/********************************************************************************
* arch/arm/src/lpc214x/lpc214x_decodeirq.c
*
* Copyright (C) 2007-2009, 2011 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 <nuttx/irq.h>
#include <nuttx/arch.h>
#include <assert.h>
#include <debug.h>
#include "chip.h"
#include "up_arch.h"
#include "os_internal.h"
#include "up_internal.h"
#include "lpc214x_vic.h"
/********************************************************************************
* Definitions
********************************************************************************/
/********************************************************************************
* Private Types
********************************************************************************/
/********************************************************************************
* Public Data
********************************************************************************/
/********************************************************************************
* Private Data
********************************************************************************/
/* This array maps 4 bits into the bit number of the lowest bit that it set */
#ifndef CONFIG_SUPPRESS_INTERRUPTS
static uint8_t g_nibblemap[16] = { 0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 };
#endif
/********************************************************************************
* Private Functions
********************************************************************************/
/********************************************************************************
* Public Funstions
********************************************************************************/
/********************************************************************************
* up_decodeirq() and/or lpc214x_decodeirq()
*
* Description:
* The vectored interrupt controller (VIC) takes 32 interrupt request inputs
* and programmatically assigns them into 3 categories: FIQ, vectored IRQ,
* and non-vectored IRQ.
*
* - FIQs have the highest priority. There is a single FIQ vector, but multiple
* interrupt sources can be ORed to this FIQ vector.
*
* - Vectored IRQs have the middle priority. Any 16 of the 32 interrupt sources
* can be assigned to vectored IRQs.
*
* - Non-vectored IRQs have the lowest priority.
*
* The general flow of IRQ processing is to simply read the VIC vector address
* and jump to the address of the vector provided in the register. The VIC will
* provide the address of the highest priority vectored IRQ. If a non-vectored
* IRQ is requesting, the address of a default handler is provided.
*
********************************************************************************/
#ifndef CONFIG_VECTORED_INTERRUPTS
void up_decodeirq(uint32_t *regs)
#else
static void lpc214x_decodeirq( uint32_t *regs)
#endif
{
#ifdef CONFIG_SUPPRESS_INTERRUPTS
lib_lowprintf("Unexpected IRQ\n");
current_regs = regs;
PANIC(OSERR_ERREXCEPTION);
#else
/* Decode the interrupt. We have to do this by search for the lowest numbered
* non-zero bit in the interrupt status register.
*/
uint32_t pending = vic_getreg(LPC214X_VIC_IRQSTATUS_OFFSET) & 0x007fffff;
unsigned int nibble;
unsigned int irq_base;
unsigned int irq = NR_IRQS;
/* Search in groups of four bits. For 22 sources, this is at most six
* times through the loop.
*/
for (nibble = pending & 0x0f, irq_base = 0;
pending && irq_base < NR_IRQS;
pending >>= 4, nibble = pending & 0x0f, irq_base += 4)
{
if (nibble)
{
irq = irq_base + g_nibblemap[nibble];
break;
}
}
/* Verify that the resulting IRQ number is valid */
if (irq < NR_IRQS)
{
uint32_t *savestate;
/* Current regs non-zero indicates that we are processing an interrupt;
* current_regs is also used to manage interrupt level context switches.
*/
savestate = (uint32_t*)current_regs;
current_regs = regs;
/* Deliver the IRQ */
irq_dispatch(irq, regs);
/* 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.
*/
current_regs = savestate;
}
#endif
}
#ifdef CONFIG_VECTORED_INTERRUPTS
void up_decodeirq(uint32_t *regs)
{
vic_vector_t vector = (vic_vector_t)vic_getreg(LPC214X_VIC_VECTADDR_OFFSET);
vector(regs);
}
#endif
