/* SPDX-License-Identifier: BSD-2-Clause */

/**
 * @file
 *
 * @ingroup RTEMSDriverClockImpl
 *
 * @brief This header file contains the shared Clock Driver implementation.
 *
 * This header file shall only be included by a particular Clock Driver
 * implementation source file.
 */

/*
 *  COPYRIGHT (c) 1989-2014.
 *  On-Line Applications Research Corporation (OAR).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>

#include <bsp.h>
#include <rtems/clockdrv.h>
#include <rtems/score/percpu.h>
#include <rtems/score/processormaskimpl.h>
#include <rtems/score/smpimpl.h>
#include <rtems/score/timecounter.h>
#include <rtems/score/thread.h>
#include <rtems/score/watchdogimpl.h>

/**
 * @defgroup RTEMSDriverClockImpl Clock Driver Implementation
 *
 * @ingroup RTEMSDriverClock
 *
 * @brief This group contains the Clock Driver implementation.
 */

#ifdef Clock_driver_nanoseconds_since_last_tick
#error "Update driver to use the timecounter instead of nanoseconds extension"
#endif

#if CLOCK_DRIVER_USE_FAST_IDLE && CLOCK_DRIVER_ISRS_PER_TICK
#error "Fast Idle PLUS n ISRs per tick is not supported"
#endif

#if defined(BSP_FEATURE_IRQ_EXTENSION) || \
    (CPU_SIMPLE_VECTORED_INTERRUPTS != TRUE)
typedef void * Clock_isr_argument;
#else
typedef rtems_vector_number Clock_isr_argument;
#endif

/**
 * @brief Do nothing by default.
 */
#ifndef Clock_driver_support_install_isr
  #define Clock_driver_support_install_isr(isr)
#endif

/**
 * @brief This method is rarely used so default it.
 */
#ifndef Clock_driver_support_find_timer
  #define Clock_driver_support_find_timer()
#endif

/**
 * @brief Do nothing by default.
 */
#ifndef Clock_driver_support_at_tick
  #define Clock_driver_support_at_tick( arg ) do { (void) arg; } while (0)
#endif

/**
 * @brief Do nothing by default.
 */
#ifndef Clock_driver_support_set_interrupt_affinity
  #define Clock_driver_support_set_interrupt_affinity(online_processors)
#endif

/*
 * A specialized clock driver may use for example rtems_timecounter_tick_simple()
 * instead of the default.
 */
#ifndef Clock_driver_timecounter_tick
static void Clock_driver_timecounter_tick( Clock_isr_argument arg )
{
  (void) arg;
#if defined(CLOCK_DRIVER_USE_DUMMY_TIMECOUNTER)
  rtems_clock_tick();
#elif defined(RTEMS_SMP) && defined(CLOCK_DRIVER_USE_ONLY_BOOT_PROCESSOR)
  uint32_t cpu_max;
  uint32_t cpu_index;

  cpu_max = _SMP_Get_processor_maximum();

  for ( cpu_index = 0 ; cpu_index < cpu_max ; ++cpu_index ) {
    Per_CPU_Control *cpu;

    cpu = _Per_CPU_Get_by_index( cpu_index );

    if ( _Per_CPU_Is_boot_processor( cpu ) ) {
      rtems_timecounter_tick();
    } else if ( _Processor_mask_Is_set( _SMP_Get_online_processors(), cpu_index ) ) {
      _Watchdog_Tick( cpu );
    }
  }
#else
  rtems_timecounter_tick();
#endif
}
#endif

/**
 * @brief ISRs until next clock tick
 */
#if CLOCK_DRIVER_ISRS_PER_TICK
  volatile uint32_t  Clock_driver_isrs;
#endif

/**
 * @brief Clock ticks since initialization
 */
volatile uint32_t    Clock_driver_ticks;

#ifdef Clock_driver_support_shutdown_hardware
#error "Clock_driver_support_shutdown_hardware() is no longer supported"
#endif

#if CLOCK_DRIVER_USE_FAST_IDLE
static bool _Clock_Has_watchdogs(const Per_CPU_Control *cpu)
{
  size_t i;

  for (i = 0; i < RTEMS_ARRAY_SIZE(cpu->Watchdog.Header); ++i) {
    if (_Watchdog_Header_first(&cpu->Watchdog.Header[i]) != NULL) {
      return true;
    }
  }

  return false;
}
#endif

/**
 *  @brief Clock_isr
 *
 *  This is the clock tick interrupt handler.
 *
 *  @param arg is the clock interrupt handler argument.
 */
void Clock_isr( Clock_isr_argument arg );
void Clock_isr( Clock_isr_argument arg )
{
  /*
   *  Accurate count of ISRs
   */
  Clock_driver_ticks += 1;

  #if CLOCK_DRIVER_USE_FAST_IDLE
    {
      Clock_driver_timecounter_tick( arg );

      if (_SMP_Get_processor_maximum() == 1) {
        struct timecounter *tc;
        uint64_t            us_per_tick;
        uint32_t            interval;
        Per_CPU_Control    *cpu_self;

        cpu_self = _Per_CPU_Get();
        tc = _Timecounter;
        us_per_tick = rtems_configuration_get_microseconds_per_tick();
        interval = (uint32_t) ((tc->tc_frequency * us_per_tick) / 1000000);

        while (
          cpu_self->thread_dispatch_disable_level == cpu_self->isr_nest_level
            && cpu_self->heir == cpu_self->executing
            && cpu_self->executing->is_idle
            && _Clock_Has_watchdogs(cpu_self)
        ) {
          ISR_lock_Context lock_context;

          _Timecounter_Acquire(&lock_context);
          _Timecounter_Tick_simple(
            interval,
            (*tc->tc_get_timecount)(tc),
            &lock_context
          );
        }
      }

      Clock_driver_support_at_tick( arg );
    }
  #else
    /*
     *  Do the hardware specific per-tick action.
     *
     *  The counter/timer may or may not be set to automatically reload.
     */
    Clock_driver_support_at_tick( arg );

    #if CLOCK_DRIVER_ISRS_PER_TICK
      /*
       *  The driver is multiple ISRs per clock tick.
       */
      if ( !Clock_driver_isrs ) {
        Clock_driver_timecounter_tick( arg );

        Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK_VALUE;
      }
      Clock_driver_isrs--;
    #else
      /*
       *  The driver is one ISR per clock tick.
       */
      Clock_driver_timecounter_tick( arg );
    #endif
  #endif
}

void _Clock_Initialize( void )
{
  Clock_driver_ticks = 0;

  /*
   *  Find timer -- some BSPs search buses for hardware timer
   */
  Clock_driver_support_find_timer();

  /*
   *  Install vector
   */
  Clock_driver_support_install_isr( Clock_isr );

  #ifdef RTEMS_SMP
    Clock_driver_support_set_interrupt_affinity(
      _SMP_Get_online_processors()
    );
  #endif

  /*
   *  Now initialize the hardware that is the source of the tick ISR.
   */
  Clock_driver_support_initialize_hardware();

  /*
   *  If we are counting ISRs per tick, then initialize the counter.
   */
  #if CLOCK_DRIVER_ISRS_PER_TICK
    Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK_VALUE;
  #endif
}