct macb_dma_desc *desc)
{
        struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
        struct macb_dma_desc_ptp *desc_ptp;
        struct timespec64 ts;

        if (GEM_BFEXT(DMA_RXVALID, desc->addr)) {
                desc_ptp = macb_ptp_desc(bp, desc);
                gem_hw_timestamp(bp, desc_ptp->ts_1, desc_ptp->ts_2, &ts);
                memset(shhwtstamps, 0, sizeof(struct skb_shared_hwtstamps));
                shhwtstamps->hwtstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
        }
}

static void gem_tstamp_tx(struct macb *bp, struct sk_buff *skb,
                          struct macb_dma_desc_ptp *desc_ptp)
{
        struct skb_shared_hwtstamps shhwtstamps;
        struct timespec64 ts;

        gem_hw_timestamp(bp, desc_ptp->ts_1, desc_ptp->ts_2, &ts);
        memset(&shhwtstamps, 0, sizeof(shhwtstamps));
        shhwtstamps.hwtstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
        skb_tstamp_tx(skb, &shhwtstamps);
}

int gem_ptp_txstamp(struct macb_queue *queue, struct sk_buff *skb,
                    struct macb_dma_desc *desc)
{
        unsigned long tail = READ_ONCE(queue->tx_ts_tail);
        unsigned long head = queue->tx_ts_head;
        struct macb_dma_desc_ptp *desc_ptp;
        struct gem_tx_ts *tx_timestamp;

        if (!GEM_BFEXT(DMA_TXVALID, desc->ctrl))
                return -EINVAL;

        if (CIRC_SPACE(head, tail, PTP_TS_BUFFER_SIZE) == 0)
                return -ENOMEM;

        skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
        desc_ptp = macb_ptp_desc(queue->bp, desc);
        tx_timestamp = &queue->tx_timestamps[head];
        tx_timestamp->skb = skb;
        /* ensure ts_1/ts_2 is loaded after ctrl (TX_USED check) */
        dma_rmb();
        tx_timestamp->desc_ptp.ts_1 = desc_ptp->ts_1;
        tx_timestamp->desc_ptp.ts_2 = desc_ptp->ts_2;
        /* move head */
        smp_store_release(&queue->tx_ts_head,
                          (head + 1) & (PTP_TS_BUFFER_SIZE - 1));

        schedule_work(&queue->tx_ts_task);
        return 0;
}

static void gem_tx_timestamp_flush(struct work_struct *work)
{
        struct macb_queue *queue =
                        container_of(work, struct macb_queue, tx_ts_task);
        unsigned long head, tail;
        struct gem_tx_ts *tx_ts;

        /* take current head */
        head = smp_load_acquire(&queue->tx_ts_head);
        tail = queue->tx_ts_tail;

        while (CIRC_CNT(head, tail, PTP_TS_BUFFER_SIZE)) {
                tx_ts = &queue->tx_timestamps[tail];
                gem_tstamp_tx(queue->bp, tx_ts->skb, &tx_ts->desc_ptp);
                /* cleanup */
                dev_kfree_skb_any(tx_ts->skb);
                /* remove old tail */
                smp_store_release(&queue->tx_ts_tail,
                                  (tail + 1) & (PTP_TS_BUFFER_SIZE - 1));
                tail = queue->tx_ts_tail;
        }
}

void gem_ptp_init(struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        struct macb_queue *queue;
        unsigned int q;

        bp->ptp_clock_info = gem_ptp_caps_template;

        /* nominal frequency and maximum adjustment in ppb */
        bp->tsu_rate = bp->ptp_info->get_tsu_rate(bp);
        bp->ptp_clock_info.max_adj = bp->ptp_info->get_ptp_max_adj();
        gem_ptp_init_timer(bp);
        bp->ptp_clock = ptp_clock_register(&bp->ptp_clock_info, &dev->dev);
        if (IS_ERR(bp->ptp_clock)) {
                pr_err("ptp clock register failed: %ld\n",
                        PTR_ERR(bp->ptp_clock));
                bp->ptp_clock = NULL;
                return;
        } else if (bp->ptp_clock == NULL) {
                pr_err("ptp clock register failed\n");
                return;
        }

        spin_lock_init(&bp->tsu_clk_lock);
        for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
                queue->tx_ts_head = 0;
                queue->tx_ts_tail = 0;
                INIT_WORK(&queue->tx_ts_task, gem_tx_timestamp_flush);
        }

