/*
 * linux/arch/arm/mach-omap2/timer.c
 *
 * OMAP2 GP timer support.
 *
 * Copyright (C) 2009 Nokia Corporation
 *
 * Update to use new clocksource/clockevent layers
 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
 * Copyright (C) 2007 MontaVista Software, Inc.
 *
 * Original driver:
 * Copyright (C) 2005 Nokia Corporation
 * Author: Paul Mundt <paul.mundt@nokia.com>
 *         Juha Yrjölä <juha.yrjola@nokia.com>
 * OMAP Dual-mode timer framework support by Timo Teras
 *
 * Some parts based off of TI's 24xx code:
 *
 * Copyright (C) 2004-2009 Texas Instruments, Inc.
 *
 * Roughly modelled after the OMAP1 MPU timer code.
 * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/platform_data/dmtimer-omap.h>
#include <linux/sched_clock.h>

#include <asm/mach/time.h>
#include <asm/smp_twd.h>

#include "omap_hwmod.h"
#include "omap_device.h"
#include <plat/counter-32k.h>
#include <clocksource/timer-ti-dm.h>

#include "soc.h"
#include "common.h"
#include "control.h"
#include "powerdomain.h"
#include "omap-secure.h"

#define REALTIME_COUNTER_BASE                           0x48243200
#define INCREMENTER_NUMERATOR_OFFSET                    0x10
#define INCREMENTER_DENUMERATOR_RELOAD_OFFSET           0x14
#define NUMERATOR_DENUMERATOR_MASK                      0xfffff000

/* Clockevent code */

static struct omap_dm_timer clkev;
static struct clock_event_device clockevent_gpt;

/* Clockevent hwmod for am335x and am437x suspend */
static struct omap_hwmod *clockevent_gpt_hwmod;

/* Clockesource hwmod for am437x suspend */
static struct omap_hwmod *clocksource_gpt_hwmod;

#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
static unsigned long arch_timer_freq;

void set_cntfreq(void)
{
        omap_smc1(OMAP5_DRA7_MON_SET_CNTFRQ_INDEX, arch_timer_freq);
}
#endif

static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
{
        struct clock_event_device *evt = &clockevent_gpt;

        __omap_dm_timer_write_status(&clkev, OMAP_TIMER_INT_OVERFLOW);

        evt->event_handler(evt);
        return IRQ_HANDLED;
}

static struct irqaction omap2_gp_timer_irq = {
        .name           = "gp_timer",
        .flags          = IRQF_TIMER | IRQF_IRQPOLL,
        .handler        = omap2_gp_timer_interrupt,
};

static int omap2_gp_timer_set_next_event(unsigned long cycles,
                                         struct clock_event_device *evt)
{
        __omap_dm_timer_load_start(&clkev, OMAP_TIMER_CTRL_ST,
                                   0xffffffff - cycles, OMAP_TIMER_POSTED);

        return 0;
}

static int omap2_gp_timer_shutdown(struct clock_event_device *evt)
{
        __omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);
        return 0;
}

static int omap2_gp_timer_set_periodic(struct clock_event_device *evt)
{
        u32 period;

        __omap_dm_timer_stop(&clkev, OMAP_TIMER_POSTED, clkev.rate);

        period = clkev.rate / HZ;
        period -= 1;
        /* Looks like we need to first set the load value separately */
        __omap_dm_timer_write(&clkev, OMAP_TIMER_LOAD_REG, 0xffffffff - period,
                              OMAP_TIMER_POSTED);
        __omap_dm_timer_load_start(&clkev,
                                   OMAP_TIMER_CTRL_AR | OMAP_TIMER_CTRL_ST,
                                   0xffffffff - period, OMAP_TIMER_POSTED);
        return 0;
}

static void omap_clkevt_idle(struct clock_event_device *unused)
{
        if (!clockevent_gpt_hwmod)
                return;

        omap_hwmod_idle(clockevent_gpt_hwmod);
}

static void omap_clkevt_unidle(struct clock_event_device *unused)
{
        if (!clockevent_gpt_hwmod)
                return;

        omap_hwmod_enable(clockevent_gpt_hwmod);
        __omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
}

static struct clock_event_device clockevent_gpt = {
        .features               = CLOCK_EVT_FEAT_PERIODIC |
                                  CLOCK_EVT_FEAT_ONESHOT,
        .rating                 = 300,
        .set_next_event         = omap2_gp_timer_set_next_event,
        .set_state_shutdown     = omap2_gp_timer_shutdown,
        .set_state_periodic     = omap2_gp_timer_set_periodic,
        .set_state_oneshot      = omap2_gp_timer_shutdown,
        .tick_resume            = omap2_gp_timer_shutdown,
};

