/*
 * arch/arch/mach-tegra/timer.c
 *
 * Copyright (C) 2010 Google, Inc.
 *
 * Author:
 *	Colin Cross <ccross@google.com>
 *
 * Copyright (C) 2010-2013 NVIDIA Corporation.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/init.h>
#include <linux/err.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <linux/cpu_pm.h>
#include <linux/rtc.h>

#include <asm/mach/time.h>
#include <asm/arch_timer.h>
#include <asm/cputype.h>
#include <asm/smp_twd.h>
#include <asm/system.h>
#include <asm/sched_clock.h>

#include <mach/iomap.h>
#include <mach/io.h>
#include <mach/irqs.h>
#include <mach/hardware.h>

#include "board.h"
#include "clock.h"
#include "timer.h"
#include "fuse.h"

extern int __init arch_timer_register(struct arch_timer *at);

static void __iomem *timer_reg_base = IO_ADDRESS(TEGRA_TMR1_BASE);
static void __iomem *rtc_base = IO_ADDRESS(TEGRA_RTC_BASE);

static struct timespec persistent_ts;
#ifdef CONFIG_ARM_ARCH_TIMER
static u32 arch_timer_ns_mult, arch_timer_ns_shift;
static u32 arch_timer_us_mult, arch_timer_us_shift;
static u64 persistent_cycles, last_persistent_cycles;
#else
static u64 persistent_ms, last_persistent_ms;
#endif
static u32 usec_config;
static u32 usec_offset;
static bool usec_suspended;

#ifdef CONFIG_ARCH_TEGRA_2x_SOC
static u32 system_timer = (TEGRA_TMR3_BASE - TEGRA_TMR1_BASE);
#else
static u32 system_timer = 0;
#endif

#define timer_writel(value, reg) \
	__raw_writel(value, timer_reg_base + (reg))
#define timer_readl(reg) \
	__raw_readl(timer_reg_base + (reg))

static int tegra_timer_set_next_event(unsigned long cycles,
					 struct clock_event_device *evt)
{
	u32 reg;

	reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0);
	timer_writel(reg, system_timer + TIMER_PTV);

	return 0;
}

static void tegra_timer_set_mode(enum clock_event_mode mode,
				    struct clock_event_device *evt)
{
	u32 reg;

	timer_writel(0, system_timer + TIMER_PTV);

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		reg = 0xC0000000 | ((1000000/HZ)-1);
		timer_writel(reg, system_timer + TIMER_PTV);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_RESUME:
		break;
	}
}

static struct clock_event_device tegra_clockevent = {
	.name		= "timer0",
	.rating		= 300,
	.features	= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
	.set_next_event	= tegra_timer_set_next_event,
	.set_mode	= tegra_timer_set_mode,
};

static u32 notrace tegra_read_usec(void)
{
	u32 cyc = usec_offset;
	if (!usec_suspended)
		cyc += timer_readl(TIMERUS_CNTR_1US);
	return cyc;
}

u32 notrace tegra_read_usec_raw(void)
{
	return timer_readl(TIMERUS_CNTR_1US);
}

static u32 notrace tegra_read_sched_clock(void)
{
	return tegra_read_usec();
}

/*
 * tegra_rtc_read - Reads the Tegra RTC registers
 * Care must be taken that this funciton is not called while the
 * tegra_rtc driver could be executing to avoid race conditions
 * on the RTC shadow register
 */
u64 tegra_rtc_read_ms(void)
{
	u32 ms = readl(rtc_base + RTC_MILLISECONDS);
	u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
	return (u64)s * MSEC_PER_SEC + ms;
}

