Bluetooth: controller: openisa: Fix to use compiler memory barrier

Fix OpenISA port to include compiler memory barrier as in
commit 1a14f8b3a6 ("Bluetooth: controller: Use DMB instead
of DSB").

Relates to commit 1af2b91c23 ("Bluetooth: controller: Fix
Tx Buffer Overflow") and to commit ef2ece82c0 ("Bluetooth:
controller: openisa: Fix sanitycheck failures") and to
commit c2fc629dd2 ("Bluetooth: controller: 255 byte AD
payload support").

Fixes #31937.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>

subsys/bluetooth/controller/ll_sw/openisa/hal/cpu.h

@@ -11,3 +11,12 @@ static inline void cpu_sleep(void)
 	/* __SEV(); */
 	__WFE();
 }
+
+static inline void cpu_dmb(void)
+{
+	/* FIXME: Add necessary host machine required Data Memory Barrier
+	 *        instruction alongwith the below defined compiler memory
+	 *        clobber.
+	 */
+	__asm__ volatile ("" : : : "memory");
+}

subsys/bluetooth/controller/ll_sw/openisa/lll/lll_adv.c

@@ -7,12 +7,12 @@
 #include <stdbool.h>
 #include <stddef.h>
 
-#include <zephyr/types.h>
+#include <toolchain.h>
+#include <soc.h>
+#include <bluetooth/hci.h>
 #include <sys/byteorder.h>
 
-#include <toolchain.h>
-#include <bluetooth/hci.h>
-
+#include "hal/cpu.h"
 #include "hal/ccm.h"
 #include "hal/radio.h"
 #include "hal/ticker.h"
@@ -40,7 +40,6 @@
 
 #define LOG_MODULE_NAME bt_ctlr_llsw_openisa_lll_adv
 #include "common/log.h"
-#include <soc.h>
 #include "hal/debug.h"
 
 static int init_reset(void);
@@ -212,14 +211,11 @@ struct pdu_adv *lll_adv_pdu_alloc(struct lll_adv_pdu *pdu, uint8_t *idx)
 		uint8_t first_latest;
 
 		pdu->last = first;
-		/* FIXME: Ensure that data is synchronized so that an ISR
+		/* NOTE: Ensure that data is synchronized so that an ISR
 		 *        vectored, after pdu->last has been updated, does
-		 *        access the latest value. __DMB() is used in ARM
-		 *        Cortex M4 architectures. Use appropriate
-		 *        instructions on other platforms.
-		 *
-		 *        cpu_dmb();
+		 *        access the latest value.
 		 */
+		cpu_dmb();
 		first_latest = pdu->first;
 		if (first_latest != first) {
 			last++;

subsys/bluetooth/controller/ll_sw/openisa/lll/lll_conn.c

@@ -8,16 +8,17 @@
 #include <stddef.h>
 
 #include <toolchain.h>
-#include <zephyr/types.h>
+#include <soc.h>
 #include <sys/util.h>
 
+#include "hal/cpu.h"
+#include "hal/ccm.h"
+#include "hal/radio.h"
+
 #include "util/mem.h"
 #include "util/memq.h"
 #include "util/mfifo.h"
 
-#include "hal/ccm.h"
-#include "hal/radio.h"
-
 #include "pdu.h"
 
 #include "lll.h"
@@ -29,7 +30,6 @@
 
 #define LOG_MODULE_NAME bt_ctlr_llsw_openisa_lll_conn
 #include "common/log.h"
-#include <soc.h>
 #include "hal/debug.h"
 
 static int init_reset(void);