static const struct of_device_id omap_timer_match[] __initconst = {
        { .compatible = "ti,omap2420-timer", },
        { .compatible = "ti,omap3430-timer", },
        { .compatible = "ti,omap4430-timer", },
        { .compatible = "ti,omap5430-timer", },
        { .compatible = "ti,dm814-timer", },
        { .compatible = "ti,dm816-timer", },
        { .compatible = "ti,am335x-timer", },
        { .compatible = "ti,am335x-timer-1ms", },
        { }
};

static int omap_timer_add_disabled_property(struct device_node *np)
{
        struct property *prop;

        prop = kzalloc(sizeof(*prop), GFP_KERNEL);
        if (!prop)
                return -ENOMEM;

        prop->name = "status";
        prop->value = "disabled";
        prop->length = strlen(prop->value);

        return of_add_property(np, prop);
}

static int omap_timer_update_dt(struct device_node *np)
{
        int error = 0;

        if (!of_device_is_compatible(np, "ti,omap-counter32k")) {
                error = omap_timer_add_disabled_property(np);
                if (error)
                        return error;
        }

        /* No parent interconnect target module configured? */
        if (of_get_property(np, "ti,hwmods", NULL))
                return error;

        /* Tag parent interconnect target module disabled */
        error = omap_timer_add_disabled_property(np->parent);
        if (error)
                return error;

        return 0;
}

/**
 * omap_get_timer_dt - get a timer using device-tree
 * @match       - device-tree match structure for matching a device type
 * @property    - optional timer property to match
 *
 * Helper function to get a timer during early boot using device-tree for use
 * as kernel system timer. Optionally, the property argument can be used to
 * select a timer with a specific property. Once a timer is found then mark
 * the timer node in device-tree as disabled, to prevent the kernel from
 * registering this timer as a platform device and so no one else can use it.
 */
static struct device_node * __init omap_get_timer_dt(const struct of_device_id *match,
                                                     const char *property)
{
        struct device_node *np;
        int error;

        for_each_matching_node(np, match) {
                if (!of_device_is_available(np))
                        continue;

                if (property && !of_get_property(np, property, NULL))
                        continue;

                if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
                                  of_get_property(np, "ti,timer-dsp", NULL) ||
                                  of_get_property(np, "ti,timer-pwm", NULL) ||
                                  of_get_property(np, "ti,timer-secure", NULL)))
                        continue;

                error = omap_timer_update_dt(np);
                WARN(error, "%s: Could not update dt: %i\n", __func__, error);

                return np;
        }

        return NULL;
}

/**
 * omap_dmtimer_init - initialisation function when device tree is used
 *
 * For secure OMAP3/DRA7xx devices, timers with device type "timer-secure"
 * cannot be used by the kernel as they are reserved. Therefore, to prevent the
 * kernel registering these devices remove them dynamically from the device
 * tree on boot.
 */
static void __init omap_dmtimer_init(void)
{
        struct device_node *np;

        if (!cpu_is_omap34xx() && !soc_is_dra7xx())
                return;

        /* If we are a secure device, remove any secure timer nodes */
        if ((omap_type() != OMAP2_DEVICE_TYPE_GP)) {
                np = omap_get_timer_dt(omap_timer_match, "ti,timer-secure");
                of_node_put(np);
        }
}

/**
 * omap_dm_timer_get_errata - get errata flags for a timer
 *
 * Get the timer errata flags that are specific to the OMAP device being used.
 */
static u32 __init omap_dm_timer_get_errata(void)
{
        if (cpu_is_omap24xx())
                return 0;

        return OMAP_TIMER_ERRATA_I103_I767;
}

static int __init omap_dm_timer_init_one(struct omap_dm_timer *timer,
                                         const char *fck_source,
                                         const char *property,
                                         const char **timer_name,
                                         int posted)
{
        const char *oh_name = NULL;
        struct device_node *np;
        struct omap_hwmod *oh;
        struct clk *src;
        int r = 0;

        np = omap_get_timer_dt(omap_timer_match, property);
        if (!np)
                return -ENODEV;

        of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
        if (!oh_name) {
                of_property_read_string_index(np->parent, "ti,hwmods", 0,
                                              &oh_name);
                if (!oh_name)
                        return -ENODEV;
        }

        timer->irq = irq_of_parse_and_map(np, 0);
        if (!timer->irq)
                return -ENXIO;

        timer->io_base = of_iomap(np, 0);

        timer->fclk = of_clk_get_by_name(np, "fck");

        of_node_put(np);

        oh = omap_hwmod_lookup(oh_name);
        if (!oh)
                return -ENODEV;

