// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PTP 1588 clock for Freescale QorIQ 1588 timer
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/device.h>
#include <linux/hrtimer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/clk.h>

#include <linux/fsl/ptp_qoriq.h>

/*
 * Register access functions
 */

/* Caller must hold ptp_qoriq->lock. */
static u64 tmr_cnt_read(struct ptp_qoriq *ptp_qoriq)
{
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;
        u64 ns;
        u32 lo, hi;

        lo = ptp_qoriq->read(&regs->ctrl_regs->tmr_cnt_l);
        hi = ptp_qoriq->read(&regs->ctrl_regs->tmr_cnt_h);
        ns = ((u64) hi) << 32;
        ns |= lo;
        return ns;
}

/* Caller must hold ptp_qoriq->lock. */
static void tmr_cnt_write(struct ptp_qoriq *ptp_qoriq, u64 ns)
{
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;
        u32 hi = ns >> 32;
        u32 lo = ns & 0xffffffff;

        ptp_qoriq->write(&regs->ctrl_regs->tmr_cnt_l, lo);
        ptp_qoriq->write(&regs->ctrl_regs->tmr_cnt_h, hi);
}

/* Caller must hold ptp_qoriq->lock. */
static void set_alarm(struct ptp_qoriq *ptp_qoriq)
{
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;
        u64 ns;
        u32 lo, hi;

        ns = tmr_cnt_read(ptp_qoriq) + 1500000000ULL;
        ns = div_u64(ns, 1000000000UL) * 1000000000ULL;
        ns -= ptp_qoriq->tclk_period;
        hi = ns >> 32;
        lo = ns & 0xffffffff;
        ptp_qoriq->write(&regs->alarm_regs->tmr_alarm1_l, lo);
        ptp_qoriq->write(&regs->alarm_regs->tmr_alarm1_h, hi);
}

/* Caller must hold ptp_qoriq->lock. */
static void set_fipers(struct ptp_qoriq *ptp_qoriq)
{
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;

        set_alarm(ptp_qoriq);
        ptp_qoriq->write(&regs->fiper_regs->tmr_fiper1, ptp_qoriq->tmr_fiper1);
        ptp_qoriq->write(&regs->fiper_regs->tmr_fiper2, ptp_qoriq->tmr_fiper2);
}

int extts_clean_up(struct ptp_qoriq *ptp_qoriq, int index, bool update_event)
{
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;
        struct ptp_clock_event event;
        void __iomem *reg_etts_l;
        void __iomem *reg_etts_h;
        u32 valid, lo, hi;

        switch (index) {
        case 0:
                valid = ETS1_VLD;
                reg_etts_l = &regs->etts_regs->tmr_etts1_l;
                reg_etts_h = &regs->etts_regs->tmr_etts1_h;
                break;
        case 1:
                valid = ETS2_VLD;
                reg_etts_l = &regs->etts_regs->tmr_etts2_l;
                reg_etts_h = &regs->etts_regs->tmr_etts2_h;
                break;
        default:
                return -EINVAL;
        }

        event.type = PTP_CLOCK_EXTTS;
        event.index = index;

        if (ptp_qoriq->extts_fifo_support)
                if (!(ptp_qoriq->read(&regs->ctrl_regs->tmr_stat) & valid))
                        return 0;

        do {
                lo = ptp_qoriq->read(reg_etts_l);
                hi = ptp_qoriq->read(reg_etts_h);

                if (update_event) {
                        event.timestamp = ((u64) hi) << 32;
                        event.timestamp |= lo;
                        ptp_clock_event(ptp_qoriq->clock, &event);
                }

                if (!ptp_qoriq->extts_fifo_support)
                        break;
        } while (ptp_qoriq->read(&regs->ctrl_regs->tmr_stat) & valid);

        return 0;
}
EXPORT_SYMBOL_GPL(extts_clean_up);

