arch/misoc/src/minerva/minerva_doirq.c

/****************************************************************************
 * arch/misoc/src/minerva/minerva_doirq.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <assert.h>
#include <debug.h>

#include <nuttx/addrenv.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/board.h>

#include <arch/irq.h>
#include <arch/board/board.h>
#include <sched/sched.h>

#include "minerva.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

uint32_t *minerva_doirq(int irq, uint32_t * regs)
{
  board_autoled_on(LED_INIRQ);

  /* Current regs non-zero indicates that we are processing an interrupt;
   * g_current_regs is also used to manage interrupt level context switches.
   * Nested interrupts are not supported
   */

  DEBUGASSERT(g_current_regs == NULL);
  g_current_regs = regs;

  /* Disable further occurrences of this interrupt (until the interrupt
   * sources have been clear by the driver).
   */

  up_disable_irq(irq);

  /* Deliver the IRQ */

  irq_dispatch(irq, regs);

  /* Check for a context switch.  If a context switch occurred, then
   * g_current_regs will have a different value than it did on entry.  If an
   * interrupt level context switch has occurred, then restore the floating
   * point state and the establish the correct address environment before
   * returning from the interrupt.
   */

  if (regs != g_current_regs)
    {
#ifdef CONFIG_ARCH_FPU
      /* Restore floating point registers */

      up_restorefpu((uint32_t *) g_current_regs);
#endif

#ifdef CONFIG_ARCH_ADDRENV
      /* Make sure that the address environment for the previously running
       * task is closed down gracefully (data caches dump, MMU flushed) and
       * set up the address environment for the new thread at the head of
       * the ready-to-run list.
       */

      addrenv_switch(NULL);
#endif

      /* Record the new "running" task when context switch occurred.
       * g_running_tasks[] is only used by assertion logic for reporting
       * crashes.
       */

      g_running_tasks[this_cpu()] = this_task();
    }

  /* If a context switch occurred while processing the interrupt then
   * g_current_regs may have change value.  If we return any value different
   * from the input regs, then the lower level will know that a context
   * switch occurred during interrupt processing.
   */

  regs = (uint32_t *) g_current_regs;

  /* Set g_current_regs to NULL to indicate that we are no longer in an
   * interrupt handler.
   */

  g_current_regs = NULL;

  /* Unmask the last interrupt (global interrupts are still disabled) */

  up_enable_irq(irq);
  board_autoled_off(LED_INIRQ);
  return regs;
}