Clapper: Fix and enable timer_dos test

This adds golden wake count for each task and check at the end of the
test. The golden wake count is calculated with the seeds and the pseudo
random number generator.

BUG=None
Original-BUG=chrome-os-partner:23800
TEST=Pass the test
BRANCH=None

Change-Id: I641dcb18ef2878412161f6d864d2405e00c8a7f6
Original-Change-Id: I1f216fda91a86e4accba0d347692de57838748db
Signed-off-by: Vic (Chun-Ju) Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/181734
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182249
Commit-Queue: Dave Parker <dparker@chromium.org>
Tested-by: Dave Parker <dparker@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182428
Reviewed-by: Dave Parker <dparker@chromium.org>

3 files changed, 32 insertions, 43 deletions

diff --git a/test/build.mk b/test/build.mk
index daea926970..b0db597583 100644
--- a/test/build.mk
+++ b/test/build.mk
@@ -22,7 +22,7 @@ test-list-$(BOARD_SAMUS)=
 test-list-host=mutex pingpong utils kb_scan kb_mkbp lid_sw power_button hooks
 test-list-host+=thermal flash queue kb_8042 extpwr_gpio console_edit system
 test-list-host+=sbs_charging adapter host_command thermal_falco
-test-list-host+=bklight_lid bklight_passthru interrupt
+test-list-host+=bklight_lid bklight_passthru interrupt timer_dos
 
 adapter-y=adapter.o
 bklight_lid-y=bklight_lid.o
diff --git a/test/timer_dos.c b/test/timer_dos.c
index f941adea51..0c0f48c0a2 100644
--- a/test/timer_dos.c
+++ b/test/timer_dos.c
@@ -17,11 +17,28 @@
 
 #define TEST_TIME (3 * SECOND)
 
+#define ERROR_MARGIN 5
+
+static int calculate_golden(uint32_t seed)
+{
+	int golden = 0;
+	uint32_t elapsed = 0;
+	while (1) {
+		elapsed += PERIOD_US(seed);
+		++golden;
+		if (elapsed >= TEST_TIME)
+			return golden;
+		seed = prng(seed);
+	}
+}
+
 int task_timer(void *seed)
 {
-	uint32_t num = (uint32_t)seed;
+	uint32_t num = (uint32_t)(uintptr_t)seed;
+	int golden_cnt = calculate_golden(num);
 	task_id_t id = task_get_current();
 	timestamp_t start;
+	int cnt = 0;
 
 	while (1) {
 		task_wait_event(-1);
@@ -33,9 +50,19 @@ int task_timer(void *seed)
 			/* Wait for a "random" period */
 			task_wait_event(PERIOD_US(num));
 			ccprintf("%01d\n", id);
+			cnt++;
 			/* next pseudo random delay */
 			num = prng(num);
 		}
+		ccprintf("Task %d: Count=%d Golden=%d\n", id, cnt, golden_cnt);
+		cnt -= golden_cnt;
+		if (cnt < 0)
+			cnt = -cnt;
+		if (cnt > ERROR_MARGIN) {
+			ccprintf("Count differs from Golden by more than %d!\n",
+				 ERROR_MARGIN);
+			test_fail();
+		}
 	}
 
 	return EC_SUCCESS;
@@ -43,8 +70,11 @@ int task_timer(void *seed)
 
 void run_test(void)
 {
+	wait_for_task_started();
 	task_wake(TASK_ID_TMRD);
 	task_wake(TASK_ID_TMRC);
 	task_wake(TASK_ID_TMRB);
 	task_wake(TASK_ID_TMRA);
+	usleep(TEST_TIME + SECOND);
+	test_pass();
 }
diff --git a/test/timer_dos.py b/test/timer_dos.py
deleted file mode 100644
index 5b7e1f7d40..0000000000
--- a/test/timer_dos.py
+++ /dev/null
@@ -1,41 +0,0 @@
-# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-#
-# Timers test
-#
-
-import time
-
-# Test during 5s
-DURATION=5
-
-# Linear congruential pseudo random number generator*/
-def prng(x):
-    return (22695477 * x + 1) & 0xffffffff
-
-# period between 500us and 128ms
-def period_us(num):
-    return (((num % 256) + 1) * 500)
-
-# build the same pseudo random sequence as the target
-def build_sequence():
-    # TODO(crosbug.com/p/23800): implement
-    return []
-
-def test(helper):
-      helper.wait_output("[Timer task ")
-      deadline = time.time() + DURATION
-      seq = []
-      while time.time() < deadline:
-          tmr = helper.wait_output("(?P<t>[0-9])", use_re=True,
-                                     timeout=1)["t"]
-          seq.append(tmr)
-
-      # Check the results
-      model = build_sequence()
-      # TODO(crosbug.com/p/23800): implement
-
-      helper.trace("Got %d timer IRQ\n" % len(seq))
-
-      return True # PASS !