/*
 * Interrupt service routine
 */

irqreturn_t ptp_qoriq_isr(int irq, void *priv)
{
        struct ptp_qoriq *ptp_qoriq = priv;
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;
        struct ptp_clock_event event;
        u32 ack = 0, mask, val, irqs;

        spin_lock(&ptp_qoriq->lock);

        val = ptp_qoriq->read(&regs->ctrl_regs->tmr_tevent);
        mask = ptp_qoriq->read(&regs->ctrl_regs->tmr_temask);

        spin_unlock(&ptp_qoriq->lock);

        irqs = val & mask;

        if (irqs & ETS1) {
                ack |= ETS1;
                extts_clean_up(ptp_qoriq, 0, true);
        }

        if (irqs & ETS2) {
                ack |= ETS2;
                extts_clean_up(ptp_qoriq, 1, true);
        }

        if (irqs & PP1) {
                ack |= PP1;
                event.type = PTP_CLOCK_PPS;
                ptp_clock_event(ptp_qoriq->clock, &event);
        }

        if (ack) {
                ptp_qoriq->write(&regs->ctrl_regs->tmr_tevent, ack);
                return IRQ_HANDLED;
        } else
                return IRQ_NONE;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_isr);

/*
 * PTP clock operations
 */

int ptp_qoriq_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
{
        u64 adj, diff;
        u32 tmr_add;
        int neg_adj = 0;
        struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps);
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;

        if (scaled_ppm < 0) {
                neg_adj = 1;
                scaled_ppm = -scaled_ppm;
        }
        tmr_add = ptp_qoriq->tmr_add;
        adj = tmr_add;

        /* calculate diff as adj*(scaled_ppm/65536)/1000000
         * and round() to the nearest integer
         */
        adj *= scaled_ppm;
        diff = div_u64(adj, 8000000);
        diff = (diff >> 13) + ((diff >> 12) & 1);

        tmr_add = neg_adj ? tmr_add - diff : tmr_add + diff;

        ptp_qoriq->write(&regs->ctrl_regs->tmr_add, tmr_add);

        return 0;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_adjfine);

int ptp_qoriq_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
        s64 now;
        unsigned long flags;
        struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps);

        spin_lock_irqsave(&ptp_qoriq->lock, flags);

        now = tmr_cnt_read(ptp_qoriq);
        now += delta;
        tmr_cnt_write(ptp_qoriq, now);
        set_fipers(ptp_qoriq);

        spin_unlock_irqrestore(&ptp_qoriq->lock, flags);

        return 0;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_adjtime);

int ptp_qoriq_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
        u64 ns;
        unsigned long flags;
        struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps);

        spin_lock_irqsave(&ptp_qoriq->lock, flags);

        ns = tmr_cnt_read(ptp_qoriq);

        spin_unlock_irqrestore(&ptp_qoriq->lock, flags);

        *ts = ns_to_timespec64(ns);

        return 0;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_gettime);

int ptp_qoriq_settime(struct ptp_clock_info *ptp,
                      const struct timespec64 *ts)
{
        u64 ns;
        unsigned long flags;
        struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps);

        ns = timespec64_to_ns(ts);

        spin_lock_irqsave(&ptp_qoriq->lock, flags);

        tmr_cnt_write(ptp_qoriq, ns);
        set_fipers(ptp_qoriq);

        spin_unlock_irqrestore(&ptp_qoriq->lock, flags);

        return 0;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_settime);

int ptp_qoriq_enable(struct ptp_clock_info *ptp,
                     struct ptp_clock_request *rq, int on)
{
        struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps);
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;
        unsigned long flags;
        u32 bit, mask = 0;

        switch (rq->type) {
        case PTP_CLK_REQ_EXTTS:
                switch (rq->extts.index) {
                case 0:
                        bit = ETS1EN;
                        break;
                case 1:
                        bit = ETS2EN;
                        break;
                default:
                        return -EINVAL;
                }

                if (on)
                        extts_clean_up(ptp_qoriq, rq->extts.index, false);

                break;
        case PTP_CLK_REQ_PPS:
                bit = PP1EN;
                break;
        default:
                return -EOPNOTSUPP;
        }

        spin_lock_irqsave(&ptp_qoriq->lock, flags);

        mask = ptp_qoriq->read(&regs->ctrl_regs->tmr_temask);
        if (on) {
                mask |= bit;
                ptp_qoriq->write(&regs->ctrl_regs->tmr_tevent, bit);
        } else {
                mask &= ~bit;
        }

        ptp_qoriq->write(&regs->ctrl_regs->tmr_temask, mask);

