[PATCH] eventdev/timer: add API to get remaining ticks

[Erik Gabriel Carrillo <erik.g.carrillo@intel.com>]

Introduce an event timer adapter API which allows users to determine how
many adapter ticks remain until an event timer fires.

Signed-off-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
---
 app/test/test_event_timer_adapter.c    | 68 ++++++++++++++++++++++++++
 lib/eventdev/event_timer_adapter_pmd.h |  7 +++
 lib/eventdev/rte_event_timer_adapter.c | 52 ++++++++++++++++++++
 lib/eventdev/rte_event_timer_adapter.h | 27 ++++++++++
 lib/eventdev/version.map               |  3 ++
 5 files changed, 157 insertions(+)

diff --git a/app/test/test_event_timer_adapter.c b/app/test/test_event_timer_adapter.c
index 1a440dfd10..6529b14ff9 100644
--- a/app/test/test_event_timer_adapter.c
+++ b/app/test/test_event_timer_adapter.c
@@ -1920,6 +1920,72 @@ adapter_create_max(void)
 	return TEST_SUCCESS;
 }
 
+static inline int
+test_timer_ticks_remaining(void)
+{
+	uint64_t ticks_remaining = UINT64_MAX;
+	struct rte_event_timer *ev_tim;
+	struct rte_event ev;
+	int ret, i;
+	const struct rte_event_timer tim = {
+		.ev.op = RTE_EVENT_OP_NEW,
+		.ev.queue_id = 0,
+		.ev.sched_type = RTE_SCHED_TYPE_ATOMIC,
+		.ev.priority = RTE_EVENT_DEV_PRIORITY_NORMAL,
+		.ev.event_type =  RTE_EVENT_TYPE_TIMER,
+		.state = RTE_EVENT_TIMER_NOT_ARMED,
+	};
+
+	rte_mempool_get(eventdev_test_mempool, (void **)&ev_tim);
+	*ev_tim = tim;
+	ev_tim->ev.event_ptr = ev_tim;
+#define TEST_TICKS 5
+	ev_tim->timeout_ticks = CALC_TICKS(TEST_TICKS);
+
+	/* Test that unarmed timer returns error */
+	TEST_ASSERT_FAIL(rte_event_timer_ticks_remaining_get(timdev, ev_tim,
+							     &ticks_remaining),
+			 "Didn't fail to get ticks for unarmed event timer");
+
+	TEST_ASSERT_EQUAL(rte_event_timer_arm_burst(timdev, &ev_tim, 1), 1,
+			  "Failed to arm timer with proper timeout.");
+	TEST_ASSERT_EQUAL(ev_tim->state, RTE_EVENT_TIMER_ARMED,
+			  "Improper timer state set expected %d returned %d",
+			  RTE_EVENT_TIMER_ARMED, ev_tim->state);
+
+	for (i = 0; i < TEST_TICKS; i++) {
+		ret = rte_event_timer_ticks_remaining_get(timdev, ev_tim,
+							  &ticks_remaining);
+		if (ret < 0)
+			return TEST_FAILED;
+
+		TEST_ASSERT_EQUAL((int)ticks_remaining, TEST_TICKS - i,
+				  "Expected %d ticks remaining, got %"PRIu64"",
+				  TEST_TICKS - i, ticks_remaining);
+
+		rte_delay_ms(100);
+	}
+
+	rte_delay_ms(100);
+
+	TEST_ASSERT_EQUAL(rte_event_dequeue_burst(evdev, 0, &ev, 1, 0), 1,
+			  "Armed timer failed to trigger.");
+	TEST_ASSERT_EQUAL(ev_tim->state, RTE_EVENT_TIMER_NOT_ARMED,
+			  "Improper timer state set expected %d returned %d",
+			  RTE_EVENT_TIMER_NOT_ARMED, ev_tim->state);
+
+	/* Test that timer that fired returns error */
+	TEST_ASSERT_FAIL(rte_event_timer_ticks_remaining_get(timdev, ev_tim,
+							   &ticks_remaining),
+			 "Didn't fail to get ticks for unarmed event timer");
+
+	rte_mempool_put(eventdev_test_mempool, (void *)ev_tim);
+
+#undef TEST_TICKS
+	return TEST_SUCCESS;
+}
+
+
 static struct unit_test_suite event_timer_adptr_functional_testsuite  = {
 	.suite_name = "event timer functional test suite",
 	.setup = testsuite_setup,
@@ -1982,6 +2048,8 @@ static struct unit_test_suite event_timer_adptr_functional_testsuite  = {
 		TEST_CASE_ST(timdev_setup_msec, timdev_teardown,
 				adapter_tick_resolution),
 		TEST_CASE(adapter_create_max),
+		TEST_CASE_ST(timdev_setup_msec, timdev_teardown,
+				test_timer_ticks_remaining),
 		TEST_CASES_END() /**< NULL terminate unit test array */
 	}
 };
diff --git a/lib/eventdev/event_timer_adapter_pmd.h b/lib/eventdev/event_timer_adapter_pmd.h
index 189017b5c1..c19ff3576a 100644
--- a/lib/eventdev/event_timer_adapter_pmd.h
+++ b/lib/eventdev/event_timer_adapter_pmd.h
@@ -52,6 +52,11 @@ typedef int (*rte_event_timer_adapter_stats_get_t)(
 typedef int (*rte_event_timer_adapter_stats_reset_t)(
 		const struct rte_event_timer_adapter *adapter);
 /**< @internal Reset statistics for event timer adapter */
+typedef int (*rte_event_timer_ticks_remaining_get_t)(
+		const struct rte_event_timer_adapter *adapter,
+		const struct rte_event_timer *evtim,
+		uint64_t *ticks_remaining);
+/**< @internal Get remaining ticks for event timer */
 
