charge_manager: Allow board to reject a selected charge port

Modify board_set_active_charge_port to return status indicating whether
the selected charge port was rejected. If rejected, zero out its
available charge and attempt to select a different charge port.

Also, reduce the length of related console prints.

BUG=chrome-os-partner:34677
TEST=Manual on Samus. Plug C-to-Arec into port 1, verify that charge
manager does not select port 1 as active and charging icon is not seen
in OS.
BRANCH=Samus.

Change-Id: I56e3337f90c04b93ef7cc9873af6ee0f4b1ffc7d
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/236361
Reviewed-by: Alec Berg <alecaberg@chromium.org>

6 files changed, 126 insertions, 42 deletions

diff --git a/board/host/board.h b/board/host/board.h
index 0ae8e0c452..d33a4a56dc 100644
--- a/board/host/board.h
+++ b/board/host/board.h
@@ -56,10 +56,4 @@ enum charge_supplier {
 /* supplier_priority table defined in board.c */
 extern const int supplier_priority[];
 
-/* Set the active charge port. */
-void board_set_active_charge_port(int charge_port);
-
-/* Set the charge current limit. */
-void board_set_charge_limit(int charge_ma);
-
 #endif /* __BOARD_H */
diff --git a/board/samus_pd/board.c b/board/samus_pd/board.c
index 96070fa0cf..c9432e3efd 100644
--- a/board/samus_pd/board.c
+++ b/board/samus_pd/board.c
@@ -485,18 +485,24 @@ static void pd_send_ec_int(void)
  * Set active charge port -- only one port can be active at a time.
  *
  * @param charge_port   Charge port to enable.
+ *
+ * Returns EC_SUCCESS if charge port is accepted and made active,
+ * EC_ERROR_* otherwise.
  */
-void board_set_active_charge_port(int charge_port)
+int board_set_active_charge_port(int charge_port)
 {
 	if (charge_port >= 0 && charge_port < PD_PORT_COUNT &&
 	    pd_get_role(charge_port) != PD_ROLE_SINK) {
-		CPRINTS("Port %d is not a sink, skipping enable", charge_port);
-		charge_port = CHARGE_PORT_NONE;
+		CPRINTS("Skip enable p%d", charge_port);
+		return EC_ERROR_INVAL;
 	}
+
 	pd_status.active_charge_port = charge_port;
 	gpio_set_level(GPIO_USB_C0_CHARGE_EN_L, !(charge_port == 0));
 	gpio_set_level(GPIO_USB_C1_CHARGE_EN_L, !(charge_port == 1));
-	CPRINTS("Set active charge port %d", charge_port);
+
+	CPRINTS("New chg p%d", charge_port);
+	return EC_SUCCESS;
 }
 
 /**
@@ -517,7 +523,7 @@ void board_set_charge_limit(int charge_ma)
 	pd_status.curr_lim_ma = charge_ma;
 	pd_send_ec_int();
 
-	CPRINTS("Set ilim duty %d", pwm_duty);
+	CPRINTS("New ilim %d", charge_ma);
 }
 
 /* Send host event up to AP */
diff --git a/board/samus_pd/board.h b/board/samus_pd/board.h
index 931876df27..05233d3b09 100644
--- a/board/samus_pd/board.h
+++ b/board/samus_pd/board.h
@@ -123,12 +123,6 @@ void board_update_battery_soc(int soc);
 /* Get the last received battery level. */
 int board_get_battery_soc(void);
 
-/* Set the active charge port. */
-void board_set_active_charge_port(int charge_port);
-
-/* Set the charge current limit. */
-void board_set_charge_limit(int charge_ma);
-
 /* Send host event to AP */
 void pd_send_host_event(int mask);
 
diff --git a/common/charge_manager.c b/common/charge_manager.c
index b2ef55a796..364681abe9 100644
--- a/common/charge_manager.c
+++ b/common/charge_manager.c
@@ -87,17 +87,15 @@ static int charge_manager_is_seeded(void)
 }
 
