root/drivers/clocksource/ingenic-timer.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Ingenic SoCs TCU IRQ driver
 * Copyright (C) 2019 Paul Cercueil <paul@crapouillou.net>
 * Copyright (C) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/cpuhotplug.h>
#include <linux/interrupt.h>
#include <linux/mfd/ingenic-tcu.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/overflow.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/sched_clock.h>

#include <dt-bindings/clock/ingenic,tcu.h>

static DEFINE_PER_CPU(call_single_data_t, ingenic_cevt_csd);

struct ingenic_soc_info {
        unsigned int num_channels;
};

struct ingenic_tcu_timer {
        unsigned int cpu;
        unsigned int channel;
        struct clock_event_device cevt;
        struct clk *clk;
        char name[8];
};

struct ingenic_tcu {
        struct regmap *map;
        struct device_node *np;
        struct clk *cs_clk;
        unsigned int cs_channel;
        struct clocksource cs;
        unsigned long pwm_channels_mask;
        struct ingenic_tcu_timer timers[];
};

static struct ingenic_tcu *ingenic_tcu;

static u64 notrace ingenic_tcu_timer_read(void)
{
        struct ingenic_tcu *tcu = ingenic_tcu;
        unsigned int count;

        regmap_read(tcu->map, TCU_REG_TCNTc(tcu->cs_channel), &count);

        return count;
}

static u64 notrace ingenic_tcu_timer_cs_read(struct clocksource *cs)
{
        return ingenic_tcu_timer_read();
}

static inline struct ingenic_tcu *
to_ingenic_tcu(struct ingenic_tcu_timer *timer)
{
        return container_of(timer, struct ingenic_tcu, timers[timer->cpu]);
}

static inline struct ingenic_tcu_timer *
to_ingenic_tcu_timer(struct clock_event_device *evt)
{
        return container_of(evt, struct ingenic_tcu_timer, cevt);
}

static int ingenic_tcu_cevt_set_state_shutdown(struct clock_event_device *evt)
{
        struct ingenic_tcu_timer *timer = to_ingenic_tcu_timer(evt);
        struct ingenic_tcu *tcu = to_ingenic_tcu(timer);

        regmap_write(tcu->map, TCU_REG_TECR, BIT(timer->channel));

        return 0;
}

static int ingenic_tcu_cevt_set_next(unsigned long next,
                                     struct clock_event_device *evt)
{
        struct ingenic_tcu_timer *timer = to_ingenic_tcu_timer(evt);
        struct ingenic_tcu *tcu = to_ingenic_tcu(timer);

        if (next > 0xffff)
                return -EINVAL;

        regmap_write(tcu->map, TCU_REG_TDFRc(timer->channel), next);
        regmap_write(tcu->map, TCU_REG_TCNTc(timer->channel), 0);
        regmap_write(tcu->map, TCU_REG_TESR, BIT(timer->channel));

        return 0;
}

static void ingenic_per_cpu_event_handler(void *info)
{
        struct clock_event_device *cevt = (struct clock_event_device *) info;

        cevt->event_handler(cevt);
}

static irqreturn_t ingenic_tcu_cevt_cb(int irq, void *dev_id)
{
        struct ingenic_tcu_timer *timer = dev_id;
        struct ingenic_tcu *tcu = to_ingenic_tcu(timer);
        call_single_data_t *csd;

        regmap_write(tcu->map, TCU_REG_TECR, BIT(timer->channel));

        if (timer->cevt.event_handler) {
                csd = &per_cpu(ingenic_cevt_csd, timer->cpu);
                csd->info = (void *) &timer->cevt;
                csd->func = ingenic_per_cpu_event_handler;
                smp_call_function_single_async(timer->cpu, csd);
        }

        return IRQ_HANDLED;
}

static struct clk *ingenic_tcu_get_clock(struct device_node *np, int id)
{
        struct of_phandle_args args;

        args.np = np;
        args.args_count = 1;
        args.args[0] = id;

        return of_clk_get_from_provider(&args);
}

static int ingenic_tcu_setup_cevt(unsigned int cpu)
{
        struct ingenic_tcu *tcu = ingenic_tcu;
        struct ingenic_tcu_timer *timer = &tcu->timers[cpu];
        unsigned int timer_virq;
        struct irq_domain *domain;
        unsigned long rate;
        int err;

        timer->clk = ingenic_tcu_get_clock(tcu->np, timer->channel);
        if (IS_ERR(timer->clk))
                return PTR_ERR(timer->clk);

        err = clk_prepare_enable(timer->clk);
        if (err)
                goto err_clk_put;

        rate = clk_get_rate(timer->clk);
        if (!rate) {
                err = -EINVAL;
                goto err_clk_disable;
        }