#ifdef CONFIG_ARM_ARCH_TIMER

/*
 * read_persistent_clock -  Return time from a persistent clock.
 *
 * For systems with arch timer, TSC runs even during suspend
 */
void read_persistent_clock(struct timespec *ts)
{
	u32 cvalh, cvall;
	u64 delta;
	struct timespec *tsp = &persistent_ts;

	asm volatile("mrrc p15, 1, %0, %1, c14" : "=r" (cvall), "=r" (cvalh));

	last_persistent_cycles = persistent_cycles;
	persistent_cycles = ((u64)cvalh << 32) | cvall;
	delta = persistent_cycles - last_persistent_cycles;
	delta = (delta * arch_timer_ns_mult) >> arch_timer_ns_shift;
	timespec_add_ns(tsp, delta);
	*ts = *tsp;
}
#else
/*
 * read_persistent_clock -  Return time from a persistent clock.
 *
 * Reads the time from a source which isn't disabled during PM, the
 * 32k sync timer.  Convert the cycles elapsed since last read into
 * nsecs and adds to a monotonically increasing timespec.
 * Care must be taken that this funciton is not called while the
 * tegra_rtc driver could be executing to avoid race conditions
 * on the RTC shadow register
 */
void read_persistent_clock(struct timespec *ts)
{
	u64 delta;
	struct timespec *tsp = &persistent_ts;

	last_persistent_ms = persistent_ms;
	persistent_ms = tegra_rtc_read_ms();
	delta = persistent_ms - last_persistent_ms;

	timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
	*ts = *tsp;
}
#endif

static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
	timer_writel(1<<30, system_timer + TIMER_PCR);
	evt->event_handler(evt);
	return IRQ_HANDLED;
}

static struct irqaction tegra_timer_irq = {
	.name		= "timer0",
	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH,
	.handler	= tegra_timer_interrupt,
	.dev_id		= &tegra_clockevent,
#ifdef CONFIG_ARCH_TEGRA_2x_SOC
	.irq		= INT_TMR3,
#else
	.irq		= INT_TMR1,
#endif
};

static int tegra_timer_suspend(void)
{
	usec_config = timer_readl(TIMERUS_USEC_CFG);

	usec_offset += timer_readl(TIMERUS_CNTR_1US);
	usec_suspended = true;

	return 0;
}

static void tegra_timer_resume(void)
{
	timer_writel(usec_config, TIMERUS_USEC_CFG);

	usec_offset -= timer_readl(TIMERUS_CNTR_1US);
	usec_suspended = false;
}

static struct syscore_ops tegra_timer_syscore_ops = {
	.suspend = tegra_timer_suspend,
	.resume = tegra_timer_resume,
};

#ifdef CONFIG_HAVE_ARM_TWD
static DEFINE_TWD_LOCAL_TIMER(twd_local_timer,
			      TEGRA_ARM_PERIF_BASE + 0x600,
			      IRQ_LOCALTIMER);
static void __iomem *tegra_twd_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x600);

void __init tegra_cpu_timer_init(void)
{
	struct clk *cpu, *twd_clk;
	int err;

	/* The twd clock is a detached child of the CPU complex clock.
	   Force an update of the twd clock after DVFS has updated the
	   CPU clock rate. */

	twd_clk = tegra_get_clock_by_name("twd");
	BUG_ON(!twd_clk);
	cpu = tegra_get_clock_by_name("cpu");
	err = clk_set_rate(twd_clk, clk_get_rate(cpu));

	if (err)
		pr_err("Failed to set twd clock rate: %d\n", err);
	else
		pr_debug("TWD clock rate: %ld\n", clk_get_rate(twd_clk));
}

int tegra_twd_get_state(struct tegra_twd_context *context)
{
	context->twd_ctrl = readl(tegra_twd_base + TWD_TIMER_CONTROL);
	context->twd_load = readl(tegra_twd_base + TWD_TIMER_LOAD);
	context->twd_cnt = readl(tegra_twd_base + TWD_TIMER_COUNTER);

