Add kselftest for RTAS-based real-time clock on PowerVM systems. Tests RTC device presence, time accuracy, and time advancement.
The test verifies: - RTC device exists at /sys/class/rtc/rtc0/ - RTC time matches system time (within 2 seconds) - Year is sane (>= 2020) - Time advances correctly Signed-off-by: Shirisha G <[email protected]> --- .../selftests/powerpc/rtas/rtas_rtc_test.c | 93 +++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 tools/testing/selftests/powerpc/rtas/rtas_rtc_test.c diff --git a/tools/testing/selftests/powerpc/rtas/rtas_rtc_test.c b/tools/testing/selftests/powerpc/rtas/rtas_rtc_test.c new file mode 100644 index 000000000000..12d4f38230e6 --- /dev/null +++ b/tools/testing/selftests/powerpc/rtas/rtas_rtc_test.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * RTAS Real-Time Clock Test + * Copyright (C) 2026 IBM Corporation + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.h> +#include <errno.h> +#include "utils.h" + +#define _GNU_SOURCE +#define RTC_PATH "/sys/class/rtc/rtc0/time" +#define RTC_DATE_PATH "/sys/class/rtc/rtc0/date" + +static int read_rtc_time(time_t *rtc_time) +{ + FILE *fp; + struct tm tm = {0}; + char buf[64]; + + fp = fopen(RTC_PATH, "r"); + if (!fp) { + perror("fopen RTC_PATH"); + return -1; + } + + if (!fgets(buf, sizeof(buf), fp)) { + fclose(fp); + return -1; + } + fclose(fp); + + /* Parse HH:MM:SS format */ + if (sscanf(buf, "%d:%d:%d", &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 3) + return -1; + + /* Read date */ + fp = fopen(RTC_DATE_PATH, "r"); + if (!fp) + return -1; + + if (!fgets(buf, sizeof(buf), fp)) { + fclose(fp); + return -1; + } + fclose(fp); + + /* Parse YYYY-MM-DD format */ + if (sscanf(buf, "%d-%d-%d", &tm.tm_year, &tm.tm_mon, &tm.tm_mday) != 3) + return -1; + + tm.tm_year -= 1900; /* years since 1900 */ + tm.tm_mon -= 1; /* months since January */ + + *rtc_time = timegm(&tm); + return 0; +} + +int main(void) +{ + time_t rtc_time1, rtc_time2, sys_time; + int diff; + + test_harness_set_timeout(10); + + /* Test 1: Verify RTC device exists */ + SKIP_IF(access(RTC_PATH, R_OK) != 0); + + /* Test 2: Read RTC time */ + FAIL_IF(read_rtc_time(&rtc_time1) != 0); + + /* Test 3: Compare with system time */ + sys_time = time(NULL); + diff = abs((int)(rtc_time1 - sys_time)); + FAIL_IF_MSG(diff > 2, "RTC time differs from system time by %d seconds", diff); + + /* Test 4: Verify year > 2020 */ + struct tm *tm = localtime(&rtc_time1); + FAIL_IF_MSG(tm->tm_year + 1900 < 2020, "RTC year is %d (expected >= 2020)", + tm->tm_year + 1900); + + /* Test 5: Verify time advances */ + sleep(2); + FAIL_IF(read_rtc_time(&rtc_time2) != 0); + FAIL_IF_MSG(rtc_time2 <= rtc_time1, "RTC time did not advance"); + + printf("RTAS RTC test passed\n"); + return 0; +} -- 2.43.5
