tools/power/x86/intel-speed-select: Max CPU count calculation when CPU0 is offline

task #29499913

commit 864dc09e692f55fc7a5a87c7411da0a348ac1094 upstream

Currently /sys/devices/system/cpu/cpu0/topology/thread_siblings is used to
get the max CPU count. But when CPU0 is offline, then this file will be
absent.

So add processing so that we can get count from any first CPU in the
system. which is online.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NErwei Deng <erwei@linux.alibaba.com>
Reviewed-by: NArtie Ding <artie.ding@linux.alibaba.com>

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

@@ -316,10 +316,24 @@ static void set_max_cpu_num(void)
 {
 	FILE *filep;
 	unsigned long dummy;
+	int i;
 
 	topo_max_cpus = 0;
-	filep = fopen_or_exit(
-		"/sys/devices/system/cpu/cpu0/topology/thread_siblings", "r");
+	for (i = 0; i < 256; ++i) {
+		char path[256];
+
+		snprintf(path, sizeof(path),
+			 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings", i);
+		filep = fopen(path, "r");
+		if (filep)
+			break;
+	}
+
+	if (!filep) {
+		fprintf(stderr, "Can't get max cpu number\n");
+		exit(0);
+	}
+
 	while (fscanf(filep, "%lx,", &dummy) == 1)
 		topo_max_cpus += BITMASK_SIZE;
 	fclose(filep);