 /**
  * @internal Structure containing the functions exported by an event timer
@@ -74,6 +79,8 @@ struct event_timer_adapter_ops {
 	/**< Arm event timers with same expiration time */
 	rte_event_timer_cancel_burst_t		cancel_burst;
 	/**< Cancel one or more event timers */
+	rte_event_timer_ticks_remaining_get_t	ticks_remaining_get;
+	/**< Get remaining ticks for event timer */
 };
 
 /**
diff --git a/lib/eventdev/rte_event_timer_adapter.c b/lib/eventdev/rte_event_timer_adapter.c
index a0f14bf861..e2542e985c 100644
--- a/lib/eventdev/rte_event_timer_adapter.c
+++ b/lib/eventdev/rte_event_timer_adapter.c
@@ -8,6 +8,7 @@
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <math.h>
 
 #include <rte_memzone.h>
 #include <rte_errno.h>
@@ -458,6 +459,21 @@ rte_event_timer_adapter_stats_reset(struct rte_event_timer_adapter *adapter)
 	return adapter->ops->stats_reset(adapter);
 }
 
+int
+rte_event_timer_ticks_remaining_get(
+			const struct rte_event_timer_adapter *adapter,
+			const struct rte_event_timer *evtim,
+			uint64_t *ticks_remaining)
+{
+	ADAPTER_VALID_OR_ERR_RET(adapter, -EINVAL);
+	FUNC_PTR_OR_ERR_RET(adapter->ops->ticks_remaining_get, -ENOTSUP);
+
+	if (ticks_remaining == NULL)
+		return -EINVAL;
+
+	return adapter->ops->ticks_remaining_get(adapter, evtim, ticks_remaining);
+}
+
 /*
  * Software event timer adapter buffer helper functions
  */
@@ -1072,6 +1088,41 @@ swtim_stats_reset(const struct rte_event_timer_adapter *adapter)
 	return 0;
 }
 
+static int
+swtim_ticks_remaining_get(const struct rte_event_timer_adapter *adapter,
+			  const struct rte_event_timer *evtim,
+			  uint64_t *ticks_remaining)
+{
+	uint64_t nsecs_per_adapter_tick, opaque, cycles_remaining;
+	enum rte_event_timer_state n_state;
+	double nsecs_per_cycle;
+	struct rte_timer *tim;
+	uint64_t cur_cycles;
+
+	/* Check that timer is armed */
+	n_state = __atomic_load_n(&evtim->state, __ATOMIC_ACQUIRE);
+	if (n_state != RTE_EVENT_TIMER_ARMED)
+		return -EINVAL;
+
+	opaque = evtim->impl_opaque[0];
+	tim = (struct rte_timer *)(uintptr_t)opaque;
+
+	cur_cycles = rte_get_timer_cycles();
+	if (cur_cycles > tim->expire) {
+		*ticks_remaining = 0;
+		return 0;
+	}
+
+	cycles_remaining = tim->expire - cur_cycles;
+	nsecs_per_cycle = (double)NSECPERSEC / rte_get_timer_hz();
+	nsecs_per_adapter_tick = adapter->data->conf.timer_tick_ns;
+
+	*ticks_remaining = (uint64_t)ceil((cycles_remaining * nsecs_per_cycle) /
+					  nsecs_per_adapter_tick);
+
+	return 0;
+}
+
 static uint16_t
 __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 		struct rte_event_timer **evtims,
@@ -1286,6 +1337,7 @@ static const struct event_timer_adapter_ops swtim_ops = {
 	.arm_burst = swtim_arm_burst,
 	.arm_tmo_tick_burst = swtim_arm_tmo_tick_burst,
 	.cancel_burst = swtim_cancel_burst,
+	.ticks_remaining_get = swtim_ticks_remaining_get,
 };
 
 static int
diff --git a/lib/eventdev/rte_event_timer_adapter.h b/lib/eventdev/rte_event_timer_adapter.h
index cd10db19e4..b05d9b400d 100644
--- a/lib/eventdev/rte_event_timer_adapter.h
+++ b/lib/eventdev/rte_event_timer_adapter.h
@@ -678,6 +678,33 @@ rte_event_timer_cancel_burst(const struct rte_event_timer_adapter *adapter,
 	return adapter->cancel_burst(adapter, evtims, nb_evtims);
 }
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Get the number of ticks remaining until an event timer fires.
+ *
+ * @param adapter
+ *   A pointer to an event timer adapter structure
+ * @param evtim
+ *   A pointer to an rte_event_timer structure
+ * @param[out] ticks_remaining
+ *   Pointer to variable into which to write the number of ticks remaining
+ *   until the event timer fires
+ *
+ * @return
+ *   - 0: Success
+ *   - -EINVAL Invalid timer adapter identifier, ticks_remaining pointer is
+ *   NULL, or the event timer is not in the armed state
+ *   - -ENOTSUP The timer adapter implementation does not support this API.
+ */
+__rte_experimental
+int
+rte_event_timer_ticks_remaining_get(
+			const struct rte_event_timer_adapter *adapter,
+			const struct rte_event_timer *evtim,
+			uint64_t *ticks_remaining);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/eventdev/version.map b/lib/eventdev/version.map
index dd63ec6f68..2a46fd27dc 100644
--- a/lib/eventdev/version.map
+++ b/lib/eventdev/version.map
@@ -118,6 +118,9 @@ EXPERIMENTAL {
 	rte_event_eth_tx_adapter_instance_get;
 	rte_event_eth_tx_adapter_queue_start;
 	rte_event_eth_tx_adapter_queue_stop;
+
+	# added in 23.03
+	rte_event_timer_ticks_remaining_get;
 };
 
 INTERNAL {
-- 
2.25.1