 /**
- * Charge manager refresh -- responsible for selecting the active charge port
- * and charge power. Called as a deferred task.
+ * Select the 'best' charge port, as defined by the supplier heirarchy and the
+ * ability of the port to provide power.
  */
-static void charge_manager_refresh(void)
+static void charge_manager_get_best_charge_port(int *new_port,
+						int *new_supplier)
 {
-	int new_supplier = CHARGE_SUPPLIER_NONE;
-	int new_port = CHARGE_PORT_NONE;
-	int new_charge_current, new_charge_current_uncapped;
-	int new_charge_voltage, i, j;
-	int updated_new_port = CHARGE_PORT_NONE;
-	int updated_old_port = CHARGE_PORT_NONE;
+	int supplier = CHARGE_SUPPLIER_NONE;
+	int port = CHARGE_PORT_NONE;
+	int i, j;
 
 	/* Skip port selection on OVERRIDE_DONT_CHARGE. */
 	if (override_port != OVERRIDE_DONT_CHARGE) {
@@ -115,7 +113,7 @@ static void charge_manager_refresh(void)
 				 * charge on another override port.
 				 */
 				if (override_port != OVERRIDE_OFF &&
-				    override_port == new_port &&
+				    override_port == port &&
 				    override_port != j)
 					continue;
 
@@ -129,27 +127,62 @@ static void charge_manager_refresh(void)
 
 				if (available_charge[i][j].current > 0 &&
 				    available_charge[i][j].voltage > 0 &&
-				   (new_supplier == CHARGE_SUPPLIER_NONE ||
+				   (supplier == CHARGE_SUPPLIER_NONE ||
 				    supplier_priority[i] <
-				    supplier_priority[new_supplier] ||
+				    supplier_priority[supplier] ||
 				   (j == override_port &&
-				    new_port != override_port) ||
+				    port != override_port) ||
 				   (supplier_priority[i] ==
-				    supplier_priority[new_supplier] &&
+				    supplier_priority[supplier] &&
 				    POWER(available_charge[i][j]) >
-				    POWER(available_charge[new_supplier]
-							  [new_port])))) {
-					new_supplier = i;
-					new_port = j;
+				    POWER(available_charge[supplier][port])))) {
+					supplier = i;
+					port = j;
 				}
 			}
 
 		/* Clear override if no charge is available on override port */
 		if (override_port != OVERRIDE_OFF &&
-		    override_port != new_port)
+		    override_port != port)
 			override_port = OVERRIDE_OFF;
 	}
 
+	*new_port = port;
+	*new_supplier = supplier;
+}
+
+/**
+ * Charge manager refresh -- responsible for selecting the active charge port
+ * and charge power. Called as a deferred task.
+ */
+static void charge_manager_refresh(void)
+{
+	int new_supplier, new_port;
+	int new_charge_current, new_charge_current_uncapped;
+	int new_charge_voltage, i;
+	int updated_new_port = CHARGE_PORT_NONE;
+	int updated_old_port = CHARGE_PORT_NONE;
+
+	/* Hunt for an acceptable charge port */
+	while (1) {
+		charge_manager_get_best_charge_port(&new_port, &new_supplier);
+
+		/* If the port changed, attempt to switch to it */
+		if (new_port == charge_port ||
+		    board_set_active_charge_port(new_port) == EC_SUCCESS)
+			break;
+
+		/* 'Dont charge' request must be accepted */
+		ASSERT(new_port != CHARGE_PORT_NONE);
+
+		/*
+		 * Zero the available charge on the rejected port so that
+		 * it is no longer chosen.
+		 */
+		for (i = 0; i < CHARGE_SUPPLIER_COUNT; ++i)
+			available_charge[i][new_port].current = 0;
+	}
+
 	if (new_supplier == CHARGE_SUPPLIER_NONE) {
 		new_charge_current = 0;
 		new_charge_current_uncapped = 0;
@@ -170,11 +203,9 @@ static void charge_manager_refresh(void)
 
 	/* Change the charge limit + charge port if modified. */
 	if (new_port != charge_port || new_charge_current != charge_current) {
-		CPRINTS("New charge limit: supplier %d port %d current %d "
-			"voltage %d", new_supplier, new_port,
-			new_charge_current, new_charge_voltage);
 		board_set_charge_limit(new_charge_current);
-		board_set_active_charge_port(new_port);
+		CPRINTS("CL: p%d s%d i%d v%d", new_supplier, new_port,
+			new_charge_current, new_charge_voltage);
 	}
 
 	/*
diff --git a/include/charge_manager.h b/include/charge_manager.h
index 9cd0abeefb..d1ee472a50 100644
--- a/include/charge_manager.h
+++ b/include/charge_manager.h
@@ -35,7 +35,18 @@ int charge_manager_set_override(int port);
 /* Returns the current active charge port, as determined by charge manager */
 int charge_manager_get_active_charge_port(void);
 
