[nrf fromlist] drv: nordic_vpr_launcher: manage data cache

Write-back cache after copying VPR's code and data to the destination
memory. It allows VPRs to run from RAM regions cacheable by its host.

It allows to use FLPR in nRF54H20.

Upstream PR #: 84104

Signed-off-by: Hubert Miś <hubert.mis@nordicsemi.no>

drivers/misc/nordic_vpr_launcher/nordic_vpr_launcher.c

@@ -7,6 +7,7 @@
 
 #include <string.h>
 
+#include <zephyr/cache.h>
 #include <zephyr/devicetree.h>
 #include <zephyr/init.h>
 #include <zephyr/logging/log.h>
@@ -38,6 +39,11 @@ static int nordic_vpr_launcher_init(const struct device *dev)
 		LOG_DBG("Loading VPR (%p) from %p to %p (%zu bytes)", config->vpr,
 			(void *)config->src_addr, (void *)config->exec_addr, config->size);
 		memcpy((void *)config->exec_addr, (void *)config->src_addr, config->size);
+#if defined(CONFIG_DCACHE)
+		LOG_DBG("Writing back cache with loaded VPR (from %p %zu bytes)",
+			(void *)config->exec_addr, config->size);
+		sys_cache_data_flush_range((void *)config->exec_addr, config->size);
+#endif
 	}
 #endif