Add a few functions to apic.c to make it easier to enable and disable
the local apic timer.
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
---
lib/x86/apic.c | 38 ++++++++++++++++++++++++++++++++++++++
lib/x86/apic.h | 6 ++++++
2 files changed, 44 insertions(+)
diff --git a/lib/x86/apic.c b/lib/x86/apic.c
index 5131525a..174a8c28 100644
--- a/lib/x86/apic.c
+++ b/lib/x86/apic.c
@@ -256,3 +256,41 @@ void init_apic_map(void)
id_map[j++] = i;
}
}
+
+void apic_setup_timer(int vector, u32 mode)
+{
+ apic_cleanup_timer();
+
+ assert((mode & APIC_LVT_TIMER_MASK) == mode);
+
+ apic_write(APIC_TDCR, APIC_TDR_DIV_1);
+ apic_write(APIC_LVTT, vector | mode);
+}
+
+void apic_start_timer(u32 value)
+{
+ /*
+ * APIC timer runs with 'core crystal clock',
+ * divided by value in APIC_TDCR
+ */
+ apic_write(APIC_TMICT, value);
+}
+
+void apic_stop_timer(void)
+{
+ apic_write(APIC_TMICT, 0);
+}
+
+void apic_cleanup_timer(void)
+{
+ u32 lvtt = apic_read(APIC_LVTT);
+
+ // stop the counter
+ apic_stop_timer();
+
+ // mask the timer interrupt
+ apic_write(APIC_LVTT, lvtt | APIC_LVT_MASKED);
+
+ // enable interrupts for one cycle to ensure that a pending timer is serviced
+ sti_nop_cli();
+}
diff --git a/lib/x86/apic.h b/lib/x86/apic.h
index 6d27f047..7c539071 100644
--- a/lib/x86/apic.h
+++ b/lib/x86/apic.h
@@ -58,6 +58,12 @@ void disable_apic(void);
void reset_apic(void);
void init_apic_map(void);
+void apic_cleanup_timer(void);
+void apic_setup_timer(int vector, u32 mode);
+
+void apic_start_timer(u32 counter);
+void apic_stop_timer(void);
+
/* Converts byte-addressable APIC register offset to 4-byte offset. */
static inline u32 apic_reg_index(u32 reg)
{
--
2.34.3