-/* Board-level callback, called on delayed override timeout */
+/* Board-level callback functions */
+
+/*
+ * Set the active charge port. Returns EC_SUCCESS if the charge port is
+ * accepted, returns ec_error_list status otherwise.
+ */
+int board_set_active_charge_port(int charge_port);
+
+/* Set the charge current limit. */
+void board_set_charge_limit(int charge_ma);
+
+/* Called on delayed override timeout */
 void board_charge_manager_override_timeout(void);
 
 #endif /* __CHARGE_MANAGER_H */
diff --git a/test/charge_manager.c b/test/charge_manager.c
index ead8a6d9e0..fc184bebea 100644
--- a/test/charge_manager.c
+++ b/test/charge_manager.c
@@ -32,6 +32,7 @@ BUILD_ASSERT(ARRAY_SIZE(supplier_priority) == CHARGE_SUPPLIER_COUNT);
 
 static unsigned int active_charge_limit = CHARGE_SUPPLIER_NONE;
 static unsigned int active_charge_port = CHARGE_PORT_NONE;
+static unsigned int charge_port_to_reject = CHARGE_PORT_NONE;
 static int new_power_request[PD_PORT_COUNT];
 static int dual_role_capable[PD_PORT_COUNT];
 static int power_role[PD_PORT_COUNT];
@@ -47,9 +48,20 @@ void board_set_charge_limit(int charge_ma)
 	active_charge_limit = charge_ma;
 }
 
-void board_set_active_charge_port(int charge_port)
+/* Sets a charge port that will be rejected as the active port. */
+static void set_charge_port_to_reject(int port)
 {
+	charge_port_to_reject = port;
+}
+
+int board_set_active_charge_port(int charge_port)
+{
+	if (charge_port != CHARGE_PORT_NONE &&
+	    charge_port == charge_port_to_reject)
+		return EC_ERROR_INVAL;
+
 	active_charge_port = charge_port;
+	return EC_SUCCESS;
 }
 
 void board_charge_manager_override_timeout(void)
@@ -112,6 +124,7 @@ static void initialize_charge_table(int current, int voltage, int ceil)
 	struct charge_port_info charge;
 
 	charge_manager_set_override(OVERRIDE_OFF);
+	set_charge_port_to_reject(CHARGE_PORT_NONE);
 	charge.current = current;
 	charge.voltage = voltage;
 
@@ -487,6 +500,40 @@ static int test_dual_role(void)
 	return EC_SUCCESS;
 }
 
+static int test_rejected_port(void)
+{
+	struct charge_port_info charge;
+
+	/* Initialize table to no charge. */
+	initialize_charge_table(0, 5000, 1000);
+	TEST_ASSERT(active_charge_port == CHARGE_PORT_NONE);
+
+	/* Set a charge on P0. */
+	charge.current = 500;
+	charge.voltage = 5000;
+	charge_manager_update(CHARGE_SUPPLIER_TEST2, 0, &charge);
+	wait_for_charge_manager_refresh();
+	TEST_ASSERT(active_charge_port == 0);
+	TEST_ASSERT(active_charge_limit == 500);
+
+	/* Set P0 as rejected, and verify that it doesn't become active. */
+	set_charge_port_to_reject(1);
+	charge.current = 1000;
+	charge_manager_update(CHARGE_SUPPLIER_TEST1, 1, &charge);
+	wait_for_charge_manager_refresh();
+	TEST_ASSERT(active_charge_port == 0);
+	TEST_ASSERT(active_charge_limit == 500);
+
+	/* Don't reject P0, and verify it can become active. */
+	set_charge_port_to_reject(CHARGE_PORT_NONE);
+	charge_manager_update(CHARGE_SUPPLIER_TEST1, 1, &charge);
+	wait_for_charge_manager_refresh();
+	TEST_ASSERT(active_charge_port == 1);
+	TEST_ASSERT(active_charge_limit == 1000);
+
+	return EC_SUCCESS;
+}
+
 void run_test(void)
 {
 	test_reset();
@@ -497,6 +544,7 @@ void run_test(void)
 	RUN_TEST(test_new_power_request);
 	RUN_TEST(test_override);
 	RUN_TEST(test_dual_role);
+	RUN_TEST(test_rejected_port);
 
 	test_print_result();
 }