        spin_unlock_irqrestore(&ptp_qoriq->lock, flags);
        return 0;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_enable);

static const struct ptp_clock_info ptp_qoriq_caps = {
        .owner          = THIS_MODULE,
        .name           = "qoriq ptp clock",
        .max_adj        = 512000,
        .n_alarm        = 0,
        .n_ext_ts       = N_EXT_TS,
        .n_per_out      = 0,
        .n_pins         = 0,
        .pps            = 1,
        .adjfine        = ptp_qoriq_adjfine,
        .adjtime        = ptp_qoriq_adjtime,
        .gettime64      = ptp_qoriq_gettime,
        .settime64      = ptp_qoriq_settime,
        .enable         = ptp_qoriq_enable,
};

/**
 * ptp_qoriq_nominal_freq - calculate nominal frequency according to
 *                          reference clock frequency
 *
 * @clk_src: reference clock frequency
 *
 * The nominal frequency is the desired clock frequency.
 * It should be less than the reference clock frequency.
 * It should be a factor of 1000MHz.
 *
 * Return the nominal frequency
 */
static u32 ptp_qoriq_nominal_freq(u32 clk_src)
{
        u32 remainder = 0;

        clk_src /= 1000000;
        remainder = clk_src % 100;
        if (remainder) {
                clk_src -= remainder;
                clk_src += 100;
        }

        do {
                clk_src -= 100;

        } while (1000 % clk_src);

        return clk_src * 1000000;
}

/**
 * ptp_qoriq_auto_config - calculate a set of default configurations
 *
 * @ptp_qoriq: pointer to ptp_qoriq
 * @node: pointer to device_node
 *
 * If below dts properties are not provided, this function will be
 * called to calculate a set of default configurations for them.
 *   "fsl,tclk-period"
 *   "fsl,tmr-prsc"
 *   "fsl,tmr-add"
 *   "fsl,tmr-fiper1"
 *   "fsl,tmr-fiper2"
 *   "fsl,max-adj"
 *
 * Return 0 if success
 */
static int ptp_qoriq_auto_config(struct ptp_qoriq *ptp_qoriq,
                                 struct device_node *node)
{
        struct clk *clk;
        u64 freq_comp;
        u64 max_adj;
        u32 nominal_freq;
        u32 remainder = 0;
        u32 clk_src = 0;

        ptp_qoriq->cksel = DEFAULT_CKSEL;

        clk = of_clk_get(node, 0);
        if (!IS_ERR(clk)) {
                clk_src = clk_get_rate(clk);
                clk_put(clk);
        }

        if (clk_src <= 100000000UL) {
                pr_err("error reference clock value, or lower than 100MHz\n");
                return -EINVAL;
        }

        nominal_freq = ptp_qoriq_nominal_freq(clk_src);
        if (!nominal_freq)
                return -EINVAL;

        ptp_qoriq->tclk_period = 1000000000UL / nominal_freq;
        ptp_qoriq->tmr_prsc = DEFAULT_TMR_PRSC;

        /* Calculate initial frequency compensation value for TMR_ADD register.
         * freq_comp = ceil(2^32 / freq_ratio)
         * freq_ratio = reference_clock_freq / nominal_freq
         */
        freq_comp = ((u64)1 << 32) * nominal_freq;
        freq_comp = div_u64_rem(freq_comp, clk_src, &remainder);
        if (remainder)
                freq_comp++;

        ptp_qoriq->tmr_add = freq_comp;
        ptp_qoriq->tmr_fiper1 = DEFAULT_FIPER1_PERIOD - ptp_qoriq->tclk_period;
        ptp_qoriq->tmr_fiper2 = DEFAULT_FIPER2_PERIOD - ptp_qoriq->tclk_period;

