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/****************************************************************************
* arch/mips/src/pic32mx/pic32mx-decodeirq.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 <debug.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 "pic32mx-int.h"
#include "pic32mx-internal.h"
#include "group/group.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pic32mx_decodeirq
*
* Description:
* Called from assembly language logic when an interrupt exception occurs.
* This function decodes and dispatches the interrupt.
*
****************************************************************************/
uint32_t *pic32mx_decodeirq(uint32_t *regs)
{
#ifdef CONFIG_PIC32MX_NESTED_INTERRUPTS
uint32_t *savestate;
#endif
uint32_t regval;
int irq;
/* If the board supports LEDs, turn on an LED now to indicate that we are
* processing an interrupt.
*/
board_led_on(LED_INIRQ);
/* Save the current value of current_regs (to support nested interrupt
* handling). Then set current_regs to regs, indicating that this is
* the interrupted context that is being processed now.
*/
#ifdef CONFIG_PIC32MX_NESTED_INTERRUPTS
savestate = (uint32_t*)current_regs;
#else
DEBUGASSERT(current_regs == NULL);
#endif
current_regs = regs;
/* Loop while there are pending interrupts with priority greater than zero */
for (;;)
{
/* Read the INTSTAT register. This register contains both the priority
* and the interrupt vector number.
*/
regval = getreg32(PIC32MX_INT_INTSTAT);
if ((regval & INT_INTSTAT_RIPL_MASK) == 0)
{
/* Break out of the loop when the priority is zero meaning that
* there are no further pending interrupts.
*/
break;
}
/* Get the vector number. The IRQ numbers have been arranged so that
* vector numbers and NuttX IRQ numbers are the same value.
*/
irq = ((regval) & INT_INTSTAT_VEC_MASK) >> INT_INTSTAT_VEC_SHIFT;
/* Deliver the IRQ */
irq_dispatch(irq, regs);
}
/* If a context switch occurred while processing the interrupt then
* 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;
#if defined(CONFIG_ARCH_FPU) || defined(CONFIG_ARCH_ADDRENV)
/* Check for a context switch. If a context switch occurred, then
* 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.
*/
(void)group_addrenv(NULL);
#endif
}
#endif
#ifdef CONFIG_PIC32MX_NESTED_INTERRUPTS
/* Restore the previous value of current_regs. NULL would indicate that
* we are no longer in an interrupt handler. It will be non-NULL if we
* are returning from a nested interrupt.
*
* REVISIT: There are task switching issues! You should not enable
* nested interrupts unless you are ready to deal with the complexities
* of fixing nested context switching. The logic here is insufficient.
*/
current_regs = savestate;
if (current_regs == NULL)
{
board_led_off(LED_INIRQ);
}
#else
current_regs = NULL;
board_led_off(LED_INIRQ);
#endif
return regs;
}
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