[PATCH 08/41] clocksource: i8253: Migrate to new 'set-state' interface

From: Viresh Kumar
Date: Thu Jun 18 2015 - 07:07:47 EST


Migrate i8253 driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
arch/x86/kernel/i8253.c | 2 +-
drivers/clocksource/i8253.c | 77 ++++++++++++++++++++++-----------------------
2 files changed, 39 insertions(+), 40 deletions(-)

diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c
index f2b96de3c7c1..efb82f07b29c 100644
--- a/arch/x86/kernel/i8253.c
+++ b/arch/x86/kernel/i8253.c
@@ -34,7 +34,7 @@ static int __init init_pit_clocksource(void)
* - when local APIC timer is active (PIT is switched off)
*/
if (num_possible_cpus() > 1 || is_hpet_enabled() ||
- i8253_clockevent.mode != CLOCK_EVT_MODE_PERIODIC)
+ !clockevent_state_periodic(&i8253_clockevent))
return 0;

return clocksource_i8253_init();
diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c
index 14ee3efcc404..0efd36e483ab 100644
--- a/drivers/clocksource/i8253.c
+++ b/drivers/clocksource/i8253.c
@@ -100,44 +100,40 @@ int __init clocksource_i8253_init(void)
#endif

#ifdef CONFIG_CLKEVT_I8253
-/*
- * Initialize the PIT timer.
- *
- * This is also called after resume to bring the PIT into operation again.
- */
-static void init_pit_timer(enum clock_event_mode mode,
- struct clock_event_device *evt)
+static int pit_shutdown(struct clock_event_device *evt)
{
+ if (!clockevent_state_oneshot(evt) && !clockevent_state_periodic(evt))
+ return 0;
+
raw_spin_lock(&i8253_lock);

- switch (mode) {
- case CLOCK_EVT_MODE_PERIODIC:
- /* binary, mode 2, LSB/MSB, ch 0 */
- outb_p(0x34, PIT_MODE);
- outb_p(PIT_LATCH & 0xff , PIT_CH0); /* LSB */
- outb_p(PIT_LATCH >> 8 , PIT_CH0); /* MSB */
- break;
-
- case CLOCK_EVT_MODE_SHUTDOWN:
- case CLOCK_EVT_MODE_UNUSED:
- if (evt->mode == CLOCK_EVT_MODE_PERIODIC ||
- evt->mode == CLOCK_EVT_MODE_ONESHOT) {
- outb_p(0x30, PIT_MODE);
- outb_p(0, PIT_CH0);
- outb_p(0, PIT_CH0);
- }
- break;
-
- case CLOCK_EVT_MODE_ONESHOT:
- /* One shot setup */
- outb_p(0x38, PIT_MODE);
- break;
-
- case CLOCK_EVT_MODE_RESUME:
- /* Nothing to do here */
- break;
- }
+ outb_p(0x30, PIT_MODE);
+ outb_p(0, PIT_CH0);
+ outb_p(0, PIT_CH0);
+
+ raw_spin_unlock(&i8253_lock);
+ return 0;
+}
+
+static int pit_set_oneshot(struct clock_event_device *evt)
+{
+ raw_spin_lock(&i8253_lock);
+ outb_p(0x38, PIT_MODE);
+ raw_spin_unlock(&i8253_lock);
+ return 0;
+}
+
+static int pit_set_periodic(struct clock_event_device *evt)
+{
+ raw_spin_lock(&i8253_lock);
+
+ /* binary, mode 2, LSB/MSB, ch 0 */
+ outb_p(0x34, PIT_MODE);
+ outb_p(PIT_LATCH & 0xff, PIT_CH0); /* LSB */
+ outb_p(PIT_LATCH >> 8, PIT_CH0); /* MSB */
+
raw_spin_unlock(&i8253_lock);
+ return 0;
}

/*
@@ -160,10 +156,11 @@ static int pit_next_event(unsigned long delta, struct clock_event_device *evt)
* it can be solely used for the global tick.
*/
struct clock_event_device i8253_clockevent = {
- .name = "pit",
- .features = CLOCK_EVT_FEAT_PERIODIC,
- .set_mode = init_pit_timer,
- .set_next_event = pit_next_event,
+ .name = "pit",
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+ .set_state_shutdown = pit_shutdown,
+ .set_state_periodic = pit_set_periodic,
+ .set_next_event = pit_next_event,
};

/*
@@ -172,8 +169,10 @@ struct clock_event_device i8253_clockevent = {
*/
void __init clockevent_i8253_init(bool oneshot)
{
- if (oneshot)
+ if (oneshot) {
i8253_clockevent.features |= CLOCK_EVT_FEAT_ONESHOT;
+ i8253_clockevent.set_state_oneshot = pit_set_oneshot;
+ }
/*
* Start pit with the boot cpu mask. x86 might make it global
* when it is used as broadcast device later.
--
2.4.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/