intc.c File Reference


Detailed Description

INTC driver for AVR32 UC3.

AVR32 Interrupt Controller driver module.

Author:
Atmel Corporation: http://www.atmel.com
Support and FAQ: http://support.atmel.no/

Definition in file intc.c.

#include <avr32/io.h>
#include "compiler.h"
#include "preprocessor.h"
#include "intc.h"

Go to the source code of this file.

Defines

#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)];
 Creates a table of interrupt line handlers per interrupt group in order to optimize RAM space.
#define INSERT_INT_LINE_HANDLER_TABLE(GRP, unused)   {AVR32_INTC_NUM_IRQS_PER_GRP##GRP, _int_line_handler_table_##GRP},

Functions

__int_handler _get_interrupt_handler (unsigned int int_lev)
 Gets the interrupt handler of the current event at the int_lev interrupt priority level (called from exception.S).
static void _unhandled_interrupt (void)
 Default interrupt handler.
void INTC_init_interrupts (void)
 Initializes the hardware interrupt controller driver.
void INTC_register_interrupt (__int_handler handler, unsigned int irq, unsigned int int_lev)
 Registers an interrupt handler.
 MREPEAT (AVR32_INTC_NUM_INT_GRPS, DECL_INT_LINE_HANDLER_TABLE,~)

Variables

struct {
   volatile __int_handler *   _int_line_handler_table
   unsigned int   num_irqs
_int_handler_table [AVR32_INTC_NUM_INT_GRPS]
 Table containing for each interrupt group the number of interrupt request lines and a pointer to the table of interrupt line handlers.
const unsigned int ipr_val [AVR32_INTC_NUM_INT_LEVELS]
 Values to store in the interrupt priority registers for the various interrupt priority levels.


Define Documentation

#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)];

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.

Definition at line 57 of file intc.c.

#define INSERT_INT_LINE_HANDLER_TABLE ( GRP,
unused   )     {AVR32_INTC_NUM_IRQS_PER_GRP##GRP, _int_line_handler_table_##GRP},


Function Documentation

__int_handler _get_interrupt_handler ( unsigned int  int_lev  ) 

Gets the interrupt handler of the current event at the int_lev interrupt priority level (called from exception.S).

Parameters:
int_lev Interrupt priority level to handle.
Returns:
Interrupt handler to execute.
Note:
Taken and adapted from Newlib.

Definition at line 106 of file intc.c.

References _int_handler_table.

00107 {
00108   // ICR3 is mapped first, ICR0 last.
00109   // Code in exception.S puts int_lev in R12 which is used by AVR32-GCC to pass
00110   // a single argument to a function.
00111   unsigned int int_grp = AVR32_INTC.icr[AVR32_INTC_INT3 - int_lev];
00112   unsigned int int_req = AVR32_INTC.irr[int_grp];
00113 
00114   // As an interrupt may disappear while it is being fetched by the CPU
00115   // (spurious interrupt caused by a delayed response from an MCU peripheral to
00116   // an interrupt flag clear or interrupt disable instruction), check if there
00117   // are remaining interrupt lines to process.
00118   // If a spurious interrupt occurs, the status register (SR) contains an
00119   // execution mode and interrupt level masks corresponding to a level 0
00120   // interrupt, whatever the interrupt priority level causing the spurious
00121   // event. This behavior has been chosen because a spurious interrupt has not
00122   // to be a priority one and because it may not cause any trouble to other
00123   // interrupts.
00124   // However, these spurious interrupts place the hardware in an unstable state
00125   // and could give problems in other/future versions of the CPU, so the
00126   // software has to be written so that they never occur. The only safe way of
00127   // achieving this is to always clear or disable peripheral interrupts with the
00128   // following sequence:
00129   // 1: Mask the interrupt in the CPU by setting GM (or IxM) in SR.
00130   // 2: Perform the bus access to the peripheral register that clears or
00131   //    disables the interrupt.
00132   // 3: Wait until the interrupt has actually been cleared or disabled by the
00133   //    peripheral. This is usually performed by reading from a register in the
00134   //    same peripheral (it DOES NOT have to be the same register that was
00135   //    accessed in step 2, but it MUST be in the same peripheral), what takes
00136   //    bus system latencies into account, but peripheral internal latencies
00137   //    (generally 0 cycle) also have to be considered.
00138   // 4: Unmask the interrupt in the CPU by clearing GM (or IxM) in SR.
00139   // Note that steps 1 and 4 are useless inside interrupt handlers as the
00140   // corresponding interrupt level is automatically masked by IxM (unless IxM is
00141   // explicitly cleared by the software).
00142   //
00143   // Get the right IRQ handler.
00144   //
00145   // If several interrupt lines are active in the group, the interrupt line with
00146   // the highest number is selected. This is to be coherent with the
00147   // prioritization of interrupt groups performed by the hardware interrupt
00148   // controller.
00149   //
00150   // If no handler has been registered for the pending interrupt,
00151   // _unhandled_interrupt will be selected thanks to the initialization of
00152   // _int_line_handler_table_x by INTC_init_interrupts.
00153   //
00154   // exception.S will provide the interrupt handler with a clean interrupt stack
00155   // frame, with nothing more pushed onto the stack. The interrupt handler must
00156   // manage the `rete' instruction, what can be done thanks to pure assembly,
00157   // inline assembly or the `__attribute__((__interrupt__))' C function
00158   // attribute.
00159   return (int_req) ? _int_handler_table[int_grp]._int_line_handler_table[32 - clz(int_req) - 1] : NULL;
00160 }

