charge_ramp: initial commit of charge ramp module

Add new charge_ramp module which works with charge_manager to
slowly increase input current limit in order to find the optimal
charging current. To do this it looks for either VBUS drooping
too low or for the charger to over-current.

BUG=chrome-os-partner:34946
BRANCH=samus
TEST=tested with a variety of BC1.2 chargers, type-C only chargers,
and PD chargers to make sure we always stabilize charging at an
appropriate current limit.

Change-Id: Icc95aa2738ddb221f163f91c14a342a0674f9e0f
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/247304
Reviewed-by: Vic Yang <victoryang@chromium.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

4 files changed, 526 insertions, 0 deletions

diff --git a/test/build.mk b/test/build.mk
index 787e99a320..115fb515ee 100644
--- a/test/build.mk
+++ b/test/build.mk
@@ -36,6 +36,7 @@ test-list-host+=sbs_charging adapter host_command thermal_falco led_spring
 test-list-host+=bklight_lid bklight_passthru interrupt timer_dos button
 test-list-host+=motion_lid math_util sbs_charging_v2 battery_get_params_smart
 test-list-host+=lightbar inductive_charging usb_pd fan charge_manager
+test-list-host+=charge_ramp
 
 adapter-y=adapter.o
 battery_get_params_smart-y=battery_get_params_smart.o
@@ -43,6 +44,7 @@ bklight_lid-y=bklight_lid.o
 bklight_passthru-y=bklight_passthru.o
 button-y=button.o
 charge_manager-y=charge_manager.o
+charge_ramp-y+=charge_ramp.o
 console_edit-y=console_edit.o
 extpwr_gpio-y=extpwr_gpio.o
 flash-y=flash.o
diff --git a/test/charge_ramp.c b/test/charge_ramp.c
new file mode 100644
index 0000000000..e853b46e93
--- /dev/null
+++ b/test/charge_ramp.c
@@ -0,0 +1,502 @@
+/* Copyright 2015 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.
+ *
+ * Test AC input current ramp.
+ */
+
+#include "charge_manager.h"
+#include "charge_ramp.h"
+#include "common.h"
+#include "console.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "task.h"
+#include "test_util.h"
+#include "timer.h"
+#include "util.h"
+
+#define TASK_EVENT_OVERCURRENT (1 << 0)
+
+#define RAMP_STABLE_DELAY (120*SECOND)
+
+/*
+ * Time to delay for detecting the charger type. This value follows
+ * the value in common/charge_ramp.c.
+ */
+#define CHARGE_DETECT_DELAY (2*SECOND)
+
+static int system_load_current_ma;
+static int vbus_low_current_ma = 500;
+static int overcurrent_current_ma = 3000;
+
+static int charge_limit_ma;
+
+/* Mock functions */
+
+int board_is_ramp_allowed(int supplier)
+{
+	/* Ramp for TEST4-TEST9 */
+	return supplier > CHARGE_SUPPLIER_TEST3;
+}
+
+int board_is_consuming_full_charge(void)
+{
+	return charge_limit_ma <= system_load_current_ma;
+}
+
+int board_is_vbus_too_low(enum chg_ramp_vbus_state ramp_state)
+{
+	return MIN(system_load_current_ma, charge_limit_ma) >
+	       vbus_low_current_ma;
+}
+
+void board_set_charge_limit(int limit_ma)
+{
+	charge_limit_ma = limit_ma;
+	if (charge_limit_ma > overcurrent_current_ma)
+		task_set_event(TASK_ID_TEST_RUNNER, TASK_EVENT_OVERCURRENT, 0);
+}
+
+int board_get_ramp_current_limit(int supplier)
+{
+	if (supplier == CHARGE_SUPPLIER_TEST9)
+		return 1600;
+	else if (supplier == CHARGE_SUPPLIER_TEST8)
+		return 2400;
+	else
+		return 3000;
+}
+
+/* Test utilities */
+
+static void plug_charger_with_ts(int supplier_type, int port, int min_current,
+				 int vbus_low_current, int overcurrent_current,
+				 timestamp_t reg_time)
+{
+	vbus_low_current_ma = vbus_low_current;
+	overcurrent_current_ma = overcurrent_current;
+	chg_ramp_charge_supplier_change(port, supplier_type, min_current,
+					reg_time);
+}
+
+static void plug_charger(int supplier_type, int port, int min_current,
+			 int vbus_low_current, int overcurrent_current)
+{
+	plug_charger_with_ts(supplier_type, port, min_current,
+			     vbus_low_current, overcurrent_current,
+			     get_time());
+}
+
+static void unplug_charger(void)
+{
+	chg_ramp_charge_supplier_change(CHARGE_PORT_NONE, CHARGE_SUPPLIER_NONE,
+					0, get_time());
+}
+
+static int unplug_charger_and_check(void)
+{
+	unplug_charger();
