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-rw-r--r--arch/x86/include/asm/interrupt.h11
-rw-r--r--arch/x86/lib/pcat_interrupts.c38
2 files changed, 49 insertions, 0 deletions
diff --git a/arch/x86/include/asm/interrupt.h b/arch/x86/include/asm/interrupt.h
index 3f46e09..25abde7 100644
--- a/arch/x86/include/asm/interrupt.h
+++ b/arch/x86/include/asm/interrupt.h
@@ -27,4 +27,15 @@ void specific_eoi(int irq);
extern char exception_stack[];
+/**
+ * configure_irq_trigger() - Configure IRQ triggering
+ *
+ * Switch the given interrupt to be level / edge triggered
+ *
+ * @param int_num legacy interrupt number (3-7, 9-15)
+ * @param is_level_triggered true for level triggered interrupt, false for
+ * edge triggered interrupt
+ */
+void configure_irq_trigger(int int_num, bool is_level_triggered);
+
#endif
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
+}