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time.c

/*
 *  linux/arch/arm/mach-integrator/time.c
 *
 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/mc146818rtc.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/amba/bus.h>

#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/rtc.h>

#include <asm/mach/time.h>

#define RTC_DR          (0)
#define RTC_MR          (4)
#define RTC_STAT  (8)
#define RTC_EOI         (8)
#define RTC_LR          (12)
#define RTC_CR          (16)
#define RTC_CR_MIE      (1 << 0)

extern int (*set_rtc)(void);
static void __iomem *rtc_base;

static int integrator_set_rtc(void)
{
      __raw_writel(xtime.tv_sec, rtc_base + RTC_LR);
      return 1;
}

static int integrator_rtc_read_alarm(struct rtc_wkalrm *alrm)
{
      rtc_time_to_tm(readl(rtc_base + RTC_MR), &alrm->time);
      return 0;
}

static inline int integrator_rtc_set_alarm(struct rtc_wkalrm *alrm)
{
      unsigned long time;
      int ret;

      /*
       * At the moment, we can only deal with non-wildcarded alarm times.
       */
      ret = rtc_valid_tm(&alrm->time);
      if (ret == 0)
            ret = rtc_tm_to_time(&alrm->time, &time);
      if (ret == 0)
            writel(time, rtc_base + RTC_MR);
      return ret;
}

static int integrator_rtc_read_time(struct rtc_time *tm)
{
      rtc_time_to_tm(readl(rtc_base + RTC_DR), tm);
      return 0;
}

/*
 * Set the RTC time.  Unfortunately, we can't accurately set
 * the point at which the counter updates.
 *
 * Also, since RTC_LR is transferred to RTC_CR on next rising
 * edge of the 1Hz clock, we must write the time one second
 * in advance.
 */
static inline int integrator_rtc_set_time(struct rtc_time *tm)
{
      unsigned long time;
      int ret;

      ret = rtc_tm_to_time(tm, &time);
      if (ret == 0)
            writel(time + 1, rtc_base + RTC_LR);

      return ret;
}

static struct rtc_ops rtc_ops = {
      .owner            = THIS_MODULE,
      .read_time  = integrator_rtc_read_time,
      .set_time   = integrator_rtc_set_time,
      .read_alarm = integrator_rtc_read_alarm,
      .set_alarm  = integrator_rtc_set_alarm,
};

static irqreturn_t arm_rtc_interrupt(int irq, void *dev_id)
{
      writel(0, rtc_base + RTC_EOI);
      return IRQ_HANDLED;
}

static int rtc_probe(struct amba_device *dev, void *id)
{
      int ret;

      if (rtc_base)
            return -EBUSY;

      ret = amba_request_regions(dev, NULL);
      if (ret)
            goto out;

      rtc_base = ioremap(dev->res.start, SZ_4K);
      if (!rtc_base) {
            ret = -ENOMEM;
            goto res_out;
      }

      __raw_writel(0, rtc_base + RTC_CR);
      __raw_writel(0, rtc_base + RTC_EOI);

      xtime.tv_sec = __raw_readl(rtc_base + RTC_DR);

      /* note that 'dev' is merely used for irq disambiguation;
       * it is not actually referenced in the irq handler
       */
      ret = request_irq(dev->irq[0], arm_rtc_interrupt, IRQF_DISABLED,
                    "rtc-pl030", dev);
      if (ret)
            goto map_out;

      ret = register_rtc(&rtc_ops);
      if (ret)
            goto irq_out;

      set_rtc = integrator_set_rtc;
      return 0;

 irq_out:
      free_irq(dev->irq[0], dev);
 map_out:
      iounmap(rtc_base);
      rtc_base = NULL;
 res_out:
      amba_release_regions(dev);
 out:
      return ret;
}

static int rtc_remove(struct amba_device *dev)
{
      set_rtc = NULL;

      writel(0, rtc_base + RTC_CR);

      free_irq(dev->irq[0], dev);
      unregister_rtc(&rtc_ops);

      iounmap(rtc_base);
      rtc_base = NULL;
      amba_release_regions(dev);

      return 0;
}

static struct timespec rtc_delta;

static int rtc_suspend(struct amba_device *dev, pm_message_t state)
{
      struct timespec rtc;

      rtc.tv_sec = readl(rtc_base + RTC_DR);
      rtc.tv_nsec = 0;
      save_time_delta(&rtc_delta, &rtc);

      return 0;
}

static int rtc_resume(struct amba_device *dev)
{
      struct timespec rtc;

      rtc.tv_sec = readl(rtc_base + RTC_DR);
      rtc.tv_nsec = 0;
      restore_time_delta(&rtc_delta, &rtc);

      return 0;
}

static struct amba_id rtc_ids[] = {
      {
            .id   = 0x00041030,
            .mask = 0x000fffff,
      },
      { 0, 0 },
};

static struct amba_driver rtc_driver = {
      .drv        = {
            .name = "rtc-pl030",
      },
      .probe            = rtc_probe,
      .remove           = rtc_remove,
      .suspend    = rtc_suspend,
      .resume           = rtc_resume,
      .id_table   = rtc_ids,
};

static int __init integrator_rtc_init(void)
{
      return amba_driver_register(&rtc_driver);
}

static void __exit integrator_rtc_exit(void)
{
      amba_driver_unregister(&rtc_driver);
}

module_init(integrator_rtc_init);
module_exit(integrator_rtc_exit);

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