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timers.c

/***************************************************************************/

/*
 *  linux/arch/m68knommu/platform/68328/timers.c
 *
 *  Copyright (C) 1993 Hamish Macdonald
 *  Copyright (C) 1999 D. Jeff Dionne
 *  Copyright (C) 2001 Georges Menie, Ken Desmet
 *
 * 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/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clocksource.h>
#include <asm/setup.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/machdep.h>
#include <asm/MC68VZ328.h>

/***************************************************************************/

#if defined(CONFIG_DRAGEN2)
/* with a 33.16 MHz clock, this will give usec resolution to the time functions */
#define CLOCK_SOURCE    TCTL_CLKSOURCE_SYSCLK
#define CLOCK_PRE 7
#define TICKS_PER_JIFFY 41450

#elif defined(CONFIG_XCOPILOT_BUGS)
/*
 * The only thing I know is that CLK32 is not available on Xcopilot
 * I have little idea about what frequency SYSCLK has on Xcopilot.
 * The values for prescaler and compare registers were simply
 * taken from the original source
 */
#define CLOCK_SOURCE    TCTL_CLKSOURCE_SYSCLK
#define CLOCK_PRE 2
#define TICKS_PER_JIFFY 0xd7e4

#else
/* default to using the 32Khz clock */
#define CLOCK_SOURCE    TCTL_CLKSOURCE_32KHZ
#define CLOCK_PRE 31
#define TICKS_PER_JIFFY 10
#endif

static u32 m68328_tick_cnt;

/***************************************************************************/

static irqreturn_t hw_tick(int irq, void *dummy)
{
      /* Reset Timer1 */
      TSTAT &= 0;

      m68328_tick_cnt += TICKS_PER_JIFFY;
      return arch_timer_interrupt(irq, dummy);
}

/***************************************************************************/

static struct irqaction m68328_timer_irq = {
      .name  = "timer",
      .flags       = IRQF_DISABLED | IRQF_TIMER,
      .handler = hw_tick,
};

/***************************************************************************/

static cycle_t m68328_read_clk(void)
{
      unsigned long flags;
      u32 cycles;

      local_irq_save(flags);
      cycles = m68328_tick_cnt + TCN;
      local_irq_restore(flags);

      return cycles;
}

/***************************************************************************/

static struct clocksource m68328_clk = {
      .name = "timer",
      .rating     = 250,
      .read = m68328_read_clk,
      .shift      = 20,
      .mask = CLOCKSOURCE_MASK(32),
      .flags      = CLOCK_SOURCE_IS_CONTINUOUS,
};

/***************************************************************************/

void hw_timer_init(void)
{
      /* disable timer 1 */
      TCTL = 0;

      /* set ISR */
      setup_irq(TMR_IRQ_NUM, &m68328_timer_irq);

      /* Restart mode, Enable int, Set clock source */
      TCTL = TCTL_OM | TCTL_IRQEN | CLOCK_SOURCE;
      TPRER = CLOCK_PRE;
      TCMP = TICKS_PER_JIFFY;

      /* Enable timer 1 */
      TCTL |= TCTL_TEN;
      m68328_clk.mult = clocksource_hz2mult(TICKS_PER_JIFFY*HZ, m68328_clk.shift);
      clocksource_register(&m68328_clk);
}

/***************************************************************************/

void m68328_timer_gettod(int *year, int *mon, int *day, int *hour, int *min, int *sec)
{
      long now = RTCTIME;

      *year = *mon = *day = 1;
      *hour = (now >> 24) % 24;
      *min = (now >> 16) % 60;
      *sec = now % 60;
}

/***************************************************************************/

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