retention: Allow earlier initalization

Add Kconfig options to allow initializing retained mem and retention in
PRE_KERNEL_1 phase for platforms that require jumping to the bootloader
very early in the startup process.

Signed-off-by: Peter Johanson <[email protected]>

Author: petejohanson

drivers/retained_mem/Kconfig

@@ -15,6 +15,11 @@ config RETAINED_MEM_INIT_PRIORITY
 	help
 	  Retained memory devices initialization priority,
 
+config RETAINED_MEM_INIT_LEVEL_PRE_KERNEL_1
+	bool "Retained memory devices init during PRE_KERNEL_1"
+	help
+	  Retained memory devices initialization during PRE_KERNEL_1 level
+
 config RETAINED_MEM_MUTEXES
 	bool
 	default y

drivers/retained_mem/retained_mem_zephyr_ram.c

@@ -126,6 +126,12 @@ static DEVICE_API(retained_mem, zephyr_retained_mem_ram_api) = {
 	.clear = zephyr_retained_mem_ram_clear,
 };
 
+#if defined(CONFIG_RETAINED_MEM_INIT_LEVEL_PRE_KERNEL_1)
+#define RETAINED_MEM_LEVEL PRE_KERNEL_1
+#else
+#define RETAINED_MEM_LEVEL POST_KERNEL
+#endif
+
 #define ZEPHYR_RETAINED_MEM_RAM_DEVICE(inst)							\
 	IF_ENABLED(CONFIG_RETAINED_MEM_MUTEXES,							\
 		   (static struct zephyr_retained_mem_ram_data					\
@@ -143,7 +149,7 @@ static DEVICE_API(retained_mem, zephyr_retained_mem_ram_api) = {
 					  (&zephyr_retained_mem_ram_data_##inst), (NULL)	\
 			      ),								\
 			      &zephyr_retained_mem_ram_config_##inst,				\
-			      POST_KERNEL,							\
+			      RETAINED_MEM_LEVEL,						\
 			      CONFIG_RETAINED_MEM_INIT_PRIORITY,				\
 			      &zephyr_retained_mem_ram_api);
 

subsys/retention/Kconfig

@@ -12,6 +12,11 @@ menuconfig RETENTION
 
 if RETENTION
 
+config RETENTION_INIT_LEVEL_PRE_KERNEL_1
+	bool "Retention device init during PRE_KERNEL_1"
+	help
+	  Retention device initialization during PRE_KERNEL_1 level
+
 config RETENTION_INIT_PRIORITY
 	int "Retention devices init priority"
 	default 86

subsys/retention/retention.c

@@ -400,6 +400,13 @@ static const struct retention_api retention_api = {
 	.clear = retention_clear,
 };
 
+#if defined(CONFIG_RETENTION_INIT_LEVEL_PRE_KERNEL_1)
+#define RETENTION_INIT_LEVEL PRE_KERNEL_1
+#else
+#define RETENTION_INIT_LEVEL POST_KERNEL
+#endif
+
+
 #define RETENTION_DEVICE(inst)									\
 	static struct retention_data								\
 		retention_data_##inst = {							\
@@ -423,7 +430,7 @@ static const struct retention_api retention_api = {
 			      NULL,								\
 			      &retention_data_##inst,						\
 			      &retention_config_##inst,						\
-			      POST_KERNEL,							\
+			      RETENTION_INIT_LEVEL,						\
 			      CONFIG_RETENTION_INIT_PRIORITY,					\
 			      &retention_api);