/*
 * Copyright (c) 2008-2010 Freescale Semiconductor, Inc. All rights reserved.
 * Dave Liu <daveliu@freescale.com>
 * copy from the 83xx GTM driver and modify for MPIC global timer,
 * implement the global timer 0 function.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/sysfs.h>
#include <linux/of_platform.h>

#include <linux/io.h>
#include <linux/irq.h>

#include <sysdev/fsl_soc.h>
#include "log.h"
#include "mpic_timer.h"

#define MPIC_TIMER_TCR_OFFSET       0x200
#define MPIC_TIMER_TCR_CLKDIV_64    0x00000300
#define MPIC_TIMER_STOP         0x80000000

struct mpic_tm_regs
{
    u32 gtccr;
    u32 res0[3];
    u32 gtbcr;
    u32 res1[3];
    u32 gtvpr;
    u32 res2[3];
    u32 gtdr;
    u32 res3[3];
};

struct mpic_tm_priv
{
    struct mpic_tm_regs __iomem* regs;
    int irq;
    int ticks_per_sec;
    int ticks_per_msec;
    spinlock_t lock;
};

struct mpic_type
{
    int has_tcr;
};

struct irq_hook
{
    PMIPC_TIMER_RUNTIME hook;
    void* data;
};

static unsigned int g_CntPerMs = 0;
static unsigned int g_CurrentVal = 0;

static struct irq_hook irq_hooks[32];

static volatile uint32_t poll_hook_bitmap = 0xffffffff;


int register_mpic_timer_irq(PMIPC_TIMER_RUNTIME phooks, void* data)
{
    int ret = -ENOSPC;
    int idx = 0;

    if((idx = fls(poll_hook_bitmap) - 1) >= 0)
    {
        poll_hook_bitmap  &= ~(1 << idx);
        irq_hooks[idx].hook = phooks;
        irq_hooks[idx].data = data;
        ret = idx;
        printk("irq_poll_register %x\n", ret);
    }

    return ret;
}

EXPORT_SYMBOL(register_mpic_timer_irq);

int unregister_mpic_timer_irq(int idx)
{
    int ret = -EINVAL;
    printk("irq_poll_unregister %x\n", idx);

    if(!(poll_hook_bitmap & (1 << idx)))
    {
        poll_hook_bitmap |= (1 << idx);
    }

    return ret;
}
EXPORT_SYMBOL(unregister_mpic_timer_irq);

static unsigned int g_TimerCnt = 0;
static struct timeval g_Clock;

static irqreturn_t mpic_tm_isr(int irq, void* dev_id)
{
    struct mpic_tm_priv* priv = dev_id;
    uint32_t bits;
    int i;
    unsigned int newTimerCnt;
    struct timeval ts;
    unsigned int rlt, need;

    /*
        unsigned long flags;
        unsigned long temp;
        spin_lock_irqsave(&priv->lock, flags);
        temp = in_be32(&priv->regs->gtbcr);
        temp |= MPIC_TIMER_STOP; // counting inhibited
        out_be32(&priv->regs->gtbcr, temp);
        out_be32(&priv->regs->gtbcr, priv->ticks_per_msec);
        spin_unlock_irqrestore(&priv->lock, flags);
        //spin_lock_irqsave(&priv->lock, flags);
        //out_be32(&priv->regs->gtbcr, newTimerCnt | MPIC_TIMER_STOP);
        //spin_unlock_irqrestore(&priv->lock, flags);
    */

    bits  = ~poll_hook_bitmap;

    while((i = fls(bits) - 1) >= 0)
    {
        bits &= ~(1 << i);
        irq_hooks[i].hook(irq_hooks[i].data);
    }

    do_gettimeofday(&ts);

    // 计算时间差，单位为 US
    if(ts.tv_usec < g_Clock.tv_usec)
    {
        rlt = (ts.tv_sec - g_Clock.tv_sec - 1) * 1000000 +
              ((1000000 + ts.tv_usec) - g_Clock.tv_usec);
    }
    else
    {
        rlt = (ts.tv_sec - g_Clock.tv_sec) * 1000000 +
              (ts.tv_usec - g_Clock.tv_usec);
    }

#if 1

    // 当前标准时间差
    need = g_TimerCnt * 1000;