        /* max_adj = 1000000000 * (freq_ratio - 1.0) - 1
         * freq_ratio = reference_clock_freq / nominal_freq
         */
        max_adj = 1000000000ULL * (clk_src - nominal_freq);
        max_adj = div_u64(max_adj, nominal_freq) - 1;
        ptp_qoriq->caps.max_adj = max_adj;

        return 0;
}

int ptp_qoriq_init(struct ptp_qoriq *ptp_qoriq, void __iomem *base,
                   const struct ptp_clock_info *caps)
{
        struct device_node *node = ptp_qoriq->dev->of_node;
        struct ptp_qoriq_registers *regs;
        struct timespec64 now;
        unsigned long flags;
        u32 tmr_ctrl;

        if (!node)
                return -ENODEV;

        ptp_qoriq->base = base;
        ptp_qoriq->caps = *caps;

        if (of_property_read_u32(node, "fsl,cksel", &ptp_qoriq->cksel))
                ptp_qoriq->cksel = DEFAULT_CKSEL;

        if (of_property_read_bool(node, "fsl,extts-fifo"))
                ptp_qoriq->extts_fifo_support = true;
        else
                ptp_qoriq->extts_fifo_support = false;

        if (of_property_read_u32(node,
                                 "fsl,tclk-period", &ptp_qoriq->tclk_period) ||
            of_property_read_u32(node,
                                 "fsl,tmr-prsc", &ptp_qoriq->tmr_prsc) ||
            of_property_read_u32(node,
                                 "fsl,tmr-add", &ptp_qoriq->tmr_add) ||
            of_property_read_u32(node,
                                 "fsl,tmr-fiper1", &ptp_qoriq->tmr_fiper1) ||
            of_property_read_u32(node,
                                 "fsl,tmr-fiper2", &ptp_qoriq->tmr_fiper2) ||
            of_property_read_u32(node,
                                 "fsl,max-adj", &ptp_qoriq->caps.max_adj)) {
                pr_warn("device tree node missing required elements, try automatic configuration\n");

                if (ptp_qoriq_auto_config(ptp_qoriq, node))
                        return -ENODEV;
        }

        if (of_property_read_bool(node, "little-endian")) {
                ptp_qoriq->read = qoriq_read_le;
                ptp_qoriq->write = qoriq_write_le;
        } else {
                ptp_qoriq->read = qoriq_read_be;
                ptp_qoriq->write = qoriq_write_be;
        }

        /* The eTSEC uses differnt memory map with DPAA/ENETC */
        if (of_device_is_compatible(node, "fsl,etsec-ptp")) {
                ptp_qoriq->regs.ctrl_regs = base + ETSEC_CTRL_REGS_OFFSET;
                ptp_qoriq->regs.alarm_regs = base + ETSEC_ALARM_REGS_OFFSET;
                ptp_qoriq->regs.fiper_regs = base + ETSEC_FIPER_REGS_OFFSET;
                ptp_qoriq->regs.etts_regs = base + ETSEC_ETTS_REGS_OFFSET;
        } else {
                ptp_qoriq->regs.ctrl_regs = base + CTRL_REGS_OFFSET;
                ptp_qoriq->regs.alarm_regs = base + ALARM_REGS_OFFSET;
                ptp_qoriq->regs.fiper_regs = base + FIPER_REGS_OFFSET;
                ptp_qoriq->regs.etts_regs = base + ETTS_REGS_OFFSET;
        }

        spin_lock_init(&ptp_qoriq->lock);

        ktime_get_real_ts64(&now);
        ptp_qoriq_settime(&ptp_qoriq->caps, &now);

        tmr_ctrl =
          (ptp_qoriq->tclk_period & TCLK_PERIOD_MASK) << TCLK_PERIOD_SHIFT |
          (ptp_qoriq->cksel & CKSEL_MASK) << CKSEL_SHIFT;

        spin_lock_irqsave(&ptp_qoriq->lock, flags);

        regs = &ptp_qoriq->regs;
        ptp_qoriq->write(&regs->ctrl_regs->tmr_ctrl, tmr_ctrl);
        ptp_qoriq->write(&regs->ctrl_regs->tmr_add, ptp_qoriq->tmr_add);
        ptp_qoriq->write(&regs->ctrl_regs->tmr_prsc, ptp_qoriq->tmr_prsc);
        ptp_qoriq->write(&regs->fiper_regs->tmr_fiper1, ptp_qoriq->tmr_fiper1);
        ptp_qoriq->write(&regs->fiper_regs->tmr_fiper2, ptp_qoriq->tmr_fiper2);
        set_alarm(ptp_qoriq);
        ptp_qoriq->write(&regs->ctrl_regs->tmr_ctrl,
                         tmr_ctrl|FIPERST|RTPE|TE|FRD);