        domain = irq_find_host(tcu->np);
        if (!domain) {
                err = -ENODEV;
                goto err_clk_disable;
        }

        timer_virq = irq_create_mapping(domain, timer->channel);
        if (!timer_virq) {
                err = -EINVAL;
                goto err_clk_disable;
        }

        snprintf(timer->name, sizeof(timer->name), "TCU%u", timer->channel);

        err = request_irq(timer_virq, ingenic_tcu_cevt_cb, IRQF_TIMER,
                          timer->name, timer);
        if (err)
                goto err_irq_dispose_mapping;

        timer->cpu = smp_processor_id();
        timer->cevt.cpumask = cpumask_of(smp_processor_id());
        timer->cevt.features = CLOCK_EVT_FEAT_ONESHOT;
        timer->cevt.name = timer->name;
        timer->cevt.rating = 200;
        timer->cevt.set_state_shutdown = ingenic_tcu_cevt_set_state_shutdown;
        timer->cevt.set_next_event = ingenic_tcu_cevt_set_next;

        clockevents_config_and_register(&timer->cevt, rate, 10, 0xffff);

        return 0;

err_irq_dispose_mapping:
        irq_dispose_mapping(timer_virq);
err_clk_disable:
        clk_disable_unprepare(timer->clk);
err_clk_put:
        clk_put(timer->clk);
        return err;
}

static int __init ingenic_tcu_clocksource_init(struct device_node *np,
                                               struct ingenic_tcu *tcu)
{
        unsigned int channel = tcu->cs_channel;
        struct clocksource *cs = &tcu->cs;
        unsigned long rate;
        int err;

        tcu->cs_clk = ingenic_tcu_get_clock(np, channel);
        if (IS_ERR(tcu->cs_clk))
                return PTR_ERR(tcu->cs_clk);

        err = clk_prepare_enable(tcu->cs_clk);
        if (err)
                goto err_clk_put;

        rate = clk_get_rate(tcu->cs_clk);
        if (!rate) {
                err = -EINVAL;
                goto err_clk_disable;
        }

        /* Reset channel */
        regmap_update_bits(tcu->map, TCU_REG_TCSRc(channel),
                           0xffff & ~TCU_TCSR_RESERVED_BITS, 0);

        /* Reset counter */
        regmap_write(tcu->map, TCU_REG_TDFRc(channel), 0xffff);
        regmap_write(tcu->map, TCU_REG_TCNTc(channel), 0);

        /* Enable channel */
        regmap_write(tcu->map, TCU_REG_TESR, BIT(channel));

        cs->name = "ingenic-timer";
        cs->rating = 200;
        cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
        cs->mask = CLOCKSOURCE_MASK(16);
        cs->read = ingenic_tcu_timer_cs_read;

        err = clocksource_register_hz(cs, rate);
        if (err)
                goto err_clk_disable;

        return 0;

err_clk_disable:
        clk_disable_unprepare(tcu->cs_clk);
err_clk_put:
        clk_put(tcu->cs_clk);
        return err;
}

static const struct ingenic_soc_info jz4740_soc_info = {
        .num_channels = 8,
};

static const struct ingenic_soc_info jz4725b_soc_info = {
        .num_channels = 6,
};

static const struct of_device_id ingenic_tcu_of_match[] = {
        { .compatible = "ingenic,jz4740-tcu", .data = &jz4740_soc_info, },
        { .compatible = "ingenic,jz4725b-tcu", .data = &jz4725b_soc_info, },
        { .compatible = "ingenic,jz4760-tcu", .data = &jz4740_soc_info, },
        { .compatible = "ingenic,jz4770-tcu", .data = &jz4740_soc_info, },
        { .compatible = "ingenic,x1000-tcu", .data = &jz4740_soc_info, },
        { /* sentinel */ }
};

static int __init ingenic_tcu_init(struct device_node *np)
{
        const struct of_device_id *id = of_match_node(ingenic_tcu_of_match, np);
        const struct ingenic_soc_info *soc_info = id->data;
        struct ingenic_tcu_timer *timer;
        struct ingenic_tcu *tcu;
        struct regmap *map;
        unsigned int cpu;
        int ret, last_bit = -1;
        long rate;

        of_node_clear_flag(np, OF_POPULATED);

        map = device_node_to_regmap(np);
        if (IS_ERR(map))
                return PTR_ERR(map);

        tcu = kzalloc_flex(*tcu, timers, num_possible_cpus());
        if (!tcu)
                return -ENOMEM;

        /*
         * Enable all TCU channels for PWM use by default except channels 0/1,
         * and channel 2 if target CPU is JZ4780/X2000 and SMP is selected.
         */
        tcu->pwm_channels_mask = GENMASK(soc_info->num_channels - 1,
                                         num_possible_cpus() + 1);
        of_property_read_u32(np, "ingenic,pwm-channels-mask",
                             (u32 *)&tcu->pwm_channels_mask);