static void _unhandled_interrupt ( void   )  [static]

Default interrupt handler.

Note:
Taken and adapted from Newlib.

Definition at line 90 of file intc.c.

Referenced by INTC_init_interrupts().

00091 {
00092   // Catch unregistered interrupts.
00093   while (TRUE);
00094 }

void INTC_init_interrupts ( void   ) 

Initializes the hardware interrupt controller driver.

Note:
Taken and adapted from Newlib.

Definition at line 163 of file intc.c.

References _int_handler_table, _unhandled_interrupt(), and ipr_val.

Referenced by main().

00164 {
00165   unsigned int int_grp, int_req;
00166 
00167   // For all interrupt groups,
00168   for (int_grp = 0; int_grp < AVR32_INTC_NUM_INT_GRPS; int_grp++)
00169   {
00170     // For all interrupt request lines of each group,
00171     for (int_req = 0; int_req < _int_handler_table[int_grp].num_irqs; int_req++)
00172     {
00173       // Assign _unhandled_interrupt as default interrupt handler.
00174       _int_handler_table[int_grp]._int_line_handler_table[int_req] = &_unhandled_interrupt;
00175     }
00176 
00177     // Set the interrupt group priority register to its default value.
00178     // By default, all interrupt groups are linked to the interrupt priority
00179     // level 0 and to the interrupt vector _int0.
00180     AVR32_INTC.ipr[int_grp] = ipr_val[AVR32_INTC_INT0];
00181   }
00182 }

void INTC_register_interrupt ( __int_handler  handler,
unsigned int  irq,
unsigned int  int_lev 
)

Registers an interrupt handler.

Parameters:
handler Interrupt handler to register.
irq IRQ of the interrupt handler to register.
int_lev Interrupt priority level to assign to the group of this IRQ.
Warning:
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.

If several interrupt handlers of a same group are registered with different priority levels, only the latest priority level set will be effective.

Note:
Taken and adapted from Newlib.

Definition at line 185 of file intc.c.

References _int_handler_table, AVR32_INTC_MAX_NUM_IRQS_PER_GRP, and ipr_val.

Referenced by main().

00186 {
00187   // Determine the group of the IRQ.
00188   unsigned int int_grp = irq / AVR32_INTC_MAX_NUM_IRQS_PER_GRP;
00189 
00190   // Store in _int_line_handler_table_x the pointer to the interrupt handler, so
00191   // that _get_interrupt_handler can retrieve it when the interrupt is vectored.
00192   _int_handler_table[int_grp]._int_line_handler_table[irq % AVR32_INTC_MAX_NUM_IRQS_PER_GRP] = handler;
00193 
00194   // Program the corresponding IPRX register to set the interrupt priority level
00195   // and the interrupt vector offset that will be fetched by the core interrupt
00196   // system.
00197   // NOTE: The _intx functions are intermediate assembly functions between the
00198   // core interrupt system and the user interrupt handler.
00199   AVR32_INTC.ipr[int_grp] = ipr_val[int_lev & (AVR32_INTC_IPR_INTLEVEL_MASK >> AVR32_INTC_IPR_INTLEVEL_OFFSET)];
00200 }

MREPEAT ( AVR32_INTC_NUM_INT_GRPS  ,
DECL_INT_LINE_HANDLER_TABLE  ,
 
)


Variable Documentation

struct { ... } _int_handler_table[AVR32_INTC_NUM_INT_GRPS] [static]

Table containing for each interrupt group the number of interrupt request lines and a pointer to the table of interrupt line handlers.

Referenced by _get_interrupt_handler(), INTC_init_interrupts(), and INTC_register_interrupt().

Definition at line 71 of file intc.c.

const unsigned int ipr_val[AVR32_INTC_NUM_INT_LEVELS]

Values to store in the interrupt priority registers for the various interrupt priority levels.

Referenced by INTC_init_interrupts(), and INTC_register_interrupt().

unsigned int num_irqs

Definition at line 70 of file intc.c.


Generated on Tue Nov 25 11:16:32 2008 for AVR32 - Interrupt Controller Driver by  doxygen 1.5.6