Add port tests for ticker and lp ticker

Add a test to make sure timer events scheduled for the past fire
immediately, and add a test to ensure many events occurring at
once do not cause a stack overflow.

Author: c1728p9

TESTS/mbed_hal/ticker_port/main.cpp

@@ -0,0 +1,151 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "utest/utest.h"
+#include "unity/unity.h"
+#include "greentea-client/test_env.h"
+
+#include "mbed.h"
+#include "us_ticker_api.h"
+#include "lp_ticker_api.h"
+
+using namespace utest::v1;
+
+static const uint32_t QUICK_EVENT_COUNT = 100000;
+
+static const ticker_interface_t* intf;
+static volatile uint32_t irq_count;
+static void (*irq_cb)(void);
+
+static void ticker_irq_handler(void)
+{
+    intf->clear_interrupt();
+    irq_count++;
+    if (irq_cb) {
+        irq_cb();
+    }
+}
+
+void us_ticker_irq_handler(void)
+{
+    ticker_irq_handler();
+}
+
+#if DEVICE_LOWPOWERTIMER
+void lp_ticker_irq_handler(void)
+{
+    ticker_irq_handler();
+}
+#endif
+
+static void run_next_event(void)
+{
+    if (irq_count < QUICK_EVENT_COUNT) {
+        intf->set_interrupt(intf->read() - 1);
+    }
+}
+
+/**
+ * Test that events schedule in the past still trigger an interrupt
+ *
+ * Events can be scheduled in the past if there is a delay between the
+ * call to timer->read() and timer->set_interrupt(). This delay can be
+ * caused by a task switch or interrupt, in addition to other things.
+ * This test ensures that the hardware gracefully handles this case.
+ */
+void test_events_in_past(void)
+{
+    static const uint32_t us_in_past[] = {
+        0,
+        1,
+        10,
+        1000000,
+        0x70000000
+    };
+    irq_count = 0;
+    irq_cb = 0;
+    intf->init();
+
+    for (uint32_t i = 0; i < sizeof(us_in_past) / sizeof(us_in_past[0]); i++) {
+        printf("Testing interrupt %lu us in the past\r\n", us_in_past[i]);
+        intf->set_interrupt(intf->read() - us_in_past[i]);
+        wait(0.01);
+        TEST_ASSERT_EQUAL(i + 1, irq_count);
+    }
+
+}
+
+/**
+ * Test that the port can handle events being added non-stop
+ *
+ * In the past some ports processed new pending events recursively.
+ * With this type of implementation, if too many events are pending at
+ * the same time then the recursion will be deep enough to cause a stack
+ * overflow. This test simulates that to ensure there will not be a stack
+ * overflow.
+ */
+void test_events_quickly(void)
+{
+    irq_count = 0;
+    irq_cb = run_next_event;
+    intf->init();
+
+    printf("Running %lu events now\r\n", QUICK_EVENT_COUNT);
+    intf->set_interrupt(intf->read() - 1);
+    while (irq_count < QUICK_EVENT_COUNT) {
+        wait(0.01);
+    }
+    TEST_ASSERT_EQUAL(QUICK_EVENT_COUNT, irq_count);
+}
+
+utest::v1::status_t us_ticker_setup(const Case *const source, const size_t index_of_case)
+{
+  intf = get_us_ticker_data()->interface;
+  irq_count = 0;
+  irq_cb = 0;
+  return greentea_case_setup_handler(source, index_of_case);
+}
+
+#if DEVICE_LOWPOWERTIMER
+utest::v1::status_t lp_ticker_setup(const Case *const source, const size_t index_of_case)
+{
+    intf = get_lp_ticker_data()->interface;
+    irq_count = 0;
+    irq_cb = 0;
+  return greentea_case_setup_handler(source, index_of_case);
+}
+#endif
+
+Case cases[] = {
+    Case("Test us ticker events in the past", us_ticker_setup, test_events_in_past),
+    Case("Test us ticker events occurring quickly", us_ticker_setup, test_events_quickly),
+#if DEVICE_LOWPOWERTIMER
+    Case("Test lp ticker events in the past", lp_ticker_setup, test_events_in_past),
+    Case("Test lp ticker events occurring quickly", lp_ticker_setup, test_events_quickly),
+#endif
+};
+
+
+utest::v1::status_t greentea_test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(1200, "default_auto");
+    return greentea_test_setup_handler(number_of_cases);
+}
+
+Specification specification(greentea_test_setup, cases, greentea_test_teardown_handler);
+
+int main() {
+    return Harness::run(specification);
+}

hal/mbed_lp_ticker_api.c

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 #include "hal/lp_ticker_api.h"
+#include "mbed_toolchain.h"
 
 #if DEVICE_LOWPOWERTIMER
 
@@ -37,7 +38,8 @@ const ticker_data_t* get_lp_ticker_data(void)
     return &lp_data;
 }
 
-void lp_ticker_irq_handler(void)
+// MBED_WEAK for testing only
+MBED_WEAK void lp_ticker_irq_handler(void)
 {
     ticker_irq_handler(&lp_data);
 }

hal/mbed_us_ticker_api.c

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 #include "hal/us_ticker_api.h"
+#include "mbed_toolchain.h"
 
 static ticker_event_queue_t events = { 0 };
 
@@ -35,7 +36,8 @@ const ticker_data_t* get_us_ticker_data(void)
     return &us_data;
 }
 
-void us_ticker_irq_handler(void)
+// MBED_WEAK for testing only
+MBED_WEAK void us_ticker_irq_handler(void)
 {
     ticker_irq_handler(&us_data);
 }