tools/power/x86/intel-speed-select: Add option to delay mbox commands

Add option "p|--pause" to introduce delay between two mail box commands
for test purpose. This delay can be specified in milliseconds. By default
there is no delay between two mailbox commands.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

tools/power/x86/intel-speed-select/isst-config.c

@@ -44,6 +44,8 @@ static int force_online_offline;
 static int auto_mode;
 static int fact_enable_fail;
 
+static int mbox_delay;
+
 /* clos related */
 static int current_clos = -1;
 static int clos_epp = -1;
@@ -788,6 +790,9 @@ int isst_send_mbox_command(unsigned int cpu, unsigned char command,
 	mbox_cmds.mbox_cmd[0].parameter = parameter;
 	mbox_cmds.mbox_cmd[0].req_data = req_data;
 
+	if (mbox_delay)
+		usleep(mbox_delay * 1000);
+
 	fd = open(pathname, O_RDWR);
 	if (fd < 0)
 		err(-1, "%s open failed", pathname);
@@ -2599,6 +2604,7 @@ static void usage(void)
 	printf("\t[-i|--info] : Print platform information\n");
 	printf("\t[-o|--out] : Output file\n");
 	printf("\t\t\tDefault : stderr\n");
+	printf("\t[-p|--pause] : Delay between two mail box commands in milliseconds\n");
 	printf("\t[-v|--version] : Print version\n");
 
 	printf("\nResult format\n");
@@ -2630,6 +2636,7 @@ static void print_version(void)
 static void cmdline(int argc, char **argv)
 {
 	const char *pathname = "/dev/isst_interface";
+	char *ptr;
 	FILE *fp;
 	int opt;
 	int option_index = 0;
@@ -2641,6 +2648,7 @@ static void cmdline(int argc, char **argv)
 		{ "format", required_argument, 0, 'f' },
 		{ "help", no_argument, 0, 'h' },
 		{ "info", no_argument, 0, 'i' },
+		{ "pause", required_argument, 0, 'p' },
 		{ "out", required_argument, 0, 'o' },
 		{ "version", no_argument, 0, 'v' },
 		{ 0, 0, 0, 0 }
@@ -2694,6 +2702,13 @@ static void cmdline(int argc, char **argv)
 				fclose(outf);
 			outf = fopen_or_exit(optarg, "w");
 			break;
+		case 'p':
+			ret = strtol(optarg, &ptr, 10);
+			if (!ret)
+				fprintf(stderr, "Invalid pause interval, ignore\n");
+			else
+				mbox_delay = ret;
+			break;
 		case 'v':
 			print_version();
 			break;