        *timer_name = oh->name;

        if (!timer->io_base)
                return -ENXIO;

        omap_hwmod_setup_one(oh_name);

        /* After the dmtimer is using hwmod these clocks won't be needed */
        if (IS_ERR_OR_NULL(timer->fclk))
                timer->fclk = clk_get(NULL, omap_hwmod_get_main_clk(oh));
        if (IS_ERR(timer->fclk))
                return PTR_ERR(timer->fclk);

        src = clk_get(NULL, fck_source);
        if (IS_ERR(src))
                return PTR_ERR(src);

        WARN(clk_set_parent(timer->fclk, src) < 0,
             "Cannot set timer parent clock, no PLL clock driver?");

        clk_put(src);

        omap_hwmod_enable(oh);
        __omap_dm_timer_init_regs(timer);

        if (posted)
                __omap_dm_timer_enable_posted(timer);

        /* Check that the intended posted configuration matches the actual */
        if (posted != timer->posted)
                return -EINVAL;

        timer->rate = clk_get_rate(timer->fclk);
        timer->reserved = 1;

        return r;
}

#if !defined(CONFIG_SMP) && defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
void tick_broadcast(const struct cpumask *mask)
{
}
#endif

static void __init omap2_gp_clockevent_init(int gptimer_id,
                                                const char *fck_source,
                                                const char *property)
{
        int res;

        clkev.id = gptimer_id;
        clkev.errata = omap_dm_timer_get_errata();

        /*
         * For clock-event timers we never read the timer counter and
         * so we are not impacted by errata i103 and i767. Therefore,
         * we can safely ignore this errata for clock-event timers.
         */
        __omap_dm_timer_override_errata(&clkev, OMAP_TIMER_ERRATA_I103_I767);

        res = omap_dm_timer_init_one(&clkev, fck_source, property,
                                     &clockevent_gpt.name, OMAP_TIMER_POSTED);
        BUG_ON(res);

        omap2_gp_timer_irq.dev_id = &clkev;
        setup_irq(clkev.irq, &omap2_gp_timer_irq);

        __omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);

        clockevent_gpt.cpumask = cpu_possible_mask;
        clockevent_gpt.irq = omap_dm_timer_get_irq(&clkev);
        clockevents_config_and_register(&clockevent_gpt, clkev.rate,
                                        3, /* Timer internal resynch latency */
                                        0xffffffff);

        if (soc_is_am33xx() || soc_is_am43xx()) {
                clockevent_gpt.suspend = omap_clkevt_idle;
                clockevent_gpt.resume = omap_clkevt_unidle;

                clockevent_gpt_hwmod =
                        omap_hwmod_lookup(clockevent_gpt.name);
        }

        pr_info("OMAP clockevent source: %s at %lu Hz\n", clockevent_gpt.name,
                clkev.rate);
}

/* Clocksource code */
static struct omap_dm_timer clksrc;
static bool use_gptimer_clksrc __initdata;

/*
 * clocksource
 */
static u64 clocksource_read_cycles(struct clocksource *cs)
{
        return (u64)__omap_dm_timer_read_counter(&clksrc,
                                                     OMAP_TIMER_NONPOSTED);
}

static struct clocksource clocksource_gpt = {
        .rating         = 300,
        .read           = clocksource_read_cycles,
        .mask           = CLOCKSOURCE_MASK(32),
        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
};

static u64 notrace dmtimer_read_sched_clock(void)
{
        if (clksrc.reserved)
                return __omap_dm_timer_read_counter(&clksrc,
                                                    OMAP_TIMER_NONPOSTED);

        return 0;
}

static const struct of_device_id omap_counter_match[] __initconst = {
        { .compatible = "ti,omap-counter32k", },
        { }
};

/* Setup free-running counter for clocksource */
static int __init __maybe_unused omap2_sync32k_clocksource_init(void)
{
        int ret;
        struct device_node *np = NULL;
        struct omap_hwmod *oh;
        const char *oh_name = "counter_32k";

        /*
         * See if the 32kHz counter is supported.
         */
        np = omap_get_timer_dt(omap_counter_match, NULL);
        if (!np)
                return -ENODEV;

        of_property_read_string_index(np->parent, "ti,hwmods", 0, &oh_name);
        if (!oh_name) {
                of_property_read_string_index(np, "ti,hwmods", 0, &oh_name);
                if (!oh_name)
                        return -ENODEV;
        }

