/**
 *  @file
 *
 *  LEON3 SMP BSP Support
 */

/*
 *  COPYRIGHT (c) 1989-2011.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.com/license/LICENSE.
 */

#include <rtems.h>
#include <bsp.h>
#include <rtems/bspIo.h>
#include <rtems/bspsmp.h>
#include <stdlib.h>

#define RTEMS_DEBUG

static inline void sparc_leon3_set_cctrl( unsigned int val )
{
  __asm__ volatile( "sta %0, [%%g0] 2" : : "r" (val) );
}

static inline unsigned int sparc_leon3_get_cctrl( void )
{
  unsigned int v = 0;
  __asm__ volatile( "lda [%%g0] 2, %0" : "=r" (v) : "0" (v) );
  return v;
}

static rtems_isr bsp_ap_ipi_isr(
  rtems_vector_number vector
)
{
  LEON_Clear_interrupt(LEON3_MP_IRQ);
  rtems_smp_process_interrupt();
}

static void leon3_secondary_cpu_initialize(void)
{
  int cpu = bsp_smp_processor_id();

  sparc_leon3_set_cctrl( 0x80000F );
  LEON_Unmask_interrupt(LEON3_MP_IRQ);
  LEON3_IrqCtrl_Regs->mask[cpu] |= 1 << LEON3_MP_IRQ;

  rtems_smp_secondary_cpu_initialize();
}

/*
 *  Used to pass information to start.S when bringing secondary CPUs
 *  out of reset.
 */
void *bsp_ap_stack;
void *bsp_ap_entry;

static void bsp_smp_delay( int );

uint32_t bsp_smp_initialize( uint32_t configured_cpu_count )
{
  uint32_t cpu;
  uint32_t found_cpus = 0;

  sparc_leon3_set_cctrl( 0x80000F );
  found_cpus =
    ((LEON3_IrqCtrl_Regs->mpstat >> LEON3_IRQMPSTATUS_CPUNR) & 0xf)  + 1;
  #if defined(RTEMS_DEBUG)
    printk( "Found %d CPUs\n", found_cpus );
  #endif

  if ( found_cpus > configured_cpu_count ) {
    printk(
      "%d CPUs IS MORE THAN CONFIGURED -- ONLY USING %d\n",
      found_cpus,
      configured_cpu_count
    );
    found_cpus = configured_cpu_count;
  }

  if ( found_cpus == 1 )
    return 1;

  for ( cpu=1 ; cpu < found_cpus ; cpu++ ) {
    
    #if defined(RTEMS_DEBUG)
      printk( "Waking CPU %d\n", cpu );
    #endif

    bsp_ap_stack = _Per_CPU_Information[cpu].interrupt_stack_high -
                      CPU_MINIMUM_STACK_FRAME_SIZE;
    bsp_ap_entry = leon3_secondary_cpu_initialize;

    LEON3_IrqCtrl_Regs->mpstat = 1 << cpu;
    bsp_smp_delay( 1000000 );
    #if defined(RTEMS_DEBUG)
      printk(
        "CPU %d is %s\n",
        cpu,
        _Per_CPU_Information[cpu].state
          == PER_CPU_STATE_READY_TO_BEGIN_MULTITASKING ?
            "online" : "offline"
      );
    #endif
  }

  if ( found_cpus > 1 ) {
    LEON_Unmask_interrupt(LEON3_MP_IRQ);
    set_vector(bsp_ap_ipi_isr, LEON_TRAP_TYPE(LEON3_MP_IRQ), 1);
  }
  return found_cpus;
}

void bsp_smp_interrupt_cpu(
  int cpu
)
{
  /* send interrupt to destination CPU */
  LEON3_IrqCtrl_Regs->force[cpu] = 1 << LEON3_MP_IRQ;
}

void bsp_smp_broadcast_interrupt(void)
{
  int dest_cpu;
  int cpu;
  int max_cpus;

  cpu = bsp_smp_processor_id();
  max_cpus = rtems_smp_get_number_of_processors();

  for ( dest_cpu=0 ; dest_cpu < max_cpus ; dest_cpu++ ) {
    if ( cpu == dest_cpu )
      continue;
    bsp_smp_interrupt_cpu( dest_cpu );
    /* this is likely needed due to the ISR code not being SMP aware yet */
    bsp_smp_delay( 100000 );
  }
}

extern __inline__ void __delay(unsigned long loops)
{
   __asm__ __volatile__("cmp %0, 0\n\t"
     "1: bne 1b\n\t"
     "subcc %0, 1, %0\n" :
     "=&r" (loops) :
     "0" (loops) :
     "cc"
  );
}

/*
 *  Kill time without depending on the timer being present or programmed.
 *
 *  This is not very sophisticated.
 */
void bsp_smp_delay( int max )
{
   __delay( max );
}