text: /*
   *  Port on Texas Instruments TMS320C6x architecture
   *
   *  Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
   *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
   *
   *  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/clocksource.h>
  #include <linux/errno.h>
  #include <linux/sched.h>
  #include <linux/param.h>
  #include <linux/string.h>
  #include <linux/mm.h>
  #include <linux/interrupt.h>
  #include <linux/timex.h>
  #include <linux/profile.h>
  
  #include <asm/special_insns.h>
  #include <asm/timer64.h>
  
  static u32 sched_clock_multiplier;
  #define SCHED_CLOCK_SHIFT 16
  
  static cycle_t tsc_read(struct clocksource *cs)
  {
  	return get_cycles();
  }
  
  static struct clocksource clocksource_tsc = {
  	.name		= "timestamp",
  	.rating		= 300,
  	.read		= tsc_read,
  	.mask		= CLOCKSOURCE_MASK(64),
  	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
  };
  
  /*
   * scheduler clock - returns current time in nanoseconds.
   */
  u64 sched_clock(void)
  {
  	u64 tsc = get_cycles();
  
  	return (tsc * sched_clock_multiplier) >> SCHED_CLOCK_SHIFT;
  }
  
  void time_init(void)
  {
  	u64 tmp = (u64)NSEC_PER_SEC << SCHED_CLOCK_SHIFT;
  
  	do_div(tmp, c6x_core_freq);
  	sched_clock_multiplier = tmp;
  
  	clocksource_register_hz(&clocksource_tsc, c6x_core_freq);
  
  	/* write anything into TSCL to enable counting */
  	set_creg(TSCL, 0);
  
  	/* probe for timer64 event timer */
  	timer64_init();
  }
  