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/* This source file is part of the ATMEL AVR-UC3-SoftwareFramework-1.7.0 Release */
/*This file is prepared for Doxygen automatic documentation generation.*/
/*! \file *********************************************************************
*
* \brief INTC driver for AVR32 UC3.
*
* AVR32 Interrupt Controller driver module.
*
* - Compiler: IAR EWAVR32 and GNU GCC for AVR32
* - Supported devices: All AVR32 devices with an INTC module can be used.
* - AppNote:
*
* \author Atmel Corporation: http://www.atmel.com \n
* Support and FAQ: http://support.atmel.no/
*
******************************************************************************/
/* Copyright (c) 2009 Atmel Corporation. All rights reserved.
*
* 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. The name of Atmel may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an Atmel
* AVR product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL 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
*
*/
#include <avr32/io.h>
#include "compiler.h"
#include "preprocessor.h"
#include "intc.h"
// define _evba from exception.S
extern void _evba;
//! Values to store in the interrupt priority registers for the various interrupt priority levels.
extern const unsigned int ipr_val[AVR32_INTC_NUM_INT_LEVELS];
//! Creates a table of interrupt line handlers per interrupt group in order to optimize RAM space.
//! Each line handler table contains a set of pointers to interrupt handlers.
#if (defined __GNUC__)
#define DECL_INT_LINE_HANDLER_TABLE(GRP, unused) \
static volatile __int_handler _int_line_handler_table_##GRP[Max(AVR32_INTC_NUM_IRQS_PER_GRP##GRP, 1)];
#elif (defined __ICCAVR32__)
#define DECL_INT_LINE_HANDLER_TABLE(GRP, unused) \
static volatile __no_init __int_handler _int_line_handler_table_##GRP[Max(AVR32_INTC_NUM_IRQS_PER_GRP##GRP, 1)];
#endif
MREPEAT(AVR32_INTC_NUM_INT_GRPS, DECL_INT_LINE_HANDLER_TABLE, ~);
#undef DECL_INT_LINE_HANDLER_TABLE
//! Table containing for each interrupt group the number of interrupt request
//! lines and a pointer to the table of interrupt line handlers.
static const struct
{
unsigned int num_irqs;
volatile __int_handler *_int_line_handler_table;
} _int_handler_table[AVR32_INTC_NUM_INT_GRPS] =
{
#define INSERT_INT_LINE_HANDLER_TABLE(GRP, unused) \
{AVR32_INTC_NUM_IRQS_PER_GRP##GRP, _int_line_handler_table_##GRP},
MREPEAT(AVR32_INTC_NUM_INT_GRPS, INSERT_INT_LINE_HANDLER_TABLE, ~)
#undef INSERT_INT_LINE_HANDLER_TABLE
};
/*! \brief Default interrupt handler.
*
* \note Taken and adapted from Newlib.
*/
#if (defined __GNUC__)
__attribute__((__interrupt__))
#elif (defined __ICCAVR32__)
__interrupt
#endif
static void _unhandled_interrupt(void)
{
// Catch unregistered interrupts.
while (TRUE);
}
/*! \brief Gets the interrupt handler of the current event at the \a int_level
* interrupt priority level (called from exception.S).
*
* \param int_level Interrupt priority level to handle.
*
* \return Interrupt handler to execute.
*
* \note Taken and adapted from Newlib.
*/
__int_handler _get_interrupt_handler(unsigned int int_level)
{
// ICR3 is mapped first, ICR0 last.
// Code in exception.S puts int_level in R12 which is used by AVR32-GCC to
// pass a single argument to a function.
unsigned int int_grp = AVR32_INTC.icr[AVR32_INTC_INT3 - int_level];
unsigned int int_req = AVR32_INTC.irr[int_grp];
// As an interrupt may disappear while it is being fetched by the CPU
// (spurious interrupt caused by a delayed response from an MCU peripheral to
// an interrupt flag clear or interrupt disable instruction), check if there
// are remaining interrupt lines to process.
