1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * POWER Data Stream Control Register (DSCR) sysfs interface test
4 *
5 * This test updates to system wide DSCR default through the sysfs interface
6 * and then verifies that all the CPU specific DSCR defaults are updated as
7 * well verified from their sysfs interfaces.
8 *
9 * Copyright 2015, Anshuman Khandual, IBM Corporation.
10 */
11#include "dscr.h"
12
13static int check_cpu_dscr_default(char *file, unsigned long val)
14{
15 unsigned long cpu_dscr;
16 int err;
17
18 err = read_ulong(file, &cpu_dscr, 16);
19 if (err)
20 return err;
21
22 if (cpu_dscr != val) {
23 printf("DSCR match failed: %ld (system) %ld (cpu)\n",
24 val, cpu_dscr);
25 return 1;
26 }
27 return 0;
28}
29
30static int check_all_cpu_dscr_defaults(unsigned long val)
31{
32 DIR *sysfs;
33 struct dirent *dp;
34 char file[LEN_MAX];
35
36 sysfs = opendir(CPU_PATH);
37 if (!sysfs) {
38 perror("opendir() failed");
39 return 1;
40 }
41
42 while ((dp = readdir(sysfs))) {
43 int len;
44
45 if (!(dp->d_type & DT_DIR))
46 continue;
47 if (!strcmp(dp->d_name, "cpuidle"))
48 continue;
49 if (!strstr(dp->d_name, "cpu"))
50 continue;
51
52 len = snprintf(file, LEN_MAX, "%s%s/dscr", CPU_PATH, dp->d_name);
53 if (len >= LEN_MAX)
54 continue;
55 if (access(file, F_OK))
56 continue;
57
58 if (check_cpu_dscr_default(file, val)) {
59 closedir(sysfs);
60 return 1;
61 }
62 }
63 closedir(sysfs);
64 return 0;
65}
66
67int dscr_sysfs(void)
68{
69 unsigned long orig_dscr_default;
70
71 SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
72
73 orig_dscr_default = get_default_dscr();
74 for (int i = 0; i < DSCR_MAX; i++) {
75 set_default_dscr(i);
76 if (check_all_cpu_dscr_defaults(val: i))
77 goto fail;
78 }
79 set_default_dscr(orig_dscr_default);
80 return 0;
81fail:
82 set_default_dscr(orig_dscr_default);
83 return 1;
84}
85
86int main(int argc, char *argv[])
87{
88 return test_harness(dscr_sysfs, "dscr_sysfs_test");
89}
90

source code of linux/tools/testing/selftests/powerpc/dscr/dscr_sysfs_test.c