tools/testing/selftests/powerpc/dscr/dscr_sysfs_test.c

   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
  13 static int check_cpu_dscr_default(char *file, unsigned long val)
  14 {
  15         char buf[10];
  16         int fd, rc;
  17
  18         fd = open(file, O_RDWR);
  19         if (fd == -1) {
  20                 perror("open() failed");
  21                 return 1;
  22         }
  23
  24         rc = read(fd, buf, sizeof(buf));
  25         if (rc == -1) {
  26                 perror("read() failed");
  27                 return 1;
  28         }
  29         close(fd);
  30
  31         buf[rc] = '\0';
  32         if (strtol(buf, NULL, 16) != val) {
  33                 printf("DSCR match failed: %ld (system) %ld (cpu)\n",
  34                                         val, strtol(buf, NULL, 16));
  35                 return 1;
  36         }
  37         return 0;
  38 }
  39
  40 static int check_all_cpu_dscr_defaults(unsigned long val)
  41 {
  42         DIR *sysfs;
  43         struct dirent *dp;
  44         char file[LEN_MAX];
  45
  46         sysfs = opendir(CPU_PATH);
  47         if (!sysfs) {
  48                 perror("opendir() failed");
  49                 return 1;
  50         }
  51
  52         while ((dp = readdir(sysfs))) {
  53                 int len;
  54
  55                 if (!(dp->d_type & DT_DIR))
  56                         continue;
  57                 if (!strcmp(dp->d_name, "cpuidle"))
  58                         continue;
  59                 if (!strstr(dp->d_name, "cpu"))
  60                         continue;
  61
  62                 len = snprintf(file, LEN_MAX, "%s%s/dscr", CPU_PATH, dp->d_name);
  63                 if (len >= LEN_MAX)
  64                         continue;
  65                 if (access(file, F_OK))
  66                         continue;
  67
  68                 if (check_cpu_dscr_default(file, val))
  69                         return 1;
  70         }
  71         closedir(sysfs);
  72         return 0;
  73 }
  74
  75 int dscr_sysfs(void)
  76 {
  77         unsigned long orig_dscr_default;
  78         int i, j;
  79
  80         SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
  81
  82         orig_dscr_default = get_default_dscr();
  83         for (i = 0; i < COUNT; i++) {
  84                 for (j = 0; j < DSCR_MAX; j++) {
  85                         set_default_dscr(j);
  86                         if (check_all_cpu_dscr_defaults(j))
  87                                 goto fail;
  88                 }
  89         }
  90         set_default_dscr(orig_dscr_default);
  91         return 0;
  92 fail:
  93         set_default_dscr(orig_dscr_default);
  94         return 1;
  95 }
  96
  97 int main(int argc, char *argv[])
  98 {
  99         return test_harness(dscr_sysfs, "dscr_sysfs_test");
 100 }