soc: stm32mp2x: m33: Add soc_early_init_hook to set system clock property

Add soc_early_init_hook() function to update the SystemCoreClock variable,
which represents the reference clock.

Signed-off-by: Arnaud Pouliquen <[email protected]>

Author: arnopo

soc/st/stm32/stm32mp2x/Kconfig

@@ -12,6 +12,7 @@ config SOC_STM32MP2X_M33
 	select ARMV8_M_DSP
 	select ARM_TRUSTZONE_M
 	select CPU_CORTEX_M33
+	select SOC_EARLY_INIT_HOOK
 	select CPU_CORTEX_M_HAS_DWT
 	select CPU_HAS_ARM_MPU
 	select CPU_HAS_ARM_SAU

soc/st/stm32/stm32mp2x/m33/CMakeLists.txt

@@ -3,6 +3,9 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_include_directories(${ZEPHYR_BASE}/drivers)
+zephyr_sources(
+  soc.c
+)
 
 zephyr_include_directories(.)
 

soc/st/stm32/stm32mp2x/m33/soc.c

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2025 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief STM32MP25 Cortex-M33 initialization code
+ */
+
+#include <soc.h>
+
+/**
+ * @brief Perform basic hardware initialization at boot.
+ *
+ * This needs to be run from the very beginning.
+ */
+void soc_early_init_hook(void)
+{
+	/* Update CMSIS SystemCoreClock variable (HCLK) */
+	SystemCoreClockUpdate();
+}