Merge pull request #468 from tock/multi_alarm

alarm: rewrite alarm virtualization with better comments and simpler logic, add tests

Author: alevy

examples/tests/alarm_in_overflow/Makefile renamed to examples/tests/alarms/alarm_in_overflow/Makefile

@@ -1,7 +1,7 @@
 # Makefile for user application
 
 # Specify this directory relative to the current application.
-TOCK_USERLAND_BASE_DIR = ../../..
+TOCK_USERLAND_BASE_DIR = ../../../..
 
 # Which files to compile.
 C_SRCS := $(wildcard *.c)

examples/tests/alarm_in_overflow/README.md renamed to examples/tests/alarms/alarm_in_overflow/README.md

@@ -1,7 +1,7 @@
 # Makefile for user application
 
 # Specify this directory relative to the current application.
-TOCK_USERLAND_BASE_DIR = ../../..
+TOCK_USERLAND_BASE_DIR = ../../../..
 
 # Which files to compile.
 C_SRCS := $(wildcard *.c)

examples/tests/alarm_in_overflow/main.c renamed to examples/tests/alarms/alarm_in_overflow/main.c

@@ -0,0 +1,41 @@
+# Test Multiple Alarms (Ensure previous overflowing alarms aren't ignore)
+
+This tests the virtual alarms available to userspace. It sets three
+alarms. The first two overflow and should result in multiple
+alarms under the hood, and a third 10 second alarm started after the
+second alarm fires. The first alarm is set first, but expires second
+(1 second after overflow vs 10ms after overflow). The third alarm
+should expire last.
+
+(Not to scale; demonstrating alarm firing order)
+Alarm 1 (Overflow + 1s) ---Set----------------------Fires--------------
+Alarm 2 (Overflow + 10ms) --------Set------Fires -------------------
+Alarm 3 (Overflow + 10ms + 10s) --------------Set------------Fires
+
+When successful, the first alarm should fire after a clock overflow +
+1 second, while the third should fire after a clock overflow + 10ms +
+10 seconds.
+
+If the virtual alarm library is buggy, this test might fail by never
+firing the first alarm or firing it after the third alarm
+(specifically almost another clock overflow) because either alarm
+insertion or virtual alarm upcall handing misses it after the second
+alarm fires.
+
+# Example Output
+
+Output includes three columns on each line:
+
+1. the expected order of the alarm firing
+2. the time the alarm is delivered to userspace
+3. the time the alarm was set to expire
+
+Correct (numbers for the nRT52840DK, running with a 32768Hz timer at
+24-bits):
+
+(after an entire clock overflow, ~8 minutes)
+
+```
+1 10498816 10496827
+2 86100992 86099200
+```

examples/tests/multi_alarm_simple_overflow_test/Makefile renamed to examples/tests/alarms/multi_alarm_dont_ignore_previous_overflow/Makefile

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <libtock-sync/services/alarm.h>
+
+static void event_cb(uint32_t now, uint32_t expiration, void* ud) {
+  int i = (int)ud;
+  printf("%d %lu %lu\n", i, now, expiration);
+}
+
+int main(void) {
+  libtock_alarm_t t1;
+  libtock_alarm_t t2;
+
+  uint32_t overflow_ms = libtock_alarm_ticks_to_ms(UINT32_MAX);
+
+  libtock_alarm_in_ms(overflow_ms + 1000, event_cb, (void*)1, &t1);
+  libtocksync_alarm_delay_ms(overflow_ms + 10);
+  libtock_alarm_in_ms(10000, event_cb, (void*)2, &t2);
+
+  while (1) {
+    yield();
+  }
+}

examples/tests/alarms/multi_alarm_dont_ignore_previous_overflow/README.md

@@ -1,7 +1,7 @@
 # Makefile for user application
 
 # Specify this directory relative to the current application.
-TOCK_USERLAND_BASE_DIR = ../../..
+TOCK_USERLAND_BASE_DIR = ../../../..
 
 # Which files to compile.
 C_SRCS := $(wildcard *.c)

examples/tests/alarms/multi_alarm_dont_ignore_previous_overflow/main.c

@@ -1,7 +1,7 @@
 # Makefile for user application
 
 # Specify this directory relative to the current application.
-TOCK_USERLAND_BASE_DIR = ../../..
+TOCK_USERLAND_BASE_DIR = ../../../..
 
 # Which files to compile.
 C_SRCS := $(wildcard *.c)