tests: Added test for PTP timer

tests/periph_ptp_timer/Makefile

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+BOARD ?= nucleo-f767zi
+include ../Makefile.tests_common
+
+FEATURES_REQUIRED = periph_ptp_timer
+
+USEMODULE += event
+USEMODULE += fmt
+
+include $(RIOTBASE)/Makefile.include

tests/periph_ptp_timer/README.md

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+Peripheral PTP Timer Test Application
+=====================================
+
+This tests setting the PTP timer to the following targets:
+
+- one second into the future (using the absolute API)
+- 1st of January 1970 0:00:00 (using the absolute API)
+    - This is expected to fire right away according to the API
+- 1 µs to 99µs into the future (using the relative API)
+
+If all timeouts fire within ± 10 µs of the target time, the test succeeds.
+
+Expected Output on Success
+--------------------------
+
+    main(): This is RIOT! (Version: <INSERT VERSION HERE>)
+    TEST SUCCEEDED!

tests/periph_ptp_timer/main.c

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+/*
+ * Copyright (C) 2020 Otto-von-Guericke-Universität Magdeburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       Peripheral PTP clock test application
+ *
+ * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ *
+ * @}
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "event.h"
+#include "fmt.h"
+#include "kernel_defines.h"
+#include "periph/ptp.h"
+
+static uint64_t ts_target;
+static uint64_t ts_hit;
+static const uint64_t max_diff = 10000; /* 10 µs */
+static int failed = 0;
+static unsigned n_timeouts = 0;
+static event_queue_t q = EVENT_QUEUE_INIT_DETACHED;
+
+static inline uint64_t abs_diff(uint64_t a, uint64_t b)
+{
+    return (a >= b) ? (a - b) : (b - a);
+}
+
+static void ev_handler(event_t *ev)
+{
+    (void)ev;
+    uint64_t diff = abs_diff(ts_target, ts_hit);
+    if (diff > max_diff) {
+        failed = 1;
+        print_str("Error: Timeout missed target by ");
+        print_u64_dec(diff);
+        print_str(" ns\n");
+    }
+
+    n_timeouts++;
+
+    if (n_timeouts == 1) {
+        /* check if setting timeout in the past does trigger IRQ */
+        ts_target = ptp_clock_read_u64();
+        ptp_timer_set_absolute_u64(0);
+    }
+    else if (n_timeouts < 100) {
+        /* check if setting small relative timeouts work */
+        uint64_t delay = (99 - n_timeouts) * 1000;
+        ts_target = ptp_clock_read_u64() + delay;
+        ptp_timer_set_u64(delay);
+    }
+    else {
+        if (failed) {
+            print_str("TEST FAILED!\n");
+        }
+        else {
+            print_str("TEST SUCCEEDED!\n");
+        }
+    }
+}
+
+void ptp_timer_cb(void)
+{
+    ts_hit = ptp_clock_read_u64();
+    static event_t ev = { .handler = ev_handler };
+    event_post(&q, &ev);
+}
+
+int main(void)
+{
+    ts_target = ptp_clock_read_u64() + NS_PER_SEC;
+    ptp_timer_set_absolute_u64(ts_target);
+    event_queue_claim(&q);
+    event_loop(&q);
+    UNREACHABLE();
+}

tests/periph_ptp_timer/tests/01-run.py

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+#!/usr/bin/env python3
+
+# Copyright (C) 2020 Otto-von-Guericke-Universität Magdeburg
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+import sys
+from testrunner import run
+
+
+def testfunc(child):
+    child.expect_exact("TEST SUCCEEDED!\r\n")
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))