target/riscv: Ensure to handle all triggered a halt events

If all current halted states are due to a halt group, then
a new "triggered a halt" event has occurred.

src/target/riscv/riscv.c

@@ -3743,6 +3743,7 @@ int riscv_openocd_poll(struct target *target)
 	unsigned int should_resume = 0;
 	unsigned int halted = 0;
 	unsigned int running = 0;
+	unsigned int cause_groups = 0;
 	struct target_list *entry;
 	foreach_smp_target(entry, targets) {
 		struct target *t = entry->target;
@@ -3790,6 +3791,22 @@ int riscv_openocd_poll(struct target *target)
 		LOG_TARGET_DEBUG(target, "resume all");
 		riscv_resume(target, true, 0, 0, 0, false);
 	} else if (halted && running) {
+		foreach_smp_target(entry, targets)
+                {
+                        struct target *t = entry->target;
+                        if (t->state == TARGET_HALTED) {
+				riscv_reg_t dcsr;
+				if (riscv_reg_get(t, &dcsr, GDB_REGNO_DCSR) != ERROR_OK)
+					return ERROR_FAIL;
+				if (get_field(dcsr, CSR_DCSR_CAUSE) == CSR_DCSR_CAUSE_GROUP)
+					cause_groups++;
+				else
+					break;
+			}
+                }
+		if (halted == cause_groups)
+			return ERROR_OK;
+
 		LOG_TARGET_DEBUG(target, "halt all; halted=%d",
 			halted);
 		riscv_halt(target);