        /*
         * First check hwmod data is available for sync32k counter
         */
        oh = omap_hwmod_lookup(oh_name);
        if (!oh || oh->slaves_cnt == 0)
                return -ENODEV;

        omap_hwmod_setup_one(oh_name);

        ret = omap_hwmod_enable(oh);
        if (ret) {
                pr_warn("%s: failed to enable counter_32k module (%d)\n",
                                                        __func__, ret);
                return ret;
        }

        return ret;
}

static unsigned int omap2_gptimer_clksrc_load;

static void omap2_gptimer_clksrc_suspend(struct clocksource *unused)
{
        omap2_gptimer_clksrc_load =
                __omap_dm_timer_read_counter(&clksrc, OMAP_TIMER_NONPOSTED);

        omap_hwmod_idle(clocksource_gpt_hwmod);
}

static void omap2_gptimer_clksrc_resume(struct clocksource *unused)
{
        omap_hwmod_enable(clocksource_gpt_hwmod);

        __omap_dm_timer_load_start(&clksrc,
                                   OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR,
                                   omap2_gptimer_clksrc_load,
                                   OMAP_TIMER_NONPOSTED);
}

static void __init omap2_gptimer_clocksource_init(int gptimer_id,
                                                  const char *fck_source,
                                                  const char *property)
{
        int res;

        clksrc.id = gptimer_id;
        clksrc.errata = omap_dm_timer_get_errata();

        res = omap_dm_timer_init_one(&clksrc, fck_source, property,
                                     &clocksource_gpt.name,
                                     OMAP_TIMER_NONPOSTED);

        if (soc_is_am43xx()) {
                clocksource_gpt.suspend = omap2_gptimer_clksrc_suspend;
                clocksource_gpt.resume = omap2_gptimer_clksrc_resume;

                clocksource_gpt_hwmod =
                        omap_hwmod_lookup(clocksource_gpt.name);
        }

        BUG_ON(res);

        __omap_dm_timer_load_start(&clksrc,
                                   OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0,
                                   OMAP_TIMER_NONPOSTED);
        sched_clock_register(dmtimer_read_sched_clock, 32, clksrc.rate);

        if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
                pr_err("Could not register clocksource %s\n",
                        clocksource_gpt.name);
        else
                pr_info("OMAP clocksource: %s at %lu Hz\n",
                        clocksource_gpt.name, clksrc.rate);
}

static void __init __omap_sync32k_timer_init(int clkev_nr, const char *clkev_src,
                const char *clkev_prop, int clksrc_nr, const char *clksrc_src,
                const char *clksrc_prop, bool gptimer)
{
        omap_clk_init();
        omap_dmtimer_init();
        omap2_gp_clockevent_init(clkev_nr, clkev_src, clkev_prop);

        /* Enable the use of clocksource="gp_timer" kernel parameter */
        if (use_gptimer_clksrc || gptimer)
                omap2_gptimer_clocksource_init(clksrc_nr, clksrc_src,
                                                clksrc_prop);
        else
                omap2_sync32k_clocksource_init();
}

void __init omap_init_time(void)
{
        __omap_sync32k_timer_init(1, "timer_32k_ck", "ti,timer-alwon",
                        2, "timer_sys_ck", NULL, false);

        timer_probe();
}

#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM43XX)
void __init omap3_secure_sync32k_timer_init(void)
{
        __omap_sync32k_timer_init(12, "secure_32k_fck", "ti,timer-secure",
                        2, "timer_sys_ck", NULL, false);

        timer_probe();
}
#endif /* CONFIG_ARCH_OMAP3 */

#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) || \
        defined(CONFIG_SOC_AM43XX)
void __init omap3_gptimer_timer_init(void)
{
        __omap_sync32k_timer_init(2, "timer_sys_ck", NULL,
                        1, "timer_sys_ck", "ti,timer-alwon", true);
        if (of_have_populated_dt())
                timer_probe();
}
#endif

#if defined(CONFIG_ARCH_OMAP4) || defined(CONFIG_SOC_OMAP5) ||          \
        defined(CONFIG_SOC_DRA7XX)
static void __init omap4_sync32k_timer_init(void)
{
        __omap_sync32k_timer_init(1, "timer_32k_ck", "ti,timer-alwon",
                        2, "sys_clkin_ck", NULL, false);
}

void __init omap4_local_timer_init(void)
{
        omap4_sync32k_timer_init();
        timer_probe();
}
#endif