+	usleep(CHARGE_DETECT_DELAY);
+	return charge_limit_ma == 0;
+}
+
+static int wait_stable_no_overcurrent(void)
+{
+	return task_wait_event(RAMP_STABLE_DELAY) != TASK_EVENT_OVERCURRENT;
+}
+
+static int is_in_range(int x, int min, int max)
+{
+	return x >= min && x <= max;
+}
+
+/* Tests */
+
+static int test_no_ramp(void)
+{
+	system_load_current_ma = 3000;
+	/* A powerful charger, but hey, you're not allowed to ramp! */
+	plug_charger(CHARGE_SUPPLIER_TEST1, 0, 500, 3000, 3000);
+	usleep(CHARGE_DETECT_DELAY);
+	/* That's right. Start at 500 mA */
+	TEST_ASSERT(charge_limit_ma == 500);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	/* ... and stays at 500 mA */
+	TEST_ASSERT(charge_limit_ma == 500);
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_full_ramp(void)
+{
+	system_load_current_ma = 3000;
+	/* Now you get to ramp with this 3A charger */
+	plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 3000, 3000);
+	usleep(CHARGE_DETECT_DELAY);
+	/* Start with something around 500 mA */
+	TEST_ASSERT(is_in_range(charge_limit_ma, 500, 800));
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	/* And ramp up to 3A */
+	TEST_ASSERT(charge_limit_ma == 3000);
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_vbus_dip(void)
+{
+	system_load_current_ma = 3000;
+	/* VBUS dips too low right before the charger shuts down */
+	plug_charger(CHARGE_SUPPLIER_TEST5, 0, 1000, 1500, 1600);
+
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1300, 1500));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_overcurrent(void)
+{
+	system_load_current_ma = 3000;
+	/* Huh...VBUS doesn't dip before the charger shuts down */
+	plug_charger(CHARGE_SUPPLIER_TEST6, 0, 500, 3000, 1500);
+	usleep(CHARGE_DETECT_DELAY);
+	/* Ramp starts at 500 mA */
+	TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+
+	while (task_wait_event(RAMP_STABLE_DELAY) == TASK_EVENT_OVERCURRENT) {
+		/* Charger goes away but comes back after 0.6 seconds */
+		unplug_charger();
+		usleep(MSEC * 600);
+		plug_charger(CHARGE_SUPPLIER_TEST6, 0, 500, 3000, 1500);
+		usleep(CHARGE_DETECT_DELAY);
+		/* Ramp restarts at 500 mA */
+		TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	}
+
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1300, 1500));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_switch_outlet(void)
+{
+	int i;
+
+	system_load_current_ma = 3000;
+	/* Here's a nice powerful charger */
+	plug_charger(CHARGE_SUPPLIER_TEST7, 0, 500, 3000, 3000);
+
+	/*
+	 * Now the user decides to move it to a nearby outlet...actually
+	 * he decides to move it 5 times!
+	 */
+	for (i = 0; i < 5; ++i) {
+		usleep(SECOND * 20);
+		unplug_charger();
+		usleep(SECOND * 1.5);
+		plug_charger(CHARGE_SUPPLIER_TEST7, 0, 500, 3000, 3000);
+		usleep(CHARGE_DETECT_DELAY);
+		/* Ramp restarts at 500 mA */
+		TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	}
+
+	/* Should still ramp up to 3000 mA */
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 3000);
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_fast_switch(void)
+{
+	int i;
+
+	system_load_current_ma = 3000;
+	plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 3000, 3000);
+
+	/*
+	 * Here comes that naughty user again, and this time he's switching
+	 * outlet really quickly. Fortunately this time he only does it twice.
+	 */
+	for (i = 0; i < 2; ++i) {
+		usleep(SECOND * 20);
+		unplug_charger();
+		usleep(600 * MSEC);
+		plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 3000, 3000);
+		usleep(CHARGE_DETECT_DELAY);
+		/* Ramp restarts at 500 mA */
+		TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	}
+
+	/* Should still ramp up to 3000 mA */
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 3000);
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_overcurrent_after_switch_outlet(void)
+{
+	system_load_current_ma = 3000;
+	/* Here's a less powerful charger */
+	plug_charger(CHARGE_SUPPLIER_TEST5, 0, 500, 3000, 1500);
+	usleep(SECOND * 5);
+
+	/* Now the user decides to move it to a nearby outlet */
+	unplug_charger();
+	usleep(SECOND * 1.5);
