root/drivers/clocksource/sh_mtu2.c
// SPDX-License-Identifier: GPL-2.0
/*
 * SuperH Timer Support - MTU2
 *
 *  Copyright (C) 2009 Magnus Damm
 */

#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/sh_timer.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#ifdef CONFIG_SUPERH
#include <asm/platform_early.h>
#endif

struct sh_mtu2_device;

struct sh_mtu2_channel {
        struct sh_mtu2_device *mtu;
        unsigned int index;

        void __iomem *base;

        struct clock_event_device ced;
};

struct sh_mtu2_device {
        struct platform_device *pdev;

        void __iomem *mapbase;
        struct clk *clk;

        raw_spinlock_t lock; /* Protect the shared registers */

        struct sh_mtu2_channel *channels;
        unsigned int num_channels;

        bool has_clockevent;
};

#define TSTR -1 /* shared register */
#define TCR  0 /* channel register */
#define TMDR 1 /* channel register */
#define TIOR 2 /* channel register */
#define TIER 3 /* channel register */
#define TSR  4 /* channel register */
#define TCNT 5 /* channel register */
#define TGR  6 /* channel register */

#define TCR_CCLR_NONE           (0 << 5)
#define TCR_CCLR_TGRA           (1 << 5)
#define TCR_CCLR_TGRB           (2 << 5)
#define TCR_CCLR_SYNC           (3 << 5)
#define TCR_CCLR_TGRC           (5 << 5)
#define TCR_CCLR_TGRD           (6 << 5)
#define TCR_CCLR_MASK           (7 << 5)
#define TCR_CKEG_RISING         (0 << 3)
#define TCR_CKEG_FALLING        (1 << 3)
#define TCR_CKEG_BOTH           (2 << 3)
#define TCR_CKEG_MASK           (3 << 3)
/* Values 4 to 7 are channel-dependent */
#define TCR_TPSC_P1             (0 << 0)
#define TCR_TPSC_P4             (1 << 0)
#define TCR_TPSC_P16            (2 << 0)
#define TCR_TPSC_P64            (3 << 0)
#define TCR_TPSC_CH0_TCLKA      (4 << 0)
#define TCR_TPSC_CH0_TCLKB      (5 << 0)
#define TCR_TPSC_CH0_TCLKC      (6 << 0)
#define TCR_TPSC_CH0_TCLKD      (7 << 0)
#define TCR_TPSC_CH1_TCLKA      (4 << 0)
#define TCR_TPSC_CH1_TCLKB      (5 << 0)
#define TCR_TPSC_CH1_P256       (6 << 0)
#define TCR_TPSC_CH1_TCNT2      (7 << 0)
#define TCR_TPSC_CH2_TCLKA      (4 << 0)
#define TCR_TPSC_CH2_TCLKB      (5 << 0)
#define TCR_TPSC_CH2_TCLKC      (6 << 0)
#define TCR_TPSC_CH2_P1024      (7 << 0)
#define TCR_TPSC_CH34_P256      (4 << 0)
#define TCR_TPSC_CH34_P1024     (5 << 0)
#define TCR_TPSC_CH34_TCLKA     (6 << 0)
#define TCR_TPSC_CH34_TCLKB     (7 << 0)
#define TCR_TPSC_MASK           (7 << 0)

#define TMDR_BFE                (1 << 6)
#define TMDR_BFB                (1 << 5)
#define TMDR_BFA                (1 << 4)
#define TMDR_MD_NORMAL          (0 << 0)
#define TMDR_MD_PWM_1           (2 << 0)
#define TMDR_MD_PWM_2           (3 << 0)
#define TMDR_MD_PHASE_1         (4 << 0)
#define TMDR_MD_PHASE_2         (5 << 0)
#define TMDR_MD_PHASE_3         (6 << 0)
#define TMDR_MD_PHASE_4         (7 << 0)
#define TMDR_MD_PWM_SYNC        (8 << 0)
#define TMDR_MD_PWM_COMP_CREST  (13 << 0)
#define TMDR_MD_PWM_COMP_TROUGH (14 << 0)
#define TMDR_MD_PWM_COMP_BOTH   (15 << 0)
#define TMDR_MD_MASK            (15 << 0)

