text: /****************************************************************************
   * arch/mips/src/mips32/up_doirq.c
   *
   *   Copyright (C) 2011, 2014-2015 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * 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.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * 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.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <stdint.h>
  #include <assert.h>
  
  #include <nuttx/irq.h>
  #include <nuttx/arch.h>
  #include <nuttx/board.h>
  #include <arch/board/board.h>
  
  #include "up_arch.h"
  #include "up_internal.h"
  
  #include "group/group.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  /****************************************************************************
   * Public Data
   ****************************************************************************/
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  uint32_t *up_doirq(int irq, uint32_t *regs)
  {
    board_autoled_on(LED_INIRQ);
  #ifdef CONFIG_SUPPRESS_INTERRUPTS
    PANIC();
  #else
    /* 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(CURRENT_REGS == NULL);
    CURRENT_REGS = regs;
  
    /* Disable further occurrences of this interrupt (until the interrupt
     * srouce have been cleared by the driver).
     */
  
    up_disable_irq(irq);
  
    /* Deliver the IRQ */
  
    irq_dispatch(irq, regs);
  
  #if defined(CONFIG_ARCH_FPU) || defined(CONFIG_ARCH_ADDRENV)
    /* 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 != CURRENT_REGS)
      {
  #ifdef CONFIG_ARCH_FPU
        /* Restore floating point registers */
  
        up_restorefpu((uint32_t *)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.
         */
  
        group_addrenv(NULL);
  #endif
      }
  #endif
  
    /* 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 *)CURRENT_REGS;
  
    /* Set g_current_regs to NULL to indicate that we are no longer in an
     * interrupt handler.
     */
  
    CURRENT_REGS = NULL;
  
    /* Unmask the last interrupt (global interrupts are still disabled) */
  
    up_enable_irq(irq);
  #endif
    board_autoled_off(LED_INIRQ);
    return regs;
  }
  