From 0e2e0112552f98ba5f859b8f6b13343a6528b5c1 Mon Sep 17 00:00:00 2001
From: Marcin Jelinski <marcin.jelinski@nordicsemi.no>
Date: Wed, 15 Jan 2025 16:32:25 +0100
Subject: [PATCH] esb: Add ESB eventis queuing

Added queuing for ESB events.
Events are handled using the system workqueue,
reducing interrupt handling time.
This approach prevents the loss of ESB events that
may occur while the event callback is still being processed.

Ref: NCSDK-30467

Signed-off-by: Marcin Jelinski <marcin.jelinski@nordicsemi.no>
---
 .../releases/release-notes-changelog.rst      |  6 +-
 subsys/esb/esb.c                              | 69 ++++++++++++++-----
 2 files changed, 58 insertions(+), 17 deletions(-)

diff --git a/doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst b/doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst
index 8c79658b7d5f..90ae2804d3d7 100644
--- a/doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst
+++ b/doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst
@@ -125,7 +125,11 @@ DECT NR+
 Enhanced ShockBurst (ESB)
 -------------------------
 
-* Added loading of radio trims and a fix of a hardware errata for the nRF54H20 SoC to improve the RF performance.
+* Added:
+
+  * Loading of radio trims and a fix of a hardware errata for the nRF54H20 SoC to improve the RF performance.
+  * Queuing for ESB events.
+    Events are handled using the ``System Workqueue``.
 
 Gazell
 ------
diff --git a/subsys/esb/esb.c b/subsys/esb/esb.c
index e391491234f4..95360d16f0e9 100644
--- a/subsys/esb/esb.c
+++ b/subsys/esb/esb.c
@@ -277,6 +277,19 @@ static volatile uint32_t wait_for_ack_timeout_us;
 static uint32_t radio_shorts_common = RADIO_SHORTS_COMMON;
 static const bool fast_switching = IS_ENABLED(CONFIG_ESB_FAST_SWITCHING);
 
+/* Event work handler function */
+static void evt_work_handler(struct k_work *work);
+
+/* Structure representing an ESB event with associated work */
+struct esb_evt_irq {
+	struct esb_evt event;
+	struct k_work work;
+};
+
+#define ESB_EVENT_QUEUE_SIZE (CONFIG_ESB_TX_FIFO_SIZE + CONFIG_ESB_RX_FIFO_SIZE)
+static uint32_t evt_irq_idx;
+static struct esb_evt_irq evt_irq[ESB_EVENT_QUEUE_SIZE];
+
 static const mpsl_fem_event_t rx_event = {
 	.type = MPSL_FEM_EVENT_TYPE_TIMER,
 	.event.timer = {
@@ -948,6 +961,13 @@ static void initialize_fifos(void)
 	}
 }
 
+static void initialize_event_work(void)
+{
+	for (size_t i = 0; i < ESB_EVENT_QUEUE_SIZE; i++) {
+		k_work_init(&evt_irq[i].work, evt_work_handler);
+	}
+}
+
 static void tx_fifo_remove_last(void)
 {
 	if (tx_fifo.count == 0) {
@@ -1597,30 +1617,46 @@ static void radio_irq_handler(void)
 #endif /* defined(CONFIG_ESB_FAST_CHANNEL_SWITCHING) */
 }
 
-static void esb_evt_irq_handler(void)
+static void evt_work_handler(struct k_work *work)
+{
+	struct esb_evt_irq *evt = CONTAINER_OF(work, struct esb_evt_irq, work);
+
+	if (event_handler != NULL) {
+		event_handler(&evt->event);
+	}
+}
+
+static void event_handle(uint32_t interrupts, uint32_t interrupt_mask, uint32_t event_id)
 {
-	uint32_t interrupts;
 	struct esb_evt event;
 
-	event.tx_attempts = last_tx_attempts;
+	if (interrupts & interrupt_mask) {
+		event.tx_attempts = last_tx_attempts;
+		event.evt_id = event_id;
+		evt_irq[evt_irq_idx].event = event;
+		k_work_submit(&evt_irq[evt_irq_idx].work);
 
-	get_and_clear_irqs(&interrupts);
-	if (event_handler != NULL) {
-		if (interrupts & INT_TX_SUCCESS_MSK) {
-			event.evt_id = ESB_EVENT_TX_SUCCESS;
-			event_handler(&event);
-		}
-		if (interrupts & INT_TX_FAILED_MSK) {
-			event.evt_id = ESB_EVENT_TX_FAILED;
-			event_handler(&event);
-		}
-		if (interrupts & INT_RX_DATA_RECEIVED_MSK) {
-			event.evt_id = ESB_EVENT_RX_RECEIVED;
-			event_handler(&event);
+		if (++evt_irq_idx >= ESB_EVENT_QUEUE_SIZE) {
+			evt_irq_idx = 0;
 		}
 	}
 }
 
+static void event_push(uint32_t interrupts)
+{
+	event_handle(interrupts, INT_TX_SUCCESS_MSK, ESB_EVENT_TX_SUCCESS);
+	event_handle(interrupts, INT_TX_FAILED_MSK, ESB_EVENT_TX_FAILED);
+	event_handle(interrupts, INT_RX_DATA_RECEIVED_MSK, ESB_EVENT_RX_RECEIVED);
+}
+
+static void esb_evt_irq_handler(void)
+{
+	uint32_t interrupts;
+
+	get_and_clear_irqs(&interrupts);
+	event_push(interrupts);
+}
+
 #if IS_ENABLED(CONFIG_ESB_DYNAMIC_INTERRUPTS)
 
 static void radio_dynamic_irq_handler(const void *args)
@@ -1723,6 +1759,7 @@ int esb_init(const struct esb_config *config)
 	nrf_radio_prefix1_set(NRF_RADIO, 0x13E363A3);
 
 	initialize_fifos();
+	initialize_event_work();
 
 	err = sys_timer_init();
 	if (err) {