soc: arm: stm32u5 device with DCACHE for writing to NOR flash

Enable the DCACHE1 in INCR burt mode to allow writing to the external
NOR octoFlash when in MemoryMapped mode

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

soc/arm/st_stm32/stm32u5/soc.c

@@ -14,6 +14,7 @@
 #include <stm32_ll_bus.h>
 #include <stm32_ll_pwr.h>
 #include <stm32_ll_icache.h>
+#include <stm32_ll_dcache.h>
 #include <zephyr/logging/log.h>
 
 #include <cmsis_core.h>
@@ -35,6 +36,10 @@ static int stm32u5_init(void)
 	LL_ICACHE_SetMode(LL_ICACHE_1WAY);
 	LL_ICACHE_Enable();
 
+	/* Enable data cache (master port write access) */
+	LL_DCACHE_SetReadBurstType(DCACHE1, LL_DCACHE_READ_BURST_INCR);
+	LL_DCACHE_Enable(DCACHE1);
+
 	/* Update CMSIS SystemCoreClock variable (HCLK) */
 	/* At reset, system core clock is set to 4 MHz from MSIS */
 	SystemCoreClock = 4000000;