[nrf noup] soc: nordic: nrf54h20: Turn off MRAM suspend

Turn off suspending MRAM for nRF54H20 SoC.
This change is required so sections of code depending on critical
timings will not have unacceptable latency.

Signed-off-by: Jan Zyczkowski <[email protected]>
Signed-off-by: Gerard Marull-Paretas <[email protected]>
(cherry picked from commit 58284ff)
(cherry picked from commit 9b6cae8)
(cherry picked from commit 2c2f60d)

soc/nordic/nrf54h/CMakeLists.txt

@@ -12,6 +12,8 @@ zephyr_library_sources_ifdef(CONFIG_PM_S2RAM pm_s2ram.c)
 
 zephyr_include_directories(.)
 
+zephyr_library_sources_ifdef(CONFIG_SOC_NRF54H20_NO_MRAM_LATENCY mram.c)
+
 # Ensure that image size aligns with 16 bytes so that MRAMC finalizes all writes
 # for the image correctly
 zephyr_linker_sources(SECTIONS SORT_KEY zzz_place_align_at_end align.ld)

soc/nordic/nrf54h/Kconfig

@@ -75,3 +75,9 @@ config SOC_NRF54H20_CPUFLPR
 
 config SOC_NRF54H20_ENGB_CPUFLPR
 	depends on RISCV_CORE_NORDIC_VPR
+
+config SOC_NRF54H20_NO_MRAM_LATENCY
+	bool "Disallow MRAM latency"
+	imply NRFS
+	imply NRFS_MRAM_SERVICE_ENABLED
+	default y if SOC_NRF54H20_CPUAPP || SOC_NRF54H20_ENGB_CPUAPP

soc/nordic/nrf54h/mram.c

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/init.h>
+#include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/toolchain.h>
+
+#include <services/nrfs_mram.h>
+#include <nrfs_backend_ipc_service.h>
+
+LOG_MODULE_REGISTER(mram, CONFIG_SOC_LOG_LEVEL);
+
+static void mram_latency_handler(nrfs_mram_latency_evt_t const *p_evt, void *context)
+{
+	ARG_UNUSED(context);
+
+	switch (p_evt->type) {
+	case NRFS_MRAM_LATENCY_REQ_APPLIED:
+		LOG_DBG("MRAM latency not allowed setting applied");
+		break;
+	case NRFS_MRAM_LATENCY_REQ_REJECTED:
+		LOG_ERR("MRAM latency not allowed setting rejected");
+		k_panic();
+		break;
+	default:
+		LOG_WRN("Unexpected event: %d", p_evt->type);
+	}
+}
+
+/* Turn off mram automatic suspend as it causes delays in time depended code sections. */
+static int turn_off_suspend_mram(void)
+{
+	nrfs_err_t err;
+
+	/* Wait for ipc initialization */
+	nrfs_backend_wait_for_connection(K_FOREVER);
+
+	err = nrfs_mram_init(mram_latency_handler);
+	if (err != NRFS_SUCCESS) {
+		LOG_ERR("MRAM service init failed: %d", err);
+		return -EIO;
+	}
+
+	LOG_DBG("MRAM service initialized, disallow latency");
+
+	err = nrfs_mram_set_latency(MRAM_LATENCY_NOT_ALLOWED, NULL);
+	if (err != NRFS_SUCCESS) {
+		LOG_ERR("MRAM: set latency failed (%d)", err);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+SYS_INIT(turn_off_suspend_mram, APPLICATION, 90);