irq_cm3.c

Go to the documentation of this file.

#include <cfg/debug.h> /* ASSERT() */
#include <cfg/log.h> /* LOG_ERR() */
#include <cpu/irq.h>
#include "irq_cm3.h"

static void (*irq_table[NUM_INTERRUPTS])(void)
            __attribute__((section("vtable")));

/* Priority register / IRQ number table */
static const uint32_t nvic_prio_reg[] =
{
    /* System exception registers */
    0, NVIC_SYS_PRI1, NVIC_SYS_PRI2, NVIC_SYS_PRI3,

    /* External interrupts registers */
    NVIC_PRI0, NVIC_PRI1, NVIC_PRI2, NVIC_PRI3,
    NVIC_PRI4, NVIC_PRI5, NVIC_PRI6, NVIC_PRI7,
    NVIC_PRI8, NVIC_PRI9, NVIC_PRI10, NVIC_PRI11,
    NVIC_PRI12, NVIC_PRI13
};

/* Unhandled IRQ */
static NAKED NORETURN void unhandled_isr(void)
{
    register uint32_t reg;

    asm volatile ("mrs %0, ipsr" : "=r"(reg));
    LOG_ERR("unhandled IRQ %lu\n", reg);
    while (1)
        PAUSE;
}

void sysirq_setPriority(sysirq_t irq, int prio)
{
    uint32_t pos = (irq & 3) * 8;
    reg32_t reg = nvic_prio_reg[irq >> 2];
    uint32_t val;

    val = HWREG(reg);
    val &= ~(0xff << pos);
    val |= prio << pos;
    HWREG(reg) = val;
}

static void sysirq_enable(sysirq_t irq)
{
    /* Enable the IRQ line (only for generic IRQs) */
    if (irq >= 16 && irq < 48)
        NVIC_EN0_R = 1 << (irq - 16);
    else if (irq >= 48)
        NVIC_EN1_R = 1 << (irq - 48);
}

void sysirq_setHandler(sysirq_t irq, sysirq_handler_t handler)
{
    cpu_flags_t flags;

    ASSERT(irq < NUM_INTERRUPTS);

    IRQ_SAVE_DISABLE(flags);
    irq_table[irq] = handler;
    sysirq_setPriority(irq, IRQ_PRIO);
    sysirq_enable(irq);
    IRQ_RESTORE(flags);
}

void sysirq_freeHandler(sysirq_t irq)
{
    cpu_flags_t flags;

    ASSERT(irq < NUM_INTERRUPTS);

    IRQ_SAVE_DISABLE(flags);
    irq_table[irq] = unhandled_isr;
    IRQ_RESTORE(flags);
}

void sysirq_init(void)
{
    cpu_flags_t flags;
    int i;

    IRQ_SAVE_DISABLE(flags);
    for (i = 0; i < NUM_INTERRUPTS; i++)
        irq_table[i] = unhandled_isr;

    /* Update NVIC to point to the new vector table */
    NVIC_VTABLE_R = (size_t)irq_table;
    IRQ_RESTORE(flags);
}