+	plug_charger(CHARGE_SUPPLIER_TEST5, 0, 500, 3000, 1500);
+
+	/* Okay the user is satisified */
+	while (task_wait_event(RAMP_STABLE_DELAY) == TASK_EVENT_OVERCURRENT) {
+		/* Charger goes away but comes back after 0.6 seconds */
+		unplug_charger();
+		usleep(MSEC * 600);
+		plug_charger(CHARGE_SUPPLIER_TEST5, 0, 500, 3000, 1500);
+		usleep(CHARGE_DETECT_DELAY);
+		/* Ramp restarts at 500 mA */
+		TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	}
+
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1300, 1500));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_partial_load(void)
+{
+	/* We have a 3A charger, but we just want 1.5A */
+	system_load_current_ma = 1500;
+	plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 3000, 2500);
+
+	/* We should end up with a little bit more than 1.5A */
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1500, 1600));
+
+	/* Ok someone just started watching YouTube */
+	system_load_current_ma = 2000;
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 2000, 2100));
+
+	/* Somehow the system load increases again */
+	system_load_current_ma = 2600;
+	while (task_wait_event(RAMP_STABLE_DELAY) == TASK_EVENT_OVERCURRENT) {
+		/* Charger goes away but comes back after 0.6 seconds */
+		unplug_charger();
+		usleep(MSEC * 600);
+		plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 3000, 2500);
+		usleep(CHARGE_DETECT_DELAY);
+		/* Ramp restarts at 500 mA */
+		TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	}
+
+	/* Alright the charger isn't powerful enough, so we'll stop at 2.5A */
+	TEST_ASSERT(is_in_range(charge_limit_ma, 2300, 2500));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_charge_supplier_stable(void)
+{
+	system_load_current_ma = 3000;
+	/* The charger says it's of type TEST4 initially */
+	plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 1500, 1600);
+	/*
+	 * And then it decides it's actually TEST2 after 0.5 seconds,
+	 * why? Well, this charger is just evil.
+	 */
+	usleep(500 * MSEC);
+	plug_charger(CHARGE_SUPPLIER_TEST2, 0, 3000, 3000, 3000);
+	/* We should get 3A right away. */
+	usleep(SECOND);
+	TEST_ASSERT(charge_limit_ma == 3000);
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_charge_supplier_stable_ramp(void)
+{
+	system_load_current_ma = 3000;
+	/* This time we start with a non-ramp charge supplier */
+	plug_charger(CHARGE_SUPPLIER_TEST3, 0, 500, 3000, 3000);
+	/*
+	 * After 0.5 seconds, it's decided that the supplier is actually
+	 * a 1.5A ramp supplier.
+	 */
+	usleep(500 * MSEC);
+	plug_charger(CHARGE_SUPPLIER_TEST5, 0, 500, 1400, 1500);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1200, 1400));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_charge_supplier_change(void)
+{
+	system_load_current_ma = 3000;
+	/* Start with a 3A ramp charge supplier */
+	plug_charger(CHARGE_SUPPLIER_TEST4, 0, 500, 3000, 3000);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 3000);
+
+	/* The charger decides to change type to a 1.5A non-ramp supplier */
+	plug_charger(CHARGE_SUPPLIER_TEST1, 0, 1500, 3000, 3000);
+	usleep(500 * MSEC);
+	TEST_ASSERT(charge_limit_ma == 1500);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 1500);
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_charge_port_change(void)
+{
+	system_load_current_ma = 3000;
+	/* Start with a 1.5A ramp charge supplier on port 0 */
+	plug_charger(CHARGE_SUPPLIER_TEST5, 0, 500, 1400, 1500);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1200, 1400));
+
+	/* Here comes a 2.1A ramp charge supplier on port 1 */
+	plug_charger(CHARGE_SUPPLIER_TEST6, 0, 500, 2000, 2100);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1800, 2000));
+
+	/* Now we have a 2.5A non-ramp charge supplier on port 0 */
+	plug_charger(CHARGE_SUPPLIER_TEST1, 0, 2500, 3000, 3000);
+	usleep(SECOND);
+	TEST_ASSERT(charge_limit_ma == 2500);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 2500);
+
+	/* Unplug on port 0 */
+	plug_charger(CHARGE_SUPPLIER_TEST6, 0, 500, 2000, 2100);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1800, 2000));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_vbus_shift(void)