        /* Verify that we have at least num_possible_cpus() + 1 free channels */
        if (hweight8(tcu->pwm_channels_mask) >
                        soc_info->num_channels - num_possible_cpus() + 1) {
                pr_crit("%s: Invalid PWM channel mask: 0x%02lx\n", __func__,
                        tcu->pwm_channels_mask);
                ret = -EINVAL;
                goto err_free_ingenic_tcu;
        }

        tcu->map = map;
        tcu->np = np;
        ingenic_tcu = tcu;

        for (cpu = 0; cpu < num_possible_cpus(); cpu++) {
                timer = &tcu->timers[cpu];

                timer->cpu = cpu;
                timer->channel = find_next_zero_bit(&tcu->pwm_channels_mask,
                                                  soc_info->num_channels,
                                                  last_bit + 1);
                last_bit = timer->channel;
        }

        tcu->cs_channel = find_next_zero_bit(&tcu->pwm_channels_mask,
                                             soc_info->num_channels,
                                             last_bit + 1);

        ret = ingenic_tcu_clocksource_init(np, tcu);
        if (ret) {
                pr_crit("%s: Unable to init clocksource: %d\n", __func__, ret);
                goto err_free_ingenic_tcu;
        }

        /* Setup clock events on each CPU core */
        ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "Ingenic XBurst: online",
                                ingenic_tcu_setup_cevt, NULL);
        if (ret < 0) {
                pr_crit("%s: Unable to start CPU timers: %d\n", __func__, ret);
                goto err_tcu_clocksource_cleanup;
        }

        /* Register the sched_clock at the end as there's no way to undo it */
        rate = clk_get_rate(tcu->cs_clk);
        sched_clock_register(ingenic_tcu_timer_read, 16, rate);

        return 0;

err_tcu_clocksource_cleanup:
        clocksource_unregister(&tcu->cs);
        clk_disable_unprepare(tcu->cs_clk);
        clk_put(tcu->cs_clk);
err_free_ingenic_tcu:
        kfree(tcu);
        return ret;
}

TIMER_OF_DECLARE(jz4740_tcu_intc,  "ingenic,jz4740-tcu",  ingenic_tcu_init);
TIMER_OF_DECLARE(jz4725b_tcu_intc, "ingenic,jz4725b-tcu", ingenic_tcu_init);
TIMER_OF_DECLARE(jz4760_tcu_intc,  "ingenic,jz4760-tcu",  ingenic_tcu_init);
TIMER_OF_DECLARE(jz4770_tcu_intc,  "ingenic,jz4770-tcu",  ingenic_tcu_init);
TIMER_OF_DECLARE(x1000_tcu_intc,  "ingenic,x1000-tcu",  ingenic_tcu_init);

static int __init ingenic_tcu_probe(struct platform_device *pdev)
{
        platform_set_drvdata(pdev, ingenic_tcu);

        return 0;
}

static int ingenic_tcu_suspend(struct device *dev)
{
        struct ingenic_tcu *tcu = dev_get_drvdata(dev);
        unsigned int cpu;

        clk_disable(tcu->cs_clk);

        for (cpu = 0; cpu < num_online_cpus(); cpu++)
                clk_disable(tcu->timers[cpu].clk);

        return 0;
}

static int ingenic_tcu_resume(struct device *dev)
{
        struct ingenic_tcu *tcu = dev_get_drvdata(dev);
        unsigned int cpu;
        int ret;

        for (cpu = 0; cpu < num_online_cpus(); cpu++) {
                ret = clk_enable(tcu->timers[cpu].clk);
                if (ret)
                        goto err_timer_clk_disable;
        }

        ret = clk_enable(tcu->cs_clk);
        if (ret)
                goto err_timer_clk_disable;

        return 0;

err_timer_clk_disable:
        for (; cpu > 0; cpu--)
                clk_disable(tcu->timers[cpu - 1].clk);
        return ret;
}

static const struct dev_pm_ops ingenic_tcu_pm_ops = {
        /* _noirq: We want the TCU clocks to be gated last / ungated first */
        .suspend_noirq = ingenic_tcu_suspend,
        .resume_noirq  = ingenic_tcu_resume,
};

static struct platform_driver ingenic_tcu_driver = {
        .driver = {
                .name   = "ingenic-tcu-timer",
                .pm     = pm_sleep_ptr(&ingenic_tcu_pm_ops),
                .of_match_table = ingenic_tcu_of_match,
        },
};
builtin_platform_driver_probe(ingenic_tcu_driver, ingenic_tcu_probe);