	return 0;
}

void tegra_twd_suspend(struct tegra_twd_context *context)
{
	context->twd_ctrl = readl(tegra_twd_base + TWD_TIMER_CONTROL);
	context->twd_load = readl(tegra_twd_base + TWD_TIMER_LOAD);
	if ((context->twd_load == 0) &&
	    (context->twd_ctrl & TWD_TIMER_CONTROL_PERIODIC) &&
	    (context->twd_ctrl & (TWD_TIMER_CONTROL_ENABLE |
				  TWD_TIMER_CONTROL_IT_ENABLE))) {
		WARN("%s: TWD enabled but counter was 0\n", __func__);
		context->twd_load = 1;
	}
	__raw_writel(0, tegra_twd_base + TWD_TIMER_CONTROL);
}

void tegra_twd_resume(struct tegra_twd_context *context)
{
	BUG_ON((context->twd_load == 0) &&
	       (context->twd_ctrl & TWD_TIMER_CONTROL_PERIODIC) &&
	       (context->twd_ctrl & (TWD_TIMER_CONTROL_ENABLE |
				     TWD_TIMER_CONTROL_IT_ENABLE)));
	writel(context->twd_load, tegra_twd_base + TWD_TIMER_LOAD);
	writel(context->twd_ctrl, tegra_twd_base + TWD_TIMER_CONTROL);
}

static void __init tegra_init_late_timer(void)
{
	int err = twd_local_timer_register(&twd_local_timer);
	if (err)
		pr_err("twd_timer_register failed %d\n", err);
}
#else
#define tegra_twd_get_state	do {} while(0)
#define tegra_twd_suspend	do {} while(0)
#define tegra_twd_resume	do {} while(0)
#endif

#ifdef CONFIG_ARM_ARCH_TIMER

#ifndef CONFIG_TRUSTED_FOUNDATIONS
/* Time Stamp Counter (TSC) base address */
static void __iomem *tsc = IO_ADDRESS(TEGRA_TSC_BASE);
#endif

static bool arch_timer_initialized;

#define TSC_CNTCR		0		/* TSC control registers */
#define TSC_CNTCR_ENABLE	(1 << 0)	/* Enable*/
#define TSC_CNTCR_HDBG		(1 << 1)	/* Halt on debug */

#define TSC_CNTCV0		0x8		/* TSC counter (LSW) */
#define TSC_CNTCV1		0xC		/* TSC counter (MSW) */
#define TSC_CNTFID0		0x20		/* TSC freq id 0 */

#define tsc_writel(value, reg) \
	__raw_writel(value, (u32)tsc + (reg))
#define tsc_readl(reg) \
	__raw_readl((u32)tsc + (reg))


/* Is the optional system timer available? */
static int local_timer_is_architected(void)
{
	return (cpu_architecture() >= CPU_ARCH_ARMv7) &&
	       ((read_cpuid_ext(CPUID_EXT_PFR1) >> 16) & 0xf) == 1;
}

void __init tegra_cpu_timer_init(void)
{
	u64 sec;
	u32 tsc_ref_freq;
#ifdef CONFIG_TRUSTED_FOUNDATIONS
	tsc_ref_freq = tegra_clk_measure_input_freq();
#else
	u32 reg;

	if (!local_timer_is_architected())
		return;

	tsc_ref_freq = tegra_clk_measure_input_freq();
	if (tsc_ref_freq == 115200 || tsc_ref_freq == 230400) {
		/*
		 * OSC detection function will bug out if revision is not QT and
		 * the detected frequency is one of these two.
		 */
		tsc_ref_freq = 13000000;
		pr_info("fake tsc_ref_req=%d in QT\n", tsc_ref_freq);
	}

	/* Set the Timer System Counter (TSC) reference frequency
	   NOTE: this is a write once register */
	tsc_writel(tsc_ref_freq, TSC_CNTFID0);

	/* Program CNTFRQ to the same value.
	   NOTE: this is a write once (per CPU reset) register. */
	__asm__("mcr p15, 0, %0, c14, c0, 0\n" : : "r" (tsc_ref_freq));