    // 校正时间
    if(need > rlt)
    {
        newTimerCnt = g_CntPerMs + (need - rlt) * (g_CntPerMs / 1000);
    }
    else
    {
        if((rlt - need) > 1000)
        {
            newTimerCnt = g_CntPerMs / 2;
        }
        else
        {
            newTimerCnt = g_CntPerMs - (rlt - need) * (g_CntPerMs / 1000);
        }
    }

    g_CurrentVal = newTimerCnt;

#else

    // 当前标准时间差
    need = g_TimerCnt * 100;

    // 校正时间
    if(need > rlt)
    {
        newTimerCnt = g_CntPerMs + (need - rlt) * (g_CntPerMs / 100);
    }
    else
    {
        if((rlt - need) > 100)
        {
            newTimerCnt = g_CntPerMs / 2;
        }
        else
        {
            newTimerCnt = g_CntPerMs - (rlt - need) * (g_CntPerMs / 100);
        }
    }

    g_CurrentVal = newTimerCnt;

#endif

    // 更新定时器
    out_be32(&priv->regs->gtbcr, newTimerCnt | MPIC_TIMER_STOP);
    out_be32(&priv->regs->gtbcr, newTimerCnt & 0x7FFFFFFF);

    g_TimerCnt++;
    /*
        if(g_TimerCnt % 1000 == 0)
        {

            //printk("[T]%d.%d - %d.%d\n", ts.tv_sec, ts.tv_usec, g_Clock.tv_sec, g_Clock.tv_usec);
            //printk("[T]need = %d, rlt = %d,  newTimerCnt = %d\n", need, rlt, newTimerCnt);
            printk("[%d]Time:%d.%d\n", g_TimerCnt, ts.tv_sec, ts.tv_usec / 1000);
        }
     */
    return IRQ_HANDLED;
}

static ssize_t mpic_tm_timeout_store(struct device* dev,
                                     struct device_attribute* attr,
                                     const char* buf, size_t count)
{
    struct mpic_tm_priv* priv = dev_get_drvdata(dev);
    unsigned long interval = simple_strtoul(buf, NULL, 0);
    unsigned long temp;

    if(interval > 0x7fffffff)
    {
        dev_dbg(dev, "mpic_tm: interval %lu (in s) too long\n", interval);
        return -EINVAL;
    }

    temp = interval;
    interval *= priv->ticks_per_sec;

    if(interval > 0x7fffffff || (interval / priv->ticks_per_sec) != temp)
    {
        dev_dbg(dev, "mpic_tm: interval %lu (in ticks) too long\n",
                interval);
        return -EINVAL;
    }

    spin_lock_irq(&priv->lock);

    /* stop timer 0 */
    temp = in_be32(&priv->regs->gtbcr);
    temp |= MPIC_TIMER_STOP; /* counting inhibited */
    out_be32(&priv->regs->gtbcr, temp);

    if(interval != 0)
    {
        /* start timer */
        out_be32(&priv->regs->gtbcr, interval | MPIC_TIMER_STOP);
        out_be32(&priv->regs->gtbcr, interval);
    }

    spin_unlock_irq(&priv->lock);
    return count;
}

struct mpic_tm_priv* g_tm_priv = NULL;

int mpic_tm_get_current(void)
{
    return in_be32(&g_tm_priv->regs->gtccr);
}
EXPORT_SYMBOL(mpic_tm_get_current);



static ssize_t mpic_tm_timeout_show(struct device* dev,
                                    struct device_attribute* attr,
                                    char* buf)
{
    struct mpic_tm_priv* priv = dev_get_drvdata(dev);
    int timeout = 0;

    spin_lock_irq(&priv->lock);

    if(!(in_be32(&priv->regs->gtbcr) & MPIC_TIMER_STOP))
    {
        timeout = in_be32(&priv->regs->gtccr);
        timeout += priv->ticks_per_sec - 1;
        timeout /= priv->ticks_per_sec;
    }

    spin_unlock_irq(&priv->lock);
    return sprintf(buf, "TimeOut:0x%08X - TimerCnt:0x%08X\n", timeout,
                   g_CurrentVal);
}

static DEVICE_ATTR(timeout, 0660, mpic_tm_timeout_show, mpic_tm_timeout_store);

static int mpic_tm_probe(struct of_device* dev,
                         const struct of_device_id* match)
{
    struct device_node* np = dev->dev.of_node;
    struct resource res;
    struct mpic_tm_priv* priv;
    struct mpic_type* type = match->data;
    int has_tcr = type->has_tcr;
    u32 busfreq = fsl_get_sys_freq();
    int ret = 0;

