// SPDX-License-Identifier: GPL-2.0-only
/*
 * Rockchip timer support
 *
 * Copyright (C) Daniel Lezcano <daniel.lezcano@linaro.org>
 */
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/sched_clock.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>

#define TIMER_NAME "rk_timer"

#define TIMER_LOAD_COUNT0 0x00
#define TIMER_LOAD_COUNT1 0x04
#define TIMER_CURRENT_VALUE0 0x08
#define TIMER_CURRENT_VALUE1 0x0C
#define TIMER_CONTROL_REG3288 0x10
#define TIMER_CONTROL_REG3399 0x1c
#define TIMER_INT_STATUS 0x18

#define TIMER_DISABLE 0x0
#define TIMER_ENABLE 0x1
#define TIMER_MODE_FREE_RUNNING (0 << 1)
#define TIMER_MODE_USER_DEFINED_COUNT (1 << 1)
#define TIMER_INT_UNMASK (1 << 2)

struct rk_timer {
    void __iomem *base;
    void __iomem *ctrl;
    struct clk *clk;
    struct clk *pclk;
    u32 freq;
    int irq;
};

struct rk_clkevt {
    struct clock_event_device ce;
    struct rk_timer timer;
};

static struct rk_clkevt *rk_clkevt;
#ifndef MODULE
static struct rk_timer *rk_clksrc;
#endif

static inline struct rk_timer *rk_timer(struct clock_event_device *ce)
{
    return &container_of(ce, struct rk_clkevt, ce)->timer;
}

static inline void rk_timer_disable(struct rk_timer *timer)
{
    writel_relaxed(TIMER_DISABLE, timer->ctrl);
}

static inline void rk_timer_enable(struct rk_timer *timer, u32 flags)
{
    writel_relaxed(TIMER_ENABLE | flags, timer->ctrl);
}

static void rk_timer_update_counter(unsigned long cycles, struct rk_timer *timer)
{
    writel_relaxed(cycles, timer->base + TIMER_LOAD_COUNT0);
    writel_relaxed(0, timer->base + TIMER_LOAD_COUNT1);
}

static void rk_timer_interrupt_clear(struct rk_timer *timer)
{
    writel_relaxed(1, timer->base + TIMER_INT_STATUS);
}

static inline int rk_timer_set_next_event(unsigned long cycles, struct clock_event_device *ce)
{
    struct rk_timer *timer = rk_timer(ce);

    rk_timer_disable(timer);
    rk_timer_update_counter(cycles, timer);
    rk_timer_enable(timer, TIMER_MODE_USER_DEFINED_COUNT | TIMER_INT_UNMASK);
    return 0;
}

static int rk_timer_shutdown(struct clock_event_device *ce)
{
    struct rk_timer *timer = rk_timer(ce);

    rk_timer_disable(timer);
    return 0;
}

static int rk_timer_set_periodic(struct clock_event_device *ce)
{
    struct rk_timer *timer = rk_timer(ce);

    rk_timer_disable(timer);
    rk_timer_update_counter(timer->freq / HZ - 1, timer);
    rk_timer_enable(timer, TIMER_MODE_FREE_RUNNING | TIMER_INT_UNMASK);
    return 0;
}

static irqreturn_t rk_timer_interrupt(int irq, void *dev_id)
{
    struct clock_event_device *ce = dev_id;
    struct rk_timer *timer = rk_timer(ce);

    rk_timer_interrupt_clear(timer);

    if (clockevent_state_oneshot(ce)) {
        rk_timer_disable(timer);
    }

    ce->event_handler(ce);

    return IRQ_HANDLED;
}

#ifndef MODULE
static u64 notrace rk_timer_sched_read(void)
{
    return ~readl_relaxed(rk_clksrc->base + TIMER_CURRENT_VALUE0);
}
#endif

static int __init rk_timer_probe(struct rk_timer *timer, struct device_node *np)
{
    struct clk *timer_clk;
    struct clk *pclk;
    int ret = -EINVAL, irq;
    u32 ctrl_reg = TIMER_CONTROL_REG3288;

    timer->base = of_iomap(np, 0);
    if (!timer->base) {
        pr_err("Failed to get base address for '%s'\n", TIMER_NAME);
        return -ENXIO;
    }

    if (of_device_is_compatible(np, "rockchip,rk3399-timer")) {
        ctrl_reg = TIMER_CONTROL_REG3399;
    }

    timer->ctrl = timer->base + ctrl_reg;

    pclk = of_clk_get_by_name(np, "pclk");
    if (IS_ERR(pclk)) {
        ret = PTR_ERR(pclk);
        pr_err("Failed to get pclk for '%s'\n", TIMER_NAME);
        goto out_unmap;
    }

    ret = clk_prepare_enable(pclk);
    if (ret) {
        pr_err("Failed to enable pclk for '%s'\n", TIMER_NAME);
        goto out_unmap;
    }
    timer->pclk = pclk;

    timer_clk = of_clk_get_by_name(np, "timer");
    if (IS_ERR(timer_clk)) {
        ret = PTR_ERR(timer_clk);
        pr_err("Failed to get timer clock for '%s'\n", TIMER_NAME);
        goto out_timer_clk;
    }