	/* CNTFRQ must agree with the TSC reference frequency. */
	__asm__("mrc p15, 0, %0, c14, c0, 0\n" : "=r" (reg));
	BUG_ON(reg != tsc_ref_freq);

	/* Enable the TSC. */
	reg = tsc_readl(TSC_CNTCR);
	reg |= TSC_CNTCR_ENABLE | TSC_CNTCR_HDBG;
	tsc_writel(reg, TSC_CNTCR);
#endif
	sec = CLOCKSOURCE_MASK(56);
	do_div(sec, tsc_ref_freq);
	clocks_calc_mult_shift(&arch_timer_ns_mult, &arch_timer_ns_shift,
				tsc_ref_freq, NSEC_PER_SEC, sec);
	clocks_calc_mult_shift(&arch_timer_us_mult, &arch_timer_us_shift,
				tsc_ref_freq, USEC_PER_SEC, sec);
	return;
}

static void tegra_arch_timer_per_cpu_init(void)
{
#ifdef CONFIG_TRUSTED_FOUNDATIONS
	return;
#else
	if (arch_timer_initialized) {
		u32 tsc_ref_freq = tegra_clk_measure_input_freq();

		/*
		 * OSC detection function will bug out if revision is not QT and
		 * the detected frequency is one of these two.
		 */
		if (tsc_ref_freq == 115200 || tsc_ref_freq == 230400)
			tsc_ref_freq = 13000000;

		/* Program CNTFRQ to the input frequency.
		   NOTE: this is a write once (per CPU reset) register. */
		__asm__("mcr p15, 0, %0, c14, c0, 0\n" : : "r" (tsc_ref_freq));
	}
#endif
}

static int arch_timer_cpu_notify(struct notifier_block *self,
				    unsigned long action, void *data)
{
	switch (action) {
	case CPU_STARTING:
	case CPU_STARTING_FROZEN:
		tegra_arch_timer_per_cpu_init();
		break;
	default:
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block arch_timer_cpu_nb = {
	.notifier_call = arch_timer_cpu_notify,
};

static int arch_timer_cpu_pm_notify(struct notifier_block *self,
				    unsigned long action, void *data)
{
	switch (action) {
	case CPU_PM_EXIT:
		tegra_arch_timer_per_cpu_init();
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block arch_timer_cpu_pm_nb = {
	.notifier_call = arch_timer_cpu_pm_notify,
};

static int __init tegra_init_arch_timer(void)
{
	int err;

	if (!local_timer_is_architected())
		return -ENODEV;

	err = arch_timer_sched_clock_init();
	if (err) {
		pr_err("%s: Unable to initialize arch timer sched_clock: %d\n",
		     __func__, err);
		return err;
	}

	register_cpu_notifier(&arch_timer_cpu_nb);
	cpu_pm_register_notifier(&arch_timer_cpu_pm_nb);
	arch_timer_initialized = true;
	return 0;
}

static struct arch_timer tegra_arch_timer = {
	.res[0] = {
		.start	= 29,
		.end	= 29,
		.flags	= IORESOURCE_IRQ,
	},
	.res[1] = {
		.start	= 30,
		.end	= 30,
		.flags	= IORESOURCE_IRQ,
	},
};

static void __init tegra_init_late_timer(void)
{
	int err = -ENODEV;

	if (arch_timer_initialized) {
		err = arch_timer_register(&tegra_arch_timer);
		if (err)
			pr_err("%s: Unable to register arch timer: %d\n",
			     __func__, err);
	}
}

#ifdef CONFIG_PM_SLEEP

static void __iomem *pmc = IO_ADDRESS(TEGRA_PMC_BASE);
static u32 tsc_suspend_start;
static u32 tsc_resume_start;

#define pmc_writel(value, reg) \
		writel(value, (u32)pmc + (reg))
#define pmc_readl(reg) \
		readl((u32)pmc + (reg))

#define PMC_DPD_ENABLE			0x24
#define PMC_DPD_ENABLE_TSC_MULT_ENABLE	(1 << 1)