        spin_unlock_irqrestore(&ptp_qoriq->lock, flags);

        ptp_qoriq->clock = ptp_clock_register(&ptp_qoriq->caps, ptp_qoriq->dev);
        if (IS_ERR(ptp_qoriq->clock))
                return PTR_ERR(ptp_qoriq->clock);

        ptp_qoriq->phc_index = ptp_clock_index(ptp_qoriq->clock);
        ptp_qoriq_create_debugfs(ptp_qoriq);
        return 0;
}
EXPORT_SYMBOL_GPL(ptp_qoriq_init);

void ptp_qoriq_free(struct ptp_qoriq *ptp_qoriq)
{
        struct ptp_qoriq_registers *regs = &ptp_qoriq->regs;

        ptp_qoriq->write(&regs->ctrl_regs->tmr_temask, 0);
        ptp_qoriq->write(&regs->ctrl_regs->tmr_ctrl,   0);

        ptp_qoriq_remove_debugfs(ptp_qoriq);
        ptp_clock_unregister(ptp_qoriq->clock);
        iounmap(ptp_qoriq->base);
        free_irq(ptp_qoriq->irq, ptp_qoriq);
}
EXPORT_SYMBOL_GPL(ptp_qoriq_free);

static int ptp_qoriq_probe(struct platform_device *dev)
{
        struct ptp_qoriq *ptp_qoriq;
        int err = -ENOMEM;
        void __iomem *base;

        ptp_qoriq = kzalloc(sizeof(*ptp_qoriq), GFP_KERNEL);
        if (!ptp_qoriq)
                goto no_memory;

        ptp_qoriq->dev = &dev->dev;

        err = -ENODEV;

        ptp_qoriq->irq = platform_get_irq(dev, 0);
        if (ptp_qoriq->irq < 0) {
                pr_err("irq not in device tree\n");
                goto no_node;
        }
        if (request_irq(ptp_qoriq->irq, ptp_qoriq_isr, IRQF_SHARED,
                        DRIVER, ptp_qoriq)) {
                pr_err("request_irq failed\n");
                goto no_node;
        }

        ptp_qoriq->rsrc = platform_get_resource(dev, IORESOURCE_MEM, 0);
        if (!ptp_qoriq->rsrc) {
                pr_err("no resource\n");
                goto no_resource;
        }
        if (request_resource(&iomem_resource, ptp_qoriq->rsrc)) {
                pr_err("resource busy\n");
                goto no_resource;
        }

        base = ioremap(ptp_qoriq->rsrc->start,
                       resource_size(ptp_qoriq->rsrc));
        if (!base) {
                pr_err("ioremap ptp registers failed\n");
                goto no_ioremap;
        }

        err = ptp_qoriq_init(ptp_qoriq, base, &ptp_qoriq_caps);
        if (err)
                goto no_clock;

        platform_set_drvdata(dev, ptp_qoriq);
        return 0;

no_clock:
        iounmap(ptp_qoriq->base);
no_ioremap:
        release_resource(ptp_qoriq->rsrc);
no_resource:
        free_irq(ptp_qoriq->irq, ptp_qoriq);
no_node:
        kfree(ptp_qoriq);
no_memory:
        return err;
}

static int ptp_qoriq_remove(struct platform_device *dev)
{
        struct ptp_qoriq *ptp_qoriq = platform_get_drvdata(dev);

        ptp_qoriq_free(ptp_qoriq);
        release_resource(ptp_qoriq->rsrc);
        kfree(ptp_qoriq);
        return 0;
}

static const struct of_device_id match_table[] = {
        { .compatible = "fsl,etsec-ptp" },
        { .compatible = "fsl,fman-ptp-timer" },
        {},
};
MODULE_DEVICE_TABLE(of, match_table);

static struct platform_driver ptp_qoriq_driver = {
        .driver = {
                .name           = "ptp_qoriq",
                .of_match_table = match_table,
        },
        .probe       = ptp_qoriq_probe,
        .remove      = ptp_qoriq_remove,
};

module_platform_driver(ptp_qoriq_driver);

MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
MODULE_DESCRIPTION("PTP clock for Freescale QorIQ 1588 timer");
MODULE_LICENSE("GPL");