gdb_server, target: Add target_address_bits()

Targets can use this to expose how many address bits there are.
gdb_server uses this to send gdb the appropriate upper limit in the
memory-map. (Before this change the upper limit would only be correct
for 32-bit targets.)

Change-Id: Idb0933255ed53951fcfb05e040674bcdf19441e1
Signed-off-by: Tim Newsome <tim@sifive.com>
Reviewed-on: http://openocd.zylin.com/4947
Tested-by: jenkins
Reviewed-by: Peter Mamonov <pmamonov@gmail.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

src/target/target.c

@@ -1257,6 +1257,22 @@ int target_gdb_fileio_end(struct target *target, int retcode, int fileio_errno,
 	return target->type->gdb_fileio_end(target, retcode, fileio_errno, ctrl_c);
 }
 
+target_addr_t target_address_max(struct target *target)
+{
+	unsigned bits = target_address_bits(target);
+	if (sizeof(target_addr_t) * 8 == bits)
+		return (target_addr_t) -1;
+	else
+		return (((target_addr_t) 1) << bits) - 1;
+}
+
+unsigned target_address_bits(struct target *target)
+{
+	if (target->type->address_bits)
+		return target->type->address_bits(target);
+	return 32;
+}
+
 int target_profiling(struct target *target, uint32_t *samples,
 			uint32_t max_num_samples, uint32_t *num_samples, uint32_t seconds)
 {