#define PMC_TSC_MULT			0x2b4
#define PMC_TSC_MULT_FREQ_STS		(1 << 16)

#define TSC_TIMEOUT_US			32

void tegra_tsc_suspend(void)
{
	if (arch_timer_initialized) {
		u32 reg = pmc_readl(PMC_DPD_ENABLE);
		BUG_ON(reg & PMC_DPD_ENABLE_TSC_MULT_ENABLE);
		reg |= PMC_DPD_ENABLE_TSC_MULT_ENABLE;
		pmc_writel(reg, PMC_DPD_ENABLE);
		tsc_suspend_start = timer_readl(TIMERUS_CNTR_1US);
	}
}

void tegra_tsc_resume(void)
{
	if (arch_timer_initialized) {
		u32 reg = pmc_readl(PMC_DPD_ENABLE);
		BUG_ON(!(reg & PMC_DPD_ENABLE_TSC_MULT_ENABLE));
		reg &= ~PMC_DPD_ENABLE_TSC_MULT_ENABLE;
		pmc_writel(reg, PMC_DPD_ENABLE);
		tsc_resume_start = timer_readl(TIMERUS_CNTR_1US);
	}
}

void tegra_tsc_wait_for_suspend(void)
{
	if (arch_timer_initialized) {
		while ((timer_readl(TIMERUS_CNTR_1US) - tsc_suspend_start) <
			TSC_TIMEOUT_US) {
			if (pmc_readl(PMC_TSC_MULT) & PMC_TSC_MULT_FREQ_STS)
				break;
			cpu_relax();
		}
	}
}

void tegra_tsc_wait_for_resume(void)
{
	if (arch_timer_initialized) {
		while ((timer_readl(TIMERUS_CNTR_1US) - tsc_resume_start) <
			TSC_TIMEOUT_US) {
			if (!(pmc_readl(PMC_TSC_MULT) & PMC_TSC_MULT_FREQ_STS))
				break;
			cpu_relax();
		}
	}
}

int tegra_cpu_timer_get_remain(s64 *time)
{
	s32 cntp_tval;
	int ret = 0;

	asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (cntp_tval));

	if (cntp_tval <= 0)
		ret = -ETIME;
	else
		*time = (s64)((s64)cntp_tval * arch_timer_us_mult)
			>> arch_timer_us_shift;

	return ret;
}

#endif

#else
static inline int tegra_init_arch_timer(void) { return -ENODEV; }
static inline int tegra_init_late_arch_timer(void) { return -ENODEV; }
#endif

#ifdef CONFIG_RTC_CLASS
/**
 * has_readtime - check rtc device has readtime ability
 * @dev: current device
 * @name_ptr: name to be returned
 *
 * This helper function checks to see if the rtc device can be
 * used for reading time
 */
static int has_readtime(struct device *dev, void *name_ptr)
{
	struct rtc_device *candidate = to_rtc_device(dev);

	if (!candidate->ops->read_time)
		return 0;

	return 1;
}

/**
 * tegra_get_linear_age - helper function to return linear age
 * from Jan 2012.
 *
 * @return
 * 1 - Jan 2012,
 * 2 - Feb 2012,
 * .....
 * 13 - Jan 2013
 */
int tegra_get_linear_age(void)
{
	struct rtc_time tm;
	int year, month, linear_age;
	struct rtc_device *rtc_dev = NULL;
	const char *name = NULL;
	int ret;
	struct device *dev = NULL;

	linear_age = -1;
	year = month = 0;
	dev = class_find_device(rtc_class, NULL, &name, has_readtime);

	if (!dev) {
		pr_err("DVFS: No device with readtime capability\n");
		goto done;
	}

	name = dev_name(dev);

	pr_info("DVFS: Got RTC device name:%s\n", name);

	if (name)
		rtc_dev = rtc_class_open((char *)name);

	if (!rtc_dev) {
		pr_err("DVFS: No RTC device\n");
		goto error_dev;
	}

	ret = rtc_read_time(rtc_dev, &tm);

	if (ret < 0) {
		pr_err("DVFS: Can't read RTC time\n");
		goto error_rtc;
	}

	year = tm.tm_year;
	/*Normalize it to 2012*/
	year -= 112;
	month = tm.tm_mon + 1;

	if (year >= 0)
		linear_age = year * 12 + month;

error_rtc:
	rtc_class_close(rtc_dev);
error_dev:
	put_device(dev);
done:
	return linear_age;

