/*
 * Copyright (c) 2013, 2016 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Dornierstr. 4
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rtems.org/license/LICENSE.
 */

#include <rtems/score/smpimpl.h>

#include <libfdt.h>

#include <libcpu/powerpc-utility.h>

#include <bsp.h>
#include <bsp/fdt.h>
#include <bsp/mmu.h>
#include <bsp/fatal.h>
#include <bsp/qoriq.h>
#include <bsp/vectors.h>
#include <bsp/bootcard.h>
#include <bsp/irq-generic.h>
#include <bsp/linker-symbols.h>

LINKER_SYMBOL(bsp_exc_vector_base);

#if QORIQ_THREAD_COUNT > 1
void _start_thread(void);
#endif

void _start_secondary_processor(void);

#define IPI_INDEX 0

#define TLB_BEGIN (3 * QORIQ_TLB1_ENTRY_COUNT / 4)

#define TLB_END QORIQ_TLB1_ENTRY_COUNT

#define TLB_COUNT (TLB_END - TLB_BEGIN)

#ifdef HAS_UBOOT
  /*
   * These values can be obtained with the debugger or a look into the U-Boot
   * sources (arch/powerpc/cpu/mpc85xx/release.S).
   */
  #define BOOT_BEGIN U_BOOT_BOOT_PAGE_BEGIN
  #define BOOT_LAST U_BOOT_BOOT_PAGE_LAST
  #define SPIN_TABLE (BOOT_BEGIN + U_BOOT_BOOT_PAGE_SPIN_OFFSET)
#endif

typedef struct {
  uint32_t addr_upper;
  uint32_t addr_lower;
  uint32_t r3_upper;
  uint32_t r3_lower;
  uint32_t reserved_0;
  uint32_t pir;
  uint32_t r6_upper;
  uint32_t r6_lower;
  uint32_t reserved_1[8];
} uboot_spin_table;

#if QORIQ_THREAD_COUNT > 1
static bool is_started_by_u_boot(uint32_t cpu_index)
{
  return cpu_index % QORIQ_THREAD_COUNT == 0;
}

void qoriq_start_thread(void)
{
  const Per_CPU_Control *cpu_self = _Per_CPU_Get();

  ppc_exc_initialize_interrupt_stack(
    (uintptr_t) cpu_self->interrupt_stack_low,
    rtems_configuration_get_interrupt_stack_size()
  );

  bsp_interrupt_facility_initialize();

  _SMP_Start_multitasking_on_secondary_processor();
}
#endif

static void start_thread_if_necessary(uint32_t cpu_index_self)
{
#if QORIQ_THREAD_COUNT > 1
  uint32_t i;

  for (i = 1; i < QORIQ_THREAD_COUNT; ++i) {
    uint32_t cpu_index_next = cpu_index_self + i;

    if (
      is_started_by_u_boot(cpu_index_self)
        && cpu_index_next < rtems_configuration_get_maximum_processors()
        && _SMP_Should_start_processor(cpu_index_next)
    ) {
      /* Thread Initial Next Instruction Address (INIA) */
      PPC_SET_THREAD_MGMT_REGISTER(321, (uint32_t) _start_thread);

      /* Thread Initial Machine State (IMSR) */
      PPC_SET_THREAD_MGMT_REGISTER(289, QORIQ_INITIAL_MSR);

      /* Thread Enable Set (TENS) */
      PPC_SET_SPECIAL_PURPOSE_REGISTER(438, 1U << i);
    }
  }
#endif
}

void bsp_start_on_secondary_processor(void)
{
  uint32_t cpu_index_self = _SMP_Get_current_processor();
  const Per_CPU_Control *cpu_self = _Per_CPU_Get_by_index(cpu_index_self);

  ppc_exc_initialize_with_vector_base(
    (uintptr_t) cpu_self->interrupt_stack_low,
    rtems_configuration_get_interrupt_stack_size(),
    bsp_exc_vector_base
  );

  /* Now it is possible to make the code execute only */
  qoriq_mmu_change_perm(
    FSL_EIS_MAS3_SR | FSL_EIS_MAS3_SX,
    FSL_EIS_MAS3_SX,
    FSL_EIS_MAS3_SR
  );

  bsp_interrupt_facility_initialize();

  start_thread_if_necessary(cpu_index_self);

  _SMP_Start_multitasking_on_secondary_processor();
}

static void bsp_inter_processor_interrupt(void *arg)
{
  _SMP_Inter_processor_interrupt_handler();
}