    ret = clk_prepare_enable(timer_clk);
    if (ret) {
        pr_err("Failed to enable timer clock\n");
        goto out_timer_clk;
    }
    timer->clk = timer_clk;

    timer->freq = clk_get_rate(timer_clk);

    irq = irq_of_parse_and_map(np, 0);
    if (!irq) {
        ret = -EINVAL;
        pr_err("Failed to map interrupts for '%s'\n", TIMER_NAME);
        goto out_irq;
    }
    timer->irq = irq;

    rk_timer_interrupt_clear(timer);
    rk_timer_disable(timer);
    return 0;

out_irq:
    clk_disable_unprepare(timer_clk);
out_timer_clk:
    clk_disable_unprepare(pclk);
out_unmap:
    iounmap(timer->base);

    return ret;
}

static void __init rk_timer_cleanup(struct rk_timer *timer)
{
    clk_disable_unprepare(timer->clk);
    clk_disable_unprepare(timer->pclk);
    iounmap(timer->base);
}

static int __init rk_clkevt_init(struct device_node *np)
{
    struct clock_event_device *ce;
    int ret = -EINVAL;

    rk_clkevt = kzalloc(sizeof(struct rk_clkevt), GFP_KERNEL);
    if (!rk_clkevt) {
        ret = -ENOMEM;
        goto out;
    }

    ret = rk_timer_probe(&rk_clkevt->timer, np);
    if (ret) {
        goto out_probe;
    }

    ce = &rk_clkevt->ce;
    ce->name = TIMER_NAME;
    ce->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_DYNIRQ;
    ce->set_next_event = rk_timer_set_next_event;
    ce->set_state_shutdown = rk_timer_shutdown;
    ce->set_state_periodic = rk_timer_set_periodic;
    ce->irq = rk_clkevt->timer.irq;
    ce->cpumask = cpu_possible_mask;
    ce->rating = 250;

    ret = request_irq(rk_clkevt->timer.irq, rk_timer_interrupt, IRQF_TIMER, TIMER_NAME, ce);
    if (ret) {
        pr_err("Failed to initialize '%s': %d\n", TIMER_NAME, ret);
        goto out_irq;
    }

    clockevents_config_and_register(&rk_clkevt->ce, rk_clkevt->timer.freq, 1, UINT_MAX);
    return 0;

out_irq:
    rk_timer_cleanup(&rk_clkevt->timer);
out_probe:
    kfree(rk_clkevt);
out:
    /* Leave rk_clkevt not NULL to prevent future init */
    rk_clkevt = ERR_PTR(ret);
    return ret;
}

#ifndef MODULE
static int __init rk_clksrc_init(struct device_node *np)
{
    int ret = -EINVAL;

    rk_clksrc = kzalloc(sizeof(struct rk_timer), GFP_KERNEL);
    if (!rk_clksrc) {
        ret = -ENOMEM;
        goto out;
    }

    ret = rk_timer_probe(rk_clksrc, np);
    if (ret) {
        goto out_probe;
    }

    rk_timer_update_counter(UINT_MAX, rk_clksrc);
    rk_timer_enable(rk_clksrc, 0);

    ret = clocksource_mmio_init(rk_clksrc->base + TIMER_CURRENT_VALUE0, TIMER_NAME, rk_clksrc->freq, 250, 32,
                                clocksource_mmio_readl_down);
    if (ret) {
        pr_err("Failed to register clocksource\n");
        goto out_clocksource;
    }

    sched_clock_register(rk_timer_sched_read, 32, rk_clksrc->freq);
    return 0;

out_clocksource:
    rk_timer_cleanup(rk_clksrc);
out_probe:
    kfree(rk_clksrc);
out:
    /* Leave rk_clksrc not NULL to prevent future init */
    rk_clksrc = ERR_PTR(ret);
    return ret;
}
#endif

static int __init rk_timer_init(struct device_node *np)
{
    if (!rk_clkevt) {
        return rk_clkevt_init(np);
    }

#ifndef MODULE
    if (!rk_clksrc) {
        return rk_clksrc_init(np);
    }
#endif

    pr_err("Too many timer definitions for '%s'\n", TIMER_NAME);
    return -EINVAL;
}

TIMER_OF_DECLARE(rk3288_timer, "rockchip,rk3288-timer", rk_timer_init);
TIMER_OF_DECLARE(rk3399_timer, "rockchip,rk3399-timer", rk_timer_init);

#ifdef MODULE
static int __init rk_timer_driver_probe(struct platform_device *pdev)
{
    return rk_timer_init(pdev->dev.of_node);
}

static const struct of_device_id rk_timer_match_table[] = {
    {.compatible = "rockchip,rk3288-timer"},
    {.compatible = "rockchip,rk3399-timer"},
    {},
};

static struct platform_driver rk_timer_driver = {
    .driver =
        {
            .name = TIMER_NAME,
            .of_match_table = rk_timer_match_table,
        },
};
module_platform_driver_probe(rk_timer_driver, rk_timer_driver_probe);

MODULE_LICENSE("GPL");
#endif