#define TIOC_IOCH(n)            ((n) << 4)
#define TIOC_IOCL(n)            ((n) << 0)
#define TIOR_OC_RETAIN          (0 << 0)
#define TIOR_OC_0_CLEAR         (1 << 0)
#define TIOR_OC_0_SET           (2 << 0)
#define TIOR_OC_0_TOGGLE        (3 << 0)
#define TIOR_OC_1_CLEAR         (5 << 0)
#define TIOR_OC_1_SET           (6 << 0)
#define TIOR_OC_1_TOGGLE        (7 << 0)
#define TIOR_IC_RISING          (8 << 0)
#define TIOR_IC_FALLING         (9 << 0)
#define TIOR_IC_BOTH            (10 << 0)
#define TIOR_IC_TCNT            (12 << 0)
#define TIOR_MASK               (15 << 0)

#define TIER_TTGE               (1 << 7)
#define TIER_TTGE2              (1 << 6)
#define TIER_TCIEU              (1 << 5)
#define TIER_TCIEV              (1 << 4)
#define TIER_TGIED              (1 << 3)
#define TIER_TGIEC              (1 << 2)
#define TIER_TGIEB              (1 << 1)
#define TIER_TGIEA              (1 << 0)

#define TSR_TCFD                (1 << 7)
#define TSR_TCFU                (1 << 5)
#define TSR_TCFV                (1 << 4)
#define TSR_TGFD                (1 << 3)
#define TSR_TGFC                (1 << 2)
#define TSR_TGFB                (1 << 1)
#define TSR_TGFA                (1 << 0)

static unsigned long mtu2_reg_offs[] = {
        [TCR] = 0,
        [TMDR] = 1,
        [TIOR] = 2,
        [TIER] = 4,
        [TSR] = 5,
        [TCNT] = 6,
        [TGR] = 8,
};

static inline unsigned long sh_mtu2_read(struct sh_mtu2_channel *ch, int reg_nr)
{
        unsigned long offs;

        if (reg_nr == TSTR)
                return ioread8(ch->mtu->mapbase + 0x280);

        offs = mtu2_reg_offs[reg_nr];

        if ((reg_nr == TCNT) || (reg_nr == TGR))
                return ioread16(ch->base + offs);
        else
                return ioread8(ch->base + offs);
}

static inline void sh_mtu2_write(struct sh_mtu2_channel *ch, int reg_nr,
                                unsigned long value)
{
        unsigned long offs;

        if (reg_nr == TSTR)
                return iowrite8(value, ch->mtu->mapbase + 0x280);

        offs = mtu2_reg_offs[reg_nr];

        if ((reg_nr == TCNT) || (reg_nr == TGR))
                iowrite16(value, ch->base + offs);
        else
                iowrite8(value, ch->base + offs);
}

static void sh_mtu2_start_stop_ch(struct sh_mtu2_channel *ch, int start)
{
        unsigned long flags, value;

        /* start stop register shared by multiple timer channels */
        raw_spin_lock_irqsave(&ch->mtu->lock, flags);
        value = sh_mtu2_read(ch, TSTR);

        if (start)
                value |= 1 << ch->index;
        else
                value &= ~(1 << ch->index);

        sh_mtu2_write(ch, TSTR, value);
        raw_spin_unlock_irqrestore(&ch->mtu->lock, flags);
}

static int sh_mtu2_enable(struct sh_mtu2_channel *ch)
{
        unsigned long periodic;
        unsigned long rate;
        int ret;

        pm_runtime_get_sync(&ch->mtu->pdev->dev);
        dev_pm_syscore_device(&ch->mtu->pdev->dev, true);

        /* enable clock */
        ret = clk_enable(ch->mtu->clk);
        if (ret) {
                dev_err(&ch->mtu->pdev->dev, "ch%u: cannot enable clock\n",
                        ch->index);
                return ret;
        }

        /* make sure channel is disabled */
        sh_mtu2_start_stop_ch(ch, 0);

        rate = clk_get_rate(ch->mtu->clk) / 64;
        periodic = (rate + HZ/2) / HZ;

        /*
         * "Periodic Counter Operation"
         * Clear on TGRA compare match, divide clock by 64.
         */
        sh_mtu2_write(ch, TCR, TCR_CCLR_TGRA | TCR_TPSC_P64);
        sh_mtu2_write(ch, TIOR, TIOC_IOCH(TIOR_OC_0_CLEAR) |
                      TIOC_IOCL(TIOR_OC_0_CLEAR));
        sh_mtu2_write(ch, TGR, periodic);
        sh_mtu2_write(ch, TCNT, 0);
        sh_mtu2_write(ch, TMDR, TMDR_MD_NORMAL);
        sh_mtu2_write(ch, TIER, TIER_TGIEA);