// If a spurious interrupt occurs, the status register (SR) contains an
// execution mode and interrupt level masks corresponding to a level 0
// interrupt, whatever the interrupt priority level causing the spurious
// event. This behavior has been chosen because a spurious interrupt has not
// to be a priority one and because it may not cause any trouble to other
// interrupts.
// However, these spurious interrupts place the hardware in an unstable state
// and could give problems in other/future versions of the CPU, so the
// software has to be written so that they never occur. The only safe way of
// achieving this is to always clear or disable peripheral interrupts with the
// following sequence:
// 1: Mask the interrupt in the CPU by setting GM (or IxM) in SR.
// 2: Perform the bus access to the peripheral register that clears or
// disables the interrupt.
// 3: Wait until the interrupt has actually been cleared or disabled by the
// peripheral. This is usually performed by reading from a register in the
// same peripheral (it DOES NOT have to be the same register that was
// accessed in step 2, but it MUST be in the same peripheral), what takes
// bus system latencies into account, but peripheral internal latencies
// (generally 0 cycle) also have to be considered.
// 4: Unmask the interrupt in the CPU by clearing GM (or IxM) in SR.
// Note that steps 1 and 4 are useless inside interrupt handlers as the
// corresponding interrupt level is automatically masked by IxM (unless IxM is
// explicitly cleared by the software).
//
// Get the right IRQ handler.
//
// If several interrupt lines are active in the group, the interrupt line with
// the highest number is selected. This is to be coherent with the
// prioritization of interrupt groups performed by the hardware interrupt
// controller.
//
// If no handler has been registered for the pending interrupt,
// _unhandled_interrupt will be selected thanks to the initialization of
// _int_line_handler_table_x by INTC_init_interrupts.
//
// exception.S will provide the interrupt handler with a clean interrupt stack
// frame, with nothing more pushed onto the stack. The interrupt handler must
// manage the `rete' instruction, what can be done thanks to pure assembly,
// inline assembly or the `__attribute__((__interrupt__))' C function
// attribute.
return (int_req) ? _int_handler_table[int_grp]._int_line_handler_table[32 - clz(int_req) - 1] : NULL;
}
//! Init EVBA address. This sequence might also be done in the UTILS/STARTUP/GCC/crt0.S
static __inline__ void INTC_init_evba(void)
{
Set_system_register(AVR32_EVBA, (int)&_evba );
}
void INTC_init_interrupts(void)
{
unsigned int int_grp, int_req;
INTC_init_evba();
// For all interrupt groups,
for (int_grp = 0; int_grp < AVR32_INTC_NUM_INT_GRPS; int_grp++)
{
// For all interrupt request lines of each group,
for (int_req = 0; int_req < _int_handler_table[int_grp].num_irqs; int_req++)
{
// Assign _unhandled_interrupt as default interrupt handler.
_int_handler_table[int_grp]._int_line_handler_table[int_req] = &_unhandled_interrupt;
}
// Set the interrupt group priority register to its default value.
// By default, all interrupt groups are linked to the interrupt priority
// level 0 and to the interrupt vector _int0.
AVR32_INTC.ipr[int_grp] = ipr_val[AVR32_INTC_INT0];
}
}
void INTC_register_interrupt(__int_handler handler, unsigned int irq, unsigned int int_level)
{
// Determine the group of the IRQ.
unsigned int int_grp = irq / AVR32_INTC_MAX_NUM_IRQS_PER_GRP;
// Store in _int_line_handler_table_x the pointer to the interrupt handler, so
// that _get_interrupt_handler can retrieve it when the interrupt is vectored.
_int_handler_table[int_grp]._int_line_handler_table[irq % AVR32_INTC_MAX_NUM_IRQS_PER_GRP] = handler;
// Program the corresponding IPRX register to set the interrupt priority level
// and the interrupt vector offset that will be fetched by the core interrupt
// system.
// NOTE: The _intx functions are intermediate assembly functions between the
// core interrupt system and the user interrupt handler.
AVR32_INTC.ipr[int_grp] = ipr_val[int_level & (AVR32_INTC_IPR_INTLEVEL_MASK >> AVR32_INTC_IPR_INTLEVEL_OFFSET)];
}
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