+{
+	system_load_current_ma = 3000;
+	/*
+	 * At first, the charger is able to supply up to 1900 mA before
+	 * the VBUS voltage starts to drop.
+	 */
+	plug_charger(CHARGE_SUPPLIER_TEST7, 0, 500, 1900, 2000);
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1700, 1900));
+
+	/* The charger heats up and VBUS voltage drops by 100mV */
+	vbus_low_current_ma = 1800;
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1600, 1800));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_equal_priority_overcurrent(void)
+{
+	int overcurrent_count = 0;
+	timestamp_t oc_time = get_time();
+
+	system_load_current_ma = 3000;
+
+	/*
+	 * Now we have two charge suppliers of equal priorties plugged into
+	 * port 0 and port 1. If the active one browns out, charge manager
+	 * switches to the other one.
+	 */
+	while (1) {
+		plug_charger_with_ts(CHARGE_SUPPLIER_TEST4, 0, 500, 3000,
+				     2000, oc_time);
+		oc_time = get_time();
+		oc_time.val += 600 * MSEC;
+		if (wait_stable_no_overcurrent())
+			break;
+		plug_charger_with_ts(CHARGE_SUPPLIER_TEST4, 1, 500, 3000,
+				     2000, oc_time);
+		oc_time = get_time();
+		oc_time.val += 600 * MSEC;
+		if (wait_stable_no_overcurrent())
+			break;
+		if (overcurrent_count++ >= 10) {
+			/*
+			 * Apparently we are in a loop and can never reach
+			 * stable state.
+			 */
+			unplug_charger();
+			return EC_ERROR_UNKNOWN;
+		}
+	}
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+static int test_ramp_limit(void)
+{
+	system_load_current_ma = 3000;
+
+	/* Plug in supplier that is limited to 1.6A */
+	plug_charger(CHARGE_SUPPLIER_TEST9, 0, 500, 3000, 3000);
+	usleep(SECOND);
+	TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 1600);
+
+	/* Switch to supplier that is limited to 2.4A */
+	plug_charger(CHARGE_SUPPLIER_TEST8, 1, 500, 3000, 3000);
+	usleep(SECOND);
+	TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(charge_limit_ma == 2400);
+
+	/* Go back to 1.6A limited, but VBUS goes low before that point */
+	plug_charger(CHARGE_SUPPLIER_TEST9, 0, 500, 1200, 1300);
+	usleep(SECOND);
+	TEST_ASSERT(is_in_range(charge_limit_ma, 500, 700));
+	TEST_ASSERT(wait_stable_no_overcurrent());
+	TEST_ASSERT(is_in_range(charge_limit_ma, 1000, 1200));
+
+	TEST_ASSERT(unplug_charger_and_check());
+	return EC_SUCCESS;
+}
+
+void run_test(void)
+{
+	test_reset();
+
+	RUN_TEST(test_no_ramp);
+	RUN_TEST(test_full_ramp);
+	RUN_TEST(test_vbus_dip);
+	RUN_TEST(test_overcurrent);
+	RUN_TEST(test_switch_outlet);
+	RUN_TEST(test_fast_switch);
+	RUN_TEST(test_overcurrent_after_switch_outlet);
+	RUN_TEST(test_partial_load);
+	RUN_TEST(test_charge_supplier_stable);
+	RUN_TEST(test_charge_supplier_stable_ramp);
+	RUN_TEST(test_charge_supplier_change);
+	RUN_TEST(test_charge_port_change);
+	RUN_TEST(test_vbus_shift);
+	RUN_TEST(test_equal_priority_overcurrent);
+	RUN_TEST(test_ramp_limit);
+
+	test_print_result();
+}
diff --git a/test/charge_ramp.tasklist b/test/charge_ramp.tasklist
new file mode 100644
index 0000000000..97a94fef6c
--- /dev/null
+++ b/test/charge_ramp.tasklist
@@ -0,0 +1,18 @@
+/* Copyright 2015 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.
+ */
+
+/**
+ * List of enabled tasks in the priority order
+ *
+ * The first one has the lowest priority.
+ *
+ * For each task, use the macro TASK_TEST(n, r, d, s) where :
+ * 'n' in the name of the task
+ * 'r' in the main routine of the task
+ * 'd' in an opaque parameter passed to the routine at startup
+ * 's' is the stack size in bytes; must be a multiple of 8
+ */
+#define CONFIG_TEST_TASK_LIST \
+	TASK_TEST(CHG_RAMP, chg_ramp_task, NULL, SMALLER_TASK_STACK_SIZE)
diff --git a/test/test_config.h b/test/test_config.h
index 56fdf87772..c4bf3f57fa 100644
--- a/test/test_config.h
+++ b/test/test_config.h
@@ -139,5 +139,9 @@ int board_discharge_on_ac(int enabled);
 #define CONFIG_USB_PD_DUAL_ROLE
 #endif
 
+#ifdef TEST_CHARGE_RAMP
+#define CONFIG_CHARGE_RAMP
+#endif
+
 #endif  /* TEST_BUILD */
 #endif  /* __CROS_EC_TEST_CONFIG_H */