        /* enable channel */
        sh_mtu2_start_stop_ch(ch, 1);

        return 0;
}

static void sh_mtu2_disable(struct sh_mtu2_channel *ch)
{
        /* disable channel */
        sh_mtu2_start_stop_ch(ch, 0);

        /* stop clock */
        clk_disable(ch->mtu->clk);

        dev_pm_syscore_device(&ch->mtu->pdev->dev, false);
        pm_runtime_put(&ch->mtu->pdev->dev);
}

static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id)
{
        struct sh_mtu2_channel *ch = dev_id;

        /* acknowledge interrupt */
        sh_mtu2_read(ch, TSR);
        sh_mtu2_write(ch, TSR, ~TSR_TGFA);

        /* notify clockevent layer */
        ch->ced.event_handler(&ch->ced);
        return IRQ_HANDLED;
}

static struct sh_mtu2_channel *ced_to_sh_mtu2(struct clock_event_device *ced)
{
        return container_of(ced, struct sh_mtu2_channel, ced);
}

static int sh_mtu2_clock_event_shutdown(struct clock_event_device *ced)
{
        struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);

        if (clockevent_state_periodic(ced))
                sh_mtu2_disable(ch);

        return 0;
}

static int sh_mtu2_clock_event_set_periodic(struct clock_event_device *ced)
{
        struct sh_mtu2_channel *ch = ced_to_sh_mtu2(ced);

        if (clockevent_state_periodic(ced))
                sh_mtu2_disable(ch);

        dev_info(&ch->mtu->pdev->dev, "ch%u: used for periodic clock events\n",
                 ch->index);
        sh_mtu2_enable(ch);
        return 0;
}

static void sh_mtu2_clock_event_suspend(struct clock_event_device *ced)
{
        dev_pm_genpd_suspend(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
}

static void sh_mtu2_clock_event_resume(struct clock_event_device *ced)
{
        dev_pm_genpd_resume(&ced_to_sh_mtu2(ced)->mtu->pdev->dev);
}

static void sh_mtu2_register_clockevent(struct sh_mtu2_channel *ch,
                                        const char *name)
{
        struct clock_event_device *ced = &ch->ced;

        ced->name = name;
        ced->features = CLOCK_EVT_FEAT_PERIODIC;
        ced->rating = 200;
        ced->cpumask = cpu_possible_mask;
        ced->set_state_shutdown = sh_mtu2_clock_event_shutdown;
        ced->set_state_periodic = sh_mtu2_clock_event_set_periodic;
        ced->suspend = sh_mtu2_clock_event_suspend;
        ced->resume = sh_mtu2_clock_event_resume;

        dev_info(&ch->mtu->pdev->dev, "ch%u: used for clock events\n",
                 ch->index);
        clockevents_register_device(ced);
}

static int sh_mtu2_register(struct sh_mtu2_channel *ch, const char *name)
{
        ch->mtu->has_clockevent = true;
        sh_mtu2_register_clockevent(ch, name);

        return 0;
}

static const unsigned int sh_mtu2_channel_offsets[] = {
        0x300, 0x380, 0x000,
};

static int sh_mtu2_setup_channel(struct sh_mtu2_channel *ch, unsigned int index,
                                 struct sh_mtu2_device *mtu)
{
        char name[6];
        int irq;
        int ret;

        ch->mtu = mtu;

        sprintf(name, "tgi%ua", index);
        irq = platform_get_irq_byname(mtu->pdev, name);
        if (irq < 0) {
                /* Skip channels with no declared interrupt. */
                return 0;
        }

        ret = request_irq(irq, sh_mtu2_interrupt,
                          IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
                          dev_name(&ch->mtu->pdev->dev), ch);
        if (ret) {
                dev_err(&ch->mtu->pdev->dev, "ch%u: failed to request irq %d\n",
                        index, irq);
                return ret;
        }

        ch->base = mtu->mapbase + sh_mtu2_channel_offsets[index];
        ch->index = index;

        return sh_mtu2_register(ch, dev_name(&mtu->pdev->dev));
}

static int sh_mtu2_map_memory(struct sh_mtu2_device *mtu)
{
        struct resource *res;

        res = platform_get_resource(mtu->pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(&mtu->pdev->dev, "failed to get I/O memory\n");
                return -ENXIO;
        }

        mtu->mapbase = ioremap(res->start, resource_size(res));
        if (mtu->mapbase == NULL)
                return -ENXIO;

        return 0;
}

static int sh_mtu2_setup(struct sh_mtu2_device *mtu,
                         struct platform_device *pdev)
{
        unsigned int i;
        int ret;

        mtu->pdev = pdev;

        raw_spin_lock_init(&mtu->lock);