#ifdef U_BOOT_USE_FDT
static uboot_spin_table *spin_table_addr[QORIQ_CPU_COUNT / QORIQ_THREAD_COUNT];
#endif

static uint32_t discover_processors(void)
{
#if defined(HAS_UBOOT)
  return QORIQ_CPU_COUNT;
#elif defined(U_BOOT_USE_FDT)
  const void *fdt = bsp_fdt_get();
  int cpus = fdt_path_offset(fdt, "/cpus");
  int node = fdt_first_subnode(fdt, cpus);
  uint32_t cpu = 0;
  uintptr_t last = 0;
  uintptr_t begin = last - 1;

  while (node >= 0) {
    int len;
    fdt64_t *addr_fdt = (fdt64_t *)
      fdt_getprop(fdt, node, "cpu-release-addr", &len);

    if (addr_fdt != NULL && cpu < RTEMS_ARRAY_SIZE(spin_table_addr)) {
      uintptr_t addr = (uintptr_t) fdt64_to_cpu(*addr_fdt);

      if (addr < begin) {
        begin = addr;
      }

      if (addr > last) {
        last = addr;
      }

      spin_table_addr[cpu] = (uboot_spin_table *) addr;
      ++cpu;
    }

    node = fdt_next_subnode(fdt, node);
  }

  return cpu * QORIQ_THREAD_COUNT;
#endif
}

uint32_t _CPU_SMP_Initialize(void)
{
  uint32_t cpu_count = 1;

  if (rtems_configuration_get_maximum_processors() > 0) {
    cpu_count = discover_processors();
  }

  start_thread_if_necessary(0);

  return cpu_count;
}

static void release_processor(uboot_spin_table *spin_table, uint32_t cpu_index)
{
  const Per_CPU_Control *cpu = _Per_CPU_Get_by_index(cpu_index);

  spin_table->pir = cpu_index;
  spin_table->r3_lower = (uint32_t) cpu->interrupt_stack_high;
  spin_table->addr_upper = 0;
  rtems_cache_flush_multiple_data_lines(spin_table, sizeof(*spin_table));
  ppc_synchronize_data();
  spin_table->addr_lower = (uint32_t) _start_secondary_processor;
  rtems_cache_flush_multiple_data_lines(spin_table, sizeof(*spin_table));
}

static uboot_spin_table *get_spin_table(uint32_t cpu_index)
{
#if defined(HAS_UBOOT)
#if QORIQ_THREAD_COUNT > 1
  return &((uboot_spin_table *) SPIN_TABLE)[cpu_index / 2 - 1];
#else
  return (uboot_spin_table *) SPIN_TABLE;
#endif
#elif defined(U_BOOT_USE_FDT)
  return spin_table_addr[cpu_index / 2];
#endif
}

bool _CPU_SMP_Start_processor(uint32_t cpu_index)
{
#if QORIQ_THREAD_COUNT > 1
  if (is_started_by_u_boot(cpu_index)) {
    uboot_spin_table *spin_table = get_spin_table(cpu_index);

    release_processor(spin_table, cpu_index);

    return true;
  } else {
    return _SMP_Should_start_processor(cpu_index - 1);
  }
#else
  uboot_spin_table *spin_table = get_spin_table(cpu_index);

  release_processor(spin_table, cpu_index);

  return true;
#endif
}

void _CPU_SMP_Finalize_initialization(uint32_t cpu_count)
{
  if (cpu_count > 1) {
    rtems_status_code sc;

    sc = rtems_interrupt_handler_install(
      QORIQ_IRQ_IPI_0,
      "IPI",
      RTEMS_INTERRUPT_UNIQUE,
      bsp_inter_processor_interrupt,
      NULL
    );
    if (sc != RTEMS_SUCCESSFUL) {
      bsp_fatal(QORIQ_FATAL_SMP_IPI_HANDLER_INSTALL);
    }
  }
}

void _CPU_SMP_Prepare_start_multitasking(void)
{
  /* Do nothing */
}

void _CPU_SMP_Send_interrupt(uint32_t target_processor_index)
{
#ifdef __PPC_CPU_E6500__
  ppc_light_weight_synchronize();
#else
  ppc_synchronize_data();
#endif
  qoriq.pic.ipidr [IPI_INDEX].reg = 1U << target_processor_index;
}