#if defined(CONFIG_SOC_OMAP5) || defined(CONFIG_SOC_DRA7XX)

/*
 * The realtime counter also called master counter, is a free-running
 * counter, which is related to real time. It produces the count used
 * by the CPU local timer peripherals in the MPU cluster. The timer counts
 * at a rate of 6.144 MHz. Because the device operates on different clocks
 * in different power modes, the master counter shifts operation between
 * clocks, adjusting the increment per clock in hardware accordingly to
 * maintain a constant count rate.
 */
static void __init realtime_counter_init(void)
{
#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
        void __iomem *base;
        static struct clk *sys_clk;
        unsigned long rate;
        unsigned int reg;
        unsigned long long num, den;

        base = ioremap(REALTIME_COUNTER_BASE, SZ_32);
        if (!base) {
                pr_err("%s: ioremap failed\n", __func__);
                return;
        }
        sys_clk = clk_get(NULL, "sys_clkin");
        if (IS_ERR(sys_clk)) {
                pr_err("%s: failed to get system clock handle\n", __func__);
                iounmap(base);
                return;
        }

        rate = clk_get_rate(sys_clk);

        if (soc_is_dra7xx()) {
                /*
                 * Errata i856 says the 32.768KHz crystal does not start at
                 * power on, so the CPU falls back to an emulated 32KHz clock
                 * based on sysclk / 610 instead. This causes the master counter
                 * frequency to not be 6.144MHz but at sysclk / 610 * 375 / 2
                 * (OR sysclk * 75 / 244)
                 *
                 * This affects at least the DRA7/AM572x 1.0, 1.1 revisions.
                 * Of course any board built without a populated 32.768KHz
                 * crystal would also need this fix even if the CPU is fixed
                 * later.
                 *
                 * Either case can be detected by using the two speedselect bits
                 * If they are not 0, then the 32.768KHz clock driving the
                 * coarse counter that corrects the fine counter every time it
                 * ticks is actually rate/610 rather than 32.768KHz and we
                 * should compensate to avoid the 570ppm (at 20MHz, much worse
                 * at other rates) too fast system time.
                 */
                reg = omap_ctrl_readl(DRA7_CTRL_CORE_BOOTSTRAP);
                if (reg & DRA7_SPEEDSELECT_MASK) {
                        num = 75;
                        den = 244;
                        goto sysclk1_based;
                }
        }

        /* Numerator/denumerator values refer TRM Realtime Counter section */
        switch (rate) {
        case 12000000:
                num = 64;
                den = 125;
                break;
        case 13000000:
                num = 768;
                den = 1625;
                break;
        case 19200000:
                num = 8;
                den = 25;
                break;
        case 20000000:
                num = 192;
                den = 625;
                break;
        case 26000000:
                num = 384;
                den = 1625;
                break;
        case 27000000:
                num = 256;
                den = 1125;
                break;
        case 38400000:
        default:
                /* Program it for 38.4 MHz */
                num = 4;
                den = 25;
                break;
        }

sysclk1_based:
        /* Program numerator and denumerator registers */
        reg = readl_relaxed(base + INCREMENTER_NUMERATOR_OFFSET) &
                        NUMERATOR_DENUMERATOR_MASK;
        reg |= num;
        writel_relaxed(reg, base + INCREMENTER_NUMERATOR_OFFSET);

        reg = readl_relaxed(base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET) &
                        NUMERATOR_DENUMERATOR_MASK;
        reg |= den;
        writel_relaxed(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);

        arch_timer_freq = DIV_ROUND_UP_ULL(rate * num, den);
        set_cntfreq();

        iounmap(base);
#endif
}

void __init omap5_realtime_timer_init(void)
{
        omap4_sync32k_timer_init();
        realtime_counter_init();

        timer_probe();
}
#endif /* CONFIG_SOC_OMAP5 || CONFIG_SOC_DRA7XX */

/**
 * omap2_override_clocksource - clocksource override with user configuration
 *
 * Allows user to override default clocksource, using kernel parameter
 *   clocksource="gp_timer"     (For all OMAP2PLUS architectures)
 *
 * Note that, here we are using same standard kernel parameter "clocksource=",
 * and not introducing any OMAP specific interface.
 */
static int __init omap2_override_clocksource(char *str)
{
        if (!str)
                return 0;
        /*
         * For OMAP architecture, we only have two options
         *    - sync_32k (default)
         *    - gp_timer (sys_clk based)
         */
        if (!strcmp(str, "gp_timer"))
                use_gptimer_clksrc = true;

        return 0;
}
early_param("clocksource", omap2_override_clocksource);