        gem_ptp_init_tsu(bp);

        dev_info(&bp->pdev->dev, "%s ptp clock registered.\n",
                 GEM_PTP_TIMER_NAME);
}

void gem_ptp_remove(struct net_device *ndev)
{
        struct macb *bp = netdev_priv(ndev);

        if (bp->ptp_clock)
                ptp_clock_unregister(bp->ptp_clock);

        gem_ptp_clear_timer(bp);

        dev_info(&bp->pdev->dev, "%s ptp clock unregistered.\n",
                 GEM_PTP_TIMER_NAME);
}

static int gem_ptp_set_ts_mode(struct macb *bp,
                               enum macb_bd_control tx_bd_control,
                               enum macb_bd_control rx_bd_control)
{
        gem_writel(bp, TXBDCTRL, GEM_BF(TXTSMODE, tx_bd_control));
        gem_writel(bp, RXBDCTRL, GEM_BF(RXTSMODE, rx_bd_control));

        return 0;
}

int gem_get_hwtst(struct net_device *dev, struct ifreq *rq)
{
        struct hwtstamp_config *tstamp_config;
        struct macb *bp = netdev_priv(dev);

        tstamp_config = &bp->tstamp_config;
        if ((bp->hw_dma_cap & HW_DMA_CAP_PTP) == 0)
                return -EOPNOTSUPP;

        if (copy_to_user(rq->ifr_data, tstamp_config, sizeof(*tstamp_config)))
                return -EFAULT;
        else
                return 0;
}

static int gem_ptp_set_one_step_sync(struct macb *bp, u8 enable)
{
        u32 reg_val;

        reg_val = macb_readl(bp, NCR);

        if (enable)
                macb_writel(bp, NCR, reg_val | MACB_BIT(OSSMODE));
        else
                macb_writel(bp, NCR, reg_val & ~MACB_BIT(OSSMODE));

        return 0;
}

int gem_set_hwtst(struct net_device *dev, struct ifreq *ifr, int cmd)
{
        enum macb_bd_control tx_bd_control = TSTAMP_DISABLED;
        enum macb_bd_control rx_bd_control = TSTAMP_DISABLED;
        struct hwtstamp_config *tstamp_config;
        struct macb *bp = netdev_priv(dev);
        u32 regval;

        tstamp_config = &bp->tstamp_config;
        if ((bp->hw_dma_cap & HW_DMA_CAP_PTP) == 0)
                return -EOPNOTSUPP;

        if (copy_from_user(tstamp_config, ifr->ifr_data,
                           sizeof(*tstamp_config)))
                return -EFAULT;

        /* reserved for future extensions */
        if (tstamp_config->flags)
                return -EINVAL;

        switch (tstamp_config->tx_type) {
        case HWTSTAMP_TX_OFF:
                break;
        case HWTSTAMP_TX_ONESTEP_SYNC:
                if (gem_ptp_set_one_step_sync(bp, 1) != 0)
                        return -ERANGE;
                /* fall through */
        case HWTSTAMP_TX_ON:
                tx_bd_control = TSTAMP_ALL_FRAMES;
                break;
        default:
                return -ERANGE;
        }

        switch (tstamp_config->rx_filter) {
        case HWTSTAMP_FILTER_NONE:
                break;
        case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
                break;
        case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
                break;
        case HWTSTAMP_FILTER_PTP_V2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
        case HWTSTAMP_FILTER_PTP_V2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
        case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
        case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
                rx_bd_control =  TSTAMP_ALL_PTP_FRAMES;
                tstamp_config->rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
                regval = macb_readl(bp, NCR);
                macb_writel(bp, NCR, (regval | MACB_BIT(SRTSM)));
                break;
        case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
        case HWTSTAMP_FILTER_ALL:
                rx_bd_control = TSTAMP_ALL_FRAMES;
                tstamp_config->rx_filter = HWTSTAMP_FILTER_ALL;
                break;
        default:
                tstamp_config->rx_filter = HWTSTAMP_FILTER_NONE;
                return -ERANGE;
        }

        if (gem_ptp_set_ts_mode(bp, tx_bd_control, rx_bd_control) != 0)
                return -ERANGE;

        if (copy_to_user(ifr->ifr_data, tstamp_config, sizeof(*tstamp_config)))
                return -EFAULT;
        else
                return 0;
}