drivers: memc: MAX32 memc linker support improvements

In order to allow the linker to place certain objects into external RAM,
e.g. heaps, adjust the memc initialization level to PRE_KERNEL_1, allowing
clock control and memc to come up before priority objects like heaps are
initialized.

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

Author: petejohanson-adi

drivers/memc/Kconfig.max32_hpb

@@ -8,3 +8,10 @@ config MEMC_MAX32_HPB
 	select PINCTRL
 	help
 	  Enable ADI MAX32 HyperBus controller.
+
+	  If you want to rely on the linker to place symbols in this memory
+	  (using`zephyr_code_relocate() or Z_GENERIC_SECTION()), you have to
+	  ensure this driver in initialized before KERNEL_INIT_PRIORITY_OBJECTS
+	  (=30). In addition, this driver depends on a clock, so you have to
+	  ensure the clock will be started before this driver as well (see
+	  CLOCK_CONTROL_INIT_PRIORITY)

drivers/memc/memc_max32_hpb.c

@@ -136,5 +136,5 @@ static const struct memc_max32_hpb_config config = {
 	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(0),
 };
 
-DEVICE_DT_INST_DEFINE(0, memc_max32_hpb_init, NULL, NULL, &config, POST_KERNEL,
+DEVICE_DT_INST_DEFINE(0, memc_max32_hpb_init, NULL, NULL, &config, PRE_KERNEL_1,
 		      CONFIG_MEMC_INIT_PRIORITY, NULL);

tests/drivers/memc/ram/boards/apard32690_max32690_m4.conf

@@ -0,0 +1,4 @@
+CONFIG_ZTEST=y
+CONFIG_MEMC=y
+CONFIG_CLOCK_CONTROL_INIT_PRIORITY=15
+CONFIG_MEMC_INIT_PRIORITY=20