}

#else
int tegra_get_linear_age()
{
	return -1;
}
#endif

void __init tegra_init_timer(void)
{
	struct clk *clk;
	int ret;
	unsigned long rate;

	clk = clk_get_sys("timer", NULL);
	if (IS_ERR(clk)) {
		pr_warn("Unable to get timer clock."
			" Assuming 12Mhz input clock.\n");
		rate = 12000000;
	} else {
		tegra_clk_prepare_enable(clk);
		rate = clk_get_rate(clk);
	}

	/*
	 * rtc registers are used by read_persistent_clock, keep the rtc clock
	 * enabled
	 */
	clk = clk_get_sys("rtc-tegra", NULL);
	if (IS_ERR(clk))
		pr_warn("Unable to get rtc-tegra clock\n");
	else
		tegra_clk_prepare_enable(clk);

	switch (rate) {
	case 12000000:
		timer_writel(0x000b, TIMERUS_USEC_CFG);
		break;
	case 13000000:
		timer_writel(0x000c, TIMERUS_USEC_CFG);
		break;
	case 19200000:
		timer_writel(0x045f, TIMERUS_USEC_CFG);
		break;
	case 26000000:
		timer_writel(0x0019, TIMERUS_USEC_CFG);
		break;
#ifndef CONFIG_ARCH_TEGRA_2x_SOC
	case 16800000:
		timer_writel(0x0453, TIMERUS_USEC_CFG);
		break;
	case 38400000:
		timer_writel(0x04BF, TIMERUS_USEC_CFG);
		break;
	case 48000000:
		timer_writel(0x002F, TIMERUS_USEC_CFG);
		break;
#endif
	default:
		if (tegra_revision == TEGRA_REVISION_QT) {
			timer_writel(0x000c, TIMERUS_USEC_CFG);
			break;
		}
		WARN(1, "Unknown clock rate");
	}

#ifdef CONFIG_ARCH_TEGRA_2x_SOC
	tegra20_init_timer();
#else
	tegra30_init_timer();
#endif

	/* Architectural timers take precedence over broadcast timers.
	   Only register a broadcast clockevent device if architectural
	   timers do not exist or cannot be initialized. */
	if (tegra_init_arch_timer())
		/* Architectural timers do not exist or cannot be initialzied.
		   Fall back to using the broadcast timer as the sched clock. */
		setup_sched_clock(tegra_read_sched_clock, 32, 1000000);

	ret = clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US,
		"timer_us", 1000000, 300, 32,
		clocksource_mmio_readl_up);
	if (ret) {
		pr_err("%s: Failed to register clocksource: %d\n",
			__func__, ret);
		BUG();
	}

	ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
	if (ret) {
		pr_err("%s: Failed to register timer IRQ: %d\n",
			__func__, ret);
		BUG();
	}

	clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5);
	tegra_clockevent.max_delta_ns =
		clockevent_delta2ns(0x1fffffff, &tegra_clockevent);
	tegra_clockevent.min_delta_ns =
		clockevent_delta2ns(0x1, &tegra_clockevent);
	tegra_clockevent.cpumask = cpu_all_mask;
	tegra_clockevent.irq = tegra_timer_irq.irq;
	clockevents_register_device(&tegra_clockevent);

	register_syscore_ops(&tegra_timer_syscore_ops);
	late_time_init = tegra_init_late_timer;
}

struct sys_timer tegra_timer = {
	.init = tegra_init_timer,
};