        /* Get hold of clock. */
        mtu->clk = clk_get(&mtu->pdev->dev, "fck");
        if (IS_ERR(mtu->clk)) {
                dev_err(&mtu->pdev->dev, "cannot get clock\n");
                return PTR_ERR(mtu->clk);
        }

        ret = clk_prepare(mtu->clk);
        if (ret < 0)
                goto err_clk_put;

        /* Map the memory resource. */
        ret = sh_mtu2_map_memory(mtu);
        if (ret < 0) {
                dev_err(&mtu->pdev->dev, "failed to remap I/O memory\n");
                goto err_clk_unprepare;
        }

        /* Allocate and setup the channels. */
        ret = platform_irq_count(pdev);
        if (ret < 0)
                goto err_unmap;

        mtu->num_channels = min_t(unsigned int, ret,
                                  ARRAY_SIZE(sh_mtu2_channel_offsets));

        mtu->channels = kzalloc_objs(*mtu->channels, mtu->num_channels);
        if (mtu->channels == NULL) {
                ret = -ENOMEM;
                goto err_unmap;
        }

        for (i = 0; i < mtu->num_channels; ++i) {
                ret = sh_mtu2_setup_channel(&mtu->channels[i], i, mtu);
                if (ret < 0)
                        goto err_unmap;
        }

        platform_set_drvdata(pdev, mtu);

        return 0;

err_unmap:
        kfree(mtu->channels);
        iounmap(mtu->mapbase);
err_clk_unprepare:
        clk_unprepare(mtu->clk);
err_clk_put:
        clk_put(mtu->clk);
        return ret;
}

static int sh_mtu2_probe(struct platform_device *pdev)
{
        struct sh_mtu2_device *mtu = platform_get_drvdata(pdev);
        int ret;

        if (!is_sh_early_platform_device(pdev)) {
                pm_runtime_set_active(&pdev->dev);
                pm_runtime_enable(&pdev->dev);
        }

        if (mtu) {
                dev_info(&pdev->dev, "kept as earlytimer\n");
                goto out;
        }

        mtu = kzalloc_obj(*mtu);
        if (mtu == NULL)
                return -ENOMEM;

        ret = sh_mtu2_setup(mtu, pdev);
        if (ret) {
                kfree(mtu);
                pm_runtime_idle(&pdev->dev);
                return ret;
        }
        if (is_sh_early_platform_device(pdev))
                return 0;

 out:
        if (mtu->has_clockevent)
                pm_runtime_irq_safe(&pdev->dev);
        else
                pm_runtime_idle(&pdev->dev);

        return 0;
}

static const struct platform_device_id sh_mtu2_id_table[] = {
        { "sh-mtu2", 0 },
        { },
};
MODULE_DEVICE_TABLE(platform, sh_mtu2_id_table);

static const struct of_device_id sh_mtu2_of_table[] __maybe_unused = {
        { .compatible = "renesas,mtu2" },
        { }
};
MODULE_DEVICE_TABLE(of, sh_mtu2_of_table);

static struct platform_driver sh_mtu2_device_driver = {
        .probe          = sh_mtu2_probe,
        .driver         = {
                .name   = "sh_mtu2",
                .of_match_table = of_match_ptr(sh_mtu2_of_table),
                .suppress_bind_attrs = true,
        },
        .id_table       = sh_mtu2_id_table,
};

static int __init sh_mtu2_init(void)
{
        return platform_driver_register(&sh_mtu2_device_driver);
}

static void __exit sh_mtu2_exit(void)
{
        platform_driver_unregister(&sh_mtu2_device_driver);
}

#ifdef CONFIG_SUPERH
sh_early_platform_init("earlytimer", &sh_mtu2_device_driver);
#endif

subsys_initcall(sh_mtu2_init);
module_exit(sh_mtu2_exit);

MODULE_AUTHOR("Magnus Damm");
MODULE_DESCRIPTION("SuperH MTU2 Timer Driver");