    if(busfreq == 0)
    {
        dev_err(&dev->dev, "mpic_tm: No bus frequency in device tree.\n");
        return -ENODEV;
    }

    priv = kmalloc(sizeof(struct mpic_tm_priv), GFP_KERNEL);

    if(!priv)
    {
        return -ENOMEM;
    }

    spin_lock_init(&priv->lock);
    dev_set_drvdata(&dev->dev, priv);

    ret = of_address_to_resource(np, 0, &res);

    if(ret)
    {
        goto out;
    }

    priv->irq = irq_of_parse_and_map(np, 0);

    if(priv->irq == NO_IRQ)
    {
        dev_err(&dev->dev, "MPIC global timer0 exists in device tree "
                "without an IRQ.\n");
        ret = -ENODEV;
        goto out;
    }

    ret = request_irq(priv->irq, mpic_tm_isr, 0, "mpic timer 0", priv);

    if(ret)
    {
        goto out;
    }

    priv->regs = ioremap(res.start, res.end - res.start + 1);

    if(!priv->regs)
    {
        ret = -ENOMEM;
        goto out;
    }

    /*
     * MPIC implementation from Freescale has the TCR register,
     * the MPIC_TIMER_TCR_OFFSET is 0x200 from global timer base
     * the default clock source to the MPIC timer 0 is CCB freq / 8.
     * to extend the timer period, we divide the timer clock source
     * as CCB freq / 64, so the max timer period is 336 seconds
     * when the CCB frequence is 400MHz.
     */
    if(!has_tcr)
    {
        priv->ticks_per_sec = busfreq / 8;
    }
    else
    {
        u32 __iomem* tcr;
        tcr = (u32 __iomem*)((u32)priv->regs + MPIC_TIMER_TCR_OFFSET);
        out_be32(tcr, in_be32(tcr) | MPIC_TIMER_TCR_CLKDIV_64);
        priv->ticks_per_sec = busfreq / 64;
    }

    g_CntPerMs = priv->ticks_per_sec / 1000;

    priv->ticks_per_msec = g_CntPerMs;

    LOG_EX(LOG_Info, "freq = 0x%08X, msec = 0x%08X\n",
           busfreq, priv->ticks_per_msec);

    ret = device_create_file(&dev->dev, &dev_attr_timeout);

    if(ret)
    {
        goto out;
    }

    /* start timer now */
    out_be32(&priv->regs->gtbcr, priv->ticks_per_msec | MPIC_TIMER_STOP);
    out_be32(&priv->regs->gtbcr, priv->ticks_per_msec);

    do_gettimeofday(&g_Clock);

    g_tm_priv = priv;

    return 0;

out:

    kfree(priv);
    return ret;
}

static int mpic_tm_remove(struct of_device* dev)
{
    struct mpic_tm_priv* priv = dev_get_drvdata(&dev->dev);

    device_remove_file(&dev->dev, &dev_attr_timeout);
    free_irq(priv->irq, priv);
    iounmap(priv->regs);

    dev_set_drvdata(&dev->dev, NULL);
    kfree(priv);
    return 0;
}

static struct mpic_type mpic_types[] =
{
    {
        .has_tcr = 0,
    },
    {
        .has_tcr = 1,
    }
};

static struct of_device_id mpic_tm_match[] =
{
    {
        .compatible = "fsl,mpic-global-timer",
        .data = &mpic_types[1],
    },
    {},
};

static struct of_platform_driver mpic_tm_driver =
{
    .driver = {
        .name = "mpic-global-timer",
        .owner = THIS_MODULE,
        .of_match_table = mpic_tm_match,
    },
    .probe = mpic_tm_probe,
    .remove = mpic_tm_remove,
};

static int __init mpic_tm_init(void)
{
    printk("Gianfar Build:%s(%s)\n", __DATE__, __TIME__);
    return of_register_platform_driver(&mpic_tm_driver);
}

static void __exit mpic_tm_exit(void)
{
    of_unregister_platform_driver(&mpic_tm_driver);
}

module_init(mpic_tm_init);
module_exit(mpic_tm_exit);

MODULE_AUTHOR("Freescale Semiconductor, Inc");
MODULE_DESCRIPTION("MPIC Timer Driver");
MODULE_LICENSE("GPL");