mpsl: provide implementation for NVM low-latency request and release

The MPSL library expects implementations of two new public functions
declared in mpsl.h. MPSL calls them to request and release low-latency
mode on the NVM controller.

The integration layer supplies this for all MPSL users in the SDK.
It builds on the nrf_sys_event subsystem, which is required whenever
MPSL is enabled in the application configuration.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>

Author: ppryga-nordic

subsys/mpsl/init/mpsl_init.c

@@ -23,6 +23,10 @@
 #if IS_ENABLED(CONFIG_SOC_COMPATIBLE_NRF54LX)
 #include <nrfx_power.h>
 #endif
+#if IS_ENABLED(CONFIG_SOC_SERIES_NRF54L)
+#include <nrf_sys_event.h>
+#endif
+
 #if defined(CONFIG_SOC_SERIES_NRF54H)
 #include <hal/nrf_dppi.h>
 #endif
@@ -190,6 +194,12 @@ static struct k_work mpsl_low_prio_work;
 struct k_work_q mpsl_work_q;
 static K_THREAD_STACK_DEFINE(mpsl_work_stack, CONFIG_MPSL_WORK_STACK_SIZE);
 
+#if IS_ENABLED(CONFIG_SOC_SERIES_NRF54L) && !IS_ENABLED(CONFIG_TRUSTED_EXECUTION_NONSECURE)
+#if IS_ENABLED(CONFIG_NRF_SYS_EVENT_IRQ_LATENCY)
+static int m_nvm_low_latency_event_handle = -1;
+#endif /* IS_ENABLED(CONFIG_NRF_SYS_EVENT_IRQ_LATENCY) */
+#endif /* IS_ENABLED(CONFIG_SOC_SERIES_NRF54L) && !IS_ENABLED(CONFIG_TRUSTED_EXECUTION_NONSECURE) */
+
 #define MPSL_TIMESLOT_SESSION_COUNT (\
 	CONFIG_MPSL_TIMESLOT_SESSION_COUNT + \
 	CONFIG_SOC_FLASH_NRF_RADIO_SYNC_MPSL_TIMESLOT_SESSION_COUNT)
@@ -603,6 +613,35 @@ void mpsl_lowpower_request_callback(void)
 	nrf_power_task_trigger(NRF_POWER, NRF_POWER_TASK_LOWPWR);
 #endif
 }
+
+void mpsl_nvm_low_latency_request_callback(void)
+{
+#if IS_ENABLED(CONFIG_NRF_SYS_EVENT_IRQ_LATENCY) && !IS_ENABLED(CONFIG_TRUSTED_EXECUTION_NONSECURE)
+	int event_handle = nrf_sys_event_register(0, true);
+
+	if (event_handle < 0) {
+		LOG_ERR("NVM low latency request has failed (%d)", event_handle);
+	}
+
+	m_nvm_low_latency_event_handle = event_handle;
+#endif /* IS_ENABLED(CONFIG_NRF_SYS_EVENT_IRQ_LATENCY) &&                                          \
+	  !IS_ENABLED(CONFIG_TRUSTED_EXECUTION_NONSECURE) */
+}
+
+void mpsl_nvm_low_latency_release_callback(void)
+{
+#if IS_ENABLED(CONFIG_NRF_SYS_EVENT_IRQ_LATENCY) && !IS_ENABLED(CONFIG_TRUSTED_EXECUTION_NONSECURE)
+
+	int ret = nrf_sys_event_unregister(m_nvm_low_latency_event_handle, false);
+	if (ret != 0) {
+		LOG_ERR("NVM low latency release has failed (%d)", ret);
+	}
+
+	m_nvm_low_latency_event_handle = -1;
+#endif /* IS_ENABLED(CONFIG_NRF_SYS_EVENT_IRQ_LATENCY) &&                                          \
+	  !IS_ENABLED(CONFIG_TRUSTED_EXECUTION_NONSECURE) */
+}
+
 #endif /* defined(CONFIG_SOC_COMPATIBLE_NRF54LX) */
 
 #if defined(CONFIG_MPSL_USE_EXTERNAL_CLOCK_CONTROL)