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

#include <asm/arch_timer.h>
#include "omap_hwmod.h"
#include "omap_device.h"
#include <plat/counter-32k.h>
#include <plat/dmtimer.h>
#include "omap-pm.h"

#include "soc.h"
#include "common.h"
#include "powerdomain.h"

/* Parent clocks, eventually these will come from the clock framework */

#define OMAP2_MPU_SOURCE	"sys_ck"
#define OMAP3_MPU_SOURCE	OMAP2_MPU_SOURCE
#define OMAP4_MPU_SOURCE	"sys_clkin_ck"
#define OMAP2_32K_SOURCE	"func_32k_ck"
#define OMAP3_32K_SOURCE	"omap_32k_fck"
#define OMAP4_32K_SOURCE	"sys_32k_ck"

#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;

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_DISABLED | 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 void omap2_gp_timer_set_mode(enum clock_event_mode mode,
				    struct clock_event_device *evt)
{
	u32 period;

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

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		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);
		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 clockevent_gpt = {
	.name		= "gp_timer",
	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.shift		= 32,
	.rating		= 300,
	.set_next_event	= omap2_gp_timer_set_next_event,
	.set_mode	= omap2_gp_timer_set_mode,
};

static struct property device_disabled = {
	.name = "status",
	.length = sizeof("disabled"),
	.value = "disabled",
};

static struct of_device_id omap_timer_match[] __initdata = {
	{ .compatible = "ti,omap2-timer", },
	{ }
};

/**
 * 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(struct of_device_id *match,
						     const char *property)
{
	struct device_node *np;

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

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

		of_add_property(np, &device_disabled);
		return np;
	}

	return NULL;
}

/**
 * omap_dmtimer_init - initialisation function when device tree is used
 *
 * For secure OMAP3 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())
		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");
		if (np)
			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,
						int gptimer_id,
						const char *fck_source,
						const char *property,
						int posted)
{
	char name[10]; /* 10 = sizeof("gptXX_Xck0") */
	const char *oh_name;
	struct device_node *np;
	struct omap_hwmod *oh;
	struct resource irq, mem;
	int r = 0;

	if (of_have_populated_dt()) {
		np = omap_get_timer_dt(omap_timer_match, NULL);
		if (!np)
			return -ENODEV;

		of_property_read_string_index(np, "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);

		of_node_put(np);
	} else {
		if (omap_dm_timer_reserve_systimer(gptimer_id))
			return -ENODEV;

		sprintf(name, "timer%d", gptimer_id);
		oh_name = name;
	}

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

	if (!of_have_populated_dt()) {
		r = omap_hwmod_get_resource_byname(oh, IORESOURCE_IRQ, NULL,
						   &irq);
		if (r)
			return -ENXIO;
		timer->irq = irq.start;

		r = omap_hwmod_get_resource_byname(oh, IORESOURCE_MEM, NULL,
						   &mem);
		if (r)
			return -ENXIO;

		/* Static mapping, never released */
		timer->io_base = ioremap(mem.start, mem.end - mem.start);
	}

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

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

	/* FIXME: Need to remove hard-coded test on timer ID */
	if (gptimer_id != 12) {
		struct clk *src;

		src = clk_get(NULL, fck_source);
		if (IS_ERR(src)) {
			r = -EINVAL;
		} else {
			r = clk_set_parent(timer->fclk, src);
			if (IS_ERR_VALUE(r))
				pr_warn("%s: %s cannot set source\n",
					__func__, oh->name);
			clk_put(src);
		}
	}

	omap_hwmod_setup_one(oh_name);
	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;
}

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

	clkev.errata = omap_dm_timer_get_errata();

	/*