diff options
Diffstat (limited to 'arch/x86/lib/pcat_interrupts.c')
| -rw-r--r-- | arch/x86/lib/pcat_interrupts.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/x86/lib/pcat_interrupts.c b/arch/x86/lib/pcat_interrupts.c index 4c86f7f..2dc2fbd 100644 --- a/arch/x86/lib/pcat_interrupts.c +++ b/arch/x86/lib/pcat_interrupts.c @@ -62,6 +62,9 @@ int interrupt_init(void) */ unmask_irq(2); + /* Interrupt 9 should be level triggered (SCI). The OS might do this */ + configure_irq_trigger(9, true); + enable_interrupts(); return 0; @@ -114,3 +117,38 @@ void specific_eoi(int irq) outb(OCW2_SEOI | irq, MASTER_PIC + OCW2); } + +#define ELCR1 0x4d0 +#define ELCR2 0x4d1 + +void configure_irq_trigger(int int_num, bool is_level_triggered) +{ + u16 int_bits = inb(ELCR1) | (((u16)inb(ELCR2)) << 8); + + debug("%s: current interrupts are 0x%x\n", __func__, int_bits); + if (is_level_triggered) + int_bits |= (1 << int_num); + else + int_bits &= ~(1 << int_num); + + /* Write new values */ + debug("%s: try to set interrupts 0x%x\n", __func__, int_bits); + outb((u8)(int_bits & 0xff), ELCR1); + outb((u8)(int_bits >> 8), ELCR2); + +#ifdef PARANOID_IRQ_TRIGGERS + /* + * Try reading back the new values. This seems like an error but is + * not + */ + if (inb(ELCR1) != (int_bits & 0xff)) { + printf("%s: lower order bits are wrong: want 0x%x, got 0x%x\n", + __func__, (int_bits & 0xff), inb(ELCR1)); + } + + if (inb(ELCR2) != (int_bits >> 8)) { + printf("%s: higher order bits are wrong: want 0x%x, got 0x%x\n", + __func__, (int_bits>>8), inb(ELCR2)); + } +#endif +} |